:-NRLF Eb D7M OGRESS!VE FURNACE HEATING PROGRESSIVE FURNACE HEATING By ALFRED G. KING A PRACTICAL MANUAL OF DESIGNING, ESTIMATING AND INSTALLING MODERN SYSTEMS FOR HEATING AND VENTILATING BUILDINGS WITH WARM AIR Supplemented by A COMPLETE TREATISE ON THE CONSTRUCTION AND PATTERNS OF FURNACE FITTINGS By WILLIAM NEUBECKER NEW YORK SHEET METAL PUBLICATION COMPANY 1914 , t Copyright 1914 BY The Sheet Metal Publication Company TABLE OF CONTENTS 3 CHAPTER I. The Chimney Flue Character and Size of Flue Area and Height Required How Correct Tests are Made Loca- tion of the Chimney Common Sources of Trouble Chimney Flue Troubles. CHAPTER II. The Furnace History of the Furnace Character and Size of the Furnace Furnace Casing and Top Location of Furnace Methods of Setting The Cold Air Supply Size of Furnace Required. CHAPTER III. Pipe, Fittings and Registers Size and Location of Reg- isters Table of Sizes Required. CHAPTER IV. Installation of the Furnace Tabulated Estimate How to Determine Size of Furnace Required Sizes of Pipes and Risers. CHAPTER V. Trunk Line and Fan-Blast Hot Air Heating Methods of Trunk Line Piping Sizes of Piping for Trunk Lines Fan-Blast Heating Methods of Installation A Typical Installation of Fan-Blast Heating. CHAPTER VI. Estimating Furnace Work How to Estimate An Illustrated Example Form of Estimate Sheet Determining Cost. CHAPTER VII. Intelligent Application of Heating Rules Heat Losses are the Basis of Sizes Required An Automatic Air Damper. CHAPTER VIII. Practical Methods of Construction A Detailed Illustration- Superior Work Brings Best Results School House Warming and Ventilation An Example of Fan-Blast Heating for Schools A Trunk Line Installation. CHAPTER IX. What Constitutes Good Furnace Work Dust Discharge The Casing The Furnace Top The Piping Concern- ing Bends Heating Surface Added Cost of Hard Firing An Example of High Class Work. 387478 4 TABLE OF CONTENTS CHAPTER X. Ventilation The Need of Pure Air Amount of Fresh Air Required Methods of Ventilating A Ventilating Chimney. CHAPTER XL Ventilation by the Use of Propeller Fan Methods Em- ployed Volume of Air Moved by Fans of Various Sizes Efficiency of Exhaust Fans Tables of Speed and Capacity. CHAPTER XII. Humidity and the Value of Air Moistening Reduction of Fuel Results of Investigation Coke Air Moistener The Herr Humidizer The Water Pan The Hygro- meter. CHAPTER XIII. Recirculation of Air in Furnace Heating Quality of Air Air Outlet Necessary Heating Windward Side Op- position to the Method Obtaining Best Results Con- necting Duct. CHAPTER XIV. Auxiliary Heating from Furnaces Computing Size of Radi- ator Heating Surface Required Installing the Ap- paratus. CHAPTER XV. Temperature Regulation and Fuel Saving Devices Fuel Saving Appliances Electric Regulators Non-Electric Regulators How to Sell Thermostats The Cost of Heat Regulation How to Attach Thermostats Automatic Draft Regulators Operation and Installation Chain Control of Drafts. CHAPTER XVI. Fuel Its Chemical Components and Combustion Classifi- cation of Coal Methods of Burning Coal Coal: The Universal Fuel. CHAPTER XVII. Cement Construction for Furnace Men Concrete Mixtures Mixing Concrete Tools Required Determining Qanti- ties Methods Employed. TABLE OF CONTENTS 5 CONSTRUCTION AND PATTERNS OF FURNACE FITTINGS CHAPTER XVIII. Remarks Conical Bonnets or Hoods Furnace Casings Various Styles of Collars Patterns for Collar on Pitched Bonnet Patterns for Collar on Straight Bonnet Fasten- ing the Collars to the Bonnet Elbows Applying the Rule Elbows Less Than Right Angles Seaming the Circular Joints Oval Elbows Developing the Patterns for a Reducing Elbow T Joint Between Pipes of Un- equal Diameters at an Angle Construction of Riveted Joints in Tees Construction of Cold Air Shoes Pattern for Shoe Connecting to Center of Furnace Patterns for Shoe Connecting to One Side of Furnace Frictionless Cold Air Duct Elbows Seaming Cold Air Duct Elbows Developing and Constructing Floor Register Boxes Rule for Determining the Size of the Register Box Table of Areas of Round Pipes and Registers Pattern for Floor Register Box in One Piece Pattern for Floor Register in Four Pieces Quick Method of Joining Collar to Register Box Two Other Methods of Connecting Register Boxes Construction of Combination Header and Register Box Boots or Wall Pipe Starters Devel- oping the Pattern for a Round to "Oval" Frictionless Starter Various Styles of Frictionless Starters Offset Boot Developing the Patterns Wall Pipes or Risers Covering Single Wall Pipes With Paper Double Wall Pipes Metal Flues in Brick Walls The Various Fittings Used in Furnace Piping Compound Wall Pipe Offsets Patterns for a Double Offset Fittings for Truck Line Heating Systems Short Rule for Reducing Joint De- 'termining the Unknown Diameter of the Main Pipe Pattern for a Fork of Equal Prongs in Trunk Line System Determining the Unknown Diameter in an Un- equal Two Pronged Fork Placing the Half Profiles Previous to Developing the Patterns Three Equal Pronged Fork Method of Drawing Three Pronged Fork so That the Patterns for One Will Answer for All Times Unequal Three Pronged Fork Finding the True Sec- tions and Placing the Two Profiles in an Unequal Three Pronged Fork Finding True Angles in Cold Air Duct Elbows Method Employed When Developing the El- bow Patterns True Angles in Warm Air Elbows Find- ing True Angles With Line and Bevel. 6 TABLE OF CONTENTS CHAPTER XIX. Rules, Tables and Useful Information Weights of Steel- Gauges and Weights of Black Sheets Galvanized Sheets Weights of Galvanized Pipe and Elbows Sheet Copper Sheet Zinc Net Weight Box Tin Plates Stock Sizes Tin Pipe Roofing Tin Tables Cost of Stand- ing Seam Tin Roofing Weight, Strength and Size of Wire Wire Gauge Dimensions of Registers Size of Registers Weights and Measures Common Fractions and Decimals Millimeters and Decimals Gallons in Rectangular Tanks Gallons in Round Tanks Barrel Capacity of Tanks and Cisterns Areas and Circumfer- ences of Circles Rules Relative to the Circle Melting Points of Metals Boiling Points of Fluids Horse Power of Belting Cubical Contents of Rooms, CHAPTER XX. Receipts and Miscellaneous Information To Clean Brass To Clean Zinc To Clean Water Front of Rust To Re- move Lime Deposit From Water Front Government Receipt for Cleaning Brass To prevent Rusting of Iron and Steel To Prevent Polished Iron From Rusting To Clean Zinc How to Clean Steel Tapes To Paint Galvanized Iron To Keep Plaster of Paris From Setting Too Quickly To Solder Galvanized Iron A Flux for Tin Roofing Fluxes for Various Metals To Keep Soldering Coppers Hot A Good Soldering Acid A Non- Corrosive Soldering Paste. Waterproof Glue How to Make Putty Fireproof Cement for Furnaces Rust Joints Friction of Water in Passing Through Pipes Heating Capacity of Stove and Furnace Coils. Index I Furnace Heating Page 269 Index II Furnace Fittings Page 276 INTRODUCTORY. A large part of the following text is compiled from a series of articles written for SHEET METAL. To this text new material has been added, and the original work has been edited, revised and extended to make the book a useful, practical and instructive treatise on the subject of furnace heating. Few of those at present engaged in the installation of the warm air furnace realize the possibilities of warm air heating. The trouble has been with the many furnace dealers who have failed to be honest with themselves. Instead of adopt- ing and following the motto "onward and upward" and work- ing to uplift and develop the science of warm air heating (for it is a science) their rule seemingly has been "downward and cheapward," if the use of such 'an expression is permis- sible. They have thus done much to discredit this method of heating with the house owner and even with physicians and heating and ventilating engineers, who, of course, regard it strictly from the standpoint of efficiency and economy. It has not been the furnace (as it should be constructed) or the method of furnace heating (as the work should be installed), but rather the cheap, claptrap methods of furnace building and installation which have in a measure served to bring discredit on the dealer and manufacturer alike. It is one of the peculiar laws of progression that while it often takes years of constant labor, energy and attention to work out the salvation of a business or a principle, the repu- tation and standing thus attained may be throttled as it were, over night, or, putting this thought into a concrete form bearing on our present discussion, one good job of heating will sell two or three other jobs and one poor job will result in the loss of ten others. The indications point to a much more general popularity for the warm air furnace and an encouraging view obtains for a general expansion of the industry, hence every precaution should be taken to safeguard its growth. 8 INTRODUCTORY Cheap competition work, the feverish endeavor to beat out a competitor by lowering prices to ridiculous figures, the use of inferior furnaces and materials, the catering to so- called "operation work" where from ten to one hundred or more houses are fitted with heating apparatus and where the saving of from five to ten dollars per house is looked upon as being a good stroke of business these are some of the causes of condemnation brought about by the contractor. Cheap furnace construction, the use of inferior materials, the gross overrating of capacities and the sale of furnaces to dealers who are ignorant of the principles of heating have been the manufacturer's contribution to the unsatisfactory conditions which long existed in this field. In actual results attained, this practice of cheap work is demoralizing. The inability to properly warm a room may be due to faulty construction, an improper location of stack or register, lack of capacity at the heart of the system the furnace or any one of a dozen other causes. The dissemination of gas and dust into the rooms, the excessive consumption of fuel, the dry, oppressive atmosphere present in the heated dwell- ing these and other marks of failure or unhealthful condi- tions may be remedied by the application of common sense methods. ALFRED G. KING. January, 1914. Progressive Furnace Heating CHAPTER I THE CHIMNEY FLUE The preparation for the installation of a furnace heating system should begin with the foundation of the building to be heated if the best results are to be expected from the operation of the apparatus. The erection of a chimney flue of proper size placed in the proper location is one of the principal points of building construction, making, as it does, for efficiency and economy in so far as the heating apparatus is concerned. Chimneys defective in construction and those located in isolated or inaccessible parts cause a large share of the failures of furnaces to work properly. It therefore behooves the installer to look well to the character and position of the chimney. The human body has been likened to a furnace, and it is indeed a heating apparatus of the most delicate and intri- cate kind. The mouth and nose may be called the draft door and chimney of the human furnace, and should the nose become clogged and the throat filled with matter, the fire of the body is suffocated for want of oxygen, the furnace ceases to work and the body dies. As the ability of the human furnace to breathe properly is necessary, just so is the ability of the hot air furnace to breathe properly a necessity, if the full measure of work and activity of either are to be maintained. The question of the chimney for use with a furnace is so important that it is the first thing to be examined when planning to install a heating apparatus. Character and Size of Flue. It is a well established fact that the draft in a chimney flue is spiral that, as the air in the flue is heated and expanded by the hot gases and products of combustion, it rises in the flue, ascending with a spiral motion and increas- ing in velocity according to the amount of air passed through the grate of the furnace. In other words, the greater the opening resulting from the setting of the draft door, the more active will be the combustion of the fuel, and, if the 10 FLUES AND CHIMNEYS chimney be of the proper height and area, the greater the velocity of the draft. It is by reason of the fact that the draft is spiral that a round smooth flue is preferable to all other styles of chim- ney construction. Next in value is the square flue, or one as nearly square as conditions of construction will permit. Fig. i illustrates a round tile flue encased in brick, represent- ing the best possible type of construction. Should we suppose the tile to be 12 inches inside diameter, the chimney would have an area of 113 square inches. Fig. i Brick Chimney with Round Tile Flue. Fig. 2 illustrates a square tile-lined flue, encased in brick. Assuming the width to be 12 inches, same as the diameter in Fig. i, this flue would have an area of 144 square inches, or 31 square inches of area more than the round flue, and yet the latter will do the same work equally well, if not better. Builders, and frequently owners, complain that a tile- lined specially built flue is costly. It is costly not to build it. It is a continual fuel saver, and by saving from one to three tons of fuel yearly will soon pay for the increased cost. Very few investments will afford the same return in dividends as will the money expended for a good chimney flue. The depth of a rectangular flue should never be less than the diameter of the smoke pipe which enters it. Do not be deceived into thinking that a flue full large for the work means a corresponding increase in the consump- tion of fuel, as tests have demonstrated that a poor flue will frequently consume more fuel than one of proper size, and at the same time produce less results in heat units delivered to the rooms to be warmed. When fuel is burning under the former condition there seems to be no life to the combustion. FLUES AND CHIMNEYS ii The fire is a dull red, the smoke pipe is cool, and the tem- perature of the gases in the flue is so low that proper condi- tions of draft are out of the question. It is all important that the furnace dealer should post himself thoroughly on chimney construction. It is the first and most necessary study in qualifying as a heating expert. A furnace man has no business to install furnaces when he is not capable of advising as to proper chimney construction. Beware of long narrow flues, because but a small portion of the area of such can be counted upon to prove effective. Fig. 2 Brick Chimney with Square Tile Flue. For example, a flue 4 by 16 inches may be rightly considered as being no more effective than a 6 inch round pipe. The dead air area in the ends of this rectangular flue is of no value whatever. On the contrary, it is frequently a hindrance, owing to friction and down-draft likely to prevail. Fig. 3 illustrates this fact, the shaded portion of the flue representing its effective area. If a flue be built of brick without a tile lining, it should be pointed smooth on the inside, not plastered, as the plaster lining will loosen and drop down in patches, frequently taking a quantity from between the bricks, thereby loosening them and damaging the chimney. By adding to the height of a chimney the velocity of the flue may be increased at small expense. The area, however, cannot be well increased without considerable cost, and it should therefore be great enough from the start to fulfill all possible requirements. All chimneys should be built straight from bottom to top without offsets of any character. Where an abrupt 12 FLUES AND CHIMNEYS offset is made in a chimney a place is provided upon which soot will lodge and after a time clog the flue opening, as shown by Fig. 4. This is a common cause of the failure of many flues in city houses where a block is built up solid with openings or area-ways left for passage between houses, the second floor being set out over the area-way. Chimneys are often offsetted three or four feet in this style of building construction, and as a result prove a great detriment to the successful working of the furnace, Fig. 3 Rectangular Flue Showing Effective Area. A chimney to be effective at all times and under all con- ditions of wind and weather, should extend at least two feet above the highest part of the roof. The wind will travel over the roof of a house or that of an adjacent building and practically cut off the draft of a low chimney beneath. Fig. 5 illustrates this condition, the arrows indicating the direc- tion of the wind and the dotted portion of the chimney show- ing the height to which it should have been erected. Area and Height Required. A chimney has two principal factors area and height. There must be sufficient area to pass the volume of air required to properly burn the fuel. Three hundred cubic feet of air is necessary to supply the oxygen required to con- sume each pound of coal. For example, suppose we are operating a furnace having a 27 inch grate, the rate of combustion being 4 pounds of coal per square foot of grate per hour. A 27 inch grate has practically 4 sq. ft. of area, hence 4X4=16, the number of pounds of coal required per hour; and 16X300=4,800 cu. ft. of air per hour, the volume iiecessary to properly burn this amount of fuel. One authority says: "Each atom of carbon requires for its perfect combustion two atoms of oxygen. When this FLUES AND CHIMNEYS 13 union is effected it burns to carbon dioxide and yields per pound 14,500 B.T.U. (heat units). Fig. 4 'Offset Flue Showing Accumulation of Soot. "If, however, through insufficient air supply there is but one atom of oxygen to one of carbon, the result is carbon monoxide yielding 4,500 B.T.U., or less than one-third the heat given off where combustion is perfect." Fig. 5 Effect of Wind on a Low Chimney. We know the statement of this chemist to be true, be- cause it has been demonstrated that when the flue is too small and too little air passes upward through the coal, the fire has nc life or activity, and the fuel is consumed without pro- ducing effective results. 14 FLUES AND CHIMNEYS The height of the flue should be sufficient to clear the roof of the building or any surrounding roofs or obstacles, so that the wind striking the roof will not cut off the draft by being deflected over the top of the chimney, as illustrated by Fig. 6, which gives another example of the action of the wind upon a low chimney. Fig. 6 Illustrating Action of the Wind Upon a Low Chimney. The height (preferred) of the chimney for the average house is from 30 to 40 feet, and this height is sufficient for the velocity or sharpness of draft demanded. Many owners of buildings have mistaken intensity of draft for volume, and many heating contractors test chimneys by setting fire to a newspaper and crowding the same into the chimney flue through the opening for the smoke pipe. If the charred paper goes up the flue with a roar they think the chimney is perfectly satisfactory. The fact is that a six inch pipe would show exactly the same results. FLUES AND CHIMNEYS 15 How Correct Tests Are Made. Draft gauges of various kinds are used for testing pur- poses. Among heating engineers the strength of draft in a chimney is measured by the inches of water required to equalize it. Fig. 7 illustrates a portable draft gauge with a funnel. A piece of glass testing tube is heated and bent to the form shown. The funnel is made of tin and is of sufficient size to cover the ordinary smoke pipe hole of the chimney. Some felt cloth or soft felt paper tacked or pasted around the smoke pipe opening will allow the funnel to seal the opening tightly and thus will show more accurate results. A gauge scaled in inches and tenths of an inch is adjusted into the upright end of the tube as shown. The tube is fastened to the small end of the funnel with plaster of Paris and is filled with water to a point one-half way up the scale. Fig. 7 Portable Draft Gauge with Funnel. A column of water 28 inches high (or to be exact, 27.77) is the equivalent of one pound presure. In reading the testing gauge the difference in height be- tween the two columns should be noted. If a chimney draft was balanced by a column of water one inch high the strength of the draft would be 1/28 of a pound per square inch of area. The chimney draft of a good flue will equal at least .2 of an inch of water, as shown by the scale. i6 FLUES AND CHIMNEYS If a bent glass tube can- not be procured, or if the heating contractor cannot bend a tube, a draft gauge as illustrated by Fig. 8 may be made of straight pieces of glass tube and some short pieces of rub- ber tubing. A small piece of iron pipe is inserted into the smoke flue and the draft gauge attached as shown. The following table com- piled by a standard author- ity may be used in connec- tion with the testing gauge : Fig. 8 A Simple Draft Gauge Easily Constructed. Height, water, in inches. .1 .2 3 4 5 .6- 7 .8 9 i.o i.i 1.2 1-3 M 1-5 1.6 17 1.8 1.9 2.0 Pressure in Ibs. per sq. ft. 521 1.042 I-563 2.084 2.605 3.126 4.168 4.689 5.210 5-731 6.252 6773 7.294 7.815 8.336 8.857 9.378 9.899 10.420 Velocity, ft. per sec. 15.05 21.3 26.06 30.1 33-6 36.8 39-8 42.5 45-1 47-5 49-9 52.1 54.2 56.3 58.2 60.2 62.0 63.8 65.6 67.3 Velocity, ft. per min. 903 1278 1564 1806 2Ol6 2208 2 3 88 2550 2706 2850 2994 3126 3252 3378 3492 3612 3720 3828 3936 4038 FLUES AND CHIMNEYS The area of a flue must be determined by measurement, as no form of testing will give the requirements, which are determined by the work in hand. The size of furnace to be connected with the flue determines the area required. Suppose a furnace with an 8-inch smoke outlet is re- quired. An 8 inch pipe has an area of 50.265 square inches, and under the most favorable circumstances of draft a round flue less than 8 inches in diameter or a square flue 8X8 inches in size should not be used. If a rectangular flue is provided, the narrow sides of the same should not be less than 8 inches. The following table of flue areas will serve as a guide to flue construction, it being assumed that the chimney is from forty to sixty feet in height, or such as would be used for a two or three story building: TABLE OF FLUE SIZES. Equivalent cubic feet of space to be heated. 10,000 to 15,000 15,000 to 25,000 25,000 to 40,000 40,000 to 75,ooo 75,000 to 125,000 125,000 to 200,000 Round tile, Rectangular standard tile, sizes. standard sizes. 8 in. 8^ x &/ 2 in. 10 in. S l / 2 x 13 in. 12 in. 13 x 13 in. 16 in. 13 x 18 in. 20 in. 18 x 18 in. 24 in. 18 x20 T / 2 in. Brick, inside di- mensions. 8x 8 in. 8x 12 in. 12 x 12 in. 12 x 16 in. i6x 16 in. 16x20 in. When soft coal is used as fuel, 25 per cent, should be added to the rated size of flue. Location of the Chimney. We have previously mentioned city built houses and the character of their construction ; in connection therewith there is another point which should be considered in providing the chimneys. They are usually built in the party wall separating the parlors or front rooms and the custom in this respect fre- quently locates the flue but ten feet or less from the front wall of the building. No matter in which direction the house faces the chimney will be found in the same location. Sup- pose the structure be five rooms deep ; it may extend from eighty to one hundred feet from front to rear wall. Again, suppose the house faces the south, the chimney being within ten feet of the front wall; it is then necessary to run the warm air pipes from fifty to seventy feet toward the north, a condition beyond all reason to insure satisfactory and economical service. The chimney should be centrally located, to the north and west rather than to the south and east in order that the longer warm air supply pipes may extend to and serve rooms i8 FLUES AND CHIMNEYS on the south and east sides of the building, and the shorter and more direct pipes to those rooms on the north and west sides of the building. If possible to do so, it is well to erect the chimney up through the center of the building where the greater part of it will be surrounded by warm air, or rooms which are heated. In such a flue the smoke will not condense so rapidly, nor the gases cool as quickly as in a chimney built in an outside wall. When a chimney flue is erected in an outside wall it should be two bricks thick on the outside and, if possible, should be provided also with an air space between the bricks, as illustrated by Fig. 9. This air space should be closed and sealed at the roof line. DEAD AIR SPACE Fig. 9 Air Space on Exposed Side of Chimney. The flue for use of the heating apparatus should have no other openings than that at the top and that for the smoke pipe. It should extend from twelve inches to two feet below the smoke pipe opening in order to provide a pocket for the soot. We have called attention to the fact that the smoke and other products of combustion ascend the chimney flue spirally, and therefore a round chimney is the best form of chimney construction. Next in efficiency is the square flue, and last the rectangular flue. Common Sources of Trouble. In connection with the construction of the chimney, there are some points which should have careful attention of the architect and owner as well as the heating contractor. Make the foundation for the chimney sufficiently solid and strong to support the weight of it. We have known chimneys having two flues to settle and break an opening between the flues, thereby destroying the draft, as illustrated by Fig. 10. Beware of chimney tops. As a rule not more than one in ten of the chimney tops offered for sale is adequate in size or will improve the work of the flue. A chimney is only as FLUES AND CHIMNEYS large as its smallest area, and an 8XS-inch flue (64 sq. in.) having a top 7 inches round (internal diameter) has but 38.48 sq. in. of area. 1 ! 1 1 N 1 1 1 1 i i 1 1 1 1 ! 1 1 1 I 1 1 1 1 1 1 1 1 ! 1 1 1 1 i 1 1 1 1 1 1 1 Fig. 10 Partition Walls between Flues Frequently Crack and Spoil the Draft. Abrupt offsets should not be made, as flues of this nature clog with soot. The contractor should be careful to make the smoke connection of the size called for by the furnace, and should not reduce the pipe to save breaking out and en- larging the smoke pip.e hole. Chimney Flue Troubles. Chimney flue troubles are many, and when there seems to be sufficient height and area look for trouble from one of the following sources : (a) The smoke pipe may protrude so far into the flue as to cut off the draft. 2O FLUES AND CHIMNEYS (b) The chimney may be contracted or enlarged at some point. A chimney is only as large as its area at its smallest point. An enlargement at some point frequently acts as a damper to reduce the velocity of the draft. (c) Loose clean-cut doors, open space around smoke pipe collar, or cracks in the flue admit cold air and spoil the draft. (d) There may be openings in the flue for other smoke pipes besides that provided for the furnace. A flue for use of a heating apparatus should not serve for any other purpose. (e) The flue may be plugged with soot or filled with rubbish. Birds build nests in chimneys, and falling plaster and soot may jam in the flue, particularly if there is an offset in the chimney. Two or three pieces of brick tied in a burlap bag drawn up and down the flue by means of a rope is a good method of cleaning it of soot or other obstruction. These are some of the ordinary sources of trouble with chimneys, and while there are others they are not sufficiently common to cause frequent trouble. A good flue is a delight to the experienced heating en- gineer and contractor, while a poor flue is a bane to him and a source of trouble and expense to the owner of the building. CHAPTER II THE FURNACE Having determined that the chimney flue is adequate for the requirements demanded of it and that its location, if possible, is at such a part of the building as to prove most efficient, let us now consider the heart of the system; the furnace proper. History of the Furnace The hot air furnace was the original form Which de- veloped the later date methods of heating, and its advent, or we may possibly say its invention, was the direct result of necessity. Probably many of our readers know the story of the introduction of the furnace; nevertheless the telling of its history is interesting enough to bear repetition. The open fireplace had been found to be extravagantly wasteful of fuel and inadequate to properly heat the exposed parts of a room. The fireplace heater and later the stove were evolved to pre- vent this waste and to make possible a means to locate the source of the heat where it would prove most effective. With the growth of the country, the forests were cut away. As towns and cities grew in size, the cost and in- convenience of obtaining fuel, and the further fact that this centralizing of business and the people, demanded larger and larger buildings to accommodate the conditions, made it im- perative that some method should be produced whereby the labor of attending so many fires could be overcome. This led to the invention, if it may be called so, of the hot air furnace, which in its early stage was nothing more than an extremely large stove encased in brick combining, in a measure, the principles of Dr. Franklin, who in 1744 in- vented the wood stove, with the hollow back or casing, hav- ing an air duct or cold air tube through which air from out- side the building was heated and introduced into the room in which the stove was located. The discovery and use of anthracite coal as a fuel proved a great factor in developing the possibilities of furnace heat- ing. The early development of the furnace was largely the result of experimenting by Mr. Henry Ruttan. We are aware that many of the older manufacturers of warm air heating 22 FURNACE REQUIREMENTS apparatus have a sort of "me too" argument in this direction. It is certain, however, that when Mr. Ruttan in 1862 wrote the following words, he expounded the true principles of furnace heating and ventilation, principles we cannot neglect, if we are to meet with success in our work. Mr. Ruttan said : "If you open your aperture at the top, and the air you bring in is warm, or if you open the aperture at the bottom, and the air you bring in is cold in either case Fig. ii To Ventilate and Cool a Room. the body of air will not budge ; your warm air will go through the body, straight to and out of the top aperture ; and the cold air will do the same through the bottom aperture. The con- sequence is easily seen you will neither warm, cool, nor ventilate the room." "If you want to ventilate your room to warm it, and open the bottom aperture, you will succeed in both ; because the fresh air will be the warmest, and will not stop until it comes in contact with the ceiling, where spreading out in a level strata over the whole ceiling, it will keep its relative position to the whole body until it reaches the bottom and passes out through the aperture. If we want to ventilate our room to cool it, we must let the air out at or near the top. FURNACE REQUIREMENTS 23 "If on the other hand, we wish to ventilate our house to warm it, we must take the air out at or near the bottom, thus keeping up a continual exhaustion of the heated air; and if we wish to set the whole body of air in the room in motion, upward or downward, we must, of course, bring in the neces- sary amount of outside air to do it." Fig. 12 To Ventilate and Warm a Room. Figs, ii and 12 illustrate these principles, and to those who are making a study of this subject we recommend that they fix them indelibly upon their minds, as they combine the true principles governing hot air heating and ventilation. Character and Size of the Furnace. It is not our purpose to comment on or advocate any particular type of furnace, except in a general way to note such distinctive features as will assist the furnace man to make the proper selection for any work in hand. The bricked-in furnace has been succeeded by the more up-to-date portable setting, or casing, and except in very old buildings the former style of furnace is seldom seen. The grate is a very important part of a furnace. Enough open space should be provided to permit the passing of suf- ficient air to meet the requirements when re-charging with 24 FURNACE REQUIREMENTS fuel, and the bars should be strong enough to carry the heavi- est load without sagging or binding. Beware of cheap furnaces. They are expensive at any price. A few dollars saved in the price of the furnace itself must result in the furnishing of lighter castings, a smaller capacity, less radiating power, and cheaper construction throughout. In a good furnace there will be from twenty-five to thirty square feet of heating surface to one of grate surface. There should be a deep fire pot, and a grate of sufficient area for the work in order that the rate of combustion will not exceed four pounds of coal per square foot per hour in coldest weather. Definite rules will be given later for ascertaining the proper size of furnace and grate area. The gases in the combustion chamber must not be cooled by allowing the cold air to come in contact with the outside of this chamber. A furnace does its best work under conditions of perfect combustion, and one so constructed that the in- coming cold air will be partially tempered by the flue gases in their exit from the furnace before coming in contact with the hot plates of the combustion chamber, will show a higher rate of efficiency per square foot of grate surface than will a furnace in which the cold air passes immediately over the hot plates or heating surfaces. If the chimney flue is of sufficient size and is properly constructed, a temperature within it of 300 degrees will be more than adequate for perfect draft. The excess of fuel re- quired in many furnaces is due not only to poor combustion, but to the escape, at a high temperature, of the gases into the chimney flue. By bringing the cold air into contact with the heat of these gases much of this lost heat may be utilized and saved. In the construction of the furnace the joints should be gas proof and dust proof under all circumstances. Furnace Casing and Top. All furnace casing should be made double with an air space between the inner and outer casing sufficient to act as a non-conductor and keep the outer casing cool. Asbestos paper or mill board is frequently placed between these two casings, or as a covering for the outer one. This is not a necessity, however, providing there is sufficient air space between the inner and outer casing. Our preference is for a black iron inner casing and a galvanized iron outer casing. No single cased furnace will do good and economical work. There are many opinions as to the proper style of top or bonnet. The style used may be in a measure dependent FURNACE REQUIREMENTS 25 upon the height of the cellar, or the manner in which the leader pipes are attached. Any one type of top is not adaptable to all cases. Fig. 13 illustrates a straight side flat top, hav- ing a hoop or iron band around the top to hold about one inch of sand. A deflector is placed on the inner side as in- dicated by the dotted lines. The leader pipes are taken off, back of or on the inner side, of the deflector. Fig. 14 shows a common form of pitch top to which the leaders are connected by bevel elbows. Unless a deflector is i 'SAND BAND 7 \ / DEFLECTOR \ DEFLECTOR.^ \ Fig. 13 Straight Side Flat Top Bonnet Fig. 14 Common Form of Pitch Top. 1 SAND BAND % --..^ DEFLECTOR Y^"' I)/ OR 2 BAND x ASBESTOS CEMENT Fig. 15 Desirable Type of Bonnet. used the hot air will short-circuit into the shorter and more direct leader pipes. Fig. 15 illustrates what we believe to be the very best type of top. The deflector has a deep pitch toward the center. Above this the top is flat, having a one-inch sand hoop around the edge. The bottom is provided with a similar hoop one and one-half or two inches wide which fits tightly over the furnace casing and protrudes slightly above the upper edge. After the openings for the leader pipes are cut in and the pipes attached, the remaining portion of the pitched side of 26 FURNACE REQUIREMENTS the top is covered to the depth of one inch with plastic asbes- tos cement. This is supported in position by the extension of the -iron band fastening the top to the casing. The casing being double, the top of the hood being protected by sand, and the sides of the top protected with asbestos cement, there can be no loss of heat from the furnace. All leader pipes should leave the top at the same level and should be properly aligned. The careful alignment of them makes not only a better looking job, but a better work- ing one as well. Do not take the leader pipes from the top and from the side on the same job. Air will move toward the point of least resistance, and heated or expanded air will move vertically through the nearest aperture; therefore the leader pipes taken from the top will rob those taken from the side. We know a furnace man who thinks it best to take the longer runs from the top and the shorter runs from the side, and strange to say he has considerable success. Human ingenuity, however, is many times a failure, and we prefer to stick to methods, which have proven successful. Location of the Furnace. In locating the furnace many of the details entering into the construction of the building, such as the position of the piers or posts supporting girders, the position of division walls, of the chimney flue, etc., must be taken into considera- tion. When the north and west sides are well protected from the prevailing winds of the winter season, the furnace should set as near to the center of the building as conditions will allow. When the building is exposed on all sides the furnace should be placed more to the north and west of the center, and, provided the chimney has been built in accordance with our suggestions given in the second article of this series, this location is made available without the use of a long smoke pipe. Under ordinary conditions the furnace should set not more than 6 feet distant from the chimney flue. The warm air pipes supplying the rooms to the north and west, or to the principal rooms on the first floor, should be as short as possible. It is far better to double the length of the smoke pipe, if necessary, to locate the furnace to the north and west, than it is to double the length of the warm air pipes, if con- tingencies arise which make it imperative to select between the two courses. Methods of Setting. We are aware that many of those engaged in the busi- ness of installing furnaces have their individual opinions as to the correct method of setting a furnace. However, while we' FURNACE REQUIREMENTS 27 respect such motives it would seem to the writer that some furnace men are inclined to stick to certain methods and principles simply because they have had more or less suc- cess in one particular direction by following the usual method. The up-to-date furnace man should permit existing conditions to shape the method of setting the furnace, and he should be competent to judge what particular method of the number in vogue is best suited to the job in hand. Some furnace men are careless in their methods of preparation for the installa- tion of a furnace, frequently setting the furnace directly on the dirt cellar bottom when it seems sufficiently hard to sup- port its weight. This method results in a source of dirt and dust. The heat in the ash pit will dry out the earth so that the jarring, incident to attending and shaking down the fire, will cause particles of dirt to be carried upwards and into the rooms by the air currents passing through the furnace. The best practice is to build a cold air pit under the fur- nace, such as is illustrated by Fig. 16. The brick pier shown in the center will support the weight of the furnace and assist in dividing the cold air supply. Note that a corner of the pier is toward the cold air duct, thus allowing an equal distribu- tion of the cold air to each side of the furnace. ';'._--. -. !." : -.-....< . : =Ll== ; .: :! i=::is-!>i- Fig. 16 The Cold Air Pit. The pit should not be less than 12 inches nor more than 16 inches in depth. In building it a place should be excavated of sufficient depth to allow a filling of broken stone or brick about 4 inches deep. This should be covered by a layer of coarse sand and cement, leveled and well tamped down. The floor of the pit, which is also the foundation for the wall and pier, should be constructed of brick laid in cement and plastered smooth. This may add a trifle to the cost of installa- tion, but will prove in the end to afford the most satisfactory job. Frequently, because of the low location the building oc- cupies, there is trouble from water if excavation is made be- low the surface of the cellar floor, and in such cases the air duct must be connected to the furnace above the floor level. 28 FURNACE REQUIREMENTS For this purpose a special type of casing must be used, as illustrated by Fig. 17. The frame of the opening shown is called a shoe. Do not connect the cold air into a shoe on one side of the casing only, as this style of connection will not afford sufficient air to the opposite side of the furnace, as the Fig. 17 Casting for Use when Cold Air Duct is Above Floor. air space through the furnace bottom around the ash pit and fire pot is shaped very much like a horseshoe, as seen in Fig. 18. The shoe should be placed at tjie rear, or, what is better, a sparate opening or shoe should be provided for con- necting the air into either side. Fig. 18 Proper Location of Shoe for Cold Air Duct Care should be exercised in setting a furnace to care- fully cement or pack all joints where they are necessary, and the casing should be fit absolutely air tight. Loose joints in the furnace castings will allow dust and gas to enter the warm air distributing pipes, and a leaky casing interferes with the proper working of a furnace precisely in the same manner as a leaky chimney interferes with the draft. FURNACE REQUIREMENTS 29 Fig. 19 Three Methods of Supplying Cold Air. 30 FURNACE REQUIREMENTS The furnace must set sufficiently low to insure giving the proper pitch to the longest warm air pipes, and, if necessary to secure this desired feature, the furnace may be placed in a pit. When conditions make this course essential, build the pit of ample size and allow plenty of room for setting the furnace. Sufficient space should also be provided in the pit at the front of the furnace to facilitate the removal of ashes and the work of attending to the apparatus. The Cold Air Supply. The furnishing of an adequate amount of cold air, to- gether with a proper manner of supplying the furnace with it, is no doubt the key to successful hot air heating, and we can therefore consider this the most important part of furnace installation. An inspection of present day furnace work in some localities would in ninety-nine jobs out of every hundred either show no provision whatever for an outside cold air supply or, if provided, it would be an ill-shaped or leaky duct made of rough boards. It is just as important to eliminate all possible friction from the movement of the cold air as it is to provide easy movement of the heated air. Where a gal- vanized iron duct is attached, curved elbows should be used rather than miter elbows, and the cold air pipe should drop to the floor at an angle instead of pitching down vertically. Fig. 19 shows three methods of supplying cold air, the sketch on the left illustrating a common type of wood boxing frequently found on cheap work. The center illustration shows a duct made of galvanized iron, a marked improvement over the former, which can be still further bettered, however, by the use of curved elbows, as shown on the right. This latter type of duct may be easily connected to an underground tile, and, when provided with a cold air chamber or air cleans- ing box on the inside of the opening through the cellar wall, it makes an admirable method of handling the fresh air. In towns or cities where trouble is experienced from dust or soot laden air, it is advisable to filter or cleanse the supply by means of cheesecloth baffles. There are numerous plans of using these cleansing baffle cloths, but only one general method. The outside air upon entering the basement flows into a cold air chamber, striking at a sharp angle a series of filter screens partially covered with cheesecloth, which are set in the cold air chamber at such an angle that the incom- ing supply is compelled to make a number of right angle turns in passing the baffles. The chamber should be as- sembled in such a manner that one side (in the form of a door) opens to permit the ready removal of the screened FURNACE REQUIREMENTS 31 frames for cleaning. Do not use starched muslin or cloth of smooth texture for this purpose. The rougher the surface of the cloth the better will be the results obtained. Some recom- Fig. 20 Air Filter Having Cloth Baffles. mend that the cloth screens be coated with oil to assist in collecting the dust, but we have found cheesecloth well suited to the purpose without such a coating. Fig. 21 Air Filter Having Wooden Baffles. Another style is made of permanent wood baffles so ar- ranged that the first one next to the fresh air inlet acts as a deflector, precipitating a large portion of the dust to the bot- tom of the box or chamber. 32 FURNACE REQUIREMENTS The two styles are illustrated in Figs. 20 and 21, using for illustration that recommended by prominent furnace manu- facturers, which method cannot be too highly commended. These screens not only filter the supply, but also act as a damper to control the velocity of the incoming air before it enters the cold air duct. As the inlet for cold fresh air should be on the north or west side of the building it is necessary to make some provision for controlling the velocity of the prevailing winds of winter, and this, as well as the cleansing of the air, is accomplished by the method illustrated. The cold air from outside the building should enter the furnace through the pit. The recirculated air should be con- nected to furnace by attaching the piping to shoes on either side of the casing, or, if necessary to connect the inside cold air ducts into the main cold air supply, they should enter this duct in such a manner that there will be no possibility of the cold air entering the circulating ducts. Fig. 22 illustrates one method of accomplishing this result. CIRCULATING DUCT OUTSIDE AIR i \ _L C/RCULAT/NG DUCT- Fig. 22 Combining Recirculated Air with Cold Air. Some furnace men claim that all ducts, both outside and inside, should be arranged with dampers so that one or the other system only may be used. Our experience has been that occupants of a building will not give the required atten- tion to dampers, or, if they attend to them at all, will not do so properly. We therefore recommend the connection shown by Fig. 22 which should be installed without dampers of any kind other than a single one by which the outside cold air can be entirely shut off when a recirculation of the inside air only is desired. It is understood that the outside cold air is taken from a cold air chamber, which will control the flow of air in windy weather and which is not directly connected to the outside. In area, the ^old air duct should be three-quarters that of all of the warm air pipes leading from the furnace top. We think this rule is very generally known among furnace men, and, while not absolutely accurate, is sufficiently so FURNACE REQUIREMENTS 33 for all purposes. These conditions do not hold in figuring the capacity of the ducts for recirculation of the inside air. These ducts should be equal in area to the warm air pipes, or nearly so. To arrive at the proper size of the cold air duct we figure on the expansion of the outside air when heated to a normal degree. For the recirculating ducts we figure on the quantity of air delivered by the warm air pipes, which, after supplying heat to the various rooms, is not cooled sufficiently to make any considerable depreciation in its bulk or volume. Size of Furnace Required. The furnace man is held responsible by the furnace man- ufacturer for most of the trouble and for the largest share of the present condemnation of the furnace and of warm air heating. Are the trade justly open to criticism or are the manufacturers at fault? This question is of interest to every person who desires to see this class of heating work elevated to a higher standard. The furnace man is at fault in adopting methods neces- sitating cheap competitive work. The manufacturers are, however, the chief offenders. Before proceeding further per- mit us to insert a word of praise for those manufacturers who are giving definite information to the furnace man as to the ratings of their furnaces, best methods of installation, etc., and who are placing conservative ratings on their goods. We think it is not stating the case too strongly when we declare that one-half the hot air furnaces produced are grossly overrated. If furnace heating is to be placed on the higher plane it deserves there are many manufacturers who must rate their furnaces on a more conservative basis. The practice of de- termining ratings on the basis of casing sizes must be dis- continued. All methods of figuring capacities that do not take into consideration the cooling surfaces of a building i. e., the heat losses through glass (windows), outside doors and walls when computing the necessary size of furnace, must be abolished if we are to meet with success. Last, but not least, the evil practice of selling furnaces to any one who has the money to buy and pay for them, with- out regard to the purchaser's fitness and ability, or to his knowledge as a furnace man, must cease if clap-trap methods and cheap competition are to be overcome. If the past prac- tices are allowed to prevail we shall reach that stage where the owner will refuse to pay for his furnace until he has had at least one winter's trial of the apparatus and assured him- self of its satisfying qualities. 34 FURNACE REQUIREMENTS We shall not presume to dictate to manufacturers how they shall rate their furnaces. In view of the exigency of the case they should, however, adopt a basis by which all cooling surfaces of a building are reduced to an equivalent from which the schedule of the probable performance of the fur- nace can be made, and from which the furnace man can select the size suited to any purpose. The heating surface of the furnace must be sufficient to warm the amount of air the cubical contents of the building will demand, and the air outside of the building is always cooler than the air within. It is a law of nature that the temperatures of adjacent bodies will equalize. A certain portion of the heat is diffused or lost by transmission through walls and windows; therefore the furnace must not only be large enough to heat the air within the building with from two to four changes of air per hour, but it must also have sufficient capacity to compensate for the losses by diffusion. The heat losses in two buildings are never the same and yet when reduced to equivalent glass surfaces or equivalent wall surface they are easily determined. Manufacturers of steam and water warming apparatus have based their ratings on these factors and the steam fitter, by any one of a dozen rules, can determine accurately just what size of boiler is necessary for any particular require- ment. Let us see how readily this style of figuring may be adapted to the furnace. We will take for example a house 30 by 40 feet, having ten rooms to be heated. The house has twenty windows averaging 3 by 6 feet, and three outside doors 3 by 8 feet (in- cluding transoms). First floor ceilings are 10 feet, and second floor ceilings 9 feet high. The approximate cubical contents to be warmed would be: 30 X 40 X 10 plus 30 X 40 X 9, or 22,800 cubic feet. The glass surface (doors counted as glass) would be: 3' x 6' = 18 X 20 = 360 3 'X8' = 2 4 X 3= 72 Total glass surface 432 square feet. The wall surface would be: 30 + 40 = 70 X 2 = 140 X 19 (height of ceilings )= 2, 660 sq. ft. Assuming, as we properly may, that 4 square feet of exposed wall equals I square foot of glass in cooling surface or heat loss, we have : 2,660-^-4 = 665, the glass equivalent of the wall surface, which, plus 432, the FURNACE REQUIREMENTS 35 square feet of actual glass, gives the total equivalent of glass as 1,097 square feet. Let us figure on two changes of air per hour, and the total amount of air to be warmed hourly will be 22,800X2, or 45,600 cubic feet. The loss of heat by transmission through ordinary glass windows is determined as being approximately 0.8 B. T. U. (British Thermal Units) per square foot per hour, per degree difference in temperature, or, in other words, in this case the outside temperature being at o (zero) and the temperature of the rooms 70, the difference, 70 o, would be 70; therefore, 1,097 X 0.8 X 70 = 61,432 B. T. U. We also know that one heat unit will raise 55 cubic feet of air one degree in temperature. Assuming that the hot air at the registers enters the rooms at 120, we proceed as follows: 45,600 -f- 55 X 120 = 99,480 B. T. U. A good quality of anthracite coal contains approximately 14,500 heat units, of which about 10,000 are actually available for heating in a properly constructed furnace with a combustion of 3 pounds of coal per square foot of grate per hour ; therefore, 10,000 X 3 = 30,000 B. T. U. per hour per square foot of grate. To arrive at the correct size of grate to properly heat this house we add the required heat units, 61,432 -(- 99,480 = 160,912, and divide by 30,000 = 5.36 square feet. Therefore we require a grate having 5.36 square feet of area. This is based on zero weather for the winter, and, judging from the present rating of some furnace manufacturers, they are taking long chances and are expecting mild weather the better part of the heating season. CHAPTER III PIPE, FITTINGS AND REGISTERS Furnace fittings such as elbows, boots, offsets, tees, etc., are made in a great variety of shapes, the construction and patterns for which are treated by William Neubecker in the concluding portion of this book. We desire particularly to call attention to some common errors and offer suggestions for their correction. In considering the question of piping a job of furnace heating, we should naturally suppose that the later day advanced methods were far superior to those used years ago. Investigation would reveal that in many respects this is true also that in almost as many other respects it is not the case. The old plan, followed in the early days of warm air heating, of running round or square flues or risers, has not been improved upon up to this time in so far as good service is concerned. True, there have been marked im- provements in the designs of boots, tees and register boxes, but are these improvements such that they have a bearing on the reduction of friction or on increasing the flow of air through the piping? We think that they concern principally the money end or cost of the work. The infinite variety of stock patterns of all kinds of furnace pipe fittings, such as adjustable elbows and the like, make it easier and quicker to install a job, but for all-around efficiency, give us the furnace work of the good old days, when round or square risers were used, when all joints were soldered and the fittings were shaped on the job, being made to conform to the conditions of the work. The flow of air through piping is one of the first parts of the business that should be studied by the furnace man. The illus- tration, Fig. 23, represents a 12 inch diameter round pipe supply- ing a 3^ by 12 inch riser. Friction? Yes! and plenty of it. The flow of air in a pipe the area of which is 113 square inches is attempting to enter a pipe the area of which is but 42 square inches, or nearly two-thirds less in capacity. This shows a con- dition frequently found on present day furnace installations. Follow the effect of work of this character down to the furnace and it will develop that the principal results attained will be an HEATING EQUIPMENT 37 excessive coal consumption and a shortening of the life of the furnace due to an overheating of its castings. //e Ce/fe/~ 'x ,_, x * v \. X X \ vx. !i i | i! x- T^ W'x36 \ S \ ^ ^, N ' \Q" ' * ;:^/ /s^''. Co/cf ^ /s- Due/- Q Coo/ Fig. 59 Basement Plan. CONSTRUCTION METHODS 91 convenience. The latter will prove expensive in operation, will require close attention, and will consume at least 25 per cent, more fuel, to say nothing of the unsatisfactory heat produced. The owner will readily pay the difference for the better job, if these facts are properly set before him. It is therefore to the financial interest of the dealer to become sufficiently familiar with his subject to intelligently present these advantages. School House Warming and Ventilating It is said and truthfully so that a man never stands still in his profession. He either advances, becoming more and more proficient, or loses ground and finally becomes a "back number." There are many furnace men good mechanics who, while entirely competent to install almost any kind of a warm air sys- tem once it is designed or laid out, will balk and appear ignorant when questioned as to air change, the requirements for ventila- tion, the State laws governing school house warming and ven- tilation, etc. We illustrate an example of school house warming and ventila- tion designed to comply with the requirements of a State law which demands that each pupil in each school room shall be supplied with not less than 30 cubic feet of fresh air per minute. This amount of air is considered as a minimum, some cities demanding as much as 50 cubic feet per pupil per minute. The proper ventilation of school rooms is now considered as important as the heating of them, and six States Massachu- setts, New Jersey, New York, Pennsylvania, South Dakota, Utah and Virginia require the enforcement of a law demanding 30 cubic feet per minute per pupil. Main, Montana, North Carolina and Vermont require the approval of school houes plans, and South Carolina, Minnesota and Wisconsin will make no State appropriation to school dis- tricts who do not submit plans which must be approved by the Board of Education, all of which goes to show that the various States are falling into line and adopting the standard set by Massachusetts, requiring 30 cubic feet of air per pupil per minute. Can this be accomplished when a furnace is used for heating? Yes, but not with the furnace alone, as a purely gravity system will not act with sufficient rapidity to produce the necessary change of air. By employing the fan-furnace system for such service a defi- nite air change may be provided, and this system we illustrate herewith. Each school room is heated and ventilated. The halls and cloak rooms are heated, but not ventilated. CONSTRUCTION METHODS bo CONSTRUCTION METHODS 93 Fig. 60 shows a plan of the first floor, and Fig. 61 a plan of the second floor. Each floor contains two class or school rooms, 24 X 32 feet in size, with a ceiling 13 feet 6 inches in the clear, and each room is designed to accommodate 45 pupils. To determine the amount of fresh air to be supplied we pro- ceed as follows: 45 X 30 (cubic feet per minute) = 1,350 cubic feet per room per minute. 1,350 X 4 = 54OO cubic feet per minute for all four school rooms. To provide for and distribute this air in the volume required a 30 inch motor-driven disc fan is installed, as illustrated on the basement plan (Fig. 62). This fan, running at the medium speed of 450 revolutions per minute, delivers 6,700 cubic feet of air per minute, and requires about y 2 h. p. to operate it. At maximum speed, or 575 revolutions per minute, the fan delivers 10,000 cubic feet of air and requires I h. p. This shows the size of fan to be sufficient for all conditions of service, and for easy and economical operation a i l / 2 h. p. motor is installed. The speed of the fan is regulated from a rheostat located in the room of the principal of the school. The warm air registers, 24 X 30 inches in size, are located about 8 feet from the floor. The fresh air entering each school room under a slight pressure is diffused, and, seeking the cold walls, is slowly chilled as it settles to the floor, where it is drawn off through 24 X 24 inch registers into the ventilating flues. These registers are located at the floor line, and the change of air is accomplished without any drafts or discomfort to the occupants of the room. The boys' and girls' toilets in the basement are ventilated by means of special window ventilators. The cold fresh air enters the cold air room in the basement through two windows having hinged sash, and the fan is placed in a 32 inch duct leading to the pit tinder furnaces. A by-pass, 30 X 36 inches, in the form of a duct, connects the cojd air directly from the cold air chamber to the furnace pit. This is for use when the fan is not in operation, and it is provided with a damper which is closed when the fan is in use. This duct is not shown on the basement plan. It is located beneath the floor, immediately under the galvanized duct used in connection with the fan. In planning the building the architect had provided four flues, 18 X 36 inches in area, and one flue 16 X J 6 inches in area, to serve the rooms on each side of the hall. These flues are made 94 CONSTRUCTION METHODS bb CONSTRUCTION METHODS 95 96 CONSTRUCTION METHODS use of for warm air and ventilation, as shown by plans, and while they are somewhat larger than is necessary, their large- ness is a good fault. The basement rooms which receive heat from the system are the play room, girls' and boys' toilets. The construction of the air pit under the furnaces is a partic- ular feature of the installation. The furnaces proper are sup- ported on brick piers, which are built in the pit under the center of each furnace, and a deflector in the pit divides the cold air supply uniformly to both furnaces, each of which has a 35 inch pot, is encased in brick and has a cast iron front. The top of furnaces is covered by a galvanized iron hood or top casing, from which the hot air trunk lines are taken, as indicated on the plan of the basement. The installation of two furnaces is desirable, as during periods when but little warmth is necessary and it is required only to temper slighty the incoming fresh air, one furnace will produce all of the heat desired, this arrangement making a decided re- duction in the amount of fuel consumed. When estimating work of this character and figuring for a certain definite change of air, there are some facts in connec- tion with the selection of a fan which should be considered. The speed of the fan conditions the volume of the air deliv- ered; that is, the volume varies directly as the speed. Doubling the number of revolutions of the fan doubles the volume of air delivered. The pressure varies as the square of the speed; that is, if the speed is doubled, the pressure is increased four times and the power required to drive a fan varies as the cube of the speed. For example, if the speed is doubled, the power re- quired is increased eight times. It is therefore more economical to use a large fan at slow speed than a smaller fan at greater speed, and the mistake of selecting too small a fan should not be made. The motor for operating the fan may be directly connected to the fan or belted to the fan, as illustrated on the basement plan. CHAPTER IX WHAT CONSTITUTES GOOD FURNACE WORK Having so frequently been asked the question, "What do you mean by good work?" or "What constitutes good furnace work?" we will proceed to consider a number of features which char- acterize really good furnace work, and then ask ourselves if we are conforming to such a standard. A good firm foundation of masonry, whether of bricks or of concrete, is the first provision for a good job. On new work the foundation for the furnace, and also the cold air pit, should be built before the cellar is cemented, and if the cold air is to cross a section of the basement below the floor level, this trench should also be constructed before the concrete for the floor is put down. Both pit and trench should be constructed of hard brick laid in cement, or of carefully mixed concrete. It is better to build the walls of the pit of brick laid in cement. The top of the trench may be built of concrete laid over wood forms or re- inforced with perforated sheet steel now obtainable for the purpose. Dust Discharge A frequent complaint about furnace heating is that dust is discharged into the rooms. Ninety-nine per cent, of this trouble is caused by the absence of a suitable foundation, the furnace resting on the cellar bottom, or upon a poorly constructed foundation. The heat from the ash pit will soon dry the earth bottom so that the dust from it will be carried upward into the rooms, or if a poorly constructed or uneven foundation is used, the joints of the furnace will open up, due to the racking of the castings when shaking the grate. Not only is this a source of annoy- ance, but it also shortens the life of the furnace, and renders the castings liable to cracking, due to unequal expansion of the 9 8 GOOD FURNACE WORK metal. When a furnace is set upon an even, smooth foundation the parts will fit in their proper places without straining. The Casing Having properly set the furnace, the next item of importance RISER 63 Connection with Riser Improperly Made. to consider is the casing. Some furnace men prefer a double casing the inner one of black iron and the outer one of gal- Fig. 64 A Connection Better Than That Shown in Fig. 63. vanized iron with an air space between while others prefer a single casing, covered on the outside with asbestos and lined on GOOD FURNACE WORK 99 the inside with bright tin, plain or corrugated. Either method seems to us a mark of good work. The practice of encasing the castings in a single casing is a mark of cheap work and should be condemned. We know of some furnace men who use the single casing and cover it with a black iron casing, leav- ing an air space I to \y 2 inches between. This shield serves to confine the heat and increase the efficiency of the furnace. The Furnace Top The furnace top has been discussed in a former chapter, but we would say, however, that a top with a reflector or cone in Fig. 65 The Best Method of Making Connection. the center which throws the rising hot air toward the outer circumference of the casing is to be preferred to any other type. The warm air pipes may be taken from the top or on a slant, as the height of cellar and character of the job will allow. The cone fastened to the under side of the top provides an air space in the center, making the insulation of the top by covering a comparatively unimportant matter. The Piping The hot air pipes or basement leaders are essentially an im- portant part of furnace work, and in laying out this part of the work the furnace man should keep in mind the fact that the installation of the piping, if not properly done, will cause the apparatus to prove a failure. 100 GOOD FURNACE WORK In planning the piping every effort should be made to elimi- nate friction. This may be accomplished by shortening the runs and dispensing with all abrupt angles. Every bend in- creases friction and reduces the velocity of the air current. Concerning Bends Of course, bends are unavoidable, but it is a mark of good Fig. 66 Suitable Location for Rotating Register. work to find all bends made with a long sweep or easy turn. It requires but little obstruction to turn a current of air which, owing to its elasticity, will rebound when striking a surface at a right angle. Fig. 63 of the annexed diagrams illustrates a connection to a riser improperly made. The direction of the GOOD FURNACE WORK " 101 air is indicated by arrows. Fig. 64 shows a modified form of connection, showing an improvement in the direction of air currents. Fig. 65 shows the best method available, and the easy passage of the air into the riser will be quickly noted. Such methods of making connections indicate good work and a knowl- edge of the handling of air on the part of the furnace man. Heating Surface Thus far we have said nothing regarding the value of large heating surface i. e., a good generous size of furnace, particu- larly in regard to the fire pot and grate. A job may be ever so carefully installed, but if it be lacking in capacity it will prove inadequate and wasteful of fuel. Good work demand^ an economical furnace one whose grate area is sufficient to hold enough coal to give off the necessary heat units with slov; combustion, and a pot and drum, or heating surface, sufficient to warm the volume of air demanded without heating to ex- cessive temperatures, and in this connection it is well to remem- ber that the higher the temperature of the furnace the greater will be the waste of heat in the chimney. We favor the recirculation of the air in the principal room:; of the first floor. We know that many wise ones condemn this practice, yet there seems to us no reason why the air from the living rooms and hall should not, under ordinary conditions, be returned to the furnace for reheating, as it is not contami- nated to any perceptible extent. When rooms in one part of the house are "thrown together," as the parlor, reception room, library and hall, one large rotat- ing register placed at some central point, preferably in the hall, will be found sufficient. The staircase is a particularly good place for the installation of the rotating register, as the space under the steps allows of making a large galvanized duct con- nection to the register. Fig. 66 illustrates the idea. The extra expense of installing the apparatus in the right manner is money well invested in fact, like putting the money in a bank which pays large dividends. Added Cost of Hard Firing If a heating system of scant capacity or of poor construction is installed, which necessitates hard firing, with the attending waste of fuel, it is not uncommon to find such an apparatus using from 20 to 30 per cent, more fuel than would otherwise be found necessary. The additional expense of installing an adequate and properly constructed apparatus would at this rate be paid for in four IO2 GOOD FURNACE WORK or five years, and the annoyance of using a poor apparatus for that period would have been eliminated. There is absolutely no excuse for doing poor work or installing inadequate mate- rial when the argument of dollars and cents can be so strongly used with possible customers, and good furnace men are alive to this fact. Importance of Installing High Class Work Notwithstanding the fact that the makers of hot-air heating apparatus, the heating engineers, physicians and others in au- thority, who have devoted their time and attention to studying the conditions and results surrounding cheap furnace work, advocate and prove the need of ventilation and the circulation of air in connection with furnace heating, the sheet metal worker or furnace man unfortunately continues to figure and install cheap, unsanitary and unhealthful work, and when asked the reason, will invariably give as an excuse that the owner will not pay the additional price required for any other system. He may add, further, that his business rival will surely figure on doing a cheap job, and thus, by reason of the bugaboo of cheap competition, the furnace dealer will exert no effort to raise the standard of furnace work, fearing the possible loss of a contract. We wish that it were within our power to impress upon the trade the fallacy of such reasoning, and that we could clearly show to the contractor the damage he is doing to his business standing in the community and to his reputation as a heating contractor by installing cheap and inferior work. A job or two may be lost by taking a stand against and refus- ing to install low-priced work, but very soon a comfortable business of the right sort will have been established. As an example of good furnace work, we show the basement and floor plans of a compactly built two-and-a-half-story sub- urban residence. The first and second floors are of cement con- struction, and the third or half-story is of frame work. Fig. 67 illustrates the first floor plan, showing four rooms and a pantry. The reception room, living room and dining room are to be warmed and ventilated, while the kitchen is to be ventilated, but not warmed. On the second floor (Fig. 68), four bedrooms and two bath- rooms are to be heated and ventilated, and on the third floor, the plan of which is not shown, a bedroom is also to be simi- larly supplied. The living room and dining room on the first floor, and the bedroom, over dining room, on the second floor, are ventilated by means of open fireplaces. GOOD FURNACE WORK 103 Fig. 67 First Floor Plan. 104 GOOD FURNACE WORK : ' ; T 1 - " ; ": '' I 1 v. ' : .' : . ' <*-&>) w'tii&\- v.V.T 1 Fig. 68 Second Floor Plan. GOOD FURNACE WORK 105 The servant's bedroom and bathroom are ventilated by con- necting the ventilating ducts with a 9 X 10 inch ventilating flue, built against the kitchen smoke flue, from which it is heated. The ventilating ducts from all other rooms connect into a 13 X 19 inch vent flue, through which a 9 inch terra cotta smoke flue is carried. This is the smoke flue which serves the furnace. The ventilating flue is carried up through the first story 13 X 13 inches in size, being enlarged before the ventilating ducts of the second floor are connected into it. The support afforded the tiling in carrying the weight of it by this method of construction is a particularly good feature. The kitchen is not included in the above arrangement. At a point near the ceiling this room has a 10 X 14 inch ventilating register connected into the 9 X 10 inch vent flue, mentioned above, for the purpose of carrying ofl the steam and odors of cooking and also the excessive heat from the range, and it is utilized in both summer and winter. The basement plan, on which is shown the furnace, duct work and the arrangement for supplying fresh, cold air is illustrated by Fig. 69. The following is a schedule of the sizes and description of all pipes, ducts and risers; the location and sizes of all registers are given on the plans, and require no further explanation : SCHEDULE. Warm air, cellar Warm air, pipe, in. flue, in. Warm air, Ventilating register, Descrip- duct, in. 6%x 14 6^x14 First Floor. Living Room 1 1 Dining Room 1 1 Reception Room and Halls 210 Kitchen Ventilated at a point near ceiling only. Second Floor. Bedroom No. i 7 l /> Bedroom No. 2 7 Bedroom No. 3 pA Bedroom No. 4 8 Bath 6 Serv. Bath A Third Floor. Bedroom No. 5 8 size, m. 12 x 16 12 x 14 2--I2X 14 4 xii 3 1/2 x II 10 X IO 3^2 x ii 3^2 x g]/2 Sx 10 4 x 16 3^x ii 8x 10 4 x i2 l / 2 4 x ii 10 x 10 3/2 x 8 3/x 7 7x 10 ->iX x 7 10 X 10 tion. Floor Special baseboard Floor Sidewall 4 x 12^2 4 x 12^2 10x10 The method of ventilation and the size and kind of ventilating registers follow : io6 GOOD FURNACE WORK . 69 Basement Plan. GOOD FURNACE WORK 107 Ventilating register, First Floor. size, in. Description. Living Room Open fireplace Dining Room Reception Room and Halls Kitchen 10 x 12 Sidewall Second Floor. Bedroom No. 1 8 x 10 Bedroom No. 2 7 x 10 Bedroom No. 3 8xio Bedroom No. 4 10 x 10 Open fireplace Bath 6x 8 Sidewall Servants' Bath 6x 8 Third Floor. Bedroom No. 5 10x10 In building a ventilating chimney of the character shown, it should be lined with terra cotta, in order that it will be perfectly smooth and also be able to retain the heat from the smoke flue which passes through it. The plan of the flue shown on the present job is clearly shown on the second floor plan, Fig. 68. The cold air is admitted to the cold air chamber through a 24 X 30 inch screened opening in basement window, and baffle screens for filtering this supply should be provided in the cold air chamber. To obtain the practical value of this article, we ask the fur- nace man to make his own estimate on this work, as herein rec- ommended, and then to estimate for an ordinary form of cheap furnace heating for the same house. It is understood that the owner builds the ventilating chimney and the ventilating flue adjacent to the kitchen smoke flue, and that all other materials and labor are to be furnished by the heating contractor. If estimated correctly the figures will show a difference of approximately $185, or a total difference, when including the cost of the flue, of about $250. The difference in the results obtained from increased warmth and the comfort and healthfulness of a perfectly heated and ventilated home cannot be measured when compared with those secured from cheap work. Cleanliness and freedom from dust are. assured the housewife with the former, and finally, as of vital interest to our readers, the installation of such an apparatus is a standing advertisement to the furnace man. CHAPTER X VENTILATION The sciences of heating and ventilation are inseparably linked, and in the construction of a home, both should be considered jointly and proper provision made for the installation of an appa- ratus which will not only heat but ventilate as well. Profes- sional men and laymen throughout the country are awakening to the importance of ventilation, and a word about it and its value will help to spread a proper understanding of its importance. By ventilation is meant the process of changing or renewing the air within a room or building in order that the supply may remain sufficiently pure for breathing purposes. This statement indicates to us several facts : First, that ventilation is a method ; second, that air confined within a room or building becomes foul and unfit for breathing; and, third, that pure air is neces- sary to sustain life. Ventilation is a subject which until recent years has com- manded too little attention from those who should be vitally interested, and the acquisition of an adequate system of ventila- tion in connection with the heating system is not now the luxury it once was considered it is a necessity of today. The ventila- tion of a home is even of more importance than the heating of it, and we are coming to realize this, making provision for it as we recognize its worth, and the time is approaching and that not far distant when no dwelling of any size, or of the least importance, will be constructed without provision being made whereby the occupant may periodically remove the foul air and admit a pure supply. That we may the more readily comprehend the many phases of this important subject, let us determine, if possible, what air is and note the properties of its composition. Air is an invisible liquid we call atmosphere, which surrounds the earth in a belt VENTILATION 109 several miles in thickness. It is invisible (we cannot see it) ; it is transparent (it does not obstruct our vision) ; it is insipid (we cannot taste it) ; it is inodorous (pure air we cannot smell). It is composed principally of oxygen (one part), nitrogen (about four parts), and a very small proportion of carbonic acid gas and watery vapor. The volume of carbonic acid gas is from two to four parts in 10,000. The amount of vapor in the air is conditioned by the proximity to a body of water or the tem- perature of it. Oxygen is the life-sustaining quality of the air. The nitrogen is necessary to dilute it, and the carbonic acid gas to rarify and purify it. Carbonic acid gas or carbon-dioxide is poisonous, and will, when present in the air in any considerable quantity, cause dullness, headaches, and produce fainting spells. This condition is noticeable in a room in which the air contains 10 parts in 10,000. Frequently the air in a crowded hall or public room is vitiated to the extent of 25 or more parts in 10,000, rendering it so unfit for breathing that persons having delicate constitutions will faint. This is also true of many factories or workrooms in which a large number of laborers are employed. Air breathed or inhaled into the lungs of people under conditions such as these, inhaled into the room, and breathed over and over again, is more or less laden with, the germs of disease, which is all the more deadly should any of the persons present be suffering from a malignant affliction. Carbonic acid gas is the result of all combustion. Oxygen is the life-giving quality in the atmosphere. The oxygen in the air of a room is consumed by the burning of candles, coal oil in lamps or stoves, and by gas. Occupants of a room by breath- ing consume the oxygen, and their exhalations are full of car- bonic acid and other poisonous gases. If a man be shut up within a small, tight enclosure, his breathing will consume the oxygen, and the poison and gas from his exhalations will soon act to poison and suffocate him. The amount of carbonic acid gas in the air we breathe should never exceed six parts in 10,000, and when present in a greater proportion it will cause headache and a feeling of stuffiness. Relief from this condition in the form of ventilation may be had more cheaply by the combination of a ventilating apparatus and a warm air furnace than by any other method, and we shall endeavor to make this plain to our readers as we progress with this discussion. no VENTILATION It is well that we fully appreciate how vastly improtant is the necessity for providing pure air to those who are compelled to labor or remain indoors. The vitiation of the air is not caused entirely by the respiration from our bodies, although it is a matter of record that from i l / 2 to 2 l / 2 pounds of water are daily evapo- rated from the surface of the skin of a person not actively engaged in work of recreation that is, a person in still life. Another form of vitiation is the burning up of the oxygen in the air by gas lights, coal, coal oil lamps, or candles. A flame to which no oxygen can reach will sputter and die out. The mechanics of the sheet metal trade will understand the need of pure air from some statistics recently compiled. These figures were given by medical authorities, after diligent research, and are to be relied upon. Of the deaths of those between 15 and 45 years of age in the United States last year, 28.4 per cent, died from tuberculosis or consumption. The death rate among certain classes of labor due to consumption is: Marble and Stone Cutters 541 of every 100,000 Cigar Makers 479 of every 100,000 Printers 453 of every 100,000 Servants 430 of every 100,000 Formerly the percentage of death from consumption among cigar makers headed the list, but the International Cigar Makers' Union, a progressive labor body, by agitation and an aggressive campaign for light and air and more sanitary workshops, has reduced the percentage of deaths from this disease more than 50 per cent, in the last ten or fifteen years. This, then, is the need of proper ventilation, and we shall endeavor to show how adequate ventilation may be provided by the proper installation and use of a hot-air furnace. The amount of fresh air necessary to supply varies somewhat with the conditions and use of a building, depending, of course, upon the use to which the building is to be put. Dr. Billings, an authority on ventilation, estimates as follows: VENTILATION in Kind of Building. Cubic Feet Per Hour. Hospitals 3,6oo ft. per bed Assembly Halls 3,600 ft. per seat Workshops 2,000 ft. per person Theaters 2,000 ft. per seat Office Rooms 1,800 ft. per person The schedule given applies to buildings with no contamination of the air except from the respiration of the occupants and the burning of the oxygen due to gas lighting. Another authority states that the amount of carbonic impurity given off or excreted by an adult female is 0.4 to 0.5 cubic feet per hour, and by an adult male, 0.6 to 0.7 cubic feet per hour, the average for a mixed assemblage being about 0.6. Dr. De Chaumont, a French chemist, made some tests along this line, and states that when the organic matter in the air begins to be appreciated (smelt) by the senses, and the air is said to be "rather close," there is present slightly more than four parts of carbonic impurity per 10,000 cubic feet of air. When the smell begins to be disagreeable, and the air within the room seems "close," the carbonic impurity is 6.5 parts in 10,000 cubic feet. When the smell is decidedly offensive and the air "very close," the carbonic impurity is about 12 parts in 10,000 cubic feet. We may add that the air at this time has reached the danger point in its impurity. Methods of Ventilating No building of any considerable size can be ventilated except by mechanical means, although a residence or small building may be provided with a ventilating chimney, which will answer every purpose. A galvanized iron or copper ventilator of the type commonly known as the "Globe," or those of similar con- struction, when placed on a one-story building, such as a chapel, school or the like, will allow abnoxious gases, smoke or steam from manufacturing to pass into the atmosphere, the currents of surrounding air, or the wind, producing a suction which exhausts the air from within the building. Many good ven- tilators of a similar character are manufactured and have proven practical. A ventilating chimney when used in connection with a hot-air furnace will give the very best results. The requirements are that, in place of the ordinary brick flue, a large shaft or brick 112 VENTILATION shaft should be erected through the center of the house or build- ing. Through the middle of this stack the smoke pipe is run, which, if the building be a low one, may be made of terra cotta pipe, tightly cemented at the joints. However, a wrought iron stack is preferred, which may be carried to any height desired. Fig. 70 shows a plan of such a stack, in which A is the wrought iron stack, and B the smoke and ventilating space. Fig. 71 is a sectional view of such a stack as might be used in a two-story Fig. 70 Plan of Ventilating Stack. building, and shows the stack resting on a cast iron bed plate supported by a brick pier. It should be properly stayed with iron braces, one for each eight or ten feet of height. A good style of such a brace is illustrated in the plan, Fig. 70. It is made of heavy wrought iron and consists of a ring surrounding the stack, to which are bolted four braces, the ends of which are split and turned in opposite directions for tying into the brickwork as the stack is being constructed. On the top of the shaft should be placed a heavy galvanized iron hood, supported by upright standards of iron 18 to 24 inches in length, as shown. The wrought iron flue is placed in sections and riveted and braced as the stack is being built. This is also true of the frames for the foul-air registers or openings. The heat from the smoke pipe or flue will expand the air in the ventilating shaft and cause an upward movement of the air, which will exhaust the foul air from each room connected to it. A cold flue is of no use as a ventilating shaft, inasmuch as no means being provided for expanding the air and overcoming VENTILATION 113 the pressure of the atmosphere (14.7 pounds at sea level), the air in the flue remains "dead" or inactive, and it is absolutely Fig. 71 Sectional View of Ventilating Stack. necessary to overcome this pressure on the flue before an upward movement of the air in the shaft can take place. CHAPTER XI VENTILATION BY THE USE OF PROPELLER FAN In the preceding chapter we discussed a method of ventila- tion that might be termed "natural ventilation." However, not all buildings are so constructed that a ventilating flue of the character mentioned therein can be erected except at such a con- siderable expense that the owner is loath to consider such a sys- tem. Since electricity has become so common for lighting pur- poses, and by reason of the fact that nearly every town has a separate electric plant, or contracts for electric current from some adjoining city, the matter of obtaining proper ventilation of our homes, or in other buildings, can easily be arranged for. By this statement we refer to the proper use of an electric pro- peller fan. This covers a method which should be carefully studied by the furnace man. It is one so simple of adaptation, and yet so effective in operation, that it provides a long-felt want. The electric current ordinarily used by an incandescent burner is sufficient to operate a fan which will thoroughly ventilate any residence of medium proportions and construction, and the ex- pense of running the fan is so slight as to be scarcely worthy of mention, particularly when the results attained are regarded in their true light. We have reference to the propeller type of fan as illustrated in Fig. 72. A fan of this character is designed to move air against a very slight resistance, the blades being curved, pro- pelling the air forward by impact, and when installed in the attic of a building it exhausts to the atmosphere direct or through a short duct. A system of ventilation of this kind consists of register faces or open panels placed in the baseboard of each room to be ven- tilated and connected to an upright tin or galvanized iron duct from each room, terminating in the attic of the building, which is used as a plenum chamber. An opening in one of the gable ends of the attic is made and framed to the size and diameter of the fan, the flange of which is bolted to this frame. An FAN VENTILATION 115 attic window may be arranged for the purpose, the framework being built in such a manner that the window may be closed when fan is not in use. See Fig. 73. The fan is now ready for the wiring to the motor. A rheostat or speed controller is attached in a convenient place on the first floor, by which the fan may be started, stopped or the speed of it controlled. These fans are made for two speeds, namely, medium and maximum. Medium speed fans vary according to size in the number of revolutions per minute, from 800 for the 18 inch to 200 for a fan 6 feet in diameter, and this type is rec- ommended for ordinary ventilating work on account of being practically noiseless in operation. Maximum speed fans vary from 1,000 revolutions for the 1 8 inch to 270 for a 6 foot fan. The following table gives the size, revolutions per minute, horse power and cubic feet of air moved for medium speed fans from 18 to 72 inches in diameter: Propeller Fan. Diameter of fan, inches. 18 24 3 2 36 42 48 60 72 Horse power. 1/8 1/2 5/8 3/4 13/4 2 1/2 Revolutions per minute. 800 600 450 425 350 300 250 200 Cubic feet of air delivered. 2,000 4,000 6,700 9,500 12,600 16,700 25,700 37,000 In handling or moving air by a fan the amount delivered n6 FAN VENTILATION depends upon two factors, viz., size and speed. Further, if the air is forced through a duct or ducts, the element of friction, due to resistance encountered, must be considered. There are some few rules which it will be well to remember : i. The amount of air delivered by the fan varies directly as the speed of it. Doubling the number of revolutions doubles the volume of air delivered. Fig. 73 Propeller Fan in Attic Window. 2. The air pressure varies as the square of the speed; for example, if the speed is doubled the pressure is increased four times. As we desire by the method described to deliver the air directly to the atmosphere, this rule need not be regarded as important for our purpose. 3. The power required is increased eight times when the speed is doubled. Thus it is more economical to use a large fan at a low speed than a small fan at a high speed to move the same volume of air. 4. The temperature of the air to be moved affects the pres- sure required and the power necessary. Increasing the tem- perature of the air reduces its weight and diminishes the power necessary to handle a given volume. Let us consider, in ventilating an eight-room house, that there FAN VENTILATION 117 are five rooms in which the air is to be completely changed four times hourly. These rooms average 15 X 20 feet and have 10- foot ceilings. 15 X 20 X 10 X 5 = 15,000 cubic feet of air to be moved, which, when multiplied by four, the number of air changes, equals 60,000 cubic feet to be moved hourly, or 1,000 cubic feet per minute. By reference to the table given above it will be seen that only a very small fan is necessary for this work. The proper amount of pure fresh air must be admitted through the cold air duct and warmed by the furnace to such a degree that the various heat losses of the rooms are taken care of and a uniform desirable temperature is maintained. Many heating contractors contend that, providing the impure, contaminated air is removed by an exhaust fan, the inward leakage around windows and doors is sufficient to supply all of the pure air necessary for the ordinary residence. This is not true, for, considering that this applied to the building noted above, it would be necessary for 200 cubic feet per minute to leak into each of the five rooms figured, and cold air admitted in such quantities would produce unpleasant drafts dangerous to the health of the occupants. One of the first considerations in the movement of air for ventilation is that there shall be no drafts experienced by the occupants of the room or building. There is a great advantage in installing a fan of this charac- ter, viz., that proper ventilation may be provided during the warm weather period, when the heating apparatus is not in use. The effectiveness of any method is measured by the conditions of the weather. A heavy atmosphere or excessive velocities of the wind will have a much greater effect upon any system of natural ventilation than it will upon a positive mechanical system as above described. Let all furnace men become acquainted with every phase of this all important subject. There is no doubt but that heating and ventilation are to be inseparably bound together, and we must look to our system of warming to assist us in our methods of ventilation. On the other hand, every furnace man of experi- ence knows also that it is easier to warm a well-ventilated build- ing than it is to heat one in which the air is foul or dead. Efficiency of the Exhaust Fan Exhaust fans are efficient for clearing factory rooms of smoke, poisonous gases or the fumes from chemicals used in manufac- turing, and by the admission of a sufficient quantity of fresh air properly warmed it is possible to keep the rooms at a comfort- able temperature and the air fresh and pure. Furnaces may be used in connection with exhaust fans for this purpose, and for n8 FAN VENTILATION warming and ventilating small factories or other buildings a system of this kind is efficient and may be installed at low cost. The fan may be driven by a motor, belt driven or direct con- nected, and as nearly all of the larger towns, as well as cities of any size, have an electric light and power plant, the power to operate the fan may be secured at a nominal cost, as an exhaust fan run at low speed requires but a small amount of power to drive it, owing to the fact that the air is usually moved against a very slight resistance. In this connection we quote from an article by Wm. H. Hayes which was recently published in SHEET METAL. Mr. Hayes says: "I am indebted to one of the largest and best known blower concerns for the capacity table printed in this article. This is presented for the reason that the power required to drive ex- hausters is an important factor when a deal is being negotiated in the piping business. Yet it is a factor very often regarded as one of small importance. "By referring to this table the reader will see how increasing the speed of a fan by a few revolutions will more than double the amount of power required to drive it. Take, for example, the 40 inch exhauster fourth in the lower table; 4 horse power will drive it 1,090 revolutions per minute, yet to drive it 1,785 revolutions, an increase of speed of but 695 revolutions, requires 17.35 horse power. The reader will note also the last stat:ment made underneath the table, viz. : 'If the suction area is less than the inlet of the fan, the power and volume will be reduced and the pressure increased.' Thus, if it is a question of power with the prospective purchaser, sell him a larger fan. Speed, Capacity and Horse Power Required for Steel Plate Exhaust Fans "I am indebted to the same concern for another table, given below, and which shows how speed can be cut down and power saved by adopting t'.ic suggestion. "To quote the American Blower Company: 'Supposing we have 284 square inches of area in all the branch pipes and the main suction pipe after the last branch is taken in 19 inches in diameter. The various sizes of fans which can be applied, with their respective results, are shown in the table below, this being based on 100 feet of suction pipe, 100 feet of discharge pipe, four elbows in the pipe and a properly proportioned separator : FAN VENTILATION 119 Brake voc ^^RJ^ rt ' ONC>0x ^vr5fBrake 00 ^^ ^ooo^oot/jrt horsepow'r o ^ -< oi oi co -^H ^ ^ c per minute ~ of co co uSvcT t^co o co' [ per minUvte <^ Tf vo" K o 1 of 10 tx ^"oo" ^ ^ M . ^ ^ ' horsepow'r rj-vd od w rj- 1< ^ 10 ON d\'C J3 r OO** 1 ^* 1 *^^ CO CO Tj" fl\ ^ HH KH o^ 04 O4 COTJ "^ Q-^ 05 f ^ ^ C^ u< /^* t * .f 2. O l *^ O *O OOQOOQ t ^'^rH 1-1 Cubic ft ^O^OOOiOioOOn. V^UDIC I t . 0\ t^vo 00'^ < ^'QO*OO^* ^ per minute ^ ?"? "t 7 ^ ^ ^ ^ . per minute^-^ SS^oJ d S Sc5 ^f a ^ *S O M NO W Q\ W tX O\ O\-N I TJ p TIT 04 CO O TfOO ^fcoO4 Ol O'>" ^i ID r> TVT o *-" tx t^oo oi\oo>oo 1-tV' * "* - '^ JX. lr^. JVl. 01 o oo t^vc voioiori-Tf (a^^^^t^^^ bf . . cr tn Brake O ^ Os ^ x o to co ^ vo f ? r a k ^ ^.^ i d . C >corj-iot>q\o4 ^-^qtv.1 horsepow r oi co , horsepow roooooMM^oioiiu tn R P M Diam. inlet f B r a k e ,v ,vo jovo o vo tooo o (inside)in.2 a ^^ o^ ol ot ^ oT orsepow'r 2 3 ^ ^ S K S d 5 p e riphery.>->^: N inches " 2 rj J? 2" ^"2 N - per minute - w ^ ^^T K a ^ oi t<^ O O e . P. M... OH to ^ No. of fanffg^SRSSRig No. of fan^ft^^^^^ R<2 .2 I2O FAN VENTILATION Size of fan. Speed. Horse power. 45 inches 1,300 R. P. M. n 2/3 50 inches 1,010 R. P. M. 8 3/4 55 inches 810 R. P. M. 7 " 60 inches 650. R. P. M. 5 2/3 "Thus it will be seen that to use a 60 inch fan instead of a 45 inch fan is to reduce the power more than one-half." CHAPTER XII HUMIDITY AND THE VALUE OF AIR MOISTENING Up to the present time practically every furnace man seems to have had but one object in view when installing a hot-air furnace; namely, to install a furnace of such size and in such a manner that each dwelling or building may be satisfactorily warmed, notwithstanding the most adverse conditions of wind and weather prevailing. True, there are those in the trade who keep in touch with all the later improvements, who read and study the results of various experiments calculated to better the general conditions of warm-air heating in other words, k^eps up to date but they are few in number. Humidity and the value of air moistening cover a subject that should be carefully investigated and learned by all heating contractors. It is a subject easy to understand and, when prop- erly understood, easy of application. Many articles of great value on this topic appear from time to time in the trade press, and the furnace man who gives them but scant or passing atten- tion is missing instructive literature which will later prove of vast importance and necessity to him. We know that the earth is surrounded by a belt of atmos- phere several miles in thickness and that this air contains more or less vapor, the amount varying according to the temperature or its proximity to a body of water. Those of our readers who have lived in the vicinity of, or have visited the shore of any one of the Great Lakes, or even many of those inland bodies of water less extensive in area, may have noticed that, as a rule, they lie in a basin and are approached down a hill, which is sometimes very short and abrupt, and again at other times long or gradual in its descent. No matter which geographical condition exists, it is very apparent that the atmosphere after the crest of the hill is passed becomes very balmy, humid and of a satisfying nature, all of which is due to the proximity of the body of water. We may reach or obtain this same delight- ful condition and enjoy this same balmy atmosphere within our homes. The writer believes that this subject is too little understood and is given too little attention by furnace men. 122 AIR MOISTENING The great Architect of the Universe never intended that we should pass one-third or more of our lives shut up in almost air tight boxes ; neither did he intend that we should be compelled to breathe tainted and poisoned air, yet this is what we are doing day after day with the result that as a nation we are heir to all sorts of diseases of the throat and lungs, tuberculosis, bronchitis, etc. This condition and the effects of it will perhaps be better realized when we say that statistics show that over 30 per cent, of all deaths in this country are due to diseases of the throat and lungs, and today the treatment most generally prescribed by the physicians for such ailments is more fresh air, and by this advice is not meant the outside air, such as comes to us within our homes, baked by the average heating apparatus, but clean, pure, and humid air, such as an out-of-door climate provides. There is no form of artificial warming apparatus by which this ideal condition may be produced and sustained so well as by a hot air warming system properly installed. The average steam or hot water warming apparatus provides only for heat. The introduction of a supply of fresh air is generally overlooked entirely, or when introduced at all is only provided for in the homes of well-to-do people, who have ample means to pay the increased expense of installation and main- tenance of such an apparatus. As we have said before, it is by reason of the moisture in the air that it carries and retains heat, and the dryer the air, the more difficult it is to heat. The air is capable of carrying a large amount of moisture. This may be noticed during a fog and again by the dew deposited during the night at certain seasons of the year. In tropical coun- tries the dew deposited is frequently so heavy that the eaves drip water, and if this condition did not exist the tropics would not be habitable. A year or two ago, when discussing the importance of air- moistening, the writer remarked somewhat as follows: "The process of refining or manufacturing raw material into a finished product has been carried on for many centuries. Had some- body stated to the architects of ancient Rome, or to the archi- tects and constructors of our own national capitol, or of our more modern buildings, that in the twentieth century we would be manufacturing climate, they would all alike have disbelieved the statement, and considered that the speaker was bereft of reason." However, that is exactly what we are accomplishing 1 AIR MOISTENING 123 in hundreds of buildings today and it has come to be a very important factor of an up-to-date heating and ventilating ap- paratus, more particularly in our schools and public buildings. We can now provide an air supply for any building that will be free from soot and dust, that will be pure and also accompanied by a constant relative humidity, regardless of the condition of the outside air, or the location of the structure. The principal installations of air-moistening apparatus have been placed in connection with the fan or blower system of heat- ing. Very few have as yet been used with a warm-air furnace as the source of heat. Let us consider briefly the term humidity with the fact that it is necessary that there be some moisture in the air we breathe. When the air is so laden with moisture that it is deposited in the form of de\v, it has reached the point of complete saturation, or what is k.iown as the "dew point." This deposit or dew is formed by the radiation or giving off of heat from trees, plants, etc., this action reducing the temperature of the surrounding air to the point of complete saturation, when the moisture will be deposited. We will consider that this point is one hundred per cent. In the most arid deserts there is some degree of moisture present in the air, probably thirty or thirty-five per cent, of complete saturation. In ordinary or temperate climates the prevailing percentage may be from fifty to seventy-five, the rate depending largely upon the temperature. The dryer the air, the more difficult it is to heat. At high altitudes the atmosphere is dryer than that found at low points, hence it is cooler and more difficult to heat, as the cold air ab- sorbs less moisture than the warm. On a hot summer's day, with the thermometer around 90 degrees Fahr., the air is capable of absorbing about fifteen grains of moisture for each cubic foot. At 32 degrees Fahr. (freezing), the air will absorb but little more than two grains per cubic foot. It is apparent then that by reason of the moisture present, the air carries and re- tains heat. The heating apparatus which employs an air-mois- tener to properly saturate or humidify the air is not only provid- ing a healthful climate within the building, but is accomplishing it at less cost for maintenance than would otherwise be possible. Reduction of Fuel Exhaustive tests have demonstrated the fact that the saving in fuel effected by adopting proper methods of air moistening will pay the cost of such effort to say nothing of the increased comfort and health fulness secured and probable saving in the expense of physicians' services. 124 AIR MOISTENING Results of Investigation One physician says: "Investigations have proven that the higher the degree of temperature, which increases the capacity for water, the greater will be the weight of a cubic foot of saturated aqueous vapor; therefore, by the addition of heat to the colder outside atmosphere entering the building, there must be an additional amount of vapor added to overcome the de- ficiency existing between the weight of a cubic foot of saturated aqueous vapor as received from the furnace from the outside, and the weight of a cubic foot of saturated aqueous vapor raised, by the addition of heat units, to the higher indoor temperature to produce a normal condition of the latter/' So much regarding the need of proper humidity. Now, let us for a moment consider the effect of it in connection with the proper warming of a house or other building. We have said, and our readers have no doubt frequently read the statement, that a room heated to 60 degrees F., with a humidity of 55 per cent., is much more comfortable than a room heated to 75 degrees with a lower percentage of humidity. The climate, and when warmed to 60 degrees F. a building is com- fortably heated. In this country we all know that a tempera- ture of 70 degrees F. is the standard for living rooms, offices, or other rooms where the occupants are inactive. The average warmed building, having no ventilation, is as dry as the desert of Sahara, and many eminent physicians have called attention to the bad results arising from it. The irritation of the mucous membrane of the throat and lungs, causing bron- chitis and catarrh, is one of the worst evils consequent upon this condition of the air. If in cold weather we are using outside air to supply the fur- nace, and this outside air is at 65 per cent, (as we measure humidity), we reduce the moisture to probably 30 or 35 per cent, in warming our rooms to 70 degrees Fahr. In continuing to pour warm air into the rooms under these conditions the radiated heat seems to penetrate through the air within, but without warming it. If we devise and employ some method of moisten- ing it, the moist, humid air will hold and absorb the radiated heat and give it off to all cooler bodies within the room. Humidity has been aptly called "Nature's great bed-blanket for all her children," and without it they would perish. Dry air extracts the moisture from the body, and it is accordingly neces- sary to warm the rooms to a greater degree in order to feel com- fortable. If our readers will note the difference between the English climate and that of America, a very good illustration of these AIR MOISTENING 125 facts is apparent. The Englishman complains of the American winter climate because our homes, which to us are only comfort- ably warmed, are to him overheated. The American finds the reverse to be the case when visiting England, and complains of the cold. The human body can be likened to a furnace and the heat developed within it must be given off as rapidly as it is produced if we are to remain healthy. This dissemination is ac- complished largely by perspiration. The Englishman is accus- TO DRAIN Fig. 74 'Galvanized Iron and Wire Air Moistener. tomed to a low rate of perspiration, the American to a higher rate, the difference being due to the fact that each has grown up in or become susceptible to a different climate. Now, regarding the probable saving in fuel by changing these conditions, it is competently estimated that 25 per cent, of the. cost of heating is expended in raising the temperature within our homes from 60 to 70 degrees. This being established it fol- lows that one-fourth of the cost of fuel can be saved by main- taining the temperature of the rooms at 60 degrees and pro- viding for the loss in moisture (humidity) due to heating the air; in other words, by keeping the percentage of humidity at 65 or 75. The result will be a sensible temperature within the rooms which, if no thermometer is at hand to consult, will seem, and in fact is, entirely comfortable. How may we provide for properly moistening the air? This question naturally follows in our discussion of the subject. There are several methods by which the air supply of a warm- air or furnace-heating system may be moistened and made humid. The common practice of placing a small cast iron receptacle in 126 AIR MOISTENING the side of a furnace casing, called a "water-pan," "vapor-pan," etc., is but a feeble effort in this direction, and it does not amount to anything for the purpose intended. True, the water in this pan evaporates into the air supply of the furnace, but it is very much the same as would be the effort of the arid dry air of a desert to take its moisture from a small brook. The cold air may be admitted through a chamber in which are a number of compartments filled with crushed coke, over which small streams of water from a perforated water pipe trickle down, keeping the coke wet. A drip-pan at the bottom may connect with an overflow pipe leading to a drain. iX) J=>ijo 3 cffe Fig- 75 The Herr Humidizer. Fig. 74 illustrates this method, the coke being broken into small pieces and held in a galvanized iron and wire rack inside the boxing at the cold-air inlet. Another method is the spraying of the air by means of one or more small atomizers or sprays playing on the incoming air. There is but little difference as to whether the air is moistened before or after it is heated, except that moist, humid air absorbs the radiated heat better than the dry air. Spray nozzles of brass may be obtained and they are of simple construction. The centrifugal action prevents the openings from clogging. For a job of any considerable size or importance a bricked-in humidify- ing chamber with cemented floor properly drained may be pro- vided in the basement and water pipes with sprays be placed in this chamber. An apparatus for spraying the air, after it has been heated. AIR MOISTENING 127 known as the Herr Humidifier, has been found to be very effec- tive and is strongly recommended by those who have tried it. This device seems to us to be worthy of careful investigation on the part of the furnace man. It has been greatly improved and some few defects in the original apparatus have been cor- rected. Fig. 76 Humidizer Attached to Furnace Casing. ig- 75 shows a view of the humidizer proper the spray nozzle and adjustments. The small stream of water passing through the apparatus strikes the spoon C and is deflected in the form of a fine spray, which saturates the air in the top cas- ing of the furnace. The size of this stream of water, and con- sequently the amount of moisture mixed with the air, is regulated by the adjusting bar B. Fig. 76 shows the method of attaching the humidizer to the casing top of the furnace, and Fig. 77 shows a complete installa- tion of the same, with an apron provided to utilize the drip from the spray nozzle. We believe that no further description of the device is neces- 128 AIR MOISTENING sary, and that the utility of it will be apparent to every practical furnace man. The hot air as it rises to the top of the casing is moistened by the fine spray of water, which is absorbed, and then passes through the leader pipes to the rooms above, producing balmy, Fig. 77 Complete Installation of Humidizer. natural atmosphere. Tests have shown a relative humidity of from 60 to 65 per cent, of complete saturation. Placing the Water Pan The feeble effort to obtain these results by using a water pan AIR MOISTENING 129 in connection with the furnace, we all no doubt are familiar with. The pan is located at the wrong point to be effective, even to a small degree. The water should be above the source of heat. A much more effective water pan may be made by riveting and soldering a strip of galvanized iron around Fig. 78 Sectional Elevation and Plans Showing Proper Location of Water Pan. the inside of the top casing, immediately under the openings for the connection of hot air leader pipes. This ring should be from two to two and one half inches wide with the inside edge turned up a little over one-half of an inch. In Fig. 78 the sectional elevation illustrates the idea and the plan above shows a little cup riveted on the side of the casing as a device for filling small holes in the casing connecting with the pan on the inside of the casing. The Hygrometer To properly understand the relation of humidity to heating we must know that the sensible temperature (that is, the temper- 130 AIR MOISTENING ature felt by the body) corresponds to the temperature of the wet bulb thermometer; therefore, the dryer the air, the greater is the difference between the actual and the sensible temperatures. We measure or determine the temperature and humidity of the air with an instrument known as a hygrometer or hygro- Fig. 79 The Hygrometer. phant. On this instrument two standard thermometers are pro- vided, one (a dry bulb) showing the temperature of the air, and the other (a wet bulb) showing the temperature due to evapora- tion (Fig. 79). In the center is a fixed scale, and to the right of this is mounted a cylinder upon which is inscribed columns AIR MOISTENING 131 of figures with headings numbered from "i" to "22." This cylinder may be freely turned by the knob shown at the top of the instrument, and the figures appearing at the top of the col- umn represent the difference in the reading of the dry and the wet bulb thermometers. Revolve the cylinder until this number appears at the top and note the number opposite the figure on the fixed scale representing the reading of the dry bulb thermo- meter. This number gives the percentage of humidity. For example (note illustration), the dry bulb thermometer shows 70 degrees and the wet bulb 60 degrees. 70 60 = 10 number at the top of the cylinder which has been revolved until this number appears.) Now note the cylinder number opposite the figure 70 on the fixed scale. It is 56, which is the relative humidity or percentage of moisture in the air, according to the thermometer readings. This is a most interesting as well as in- structive instrument. CHAPTER XIII RECIRCULATION OF AIR IN FURNACE HEATING It is generally recognized that many of the objections to fur- nace heating are brought about by reason of the installation of cheap, unsatisfactory, and unsanitary work, or through the ig- norance displayed by the unskilled man in laying out and in- stalling the job. We will consider some of these objections, their cause and how they can be remedied and the work made satisfactory. Probably the first and most frequent objection heard is that made to the condition of the air within a building when it is warmed by a hot air apparatus, viz., that it is overheated and "stuffy." The frequency of this fault we must admit; and it is brought about through the installation of too small a furnace and the provision of too small an area for the cold or fresh air duct. A further source of complaint is found in the quality of the air supplied. Quality of Air Let us consider for a moment this complaint and the cause of it. If a certain size of a building requires the consumption of 12 pounds of coal per hour to transmit the necessary number of heat units to take care of the exposure or cooling surfaces, a certain size of grate will be required to properly burn this amount of fuel, and, in its turn, the heating surfaces of the furnace which transmit these heat units to the air passing through it, must be of a certain area if these surfaces are not to be over- heated in the effort of transmission. This means, for example, that should 12 pounds of coal per hour be burned on a grate having three (3) sq. ft. of area, the rate combustion would be 4 pounds of fuel per sq. ft. of grate per hour. Assuming that .from each pound of fuel, 8,000 heat units are available for warm- ing purposes, then 8,000 X 12 = 96,000 units per hour will re- sult from 12 pounds of fuel burned on 432 sq. in. of grate. Supposing that a furnace having but 288 sq. in. or 2 sq. ft. of grate area was installed to warm this building, the attempt to RECIRCULATION OF AIR 133 burn the fuel required on the reduced grate area requires so high a rate of combustion that the air passing through the furnace is overheated, thereby destroying its invigorating qualities, and making it unfit to breathe and "stuffy" in effect. Air Outlet Necessary Another reason for this condition (stuffy atmosphere) is due to the fact that many furnace men are trying to introduce warm Pur not in ~z^; ~ circulation. Fig. 80 Poor Air Circulation when Room has No Outlet. air into a room which has no air outlet, except the leakage around windows and doors, doubtless overlooking the fact that only as much air can be admitted to a room as the amount which passes out, and the effort to heat the room in this manner makes neces- sary such an increase in the temperature and velocity of the in- coming air as will drive it into the rooms. Heating Windward Side Right along this line is the complaint that during the prevalence of high winds it is impossible to heat the rooms on the windward side of the house. This complaint, as well as the preceding one, can be overcome wholly or in large part by the proper recircula- tion of the air within the building. Fig. 80 represents a closed 134 RECIRCULATION OF AIR room without air outlets, except the leakage through walls and around windows. Note the manner of the circulation of the air, or rather the fact that there is practically no circulation of it. Place a rotating register and flue as indicated by Fig. 81 anil note the difference in the movement of the air. Supposing the room is on the side of the house most exposed to the strong winds of winter; the placing of a rotating register and flue along the outside wall of the room will do much t.-> improve the circulation of the air in it, and consequently the proper warming of the room. Fig. 82 illustrates this condition. Fig. 81 Perfect Circulation of Air when Rotating Register and Return Air Flue are Employed. In illustrating our discussion of furnace heating, we have for convenience frequently shown floor registers. We do not like floor registers. From a healthful standpoint they are bad, as they collect dirt and organic matter, and often much of the bad air in a room may be traced to the filth and dirt which has col- lected in the boxing under a floor register. If circumstances make necessary the use of floor registers, the face should be lifted out and the boxes wiped out at least monthly with some germ destroying wash. Opposition to the Method As stated in a recent chapter, there are some people identified RECIRCULATION OF AIR 135 with furnace manufacture and installation who advise against the recirculation or rotation of the air within a building. These advocate a positive method of ventilation notwithstanding the consequent expense to be incurred in bringing about this desired condition. The objection to the recirculation of the inside air seems to be based entirely upon the feeling that the quality of the air is lowered and that the health of the occupants thereby is endan- gered. We believe that the filtration of air through outside walls and windows, considered with the fact that ordinarily less than half a dozen people inhabit a single dwelling, renders the contamina- tion of the air to the point of stuffiness next to impossible. Fig. 82 Showing Effect of High Wind Against a Building Heated with Hot Air. On occasions when a social function is given and a considerable number of people are present, the return air registers can be closed and the outside air used exclusively. This is also true in the event of any of the occupants being sick or affected with a contagious disease. While we recommend ventilation and plenty of it the fact remains that a very great number of furnace heating plants are installed without any form of ventilation, and the amount of fresh air admitted is limited because of conditions stated in this article. The installation of return air ducts with rotating registers in the principal rooms, will aid in the distribution of the fresh 136 RECIRCULATION OF AIR air admitted through the cold air duct, and this feature will not only make the furnace heat more positively, but will distribute the air at the least possible expense for fuel. Obtaining Best Results The furnace by itself cannot warm the building. It can do nothing more than warm the air, and it is up to the furnace man to take this warm air and provide methods for its carriage and distribution. Division in Co/cf Air Duct. 5 w/ngifiQ D Q/njoc. r&' Fig. 83 Proper Construction of Return or Recirculated Air. The failure to obtain proper results when the recirculation feature has been introduced in furnace heating, is usually found to result from the fact that poor judgment has been exercised by the furnace man who has not fully understood the method to be followed. Connecting Duct Ordinarily the circulating duct should not be connected to the casing, or to the cold air pit of the furnace, but rather to the RECIRCULATION OF AIR 137 cold air duct ; and dampers should be arranged in such a manner that return air or fresh air may be used at will. The cord or chains operating these dampers may extend to a convenient place on the 'first floor. Fig. 83 shows the method of connecting the duct. We recommend to the furnace man that he study the methods of return air circulation, and the advantages to be gained from the installation of such a system when properly erected. CHAPTER XIV AUXILIARY HEATING FROM FURNACES When warming a building with a hot air furnace it frequently happens that there are some rooms or portions of the building which, owing to structural conditions or remote location, cannot well be warmed in the regular manner with hot air. These conditions, which would interfere with the running of hot air pipes, will not interfere with the installation of hot water piping, and therefore several methods have been devised of com- bining a hot air and hot water heating apparatus, making use of but one fire for supplying the necessary heat for both systems. This is accomplished by installing a somewhat larger furnace than would be required for hot air alone, and by placing a coil of pipe in the fire pot of the furnace or suspending above the fire a hollow casting, called an auxiliary heater, through which the water may circulate and receive the heat. The hot water circulating through the coil or casting is distributed through piping to one or more radiators located within the rooms to be warmed. It is not necessary for the furnace man to be adept that is, thoroughly versed in the practice of steam fitting in order to successfully install combination jobs of this character. Computing Size of Radiator Probably the first knowledge that should be acquired pertain- ing to this method is to learn how to compute the size of radiator necessary to warm a room. This is determined by considering the cooling surfaces of the room, glass and exposed wall, much the same as for hot air heating. The following simple rule will give fairly accurate results : First Ascertain the square feet of glass surface (windows and outside doors). Second Ascertain the square feet of exposed wall surafce (outside walls, windows not deducted). AUXILIARY HEATING 139 Third Ascertain the cubical contents of the room to be warmed. Divide the glass surface by 2. Divide the exposed wall surface by 20. Divide the cubical contents by 200. Fire Pat of Furnace rtetu rn Fig. 84 Plan and Elevation of Pipe Coil, The product of these results plus 60 per cent., will give the amount of hot water radiation necessary to warm the room to 70 degrees in zero weather with the water at a temperature of 1 80 degrees Fahr. If the furnace contractor is in the habit of estimating accord- ing to loss per hour of heat units, he may determine the total 140 AUXILIARY HEATING loss for the room in heat units and divide this sum by 150; this calculation will give the square feet of radiation required. Heating Furnace Required The next item to consider is the amount of heating surface to be provided in the furnace to supply the radiation required. This heating surface may take the form of a pipe coil as illustrated by Fig. 84, which shows a plan and elevation of a pipe coil, or Fig. 85 Cast Iron Auxiliary Heater. of a hollow casting as illustrated by Figs. 85 and 86. These cast iron auxiliary heaters are made in a variety of shapes and sizes. Each square foot of surface in the pipe coil shown by Fig. 84 if placed low in the fire pot, so that the hot fire comes in contact with it, will supply 50 sq. ft. of radiation with hot water at 180 degrees or 60 sq. ft. of radiation with the water at 160 degrees Fig. 86 Another Form of Cast Iron Auxiliary Heater. at the radiator. If the coil is suspended above the fire it will supply from 25 to 30 sq. ft. of radiation. Should a hollow casting similar to that illustrated by Figs. 85 or 86 be employed as heating surface in the furnace, it is sus- pended above the fire and varies in efficiency from 20 sq. ft. of radiation supplied for each square foot of heating surface in AUXILIARY HEATING 141 O^erf/ow Furngce. Fig. 87 Typical Arrangement of an Auxiliary Hot Water Heating Apparatus. 142 AUXILIARY HEATING Ovzrf/ow. Fig. 88 Domestic Hot Water Supply from Furnace. AUXILIARY HEATING Fig. 89 Overhead Piping of Auxiliary Hot Water System. i/l/l AUXILIARY HEATING the casting, to possibly 25 or 30 sq. ft., depending upon how much of the casting is direct heating surface and how far above the fire it may be located. Installing the Apparatus The method of installing the piping and of connecting to the radiators has more to do with the success or failure of a job of this character than the construction of any other part of the system. Fig. 87 is a typical illustration of an auxiliary hot water heating apparatus and shows two radiators supplied by a coil in the furnace. Note the small tank at the top of the system. This is called an expansion tank. Water when heated from 32 to 212 degrees (the boiling point) expands 1/25 of its volumne, and unless some provision were made for taking care of this expansion the system would overflow when heated, and when the water in the system was again cooled and contracted, the upper part of the system would fill with air which would interfere with the cir- culation. The tank should be located in such a position that the bottom of it is well above the top of the highest radiator and the pipe connecting the tank with the system (called the ex- pansion line) should be connected as indicated on the illustration. Ordinarily an expansion tank of from eight to twelve gallons' capacity is sufficient for a combination job. An eight gallon tank will take care of 200 to 250 square feet of radiation and a twelve gallon tank, 300 to 400 square feet. The size of pipe to be used in connecting to the radiators is determined by the size of each radiator. A I inch pipe will supply 35 or 40 square feet of radiation on the first floor above the furnace or 60 to 70 square feet on the second or third floor. In like manner a ij4 inch pipe will supply 60 to 70 square feet on the first floor, or 90 to no square feet on the second or third floor. A \y 2 inch pipe will supply 100 to no square feet on the first floor or 150 to 160 square feet on the second or third floor, and the main flow pipe from the furnace must have an area equal to the combined area of all radiator connections. An installation of this kind is known as a circulating job, and no radiators or pipes are valved. The radiators are employed in exactly the same manner as would be a storage tank for do- mestic hot water use. If the radiators were valved and the valves should be closed, the excess of heating surface would boil the water in the system. The cooling surface of the radiators pre- vents this happening when they are in service. Another method of installing an auxiliary hot water apparatus is illustrated by Fig 88, which shows a cast iron auxiliary heater AUXILIARY HEATING 145 employed within the furnace. The piping system shown in the illustration indicates another of the several methods that may be used. The expansion tank is connected from the high point of the system, and therefore air valves on the radiators are not re- quired, as all air in the system passes to the atmosphere through the expansion tank. It is well that the furnace man should become acquainted with the methods of estimating and installing auxiliary heating systems, as they are frequently desired by the house owner. Auxiliary heaters are frequently employed for furnishing hot water for domestic use and are installed in connection with the kitchen boiler or storage tank. The piping is usually cross-connected with that from the kit- chen range and valved so that the auxiliary heater may be cut out during the summer season when the furnace is not in use. Fig. 89 illustrates an installation of this kind. An expansion tank is not required on a system of this kind, as the water is used under pressure, and a job of this character would be designated as a pressure system. The heating surface required in the furnace auxiliary heater is i square foot for each 20 gallons of water in the storage tank or kitchen boiler. CHAPTER XV TEMPERATURE REGULATION AND FUEL SAVING DEVICES The value of a good temperature regulator seems to be neither understood nor appreciated by the heating contractor. What the governor is to an engine the thermostat is to a fur- nace. The governor, attached to an engine, prevents the engine from "running away'' or speeding when the load or work it is doing is suddenly lightened, in other words, it regulates the speed of the engine automatically, preventing useless waste and possible danger. The thermostat or temperature regulator, attached to a furnace, prevents the overheating of the building and consequent waste of fuel. It also prevents possible damage due to overheating the furnace. There are some features of temperature regulation which, if brought to the attention of the house owner in a convincing manner, should effect a ready sale of an appliance of this nature, as little necessity exists for argument on the part of the furnace man when such features are made known. We have mentioned the saving in fuel, which may be effected by a system of thermostatic control. The health of the occupants of the home, and the comfort experienced, may also be considered as desirable features of temperature regulations. A brief argument in favor of the thermostat may be made by considering these three features : (a) Saving in fuel and consequent low cost of maintenance. (b) Healthfulness due to uniformity of temperature. (c) Personal comfort as a result of having a watchman (ther- mostat) in charge of the furnace, to open or close the draught doors at the required moment. Briefly stated, the work to be performed by the furnace may be considered as follows: Consulting a table of temperatures compiled by the United States Government, giving maximum and minimum temperatures of some thirty cities, and covering all sections of this country and Canada where heat is required in winter, we find that the average number of degrees the temperature is to be raised arti- ficially is 80. In Charleston, S. C., it is 47, while in Duluth, Minn., it is 108. TEMPERATURE REGULATION 147 The average winter temperature for the period we call "the heating year'' is a little under 40 F. As we have already re- marked, in this country we demand a temperature of 70 within our homes, and therefore we must raise the temperature approx- imately, an average of 30. It requires just so much heat, or the expenditure of just so many heat units to produce this result, and for every degree above 70, shown by the thermometer, there is a loss of fuel in a direct ratio to the increase in tempera- ture, and this loss at a low estimate is 25 per cent. Of the healthfulness due to a uniform temperature, it seems necessary only to state that all physicians and scientists, who have made a careful study of the subject, report and agree, that next to the proper ventilation of our homes, a uniform degree of heat is essential to the good health of the occupants. We are safe in saying that few colds, and few of the more serious diseases so prevalent in winter, will be experienced, if a uniform temperature is maintained in the home. Finally comes the question of personal comfort. It has been stated that this is the age of personal comfort, "the automatic age" and "the electrical age." It is now that the furnace man may deliver the solar plexus blow the final argument. The period when artificial heat is necessary comes as regularly as the time when food is necessary to sustain us, and the per- sonal comfort, due to the work of the thermostatic watchman in attending the furnace, cannot well be calculated. We may repeat what we had occasion some time ago to re- mark regarding the thermostat. "It is a boon to the busy man and a delight to the lazy man, and is more than self-sustaining, paying for itself in a season or two, after which it earns money for the owner at a rate never excelled by the best savings insti- tution." Arguments and facts such as these, when brought to the at- tention of the users of hot air furnaces, should make possible the sale of a good many thermostats, and materially add to the business of the furnace dealer. Fuel Saving Appliances Each pound of anthracite coal when used for fuel in a furnace gives off approximately 14,500 heat units. About 10,000 of these are available for heating purposes, the remainder being utilized principally in warming the air in the chimney flue to produce sufficient draft to carry off the smoke and products of combus- tion. 148 TEMPERATURE REGULATION In considering the question of economy in fuel we may say first of all that it is a poor policy to select a furnace with a grate so small that it is necessary to keep the fire in a continual state of activity to properly heat the building. The frequent "stirring up" of the fire by a shaking of the grate and the addition of more fuel are as wasteful as they are unnecessary. With a fur- nace having a grate of adequate size, or perhaps a little larger than is absolutely essential, the very best result is obtained in the way of economy, provided the heater is fired in an intelligen! manner. There is great waste in intermittent firing. By this we mean the opening of the draft door of the furnace, forcing the fire to greater activity and allowing the building to become over- heated, requiring the opening of the windows. The coal should be permitted to burn just enough to give ofif the required heat units to keep the building warmed to the desired temperature. This can be accomplished only by the use of some good system of temperature regulation which will automatically control the fire by opening and closing the draft and check dampers of the heater. The appliances to perform this work are called "regu- lators" or "thermostats," and there are many good and reliable kinds to be had. It will be impossible here to illustrate and describe all of the various makes, and therefore we shall select several of those most commonly used, showing the manner by which they ac- complish the service demanded of them and for which they are intended. It will be of interest to our readers to know some- what of the history of temperature regulation, or of the inven- tion and application of methods for automatically controlling the drafts of a heating apparatus. A device for this purpose was invented by a Frenchman, named Du Moucelle, of Paris, in 1853. The first practical temperature regulator in this country was invented in 1883 by W. S. Johnson, of Milwaukee, Wis., who placed it on the market in 1884. Some four years later W. P. Powers (then in the plumbing and steam fitting business), of La Crosse, Wis., devised a vapor thermostat for operating the draft doors of a furnace. At about this time (1885) an electric thermostat was devised in Minneapolis, Minn., and later put on the market by the Elec- tric Heat Regulator Company. This regulator in an improved form we shall later illustrate and describe. These regulators and thermostats have been followed by num- erous other varieties, all of which may be divided into two gen- eral classes, viz., electric and non-electric. In the list of the AND FUEL SAVING 149 electric thermostats and regulators are included the Minneapolis, Jewell, Beckam, Beers, Honeywell, and among the non-electric we find the Johnson, Powers, Regitherm, Howard, National, and others. Many of the automatic regulators en the market are used principally for the control of steam and hot water heating ap- paratus, for the control of gas and liquids, and for the control of water and other liquids in tanks. This latter is styled "tank control." We shall consider and describe only those which are especially used for the control of a furnace those whose operation is di- rectly governed by the temperature of the air within a room of a residence or similar building. Electric Regulators The Minneapolis, Honeywell, Jewell, Beckam and Beers regu- lators make use of devices for the electric control of the ap- paratus, which are quite similar in the operation performed. This appliance is placed on the wall of one of the principal living rooms of the residence. Fig. 90 shows the device as used with the Minneapolis regulator. Fig 91 shows the device with its shield or cover, on which is mounted a mercury thermometer. It consists of a frame holding a piece of metal in the form of a loop or ring with a tongue or strip of metal suspended from the bottom of the loop. One end of the loop is attached to the frame, the other end and the suspended tongue hanging free. The slightest change of temperature will expand or contract the ring causing a side movement of the suspended tongue or arm. An electric battery (consisting of two or three cells of dry bat- tery) is used to generate the electric current through two wires, which are attached to posts or pins located one on either side of the suspended arm. Small thumb-screws or pins are set in these posts, so adjusted as to allow the points to almost touch the sus- pended blade. As the temperature of the room rises the loop expands throwing the blade against one set screw closing the . electric circuit and operating the motor or driving power of the thermostat, which, in turn, operates the draft of the furnace by closing the draft door and opening the check door. When the temperature of the room has lowered the blade gradually works over against the pin on the opposite side of the frame. The action of the motor is then reversed and the draft door is opened and the check damper closed. The driving power or motor of the Minneapolis, shown by Fig. 92 consists of a strong spring within the motor which is 150 TEMPERATURE REGULATION wound up like the spring of a clock. Two arms or cranks point- ing in opposite directions work the chains connected with th<> draft doors. Fig. 90 Thermostat with Screen Removed. Fig. 91 Thermostat with Screen Attached. The motor of the Beckam, Fig. 93, and also that of the Honey- well regulator, is operated by a ball weight attached to a chain which is run over a sprocket pulley wheel and is wound or drawn up in much the same manner as the weights of an old-fashioned Swiss clock. The Beers regulator uses two weights, each hung by a pulley wheel, as shown by Fig. 94, which figure also illustrates in a general way the method of adjusting the chains to the draft of the furnace. Non-Electric Regulators We will now consider some of the non-electrics, among which are found the Powers and Regitherm. There are other non- electric thermostats in the market, many of them being used only with a steam or a hot water heating apparatus. Those mentioned here will be sufficient, however, to show some of the methods employed. AND FUEL SAVING The Powers thermostat operates on the vapor principal. On the wall of one of the living rooms of a residence is located a metal disc composed of two plates fastened together at the edge. This is about 12 inches in diameter, and about I inch thick. Fig. 9 The metal of the plate is spun in corruga- tions to give flexibility. A liquid is placed within the disc which will vaporize at a very low temperature, and which gen- erates a pressure within the disc. Fas- tened to the back of the disc, and open- ing into it, is a small hollow tube. Through this tube the pressure of the vapor is conveyed to a diaphragm motor located above the furnace. The pressure en the disc of the diaphragm lowers the arm, to the end of which the draught doors are connected by chains. This movement closes the draught door and opens the check damper of the furnace, checking the fire. As soon as the room cools, the pressure on the diaphragm is removed. The arm of the motor then returns to its former position, closing the check and opening -the draught door of the furnace. Fig. 95 shows the diaphragm motor of the Powers regulator and the method of attaching same to the furnace. It is held in position above the furnace by a pipe rod, attached to ceiling. The small hollow pipe, conveying the power from the thermostat to the motor, can be seen as it passes through the space between floor and ceiliing, and thence along the ceiling to point above the motor, where it drops, and is connected into the upper side of the diaphragm. The Regitherm is a temperature regulating device, entirely different in principle from any of the others. The thermostat and motor are combined into a single instrument which may be called I5 2 TEMPERATURE REGULATION a thermal motor. Fig. 96 will give a general idea of its appear- ance. The vital part or motor consists of a closed metal bellows, so constructed that it readily expands and contracts along the line of its axis. A cross section of the folds is roughly shown by Fig. 97. The theory of this construction is that strain is brought on the point marked A, and no bending occurs at B, which is the point of greatest weakness. Fig. 94 Beers Regulator Attached. This bellows contains a quantity of volatile liquid, extremely sensitive to minute variations of temperature. The bellows is rigidly attached at one end to the frame work, and at the other to a lever, which is moved up and down by the expansion and contraction of the bellows. A unique feature of the device is the fact that the power to adjust the dampers is derived entirely from the changes in tem- perature of the air of the room in which the Regitherm is lo- cated, and the movement of the bellows is communicated to the AND FUEL SAVING 153 dampers of the furnace by means of a small steel wire or cable passing over pulleys and connected to a lever above the furnace. Unlike most of the temperature regulators, the Regitherm does not accomplish the desired result by the alternate opening and closing of the dampers. Some intermediate position is assumed, and a slight shifting of the dampers takes place whenever the temperature conditions in the rooms above are changed. It may be set to control the temperature at any point between 60 and 80 degrees. Fig. 95 Diaphragm Motor Attached to Furnace. We have given somewhat of the history of temperature regula- tion, and quite fully described some of the various apparatus, in order that the furnace man may post himself regarding the sub- ject and also gain a general knowledge of the apparatus used, and the methods adopted to automatically control the work of the furnace. It is a part of the furnace business which has been neglected, and for no apparent reason. The average type of regulator is easily installed, reasonable in price, and its sale can be made a profitable and desirable adjunct to the furnace business. 154 TEMPERATURE REGULATION The value of a good temperature regulator seems to be neither understood nor appreciated by the heating contractor. What the governor is to an engine the thermostat is to a fur- nace. The governor, attached to an engine, prevents the engine Fig. 96 Thermal Motor. from "running away" or speeding when the load or work it is doing is suddenly lightened, in other words, it regulates the speed of the engine automatically, preventing useless waste and possible danger. Fig. 97 Principle of Constructing Thermal Motor. The thermostat or temperature regulator, attached to a fur- nace, prevents the overheating of the building and consequent waste of fuel. It also prevents possible damage due to over- heating the furnace. AND FUEL SAVING 155 By selling and attaching temperature or automatic damper regulators the furnace man not only provides the means of safety and economy to the owner, but in so doing adds another branch to his business which will materially increase the profits of the same each season. How to Sell Thermostats We have mentioned three arguments in favor of temperature regulation, economy, healthfulness and comfort. These fea- tures of economy and satisfaction are prominent factors to be considered. Thermostats are easily sold when their merits are brought to the attention of house owners in the right manner. Practically no argument is necessary on the part of the heating contractor to effect the ready sale of a thermostat when the convenient and economical features above referred to are made known to him. Considering the first feature, that of economy, we may say that one shovelful of coal saved daily for the heating season will approximate one ton saved for the season. Intermittent firing or coaling of the heating apparatus is one of the wasteful items to contend with. Remembering how frequently it has been neces- sary to coal the furnace, due to forgetfulness in leaving the draf \ doors open, the owner will readily understand the situation when the statement is made that the use of any good system of tem- perature regulation will save from one-quarter to one-third of the fuel ordinarily consumed when operating the furnace with- out such a device. How can we show the owner that this saving is possible ? There should be no trouble in proving to the owner that intermittent firing is costly. We have already referred to the temperature bulletin issued by the U. S. Government, which shows a wide variance of the demands for heat; it being necessary in certain portions of the extreme north to raise the temperature frequently through 80 to 100 degrees, while in southern cities, for instance in Charleston, S. C, it is necessary to raise the temperature an average of 47 degrees. When we consider that a change of 10, 20 or 30 degrees, up or down in the temperature, frequently takes place within a few hours time and that the regulator will condition the fire in the furnace to accommodate this sudden change, we can understand that automatic regulation will effect a great saving. In this country a week of solid cold weather is the exception rather than the rule. In Canada the week of mild weather in winter is the exception rather than the rule. Consequently, we have very much more need of temperature regulation in the United States than they have in Canada. 156 TEMPERATURE REGULATION Of the second feature, healthfulness, we need add but lit- tle in addition to what has already been said, as all who have investigated the subject know the desirability of keeping the temperature uniform within the home. Uniformity of tem- perature is considered as necessary as is ventilation or heat- ing. The next feature to consider is personal comfort, and here is the chance for the delivery of a telling and conclusive argu- ment. In business, as well as in pleasure, this age is spe- cialized with automatic devices. Think of the number of automatic devices which increase the efficiency of business, and the intensity of pleasure. Then why not automatic per- sonal comfort? Doesn't that sound good? The heating sea- son comes just as regularly each year as does dinner time each day. The comfort and convenience of having an automatic watchman in charge of the furnace to open and close the drafts as required, is an argument which ought to appeal as well to the busy man as to the seeker after personal comfort. The Cost of Heat Regulation Automatic temperature regulating devices cost the owner from twenty-five to fifty dollars, according to the character and make of the device. At the price named there is a fair profit to the furnace contractor for installing the same. As a matter of fact, the thermostat really costs the house owner nothing, for it saves many times the interest on the investment each season until the saving made pays the cost of the installation, after which it earns money for the owner at a greater rate than any ordinary business investment he may have. It would seem then that the cost whether twenty- five or fifty dollars is not prohibitive. In fact, it should not be considered when the economical, healthful and comfort- able features brought about by its use are known and appre- ciated. How to Attach Thermostats It is possible that the failure to sell and install more thermo- stats is due to fear, on the part of the heating contractor, that he may not be able to install the apparatus correctly. If it is a fact that the furnaceman is letting slip this oppor- tunity to better his work and add to his profits through ignor- ance of the construction and method of installation of auto- matic heat regulators, a very little investigation of the subject will show that the average thermostat is quickly and easily attached and adjusted. AND FUEL SAVING 157 All thermostats have a positive and a negative action of the motor or other mechanism which controls the drafts. This positive or negative action of the motor or other mechanism opens or closes the draft and check doors automatically in con- junction with each other, the check damper opening as the draft door closes, and vice-versa ; therefore no matter what type of a thermostat is to be installed it must be attached in such a manner that the draft and check doors will operate together, and to accomplish this result the chain connections to the doors are run over pulleys hung from the joists above the furnace and con- nected in the most simple manner. 1 MOTOR ioo\ j CHECK Fig. 98 Method of Attaching a Minneapolis Regulator. Fig. 98 illustrates a method of connecting the Minneapolis Regulator. The driving power of this thermostat is a motor operated by a strong spring and its approximate location is shown on the sketch. Note that in order to prevent the sagging of chains between pulleys a wire is employed, to which the ends of chains running over or through the pulleys are attached. Fig. 99 illustrates the manner of attaching a Honeywell Regu- lator to a hot air furnace. The driving power of this regulator 158 TEMPERATURE REGULATION is a motor operated by a weight. This weight is suspended by a chain, the links of which fit over the teeth of a sprocket, and the winding up of the motor consists of pulling up the weight much as one would wind an old fashioned grandfather's clock. Practically all of the so-called electric thermostats make use of two cells of dry battery for supplying the current for con- trolling the motor, and through this the drafts of the furnace. CABLE JO THERMOSTAT MOTOR Fig. 99 Method of Attaching a Honeywell Regulator. Three copper wires of a size simiar to that used for connecting door bell batteries are insulated in red, white and blue covering and encased in the form of a single cable. These wires are attached to various parts of the thermostat where directed, and the cable then extends down to the basement, and to the motor of the regulator, where the wires are separately connected to certain parts of the motor. The cells of dry battery should be connected together as shown by Fig. 100 which represents the top of the cells. The white covered wire in the cable should be attached to the bat- teries as indicated on the sketch. The wiring of all thermostats and regulators is practically the same, and the regulator is now ready for adjustment and attachment to the furnace. AND FUEL SAVING 159 In this connection we desire to speak of the check damper of the furnace. The check damper door of many furnaces is in- accessible for use with a regulator and also is frequently not of proper construction. When this is found to be the case it is best WIRES TO MOTOR- Fig. 100 Method of Connecting Dry Battery. to employ a specially designed balanced check damper, as illus- trated by Fig. 101. This check damper should not take the place of the regular smoke pipe damper, which should continue to be used and which should be located at a point in the smoke pipe between the furnace and the check damper. It would be quite impossible in a brief article to describe the manner of installing all thermostats now on the market. We can 101 Balanced Check Damper. say, however, that all are substantially alike in principle and are easily attached when this principle is clearly understood. Automatic Draft Regulators Before leaving the subject of temperature regulators we desire to call attention to another type of device for handling the drafts of the furnace. We refer to a device for putting the drafts on the heater at some pre-determined hour of the morning. i6o TEMPERATURE REGULATION Fig. 102 illustrates one type of such apparatus and Fig. 103 another type. These devices are known as draft regulators, although, strictly speaking, they do not "regulate" the draft. Fig. 1 02 "Mono" Type of Regulator. The office of this type of regulator is to automatically close the check damper and open the draft door of a heater in the morn- TO DAMPCRS Fig. 103 "Peerless" Type of Regulator. ing, thus allowing the fire to burn and the rooms to become warm that the family may rise and dress comfortably. AND FUEL SAVING 161 Operation and Installation An ordinary type of alarm clock is the medium by' which this type of regulator is controlled. Assuming that it requires about an hour to heat the house comfortably and that the hour of arising is seven o'clock, the heater is coaled in the evening before retiring and the dampers Fig. 104 Controlling Drafts from Living Room. are then closed. The alarm clock is then wound and set at six o'clock. There is no alarm on the clock, but in its stead the mechanism of the clock trips a little lever which allows a weight to fall a distance of twelve to fifteen inches. Chains are attached to this weight, which connect with the drafts of the heater, and when the weight falls these chains open the draft door and close the check damper. This has been called an invention for a lazy man. We think, however, that the method of running the apparatus with drafts closed at night and opened automatically in the morning will appeal to any person who realizes the health fulness of sleeping in a cool room and how comfortable it is to rise and dress in a warm room. Aside from these features, the use of such a device will cause a considerable saving in fuel,, 1 62 TEMPERATURE REGULATION Chain Control of Drafts A simple method of controlling the drafts of the furnace from one of the living rooms on the first floor should also be provided as an accessory to the furnace. A rod of light weight iron may be hung from an arm located above the furnace and the draft doors of the heater connected to this rod by means of chains. From one end of the rod, a chain, passing over pulleys, is connected to a plate located against the base-board, in a room above the furnace, by a hook on the end of the chain, and an eyebolt on the plate. Hooking the chain to the upper eye opens the draft doors of the furnace and lowering it to the bottom eye closes the drafts. Fig, 104 shows the method of making this attachment. The ornamental plate may be of cast iron, bearing the name of the heating contractor and is a standing advertisement for him. Some furnace manufacturers furnish similar plates and chains, but we find that these are seldom made use of by the furnace men. It is the consideration given by the live furnace contractor to devices of the above description that makes for success, and marks his work as above the average in the consideration of the house owner and possible customer. CHAPTER XVI FUEL: ITS CHEMICAL COMPONENTS AND COM- BUSTION To the great mass of people coal is known simply as coal anthracite or bituminous hard or soft. Most users of coal as a fuel for heating or cooking accept of conditions as they are found locally, and burn the fuel found or more properly sold in the local market, without regard to its value as a heat produc- ing commodity. To such people a ton of coal is simply a ton of coal nothing more. We wish to discuss this question, and try to determine and make clear what preparation is necessary to properly burn cer- tain kinds of fuel in the hot air furnace. The principal factor of value in coal for use as a fuel for heating is the amount of fixed carbon it contains carbon being the principal heat producing matter in all fuels. It is said by those wizards of the present age, the chemists, that all coals contain two exactly opposite matters, namely : com- bustible or heat producing matter, and non-combustible or non- heat producing matter. They sub-divide these matters ai follows : Combustible Matter Volatile Matter (Gas) Fixed Carbon (Coke) Non-combustible Matter : Moisture (Water) Ash (Refuse) In addition to the above, there is present a rank impurity called sulphur. This is sub-divided as follows: (a) Volatile sulphur, which disappears in the smoke and products of perfect combustion ; and (b) Iron pyrites or sulphuret of iron, which causes the coal to clinker and run on the grate bars. To deviate a little from the subject, we desire to say that many of our readers live in localities where a fuel is burned which is mined locally, and where these last conditions are particularly 164 COMBUSTION OF FUEL noticeable. For instance, in certain sections of Illinois a coal is mined and used which is fed to the furnace or stove in large chunks. A short time after the coal has been supplied to the furnace or stove, and while the large chunks are still intact, a slight rap with a poker or slice-bar will cause it to separate or break into small pieces, and after burning for a period it be- comes semi-liquid and can be stirred on the grate like a mass of molten lava. A like condition is found in certain varieties of coal mined in West Virginia, Ohio, and some other localities. Another condition, due to the presence of iron pyrites in some varieties of coal, is the fusing or attaching of particles of ash and partially burned coal into a mass of clinker. This is par- ticularly noticeable in furnaces or heaters not properly con- structed to admit of perfect combustion of the fuel. Returning to the consideration of the chemical analysis of coal, as given above, we may say that all coal contains gas, coke, water, sulphur, and refuse, and for all purposes the coal which con- tains the most fixed carbon (coke), together with the greatest percentage of volatile matter (gas), is the most valuable for use as a fuel. We say "for all purposes," as the great mass of users of coal as a fuel fail to consider that certain varieties of coal are best adapted for certain kinds of work. The proportions of volatile matter and fixed carbon, as found in some varieties of coal, seem to have been blended for certain uses. Some anthracite coal is very rich in carbon, containing pos- sibly 85 to 90 per cent., and low in the percentage of volatile matter (gas) ; does not clinker, and when once thoroughly ig- nited will burn for a long period. These features make it par- ticularly adaptable for use in stoves, furnaces, and other heat- ing apparatus. Some cannel coal is so full of gas and so low in carbon, con- taining as high as 60 per cent, of volatile matter, that it can be lighted with a match. While speaking of cannel coal, we may mention the fact that the word "cannel" is a corruption of the word "candle." In Lancashire, England, the name "candle" was first given to this variety of coal owing to the fact of its being easily lighted, and that when kindled it burns with a highly luminous yellow flame, much like a lamp, without melting. The Lancashire pronunciation of the word candle is "cannel," and in England and Soctland the farmers used this coal for candles hence its name. COMBUSTION OF FUEL 165 Experience has taught us that it is unprofitable to burn an- thracite coal under boilers used for power, and that where the generation of steam is the main object sought, we should use a coal with a good percentage of fixed carbon and a fairly large Dercentage of volatile matter, or gas, as such coal contains a larger amount of heat units than any other combination or blend- ing of these elements. On the contrary, it has been proven conclusively that anthracite is far superior to any bituminous coal for use in a stove or heating apparatus, owing to the larger percentage of fixed carbon and the smaller percentage of vola- tile matter contained in k. This may seem strange to those who have not studied the sub- ject, and yet it is easily accounted for. When under a factory or other power boiler, the best and most economical results are obtained from burning the largest possible number of pounds of coal per hour on each square foot of grate, and a blower is frequently used to supply large quantities of air, and thus stimulate combustion in order to accomplish this result, when the latter conditions prevail, we demand a slow rate of combustion and try to burn as little coal per square foot of grate per hour as possible to maintain the desired temperature. Tests have shown that certain manufacturing needs demand a certain grade of coal that for each different kind of coal there is a specific manufacturing or commercial need. We have compared anthracite and cannel coal as being the extremes in the percentage of fixed carbon and volatile matter contained. There are several kinds of coal which may be classi- fied between these two varieties. These may be classified as follows, the percentages given being a fair average: Kinds. Volatile Matter. Fixed Carbon. Anthracite 7 per cent. 85 to 90 per cent. Semi-Bituminous 18 per cent. 75 to 80 per cent. Bituminous 24 per cent. 70 to 72 per cent. Semi-Gas 30 per cent. 60 to 65 per cent. Cooking 33 per cent. 58 to 60 per cent. Gas 37 per cent. 55 to 58 per cent. Our discussion of fuels would not be completed without say- ing a few words about coke. Coke is a brittle, porous solid. It is a dark gray in color, and is artificially manufactured by a process called "coking," which consists in expelling all of the volatile matter (gas) fromi bituminous coal, this process being usually carried on in ovens made of firebrick. Charcoal is introduced into the top of the oven and, being lighted, a little air is admitted through openings 1 66 COMBUSTION OF FUEL in the front. When the coal in the oven ceases to emit smoking 1 vapors the supply of air is cut off, and the oven allowed to cool for a day or two. A door in the front of the oven is opened, and the hot coke is then raked out. Water is thrown upon it to stop further combustion. A net ton of coal (2,000 pounds) will make from 1,000 to 1,600 pounds of coke, depending upon the character of the coal. Coke does not smoke when burning, and gives off a large amount of heat. As we are considering the relative value of different varieties of coal as a fuel for heating apparatus, rather than the value of the coal as a commodity, this latter subject has no place in our discussion, and yet there is one thought to which we wish to call attention. As stated, from 1,000 to 1,600 pounds of coke are available for each 2,000 pounds of bituminous coal thus converted. By inquiry at any gas-making establishment gas-works we call it where coal-gas is produced, our readers will find that about 10,000 cubic feet of gas are obtained from 2,000 pounds of bituminous or coal-gas. When we consider the value in heat units, or as a heat producer, of 1,000 to 1,600 pounds of coke plus 10,000 cubic feet of coal-gas, we may learn something of the real value of one tone of bituminous coal. To burn coal, coke, gas, or any other fuel it is necessary to mix* oxygen with it. Therefore it is necessary to admit a suffi- cient amount of atmosphere to supply this oxygen. The car- buretted hydrogen (gas) and the carbon of the fuel must each be supplied with the necessary amount of oxygen, and be kept at the required temperature to produce the chemical action neces- sary for perfect combustion. Some idea of the volume of air necessary may be obtained by considering the statement that for the complete combustion of the volatile constituents of a ton of coal 100,000 cubic feet of air is required. This is figured from certain definite data, which show that we are obliged to make use of five cubic feet of air to supply one cubic foot of oxygen, and to obtain 20,000 cubic feet of oxygen, the amount necessary for the complete combustion of a ton of coal, requires five times twenty or 100,- ooo cubic feet of atmosphere air. The admission of too little air will allow much of the gas to pass off unburned, and the admission of too much air will cool the fire or combustion chamber of the furnace and reduce the temperature, thus preventing perfect combustion. From the above statement, it is evident that in order to obtain the best resuts form the fuel used, we must build our furnace in such form that the gases or volatile matter in the fuel can be COMBUSTION OF FUEL 167 properly ignited and burned, and from this, also, we may es- tablish the fact that a furnace which will give good results with Pennsylvania anthracite as a fuel will prove a flat failure with Illinois bituminous coal. It is entirely a matter of proper furnace construction, taking into consideration the character of the fuel to be used and the locality where the furnace is to be installed, and in our considera- tion of the construction of furnaces as best adapted for burning certain grades of fuel, we shall neither discuss the production of the apparatus from the standpoint of the manufacturer, nor cover the merits of any particular type of furnace. The several simple sketches, Figs. 105, 106 and 107 illustrate the three general methods employed in furnace construction to provide a means for the passing off of the smoke and products of combustion, and there are many forms and variations of each idea. Fig. 105 represents the direct method and involves a direct passage into the smoke flue of the products of combustion. By it all air moving through the furnace is warmed by the direct radiation of the heat from the fuel consumed. All furnaces of this type are wasteful of fuel, and yet there are certain grades of coal, full of iron pyrites, sulphur and other impurities, which can be successfully burned only in -a furnace of this kind. In any other type the tarry smoke will encrust the heating surfaces of the furnace, rendering them practically useless, or what is still worse, will completely clog the flue passages through it. Fig. 106 illustrates the semi-indirect plan of furnace construc- tion, and it is safe to say that ninety per cent, of the manufac- turers adopt this method or some form of it in their type of warm air apparatus. It is well known that in order to success- fully burn a large percentage of the coal gas or carburetted hydrogen, it must be retained within the fire chamber until suf- ficient oxygen can mix with it to produce combustion. This means that for every cubic foot of coal gas extracted from the fuel, two cubic feet of oxygen must be applied or enter into union with it to cause perfect combustion, and, as stated in the precious chapter, it will be remembered that in five cubic feet of reasonably pure air there is present but one cubic foot of oxygen. Hence, to properly consume a cubic foot of coal gas requires the admission of ten cubic feet of air into the fire chamber of the furnace. Now, in order to do the work advantageously this supply must be admitted at a certain time, a certain place, and in a certain manner, and it is by reason of these essential require- ments that the goods of so many manufacturers of furnaces 1 68 COMBUSTION OF FUEL have "fallen down" on efficiency tests. As stated before, too little air will not prevent the gas from passing off unburned, while an overabundant supply will cool the fire chamber too much and retard combustion. In the effort to retain the gas within the furnace until it shall be consumed, the manufacturers use some form of the indirect method illustrated by Fig. 106, although this effort is exerted in vain unless other matters are also provided for at the same Fig. 105 Construction for Indirect Draft. J COMBUS Tl'ON CHAMBER GHATE ASH PIT i Fig. 106 Construction for Direct Draft. time. An active fire will produce a cubic foot of coal gas very quickly. Suppose the rate of combustion is four pounds per square foot of grate per hour, and the size of grate three square feet. The hourly consumption of coal in such a furnace would be twelve pounds. If we consider bituminous gas coal as a fuel (10,000 cu. ft. gas to a ton of 2,000 Ibs.), the coal burned will produce about sixty cubic feet of gas per hour, each pound of fuel burned giving off five cubic feet of gas, and requiring f.'fty cubic feet of air to consume it. Now, we have said that the air must be admitted at a cer- tain place, time and manner. The place should be at a point just above the normal level of the fire in order that the air may mingle with the gases arising from the fuel. The gas ring ap- pliance usually included, and shown on Figs. 105 and 107, is made of cast iron. A fire-pot may be provided with firebrick lining so set, or held in place, as to provide an air space between COMBUSTION OF FUEL 169 the brick and the outer iron cylinder, the air passing upward from the base and into the fire chamber through small holes in the lining, as illustrated by Fig. 108. The proper time for the admission of this air is when the gas is burning off from a fresh charge of cool, because probably eighty-five per cent, of all gas in the coal burned is given off during the hour following the time that the additional fuel is added, provided the draught is on the furnace. The manner in which this air should be admitted is in small sprays above the fire, and its temperature should be practically the same as that of the gas. When the supply is taken in through a gas ring, or through the top of the firebrick, as shown by Fig. 108, its velocity is about four times as great as that of the air passing in the lower draught door and upward, and should this volume of air move upward through the coal, the rate of com- bustion would be so rapid that a large share of the gas would pass out of the smoke pipe unconsumed. Fig. 107 Construction for Semi-Indirect Draft. The principle shown by Fig. 107 is used in the construction of furnaces for both hard and soft coal. The indirect method illustrated by Fig. 106 is adapted more particularly to building furnaces for hard or anthracite coal, and a wonderful variety of forms and ideas is followed by manufacturers in carrying out the principle shown. The per- centage of volatile matter in anthracite coal is so small that little or no attention is given to burning the gases. Combustion is not so rapid as with soft coal, and any air admitted above the fire has a tendency to chill it. The temperature in the fire 170 COMBUSTION OF FUEL chamber should be high, in order to provide for complete com- bustion, and the firepot for burning anthracite should be almost straight up and down or possibly a little larger in diameter at the grate line than at the top; also, its surface should be cor- rugated. 6/tATS Fig. 1 08 Fire Pan with Air Holes in Lining. By considering the foregoing facts regarding the furnace con- struction we shall accept the following definite conclusions : (a) That furnaces should be selected according to the character of the fuel to be used. (b) That the gas or volatile matter in all coal other than anthracite is of greater value than the carbon (coke) for heat- ing purposes. (c) That, in order to utilize the greatest number of heat units in bituminous and semi-bituminous coal, it is necessary to make proper provision for burning the gas first and. the coke last, or, stated in another form, to appropriate the full value of the gas for heating, retaining the coke for rekindling requirements. (d) That the loading of a fire with fresh fuel obstructs the volume and velocity of the air admitted through the grate, mak- ing it necessary to inject a sufficient quantity of air above the fire to properly burn the gases. (e) That unless this deficiency is provided for all com- bustible gases, such as hydrogen, carburetted hydrogen, and carbonic oxide, will escape up the chimney flue, the smoke plainly indicating the loss sustained. (f) That in introducing heated, and consequently rarefied air, into the combustion chamber of the furnace in small jets, through a gas ring, or perforated firebrick, a sufficient supply of oxygen can be admitted without cooling the gases and perfect combustion obtained from the thorough mixture of the oxygen with the gases. As an all-important part of a furnace, the grate should be of such shape and character that the ashes may be removed from the firepot without stirring up the body of unconsumed coal COMBUSTION OF FUEL 171 lying above them. The nature or size of the opening between the bars has little to do with a greater or lesser consumption of coal. The grate is simply a cradle which holds the fuel and the amount burned is governed by the quantity of air passed through the grate. It is possible to consume the fuel without benefit, under which circumstances, of course, the combustion will not be perfect, and while the fire appears dead or passive, yet more fuel is burned than would be the case if the combustion were positive and the fire active. The remedy for such a condition is found in the admission of air oxygen in the right place and manner and in sufficient quantity. Coal : The Universal Fuel A brief narration of the facts regarding the discovery and development of the coal deposits of the world, and particularly those of the United States, will prove interesting to all persons connected with the manufacture and installation of heating ap- paratus. Coal is the universal fuel, and without its use it is doubtful if the nations of the world could have made such progress in manufacture and civilization as history has recorded. We are accustomed to think of coal as being principally a product of the United States; and while it is true that we now lead all other nations in the tonnage of coal mined, this stand- ing has been reached only in recent years. We know that more than 2,000 years ago coal was an article of commerce in certain parts of the Chinese empire and had been known for years prior to that period. It is also recorded that coal was shipped into London in the year 1240. Virginia bituminous coal was mined as early as the year 1750 and in 1768 anthracite coal was mined in the Wyoming Valley, Pennsylvania, near what is now the city of Wilkes-Barre, and in the years 1770-76-91 coal was mined in other sections of Pennsylvania. It is related that in the year 1812 Colonel Geo. Shoemaker of Pottsville, loaded nine wagons of coal from the Schuylkill region and hauled it to Philadelphia where, with difficulty, he sold two loads and gave the other seven loads away. He was regarded as an imposter and with some trouble avoided arrest by getting out of the city. White & Hazard, owners of a wire-works at the Falls of Schuylkill, bought one of the loads and a whole night was spent by their workmen in efforts to make the coal burn. They gave 172 COMBUSTION OF FUEL up and quit their work, leaving the door of the furnace closed and one of the workmen returning for some forgotten clothing found everything red-hot. This effort to burn coal is exceedingly interesting when we consider that 100 years later (1912) the United States produced about one-third of all the world's supply, leading England by millions of tons and Germany, her next nearest rival, by a tonnage three times greater. As a matter of fact this great development has taken place \vithin the last forty years as the coal production in the United States in 1866 was less than 15,000,000 tons. CHAPTER XVII CEMENT CONSTRUCTION FOR FURNACE MEN When engaged in the business of installing warm air heating appartus the sheet metal worker should be independent of other contractors. In making this statement we mean to say that in order to reap the full benefits accruing from a contract the fur- nace man should install his work without the services of a car- penter or mason. He should be sufficiently familiar with the use of carpenters' tools to do his own cutting and framing, and he should also be able to construct foundations, cold air pits, and ducts, and to instruct his men how to build them without the assistance of a mason or cement contractor. The present period is sometimes called the age of cement, by reason of the fact that cement is now so generally used in build- ing construction of all kinds, and we desire to call attention to the proper method of mixing and using cement. A volume would be required to treat this subject in a thorough manner. We shall, however, in this brief article be able to show how to use cement successfully, and also to point out the rea- son why so many furnace men fail to obtain proper results when attempting to build pits and ducts of concrete. Concrete Mixtures All cement mixtures are not alike in strength or consistency. A certain mixture that might be best for one class of work would not do for work of another class. Mixtures of concrete of greatly different strength and costs can be made of the same materials, simply by combining them in different quantities. In our discussion of concrete mixtures we shall make use of two terms which should be explained. These terms are aggre- gates and voids. Aggregates are the solid and coarse ingredients which are bound together by the cement in making a mass of concrete. Materials such as sand, gravel, trap rock or crushed stone, cinders, etc., are known to cement workers as aggregates. Voids are the air spaces between the particles of aggregates which must be filled or removed from all cement work in order 174 CEMENT CONSTRUCTION to make the work substantial. For example, the voids in sand are rilled with cement and this mixture is used to fill the voids in gravel or broken rock. The ability to judge by sight or determine by test the propor- tions of materials for a cement mixture is gained only through long experience, and it is essential that the mixture be right for the work in hand. A certain mixture for a foundation pit or duct in a cellar which is always dry would not do for building a foundation pit or duct, which of necessity must be watertight on account of a cellar being wet at certain periods of the year, nor would a mixture suitable for building a sidewalk be right for use in constructing a cistern. Concrete mixtures are classified in two different ways. First as to richness, meaning the quantity of cement used, and sec- ondly as to consistency or wetness. When so classified a cement mixture is known as rich, medium, ordinary and lean. A i :2 14 mixture would be called a rich mixture. The formula I 12 14 indicates one barrel of cement (four bags to the barrel) to two barrels of sand, and four barrels of gravel or broken stone or other coarse aggregates. A I 12.5 15 mixture is one barrel of cement, two and one-half barrels of sand and five barrels of broken stone or loose gravel, and this combination of materials would be classified as a ''medi- um" mixture. A I 13 :6 mixture measured in like manner is known as an "ordinary" mixture, and a I 14 :8 combination of cement, sand and gravel as a "lean" mixture. In consistency the mixture may be "very wet," "medium wet" or "dry," the amount of moisture necessary depending upon the work for which it is intended. For use in building foundations and ducts for furnace work a "medium" or "ordinary" mixture "medium wet" is desirable, provided the pit or duct is not to be waterproof. If the pit or duct must be waterproof on account of a wet basement, or trouble at certain periods from surface water, the mixture should be a i :2 14 (rich) or a I 12.5 15 (medium), and in consistency, medium to very wet. Mixing Concrete There are several methods of mixing the concrete. The sand and cement may be mixed dry, and this mixture spread layer upon layer upon the broken stone, gravel or aggregate before the water is added, or the sand and cement may first be^mixed with water into a mortar, and this mortar then mixed with the CEMENT CONSTRUCTION 175 broken stone or gravel, after which, in either case, it should be turned with a shovel until a thorough mixture of the ingredi- ents is obtained, or until all particles of the aggregates are thoroughly coated with the cement paste. There are several kinds of cement to be had, the best for general uc2 being that called Portland. Fig. 109 Trowel for Round Corner Work. Portland cement consists principally of limestone and slag crushed separately and dried to remove all moisture, after which each ingredient is ground extremely fine. After being combined in a certain proportion this mixture is calcined or burned to a clinker. This clinker is then cooled, pulverized fine, and mixed with a certain quantity of gypsum, when it is ready for the storehouse, where it is kept free from moisture until shipped or supplied for use. The Tools For use in constructing cement ducts, pits and other work of like character, but very few tools are required and these are inexpensive. Fig. no Trowel for Square Corner Work. Other than a shovel, hoe and ordinary trowel there are a few tools which are useful and convenient. Fig. 109 illustrates a smoothing trowel for round corner work. Fig. no a smoothing trowel for square corners. Fig. in another form of a round corner smoothing trowel. Fig. 112 shows two forms of a tamper (a tool for tamping or pounding the cement mixture to remove the voids), which may be made from any heavy iron casting planed smooth on the lower side and to which a handle mav 176 CEMENT CONSTRUCTION be fitted. These tools and a leveling board and straight edge are all that the furnace man will require for the class of cement work he will be called upon to construct. Determining Quantities In connection with cement work the following data will prove useful in determining quantities : Fig. in Trowel for Another Form of Round Corner. A bag of natural cement weighs 94 pounds. A bag of Portland cement weighs 94 pounds. A barrel of natural cement equals three bags, and weighs about 282 pounds. A barrel of Portland cement equals four bags, and weighs 380 pounds. A cubic foot of crushed or broken stone weighs about 90 pounds. Fig. 112 Tools for Tamping. One bushel of cement and two bushels of sand mixed to- gether to form a cement mortar will cover 3^2 square yards one inch thick, or 6^4. yards one-half inch thick. (This rule applies for a smoothing mixture for use over rough concrete, brick or stone.) CEMENT CONSTRUCTION 177 Methods To make cement mortar (as above) adhere to old or finished cement work, the surface of the old work should be thoroughly soaked with water, then dust on a little neat cement, after which apply the mortar coat before the dusted cement has set. Another method equally as good is to mix a thick paint of cement and water and brush it carefully over the surface of the old work after it has been thoroughly wet with water; then apply the mortar coat quickly before the paint coat has set. It is not a difficult matter to construct good cement work if care is exercised in the selection and mixture of materials. Do not guess at quantities. All materials used should be carefully measured or weighed. CHAPTER XVIII. CONSTRUCTION AND PATTERNS OF FURNACE FITTINGS Including Bonnets, Collars, Elbows, Cold Air Connections, Register Boxes, Transition Boots, Shoes, Tees, Offsets, Etc. By WILLIAM NEUBECKER This chapter treats the various methods for develop- ing and constructing the many styles of furnace fittings, as well as the rule to be followed for finding the true angles of elbows from given dimensions. In designing the shape of any fitting care must be taken not to reduce the given area, but to have the same area throughout the entire fitting and to draw easy, graceful, frictionless curves to facilitate the flow of air. While there are many styles of fittings which can be purchased, having single as well as double walls, it is to the advantage of the furnace man to understand the method of developing the various pattern shapes, a knowledge of which will enable him to lay out any required shape or size. FURNACE FITTINGS Conical Bonnets or Hoods 179 The first subject to be taken up will be development of the bonnet or hood. A good type of a bonnet is shown in Fig. 113 with a deep deflector. The method of developing the net patterns for the bonnet and deflector is shown in Fig. 114 and is accomplished as follows : Draw any vertical line as A B, upon which set off the vertical hight of the bonnet as X E, bearing in mind to make this 3 inches higher than the largest size leader pipe to be taken from it (to give room for dovetailing the collar. Fig. 113 Typical Conical Bonnet with Deflector which Determines the Angle of Collar. Set off the half diameter of the casing as X C, also the half diameter of the top of the bonnet E G. Now extend C G until it intersects the center line at F. Using E as cented with radius equal to E G, draw the quarter circle G6, which divide into equal parts as shown. This quarter circle represents the plan on the line E G and would be the quarter pattern for a flat top casing minus the edges. Now using F as center with radii Quarter 2* Pattern of // Deflector SECTION B HALF ELEVATION Fig. 114 Developing Patterns for Bonnet and Deflector. equal to F G and F C, draw the arcs G 6' and C C 1 . On the arc G 6' lay off the girth of the quarter circle as shown by similar numbers G to 6'. From the center F draw a line through 6' i8o FURNACE FITTINGS intersecting the outer arc at C 1 . Then will C C 1 6' G be the quarter pattern for the bonnet, to which edges must be allowed for riveting and seaming. With radius equal to D. G, from D l as center, draw the arc i" 6". Set off on the arc i" 6" the girth of the quarter circle as shown, and draw the radial lines i" D 1 and 6" D 1 . This gives the quarter pattern minus the laps fcr the deflector. Fig. 1 16 Collars Joining a Straight Bonnet. ^-=s=^- jf Fig. 115 Spacing the Casing Rings. Fig. 117 Collars Joining a Flat Top Casing The left half of the diagram is constructive, showing the seaming of the deflector to the bonnet at H, and the seaming of the bonnet to the casing collar at J. When laying out the various patterns we must consider the width of the iron being used, so as to cut without having much waste. The casing collar or rim C is usually made about 3 inhces wide so as to fit the casing ring. Another way is to allow about an inch lap along the curve C C 1 in the pattern and after the full bonnet has been riveted together, crimp the bottom edge on a crimper until it fits the casing ring snugly. The deflected part of the bonnet is usually filled with sand, but sometimes an additional sand ring is seamed to the top edge at H, making it about 2 inches high, placing a wire edge along the top. The above rule applies to any size or pitch of bonnet. FURNACE FITTINGS 181 Furnace Casings Casings should be double as indicated in Fig. 115 and care must be taken that the casing rings are so placed that stock widths of iron can be used. The rings A, B and C should be so placed that the distances between will allow using sheets either 24, 26, 28, 30 or 36 inches wide without waste. When the casing rings are not correctly placed, it necessitates using short pieces cut across the sheets, thereby using time and labor and wasting material, and does not make as neat an appearance, as when the sheets are rolled up lengthwise. The circumference of the casing is obtained by the use of a narrow strip of meH\D \ ^ V H-4 Fig. 137 Patterns for T-Joint Between Pipes of Unequal Diameters at Other Than a Right Angle. Fig. 134 shows a view of a T joint where the three openings have equal diameters. The rule employed for developing the patterns is explained in connection with Fig. 135, in which an elevation of the joint is shown. When the sizes of the two 194 FURNACE FITTINGS branches are the same, no projections of points are required in finding the miter line; all that is required is to intersect the centers of the two branches as at D and then draw the miter lines C D E. The pattern for the branch A is obtained in the usual manner. The girth of A is placed at right angles to the lines of the pipe as shown, the usual measuring lines drawn and intersected as shown resulting in the pattern for A. The shape of the opening to be cut in the main pipe B is obtained by taking one half of the girth of pipe as indicated by a b c (or 3 to i to 3 in the profile for A, since both pipes are similar) and placing it at right angles to B as shown, and then intersecting the measuring lines from the divisions in the pro- file, all as shown. This short method can only be followed when the two branches have the same diameters. Fig. 136 shows a round header with lead off collars at a and b. The principles shown in Fig. 135 can be applied to Fig. 136. T Joint Between Pipes of Unequal Diameters at an Angle When a branch is to be taken from a main pipe at an angle, the branch being of smaller diameter than the main, the rule to follow regardless of what the diameters or angle may be, is shown in Fig. 137 in which A and A 1 show the profile of the branch pipe and B the profile of the main. D C shows the side view of the T, the branch C in this case being placed at an angle of 45 degrees. First divide both profiles A and A 1 into the same number of equal parts, placing the numbers in the posi- tion shown. From the points in A 1 draw lines parallel to the lines of the pipe until they intersect the profile of the main pipe as shown, from which vertical lines are drawn and intersected by lines drawn parallel to the pipe C from the numbered points in the profile A. Through the intersection thus obtained trace the miter line shown. The pattern for the branch C is obtained in the usual manner as indicated. To obtain the opening in the main pipe D, obtain the girth by using the various spaces in the end view B, measuring each space separately, as they are un- equal, and place them at right angles to the line of the main pipe D in the side view. The usual measuring lines are now drawn, and intersected by lines from points of corresponding number shown in the miter line. This gives the opening to be cut in the pipe D. In Fig. 138 is shown a view of a reducing T joint such as is sometimes used in trunk lines of heating. The method of laying out these patterns is shown in detail in Fig. 139. First of the illustration, and place on either side of the center line A B, the widths a l' and b i in their proper positions connect the FURNACE FITTINGS 195 lines i' I extending them until they meet at C. On the line I I place the semi-profile H, which divide in equal spaces as shown from i to 3, from which points draw lines parallel to A B inter- secting the line I I, From the apex C draw radial lines Fig. 138 A Reducing T-Joint. through the points on I I until they intersect the profile of the large pipe from i' to 3'. From these intersections at right angles to A B draw lines cutting the side of the tapering pipe at i' 2" and 3". These points are used in developing the pattern for the taper joint in the following manner : Using C as center and C i as radius, draw the arc i 3" ', upon which lay off the girth of twice the semi-circle H as shown by similar numbers. Through these small figures draw radial lines from C, extending them indefinitely and intersecting them by arcs of corresponding num- ber struck from C as center with radii equal to C i', C 2" and C 3". A line traced through points thus obtained as show r n by J K L, together with 3" ' 3" will give the net pattern, to which edges must be allowed for riveting. The shape of the opening to be cut in the cylinder is obtained from the side view, which is projected as follows : Draw any horizontal line as D E, upon which locate the points C 1 , b' and i from similar points in the end view. Draw the semi-profile H 1 and divide similar to H, reversing the numbers as shown. From the small figures in H 1 draw perpendiculars to 3 3 inter- secting that line. Through the points on 3 3 draw radial lines from C 1 , extending them to intersecting lines drawn at right angles to A B from the similar numbered intersections i' 2' and 3' in the end view of large pipe, which gives the miter line in the side view. Now upon any line, as F G drawn at right angles to the line of the main pipe, place the girth of large pipe as ob- tained from the various divisions i' 2' 3', etc., in the end view, being careful to measure each space separately, as they are all 196 FURNACE FITTINGS unequal. From the points thus obtained on F G draw measuring lines at right angles to F G, and intersect them by lines drawn parallel to F G from similar points in the miter line. The shaded portion shows the opening to be cut in the main pipe. F I' 2' 3' 2' I' G- QPENING IN CYLINDER C* \ _ _ - -_-rr,r TJ --- = = *^m~ 4 - -- - -x7?5f ^ * - ^ > ///' c -^ PATTERN FOR JO//VT: Fig. 139 Laying Out a Reducing T. Construction of Riveted Joints in Tees The method of constructing the joints shown in Figs. 134, 135, 136 and 138 is explained in Fig. 140, which shows how the T is riveted to the main pipe. A flange a in the diagram is turned outside on the main pipe, while b shows the flange turned out- ward on the T through which the rivets are placed, giving an appearance similar to Fig. 138. Construction of Cold Air Shoes When making the cold air connection to the bottom of the furnace a shoe is required. Two styles of cold air shoes for FURNACE FITTINGS 197 connections to round pipe are shown in Fig. 141. The first, A, is beveled, while B is made tapering to suit the round pipe. The round collar joining the shoe is constructed similar to Fig. 122, but the connection of the shoes in Fig. 141 with the furnace is Fig. 140 Method of Riveting Reducing T. prepared as there shown, in which a in both views indicates the tiange on the shoe proper, and b is a separate flange riveted to the inside of the shoe and notched so as to allow it to be bent inward on the casing. The shoe A is shown in position on a furnace in Fig. 142, where the round cold air pipe is also con- nected. Fig. 141 Shoes for Connections to Round Cold Air Pipes. In Fig. 143 is shown a cold air shoe for inside air connection. A is the collar for the hall connection. A wire mesh is placed in die opening through which the inside basement air is admitted, Flanges are placed at a a for casing connections. In making up these shoes the corners are double seamed and the curve at the farther end of the shoe suits the curvature of the furnace cas- ings. Fig. 144 shows a galvanized sheet melal shoe for rectangular pipe. In placing the collars or shoes on the casing they must always be put on before the casing is put around the furnace. A in Fig. 145 shows the shoe in position for rectangular cold air duct, the method of fastening to the casing being indicated 198 FURNACE FITTINGS in diagram X, in which A represents the casing and B the base ring. The outerflange of the shoe collar is placed snugly against the casing and the inner notched flange a turned tightly against Fig. 142 Shoe Connected to Round Cold Air Pipe. the inside of the casing, as shown at b, and riveted. Sometimes a cast iron shoe is riveted or bolted to the casing proper, as shown in Fig. 146, holes being drilled along the cast iron flange to which the cold air duct is bolted. Fig. 143 Cold Air Shoe for Inside Air Connection. Fig. 144 Sheet Metal Cold Air Shoe for Rectangular Pipe. Pattern for Shoe Connecting to Center of Furnace When the cold air shoe is directed toward the center of the furnace, the pattern for same can be laid out as shown in Fig. FURNACE FITTINGS 199 147, in which A shows the plan view of the furnace, whose radius is D. B shows the plan of the duct whose section is shown at C. Take the girth of the duct C, from i to 2 to 3 to 4 to i and set it off on any horizontal line as shown just below. Make the length of the collar as desired, as I a, and through a I Fig. J45 Connecting Sheet Metal Shoe to Furnace Casing. draw the line E F, parallel to i-i. Through the points 2, 3 and 4 draw lines intersecting E F at a, b and b. Using D as radius, and a and b on both sides of the diagram as centers, describe arcs intersecting each other in c. With the same radius and c and c as centers draw the arcs a b and b a, which com- plete the pattern or layout. When the duct is of such size that Fig. 146 Cast Iron Shoe for Cold Air Connection. it cannot be made up of one piece the corners are then double seamed, making it up in either two or four pieces. Pattern for Shoe Connecting to One Side of Furnace When the cold air duct connects to the casing to one side or off the center, as shown in plan in Fig. 148, the layout or pattern is obtained as just below. In the cut A is the furnace, B the duct or shoe, and C its section. Take the girth of C as before and place it on any straight line, as shown below, and at the desired distance draw any line as E F. At right angle to the duct line, from the intersection with the casing at B, draw the 200 FURNACE FITTINGS line B a. Take the distance from a to b, which represents the corners 3 and 4 in the section, and set it off on lines drawn Fig. 147 Layout of Shoe for Concentric Cold Air Pipe. Fig. 148 Layout of Shoe for Excentric Cold Air Pipe. FURNACE FITTINGS 201 through 3 and 4, measuring from the line E F, as shown from a to b'. Now using the proper radius H, and b' and c in the layout as centers, intersect arcs at d. Then using d and d as centers with the same radius, describe the arcs c b' as shown. This gives the layout for a duct, intersecting the shoe or casing as shown in plan. Flanges must be ollowed for riveting and seaming. Fig. 149 Showing How Friction Is Avoided. Frictionless Cold Air Duct Elbows When connecting the outside cold air duct all possible friction should be eliminated. All elbows and bends should be curved as shown by A and B in Fig. 149. A general rule which can l)e employed in obtaining the radius for describing the throats Fig. 150 Rule for Obtaining Radii for Curves. of the elbows or bends is shown in Fig. 150. Whatever the width of the pipe may be, that width should be the radius with 2O2 FURNACE FITTINGS which to describe the throat of the bend as shown by B A. To this radius is added the width of the pipe which gives the radius B C for describing the heel C. If the width of the duct is 18 inches, the radius of the throat becomes 18 in. and that of the heel 36 in. Seaming Cold Air Duct Elbows There are two methods of seaming the corners of the elbows in cold air duct work; the first method is shown by A in Fig. 151, in which the top and bottom of the elbows have a formation m TOP OR GOT TOM TOP O/? BOTTOM B Fig. 151 Seaming the Cold Air Duct Elbows. as indicated by c, while the sides or elbow curves have a single edge. The lock is first bent as indicated by x, and after the sides are inserted in the groove a ''dolly" is held on the inside Fig. 152 Floor Register Box. corner c and x turned down with the mallet as indicated by a. The second method B is the regulation method but requires more time than the former. Developing and Constructing Floor Register Boxes Register boxes are constructed of single and double walls. Those usually employed are of the single wall type shown in Fig. 152, and are made in various sizes. The size of the register box is determined by the size of pipe to which it will be con- nected. Floor registers are usually connected to round pipes. To find the proper size box from the round pipe, the following rule is usually employed : FURNACE FITTINGS 203 Rule for Determining the Size of the Register Box Find the area of the given round pipe; then double it and find the stock size of register near to this area, and make register box to fit. For example, if the round pipe is 10 inches, its area is 78.54, which doubled gives 157.08. The nearest stock size register is 10" X 16", which equals 160, then ioj/6" X 16^6" is the proper size register box to use. The one-eighth inch added to the size of the register is for play room. FLANGE Fig. 153 Net Patterns for Floor Register Box in One Piece. Table of Areas of Round Pipes and Registers The following table gives a safe guide to determine the cor- rect sizes of registers to use with the standard sizes of round pipes : TABLE OF AREAS OF ROUND PIPES AND REGISTERS. Dimensions of pipe. 12 14" 16" 18" 20" 22 24' Area in square inches. Size of register required. 50 8X12 63 9X14 78 10X16 113 14X16 154 16X20 201 18X24 254 20X26 3M 24X27 380 24X32 452 30X30 2O4 FURNACE FITTINGS Pattern for Floor Register Box in One Piece Fig. 153 shows how a floor register box is developed in one piece when it is of such size that it can be made from one sheet of tin plate. In laying out register boxes, a slight taper should be given as shown in Fig. 152. In Fig. 153 the method of de- veloping the box is as follows: Draw the required size of the rectangle abed and draw the two diagonal lines intersecting each other at e, which is the center point with which to describe the opening to receive the collar. Parallel to the sides of the rectangle, place the hight of the box as shown, to which allow a flange. Extend the sides and ends of the box and allow the taper as indicated by i h and 2 / and draw the miter lines to the corners a b c and d. Edges must be allowed for double seaming. Patterns for Floor Register Box in Four Pieces When the register box is of a large size the register box can be made up in four pieces as indicated in Fig. 154, where a b Fig. 154 Net Patterns for Floor Register Box in Four Pieces. and b c show respectively the length and width of the register, while a i and b i show the hight of the sides, the flare being indicated by i I. To obtain the bottom of the box on each quar- ter pattern, a rectangular bottom should be drawn on the bench or elsewhere, of the desired size or as long as a b and as wide as b c similar to a b c d in Fig. 153. Then with a radius equal to b e and using a, b, b and c in Fig. 154 as centers, describe arcs, cutting each other at e and e" . Then using c i in Fig. 153 as radius and e and e" in Fig. 154 as centers draw the arcs i' and i" as shown, which intersect by the diagonals drawn from a and b to the center e and from b and c to the center e". Edges must be allowed for double seaming the corners and bottom. Sometimes, however, the boxes are made in five pieces that is, the four sides and a separate bottom. Quick Method of Joining Collar to Register Box When the corners of the register box shown in Fig. 153 have been doubled seamed, the collar can be joined to the bottom FURNACE FITTINGS 205 by a quick method as shown in Fig. 155, in which the collar is beaded about one-half inch below the end, using a quarter inch -. * Fig. 155 Two Methods of Joining Pipe Collar to Register Box. bead. ^The half-inch flange above the bead is now notched about every inch, after which the collar is placed through the bottom /7/PJr METHOD I ! & r- r- J j 1 First \ Second. \ ftnat. Operation. ^ ^ SECOA/& 156 Quick Method of Joining Collar. of the register box, as at B, then pressing the bead tightly against the bottom of the box, the notched flanges are turned down firmly as at a a. 206 FURNACE FITTINGS Two Other Methods of Constructing Register Boxes In Fig. 156 are shown two other methods of joining the collar to the boxes, each method being shown in three operations. In the first method A shows a section of a register box with the edge A turned up around the circular opening in the square bottom. On the collar B an edge is turned outward on the burring machine as shown. This collar B is then slipped over the edge A, as shown in the second operation, the lock closed with the flat plyers. The box is now set on the square head stake at a and double seamed with a mallat as shown by d in the final method. The first operation of the second method an edge is turned downward around the circular opening in the flat bottom, and F shows an edge turned inward around the collar. The collar is now placed inside of the edge E and E turned over as shown at H in the second operation. The lock is then turned down and double seamed as shown at b in the third operation. A-- Sect -/on on A~& Fig. 157 Construction of Combination l.eader and Register Box. Construction of Combination Header and Register Box In the upper part of Fig. 157 is shown a view of a combina- tion header and register box. The register box is joined to the headed oval stack as shown, the box collar being of sufficient depth to run flush with the finished plaster line of the partition. The method of joining the collar to the stack is shown in the cut below which represents a section through A B. Note that the collar has a doubled flange at a, also a projecting flange b. The stack is cut out to the required size, the collar inserted and b turned over as indicated by c. FURNACE FITTINGS 207 Boots or Wall Pipe Starters Wall pipe starters are known in some shops as "boots" or "shoes/' Fig. 158 shows a box-shaped starter connecting to two registers. There are various styles of starters but those most generally used on first class jobs are known as "box shaped" and "frictionless." Care should be taken in designing the starter Fig. 158 Box-Shaped Starter Connecting to Two Registers. previous to developing the patterns, that easy, graceful sweeps are obtained to facilitate the flow of air and avoid friction. Fig. 159 shows nine styles of box shaped starters which cover designs for almost any case that may arise. In making up these styles of starters the pattern shape is pricked direct from the drawing and edges allowed for double seaming, the round collars being attached as shown in a previous article. A frictionless round to "oval" starter is shown in Fig. 160. This same style of fric- tionless starter is also made up for rectangular risers instead of "oval," as will be explained. Developing the Pattern for a Round to "Oval" Frictionless Starter The method used for laying out the pattern for the round to oval starter is shown simplified in Fig. 161. According to this method the lines of the elevation are used as base lines and the 208 FURNACE FITTINGS Fig. 159 Nine Styles of Box-Shaped Starters. FURNACE FITTINGS 209 various heighths in the semi-profiles as altitudes, when funding the true lengths. The first step is to draw the elevation of the starter or boot as shown by 3, 4, 4", 3", on either end of which place the semi-profiles of the round and oval or oblong pipes as shown. As both halves of the starter are alike it is only necessary to Fig. 160 Round to Oval Frictionless Starter. develop one-half and duplicate it. The shaded sections in the drawing show the half profiles. In dividing the half profiles in practice more spaces must be used than are shown. In this case the upper and lower quadrants have been divided into two spaces each, as shown by the small figures I to 3 and 4 to 6. From these small figures I to 3 at right angles to 3 3" and from points 4 to 6 at right angles to 4 4", lines are drawn intersecting the lines 3-3" at i' 2' and 4 4" at 5' 6'. Connect these intersections by lines 6' to i' to 5' to 2' and to 4, which lines will represent the bases of sections to be constructed, whose altitudes are equal to the various hights of points of corresponding number in the semi-profiles. Take the various lengths in elevation from 6' to i', bases i' to 5', 5' to 2' and 2' to 4 and set them off as shown by corresponding numbers on the horizontal line A B. From these points erect lines equal in hight to the corresponding altitudes in the semi-profiles. As point 4 in the semi-profile has no hight over the base line 4-4", then 4 remains on the line A B. Con- nect the various points thus set off, which will show the true lengths desired. As the seam is usually placed along the ends 3-4 and 3"-4" in elevation, the half pattern can be developed as follows : Draw any straight line i i in the pattern equal to i i" in the elevation; then using 1-6 in the true length as radius, and i and i in the pattern as centers describe arcs intersecting each 210 FURNACE FITTINGS FURNACE FITTINGS 211 other at 6. With 6 5 in the semi-profile as radius and 6 in the pattern as center, describe the arcs on both sides at 5 and 5 of the pattern which intersect by arcs struck from I as centers and i 5 in the true lengths as radius. With i 2 in the semi- profile as radius and I and i in the pattern as centers, describe the arcs 2 and 2, which intersect by arcs struck from 5 and 5 as centers and 5 2 in the true lengths as radius. Proceed in this manner, using alternately, first the division in the round profile, then the proper true length ; the division in the oval profile, then again the proper true length, until the line 3 4 in the pattern has been obtained, which equals 3 4 in elevation, its true length. Trace a line through points thus obtained in the pattern which will give the layout for the half pattern, to which edges must be allowed for seaming purposes. Various Styles of Frictionless Starters Fig. 162 shows five styles of frictionless starters which can be used for any condition which may arise. The principles to be used in developing the patterns for these starters are similar in every respect to that shown in Fig. 161. Care, however, must be taken in placing the semi-profiles, as clearly shown in the diagram in Fig. 163, where the various starters are num- bered to correspond to those shown in Fig. 162. It will be noticed that the inlets are round, while the outlets or stack con- nections are rectangular. This makes the methods of develop- ment as simple as that shown in Fig. 161. In this case it is only necessary to measure one altitude as c d in the diagrams in Fig. 163, whereas in Fig. 161 the altitudes varied, owing to the curve at i 2 3. After the elevations of the starters have been drawn, the semi-profiles are placed as shown in Fig. 163. While the various hights must be taken in the semi-round pro- files as in the previous development, it is only necessary to take the hight marked c d in all the diagrams, for the rectangular profiles. The elbow A is joined to starter number 5 to pro- duce the starter shown by 5 in Fig. 162. After the patterns have been developed in Fig. 163, two inches should be added to the rectangular end of the patterns, to act as a collar, to receive the slip to which the pipe line is connected. Offset Boot Fig. 164 shows a perspective view of an offset boot round to "oval." In developing the patterns for this style of boot, the upper and lower pipes are developed by parallel lines, while the central piece is laid out by triangulation. The principles which 212 FURNACE FITTINGS will be employed can be applied to this or any other style, re- gardless of what the profiles of the pipes may be. Fig. 162 Five Styles of Frictionless Starters. Developing the Patterns This is shown in detail in Fig. 165, in which the center line of the boot is first drawn as shown by a 3' 8' e, making the angles as desired. Bisect these angles to obtain a true miter FURNACE FITTINGS 213 line as follows : From 3' as center, with any desired radius, draw short arcs intersecting the center line at a and b ; then using a and b as centers, with a radius slightly greater than before, draw the arcs intersecting at c, and draw the miter line indefinitely from c through 3' as shown. In a similar manner obtain the miter line / 6' by means of the arcs d, e and /. Now place the half profile of the round pipe at the lower end of the boot, on the line I 5, and the half profile of the "oval" pipe on the upper end as shewn on the line A B. Space the semi-circles in both profiles into the same number of parts, as indicated, and at right angles to I 5 and A B respectively, draw lines from the various points 2 to 4 and 10 to 6 until they cut the miter lines i' 5' and 6' 10' as shown. Connect by lines the points i' and 10' and 5' with 6', which completes the side elevation. The half pattern for the round and "oval" pipes will be laid out by parallel lines as follows : Extend the line i 5 in the side elevation as shown at the right by C D, upon which place the girth of the half profile of the round pipe as shown. From the small figures erect lines at right angles to C D, and intersect same by lines drawn parallel to C D from the various points i' to 5' on the miter line in elevation. Trace a line through the intersection thus obtained; then will i" 5" 5 i be the half pattern to which the edges must be allowed for seaming. In precisely the same manner is the half pattern for the oval pipe obtained. B A in elevation is extended as shown by / E, upon which the girth of the half profile of the "oval" pipe is placed, as shown by similar letters and figures on / E. The usual measuring lines are drawn and intersected by lines drawn parallel to / E from points of corresponding number on the miter line 6' 10'. This will give the half pattern for the "oval" pipe, to which edges must also be allowed for seaming pur- poses. To develop the middle piece of the offset, connect the various points 10', 2', 9', 3', etc., as shown. These lines will then repre- sent the bases of sections to be constructed as shown in the diagram of true lengths, whose altitudes will equal the various hights shown by corresponding numbers in the upper and lower semi-profiles in the side elevation. Draw any horizontal line as F G, upon which place off the lengths of the several lines shown in the middle section in the elevation as shown by cor- responding numbers on F G. For example, to find the true length of the line 3' 9' in elevation, take this distance and set it off on F G as shown from 3' to 9', and from these two points erect perpendiculars, making them equal respectively to the hight of lines of corresponding number in the half profiles of the side 214 FURNACE FITTINGS /VOTE: ALLOW TWO MCH5 FOX COLLAR OAf ttCr/WGULAK Fig. 163 Placing the Semi- Profiles. FURNACE FITTINGS 215 elevation as measured from the lines I 5 and A B, and draw a line from 3 to 9 in the diagram, which is the desired length. In this manner all of the true lengths are obtained. It should be understood that the lines i' 10' and 5' 6' in elevation show their true lengths, but these two lines also represent the base of the two sections, whose altitudes at 10' and 6' are equal to A 10 and B 6 respectively, the true lengths of these two invisible lines being indicated by i' 10 and 5' 6 in the diagram of true lengths. Fig. 164 Offset Boot. It will not be necessary to develop any sections on the miter lines i' 5' and 6' 10' in elevation as the true lengths along the miter cuts can be obtained along the miter cuts in patterns of the straight pieces respectively. The half pattern for the transi- tion piece can now be laid out as follows : First draw any line as A i in the pattern equal to 10' i' in the side elevation. With a radius equal to A 10 in the half profile and A in the pattern as center, describe the arc near 10, which intersect by an arc struck from i of the pattern as center and the true length i' 10 as radius. With i" 2" in the half pattern of lower pipe as radius and i in the pattern as center, describe the arc 2, which intersect by an arc struck from 10 as center and 10 2 in dia- gram as radius. With 10' 9' in the half pattern of upper pipe as radius, and 10 in pattern as center, describe the arc near 9, which intersect by an arc struck from 2 of pattern as center and 2 9 in the diagram of true lengths as radius. Proceed in this manner, using alternately first the divisions along i" 5" in the pattern for the lower pipe, with the proper true length in the diagram ; then the divisions along A' B' in the pattern for the upper pipe, with the proper true length in the diagram, until all dimensions are used. A line traced through points thus ob- tained as shown by A B 5 i completes the half pattern, to which edges must be allowed for seaming and joining. The method of seaming together the three pieces of the offset is similar to that shown in Fig. 127, but the wall pipe slips are made as in- dicated by S in Fig. 164. 216 FURNACE FITTINGS / /' + /o' 8' 7' ? J'<3' 6' 9' r/?V LENGTHS Of 2/rt/LJG A/Utf&eD UA/S /M 5/> VAT/ON. a 3 2 / ffALF PATTERN FOR fiOUA/O P/P. 7 A Fig. 165 Developing Pattern for Offset Boots. FURNACE FITTINGS 217 Wall Pipes or Risers The wall pipes used in warm air heating are also known as risers, stacks or flue pipes. They are made with single and double walls. When single wall pipes are used they should be braced on the inside by soldering a tin brace in the center of the pipe, as indicated by A in Fig. 166. Where this is not done Air ce// paper- Fig. 166 How the Area Is Decreased in Wall Pipes. Fig. 167 Method of Securing Air Tight Joints in Wall Pipe. the pressure of the plaster when forced through the lathing de- creases the area of the pipe as indicated by the dotted lines a The braces A are cut 24 mcn wide and i inch longer than the width of the pipe. An l / inch hem edge is turned on each of dsoestos ^ inch, and a y 2 inch edge on each end, which is turned at right angles to be used for soldering purposes as shown. Care must be taken to solder the brace in edgewise, so as not to interfere with the flow of the air or decrease the capacity of the pipe. Covering Single Wall Pipes with Paper The single wall pipes can be covered with either single paper or with air cell or corrugated paper. This prevents loss of heat in the walls, the paper being pasted to the flue pipes as follows : 218 FURNACE FITTINGS Cut the paper about % inch shorter than the girth required to go around the pipe. To apply the paper, roll it up, dip in water and remove immediately and apply the paste. Put the paper on the pipe while it is soft and pliable. Before bringing the two edges together in the vertical seam, take a piece of flat, stiff paper about 3 inches wide, and paste over one edge of the air cell paper as shown by a in Fig. 167, and then paste down on the tin pipe at b. Now bring the other edge of the air cell paper in place as shown by c and paste another strip of stiff paper over the joint as indicated by d. This secures the covering along the vertical joints. Do the same with the horizontal joints, and always have the corrugations next to the tin. When the paper is dry a good solid air tight covering is obtained, Double Wall Pipes Double wall pipes have the advantage over the single wall as the walls are protected from crushing by means of perforated angles and corrugations and the air space between the inner and outer pipes prevents loss of heat in the partitions, Metal Flues in Brick Walls When warm air pipes are run up in brick walls as the mason's work progresses, galvanized iron is generally used, covered with asbestos air cell covering. The corners of the asbestos covering is usually protected from injury as shown in Fig. 168, in which the metal pipe is first covered with asbestos air cell covering .as previously described, then the corners of the asbestos covering are protected by galvanized sheet iron angles 3 inches wide on each side, which prevents the paper from being torn or damaged by the brick work or studding. These galvanized iron angles are held in position by thin copper wire twisted around the pipe at intervals of about 12 inches as indicated in the diagram. The Various Fittings Used in Furnace Piping Fig. 169 shows twenty-six styles of single wall furnace fittings, including every conceivable shape usually met with in practice. The same style of fittings can also be obtained for double wall pipe. It will be noticed that the various angles, elbows, offsets, tees, register boxes, etc., are so constructed that no development is necessary when laying out the patterns, the shapes being pricked direct on the metal and edges allowed for seaming and grooving. This cut should be referred to when any job comes up, as from these twenty-six styles one or more is sure to sug- gest itself for practical use. FURNACE FITTINGS 219 Fig. 169 Twenty-six Styles of Single Wall Furnace Fittinga i Angle 45 Elbow. 8 Flat Offset Elbow. 2 Elbow of Three Pieces. 9 Two Way Tee. 3 Elbow 90. 10 Flat Angle 45. 4 Regular Elbow 90 Round Heel. 1 1 Through Tee. 5 Flat Elbow 90 Round Heel. 12 Reduced Tee. 6 Offset Elbow. 13 Flat Two Way Tee. 7 Flat Elbow 90 Octagonal Heel. 14 Flat Through Tee. 22o FURNACE FITTINGS 15 Left Compound Tee on the Flat. 21 Through Register Box. i6-Ri g ht Compound Tee on the Flat. 22 _ Top Register BQX and Riser 17 Left Compound Tee on the ^ ^ . Sharp. 2 3 T P Register Bex Connected to Combined. Oval Pipe. 18 Right Compound Tee on the 24 Semi-circular Register Box. c- 1 -r -n . r 2 5 Double Semi-circular Register 19 Single Top Register Box for . _. Rectangular Riser. Boxes for Round Rlsers - 20 Double Top Register Box for 26 Double Corner Register Boxes Rectangular Riser. for Round Riser. Compound Wall Pipe Offsets Compound pipe offsets are very often required in furnace piping. When the partition on the first floor runs in one direc- tion, and that on the next floor runs at right angles to the lower one, a compound or double offset is necessary as shown in Fig 170, where the two wall pipes cross one another at right angles, with equal projection on all four sides as shown. In an offset of this kind the pattern must be developed, the offset usually being made up in four pieces, with collar attachment and the corners double seamed. The method of developing the pattern for the offset is so clearly shown in Fig. 171 that little explanation will be required. The shape of the two pipes is clearly shown in the plan, the vertical night of the offset is indicated by 2 a in elevation, and I 2 of the elevation is the slant hight or stretchout to be used in obtaining the pattern as shown at the right. Allow for a collar at either end to make connections as shown. Patterns for a Double Offset When the upper heat pipe does not come centrally over the lower one, but offsets to one side, then a double offset is required as indicated in Fig. 172. The method of laying out the pattern is shown in Fig. 173, which method can be applied to any style of offset, regardless of what shape the profiles at either end may be, whether similar or dissimilar, or whether the upper pipe is out of center either way or not, providing, however, that the sides of the upper pipe run parallel to those of the lower pipe. Referring to Fig. 173, 2, 5, 3, 5 in plan shows the shape of the lower pipe and i, 6, 4, 6 the shape of the upper pipe, the two being similar in this case. The amount of offset is equal to 3 i in plan, the narrow side of the upper pipe being set centrally to the wide side of the lower one. The front and side elevations are projected from the plan as shown, being careful that the vertical hight a in the front is equal to a of the side. As the flare 5 6 in the front elevation is the same as that of the op- posite side, then will the pattern for one side answer for both. FURNACE FITTINGS 221 In the side elevation the flares i 2 and 3 4 are unequal ; two patterns will therefore be required. To obtain the pattern for the side shown by 5 6 in both front elevation and plan, proceed as follows: At right angles to the Fig. 170 Compound Offset. 72 Double Offset. side 6 in plan draw the line A B, upon which place the girth or stretch-out of 5 6 in the front elevation as shown. At right angles to A B, through points 5 and 6, draw the usual measuring lines, and intersect same from sides of corresponding number in plan as shown, which will give the pattern for the sides 5 6. Allow for collars, also edges for seaming at the corners. For the PLAN Pattern for Sides. Fig. 171 Developing the Pattern for Compound Offset. patterns for the sides I 2 and 3 4 in the side elevation, draw any vertical line as C D below the plan as shown, upon which place the girth of the flares i 2 and 3 4 in the side elevation. Through these small figures on C D draw the usual measuring lines, which intersect by lines projected from points of cor- responding numbers in plan, all as shown by the dotted lines. Allow collars, also edges for seaming the corners. 222 FURNACE FITTINGS Pattern forS/des /, O CO .-O "* 1< S O ^ tO '-O -H -*< t- O CO tO C> 'fj ?Z t- f- ' O O "TOO Ot-t-OOKOO>0 a f-^c*C'icicocoi-* < Tni3otootbt.~-t-GOQOC?* **a SSsiSSIlSSSll oo oo t- o in ift O O -f 30 CJ to to t- t- t- eo g s ?, s s ,t ri 5 fs r. o i-ii-- i^icir-jo o 5 t- to to to ; H lOCCCOcOCJICOt O -i* CO * lO COOOgi^30COl^OCOt^O o oco-ocici >-lp-li-li-(C4C4C)COCOCO?5'l> : : : . . . tb o d a * gSS5'SScoS3S ! " ' r-tiHi-li-lCSCMeMeNCOCOCO H . . O e = 2 too W - t- Cl O O O CO t- Cl O ; CJ Cl -r< t- O -* to d i-l ; | ; i * * ; to w ,Hr-lrti-lCNC>^c1 : : ' : : : : : 10 tO 3 S g "* 5S L 2 * ' ' : : : : : : : : '' : : ** *" " "* rt ** C1 : t : ::::::: 10 ^w^coSSSo da -T tO g^gw^g::::::;;:::;::: d S r-l da CO tO IOtOt-0 d eo -*oto :*::::,'. da <*tO J5 5 I:::":::::: d CO i 1 o 1 a a 4 a a a to to --^'-lOOO Washburn and Moen or A. S. & W. Co. X! . American or Brown and Sharpe Birmingham, Stut Peck. Stow AW., or British Standa D. 8. Standard.* [ 000000 .46 .46875 00000 .43 .4375 0000 .393 r .454 .46 ' .454 .40625 .400 000 .362 .425 41ft .425 .375 .372 00 .331 .38 -.365 M .34375 .348 .307 .34 .324 .34 .3125 .32' 1.1 .283 .289 ,3 .28125 .300 ,263 i284 .258 (284 .26562 .276 3 .244 .259 .229 .269 .25 .252 4' 225 .238 .204 .238 .23437 .232 5 ,207 .22 .182 22 .21875 ,212 6 ,192 .203 .162 1203 . ?0312 .192 7 177 .18 .144 .18 ,1875 ,176 8 .162 .165 .128 .165 .17187 ,160 9 .148 .148 .114 .148 . 15625 .144 10 .135 .134 .102, .134 .14062 .128 11 .12 .12 .091 .12 ,125 .116 12 .105 .109 .081 : .109 .10937 .104 13 .01)2 .095 .072 .095 .09375 .092 14 .08 .083 .064 .083 .07812 .080 15 .072 .072 .057 ! .072 .07031 .072 16 .063 .065 .051 .065 .064 J7 .054 .058 .045 .058 '.05625 .056 18 ,047 .049 .040 .049 .05 .04B 19 .041 .04 .036' .042 .04375 .040 20 .035 .035 .032 .035 ,0375 .036 21 .032 -.0315 .028 .032 .03437 .032 22 .028 .0295 .025 .028 .03125 .028 23 .025 .027 .023 .025 .02812 .024 24 .023 .025 .020 .022 .025 .022 25 .02 .023 .018 .02 .02187 .020 26 .018 .0205 .016 ,018 .01875 .018 27 .017 .01875 .014 .016 .01719 .0164 28 .016 .0165 .01264 .014 .01562 .0149 29 .015 .0155 .01126 .013 .01400 .0136 30 \014 .0137.5 .01002 .012 .0125 .0124 31 .0135 ;0122 ,00893 ,01 .01094 .0116 32 .013 .01125. ^00795 .009 .01016 .0108 33 ,OJ1 .01025 ,00708 .008 .00937 .0100 34 ,01 .0095'- '.-00630 .007 .00859 .0092 35 .0095 .009 /00561, ; ;005. ,00781 .0081 36 .009 .0075 .005 . 570 degrees Linseed Oil 640 degrees Water 212 degrees Water in Vacuum 98 degrees 2 5 MISCELLANEOUS TABLES STANDARD SIZES OF REGISTERS. Size of Opening. 4x6 4x8 4x10 Size of Opening.! 6 x 30 6 x 32 7x7 Size of Opening. 12 X 14 12 X 15 12 X l6 Size of Opening. 18x27 18 x 30 18x36 4x12 7x10 12 X 17 20 x 20 4x13 4x15 7x12 7X 14 12 X 18 12 X 19 2O X 23 20 X 24 4 x 18 8x8 12 X 2O 20 X 26 4 x 21 8x10 12 X 24 20 X 28 4x24 5x8 c v o 8x 12 8x14 8x 16 12 X 30 12 X 36 I4X 14 20 x 30 20 x 36 21 X 2Q 3 A y r v T O 8x18 14 x 16 22 X 22 5 A 1U SXI2 8x 20 I 4 X 18 22 X 24 s x 14 8x21 14 x 20 22 X 26 3 * c x 16 8 x 24 14 X 22 22 X j8 5x18 6x6 8x30 9x9 14 x 24 16 x 16 22 X JO 24 x 24 6x8 6x9 9x12 9 x 13 16 x 18 16 x 20 24 X 27 24X30 6x10 6x 12 6 x 14 6x16 9x14 9x16 9x18 IO X IO, 16 X 22 16 x 24 16x28 16 x 30 24 x 32 24 x 36 27X27 27X38 6 x 18 10 X 12 16 x 32 30X30 6 x 20 10 x 14. 16 x 36 30 x 36 6 X22 6 x 24 6x28 10 x 16 10 x i8f I X 20\ 12 X 12 18 x 18 i8x 21 i8x 24 30x42 30x48 36 x 36 38x43 Made to order. DIMENSIONS OF REGISTERS Size of opening, Nominal areaof opening. Effective area of opening, Galv. Iron or Extreme dimensions of Inches Square Inches Square Inches Inches 6x10 60 40 6/i x 10 e /ie 7 1 Viex llHia 8x10 80 53 8%/x 10% 9%x 11%' 8x12 96 64 8% x 12 5 / 8 9^*xl3% 8x15 120 80 8%xl5% 9^4xl6Hi 9x12 108 72 9'We x 12*7*6 10 7 /8Xl3 7 /8 9x14 126 84 9'Vi6xl4Hi6 10 7 /8Xl5 7 /8 10x12 120 80 10*710 x!2Hie H lr /i6x 13 I5 /i 10x14 140 93 10 1 Wxl4 1 We ll^/iexl^U 10x16 160 107 LOHix 16*^6 H lf >i6xl7 7 / 12x15 180 120 1294x15% 14Mox 17 12x19 228 152 12 3 /i x 1.9% 1 4 Vie- x 21 14x22 308 205 14 T /s x 22 T /s 16^x24^ 15x25 375 250 15 7 /s x 25 7 /s 17tfx27K 16x20 320 213 16% x 20 7 <8 18 5 /iox22 5 /U 16x24 384 256 16 7 /8 X 24 7 /9 18^iex26% 20x20 400 267 20 15 /i6 x 20 lr >lo 22% x 22% 20x24 480 320 20 lf >io x 24 15 /ia 22% x 26 s /* 20x26 520 347 20 15 /ie x 26 ir >io 22^8 x 28% 21x29 609- 403 21 16 /iex29 15 /io 23%x31% 27x27 729 486 27 lc /i6x27 t5 /io 29% x 29% 27x38 1026 684 27 t( Ko x 38 16 /xo 29'% x 40% 30x30 900 600 30 1B Ae x 30 1B /m 32% x 32-% Dimensions of different makes of registers vary slightly. The above are for Tuttle & Bailey Mfg. Co.'s manufacture. MISCELLANEOUS TABLES 251 TABLE FOR SIZE OF CONDUCTORS. Roof Area Discharge per Dia. of Pipe Area in Insq. ft sec. in cu. ft. inches. in. required. I2,OOO 2.25 63.61 . . . 9 10,000 8 4 8 52-5 ... 9 9,000 75 50.26. .. 8 9,000 66 47-2 ... 8 8,000. . . . 48 42 ... 8 7,250. . . . 35 38.48... 7 7,000. . . . 21 3^-7 ... 7 6,000 IO 3^-5 ... 7 5,250.... 00 28.28... 6 5,000.... 0.92 26.2 ... 6 4,000 0.74 ,. 21 , . . . 6 3,500.... 0.70 19.63... 5 3,000. . . . 0.55 v ... 15.9 ... 5 2,500 0.45 .,...; 12.56... 4 2,000 0.37 , 10.5 ... 4 1,225.... 0.25 7.06... 3 1,000 O.l85 5-25... 3 900. . . . 0.166 47 ... 3 800. ... 0.15 4.2 .... 3 700.... O.I2 3-7 ... 3 600.... O.I I .3-2 .., , 3 500. ... O.O92 ,... 2.6 3i 400. ... 0.074 2.1 3! 300. ... 0.055 1.6 ... 3 200 0.037 1.0 ... 3 100,... 0.018 0.5 ... 3 Square Feet of Surface in Round Grates of Different Diameters. Inches. Feet. Inches. Feet.) 13$..,..,. 1 26/, ... 3f 15 u 27 ... 4 164 1} 28 ... 4*. 18 1$ 28| ... 4$ 19 T 3 s 2 29$ ... 4| 20& 2* 3tVV ... 5 21$ 2$ 31$ ... 5* 22$ 2* 33 T 3 - ... 6 23] 3 34$ ... 64 244 31 35}| 7 25 / 6 3* 2 5 2 MISCELLANEOUS TABLES WEIGHTS AND MEASURES Troy Weight. '24 grains = I pwt. 20 [ .vis. = i ounce. 12 ounces r= I pound. Used for weighing gold, silver ...id jewels. Apothecaries' Weight. 20 grains = i scruple. 3 scruples = i dram 8 drams = I ounce. 12 ounces = i pound. The ounce and pound in this -are the same as in Troy weight. Avoirdupois Weight. 2 7 IJ -32 grains = i dram,, 1 6 drams = i ounce. 1 6 ounces i pound. 25 pounds = i quarter. 4 quarters = i cwt. 2.000 Ibs. = i short ton. 2,240 Ibs. = i long ton. / Dry Measure. 2 pints = i quart. 8 quarts =: i peck. 4 pecks = i bushel. 36 bushels = i chaldron. Liquid Measure. 4 gills = i pint. 2 pints = i quart. 4 quarts = i gallon. gallons = i barrel, barrels = i hogshead; Circular Measure. 60 seconds = i minute. 6o~minutes =r^ degree. 30 degrees = i sign. 90 degrees ~ i quadrant. 4 quadrants =12 signs. 360 degrees = i circle. Long Measure. 12 inches = i foot. 3 feet = i yard. 5^2 yards = i rod. 40 rods = i furlong. 8 furlongs = i sta. .mile* 3 miles = i league. Square Measure. V 6 4 81 /32 1" Decimal .515625 .53125 .546875 .5625 .578125 .59375 .609375 .625 .640625 .65625 .67*1875 .6875 .703125 .71875 .734375 .75 .765625 .78125 .796875 .8125 .828125 .84375 .859375 .875 .890625 .90625 .921875 .9375 .953125 .96875 .984375 256 MISCELLANEOUS TABLES TABLE OF A~REAS AND CIRCUMFERENCES OF CIRCLES Diam. Cir. Area Inches Inches Sq. In. Diam. Cir. Area Inches Inches Sq. In. Diam. Cir. ^."Area [nches Inches q. In. y s .393 .012 16 50.26 201.06 54 169.6 2290.2 X .785 .049 16X 51.83' 213.82 55 172.7 2375.8 H 1-178 .110 17 53.40- 226.98 56 175.9 2463. X 1.570 .196 17X 54.97 240.52 57 179. 2551.7 % 1.963 .307 18 56.54 254.46 58 182.2 2642. X 2.356 .442 18X 58.11 268.80 59 185.3 2733 9 Y 8 2.748 .601 19 59.69 283.52 60 188.4 2827.4 1 3.141 .785 19X61-26 298.64 61 191.6 2922.4 \Ys 3.534 .994 20 62.83 314.16 62 194.7 3019. IX 3.927 1.227 20X 64.40 330.06 63 197.9 3117.2 \Ys 4.319 1.484 21 65.97 346.36 64 201. 3216.9 IX 4.712 1.767 21X 67.54 563.05 65 204.2 3318.3 iy s 5.105 2.073 22 69.11 380.13 66 207.3 3421.2 IK 5.497 2.405 22X 70.68 397.60 67 210.4 3525.6 IJi 5.890 2.761 23 72.25 415.47 68 213.6 3631.6 2 6.283 3.141 23X 73.82 433.73 69 216.7 3739.2 2X 7.068 3.976 24 75.39 452.39 70 219.9 3848.4 2X 7.854 4.908 24X 76.96 471.43 71 233. 3959.2 2K 8.639 5.939 25 78.54 490.87 72 226.1 4071.5 3 9.424 7.068 26 81.68 530.93 73 229.3 4185.3 3X 10.21 8.295 27 84.82 572.55 74 232.4 4300.8 3X 10.99 9.621 28 87.96 615.75 75 235.6 4417.8 3K 11.78 11.044 29 91.10 660.52 76 238.7 4536.4 4 12.56 12.566 30 94.24 706.86 77 241.9 4656.6 4X 14.13 15.904 31 97.38 754.76 78 245. 4778.3 5 15.70 19.635 32 lOO.o 840.24 79 248.1 4901.6 5X 17-27 23.578 33 103.6 855.30 80 251.3 5026.5 6 18.84 28.274 34 106.8 907.92 81 254.4 5153. 6X 20.42 33.183 35 109.9 962.11 82 257.6 5281. 7 21.99 38.484 36 113. 1017.8 83 260.7 5410.6 7X 23.56 44.178 37 116.2 1076 2 84 263.8 5541.7 8 25.13 50.265 38 119.3 1134.1 85 267. 5674.5 8X 26.70 56.745 39 122.5 1194 5 86 270.1 5808.3 9 28.27 63.617 40 125.6 1256 6 87 273.3 5944.6. 9X 29.84 70.882 41 128.8 1320.2 88 276.4 6082. 1> 10 31.41 78.539 42 131.9 1385.4 89 279.6 6221.1 10X 32.98 86.590 43 135. 1452.2 90 282.7 6361.7 11 34.55 95.033 44 138.2 1520.5 91 285.8 6503.8 11X 36.12 103.86 45 141.3 1590.4 92 289. 6647.6 12 37.69 113.09 46 144.5 1661.9 93 292.1 6792.9 12X 39.27 122.71 47 147.6 1734.9 94 295.3 6939.7 13 40.84 132.73 48 150.7 1809.5 95 298,. 4 7088.2 13X 42.41 143.13 49 153.9 1885.7 96 301.5 7238.2 14 43.98 153.93 50 157. 1963.5 97 304.7 7389 8 14X 45.55 165.13 51 160.2 2042.8 98 307.8 7542,9 15 47.12 176.71 52 163.3 2123.7 99 311. 7697.7 15X 48.69 188.69 53 166.5 2206.1 100 314,1 7853.9 MISCELLANEOUS TABLES 257 Rules Relative to the Circle To Find Circumference: Multiply diameter by 3.1416. Or divide diameter by 0.3183. To Find Diameter: Multiply circumference by 0.3183. Or divide circumference by 3.1416. To Find Radius: Multiply circumference by 0.15915. Or divide circumference by 6.28318. To Find Size of an Inscribed Square: Multiply diameter by 0.7071. Or multiply circumference by 0.2251. Or divide circumference by 4.4428. To Find Side of an Equal Square: Multiply diameter by 0.8862. Or divide diameter by 1.1284. Or multiply circumference by 0.2821. Or divide circumference by 3.545. Square: A side multiplied by 1.4142 equals diameter of its cir- cumscribing circle. A side multiplied by 4.443 equals circumference of its circumscribing circle. A side multiplied by 1.128 equals diameter of an equal circle. A side multiplied by 3.545 equals circumference of an equal circle. Square inches multiplied by 1.273 equals circle inches of an equal circle. To Find the Area of a Circle: Multiply circumference by one-quarter of the diameter. Or multiply the square of diameter by 0.7854. Or multiply the square of circumference by 0.07958. Or multiply the square of one-half diameter by 3.1416. To Find the Area of an Ellipse: Multiply the product of its axes by .785398. Or multiply the product of its semi-axes by 3.14159. Contents of cylinder area = area of end X length. Contents of wedge = area of base X one-half altitude. Surface of cylinder length X circumference -f- area of both ends. Surface of sphere = diameter squared X 3'I4!6, or = diame- ter X circumference. Contents of sphere = diameter cubed X 0.52.36. Contents of pyramid or cone, right or oblique, regular or irregular = area of base X one-third altitude. Area of triangle = base X one-half altitude. Area of parallelogram = base X altitude. Area of trapezoid altitude X one-half the sum of parallel sides. 258 MISCELLANEOUS TABLES CUBICAL CONTENTS OF ROQMS HAVING CEILINGS OF THE FOLLOWING HEIGHTS .Floor Area 8 ft. 8% ft. Oft. Ofc.ft. 10 ft. 10V& it. 11 ft. 12 ft. 3 3 72 77 81 85 90 95 99 108 3 3# 84 89 95 99 105 110 115 120 3 4 96 102 108 114 120 126 132 144 3 4% 108 115 122 128 135 142 148 162 3 5 120 128 135 142 150 158 16,5 180 3 5% 132 140 149 156 165 173 18-1 198 3 6 144 153 162 171 ISO 189 198' 210 3& 3V6 98 104 110 116 123 129 '134' 147 3y 2 4 112 119 126 133 140 147 154 168 3% 4% 126 134 142 149 158 165' 173 189 3% 5 140 149 158 166 175 184 192 210 3% X 5% 154 164 173 182 193 202 211' 231 3% X 6 168 179 ISO 199 210 221 231 252 3V 2 X 6M. 182 193 205 216 22S 239 250 273 3^ 7 196 208 221 232 245 257 2G9 294 4 4 128 136 144 152 100 168 176 192 4 4^ 144 153 162 171 ISO 189 19$ 216 4 5 160 170 ISO 190 200 210 220 240 4 5V6 176 187 198 209 220 231 242 264 4 6 192 204 216 228 240 252 264 288 4 6y a 208 221 234 247 260 273 2S6 312 4 7 224 238 252 266 250 294 308 336 4 X 7.% 240 255 270 285 300 315 330 360 4 X 8 256 272 288 304 320 336 352 3S4 4V X 4y a 162 172 182 192 203 213 2^)9 243 4y 2 X 5 180 191 203 213 225 236 247 270 4%. X 5% 198 210 223 235 248 260 272 297 4y 2 X 6 216 230 243 2.56 270 2S4 297 324 4y 2 X ey 2 234 249 263 277 293 307 321 351 4y 2 X 7 252 268 284 299 315 331 346 378 4% X .7% 270 287 304 320 338 354 371 405 4y 2 X 8 288 306 324 342 360 378 396 432 iy 2 X 8Ms 306 325 344 363 383 402 420 459 4y 2 X 9 324 345 35 384 405 425 445 4S6 5 X 5 200 212 225 237. 250 263 275 300 5 X .6% 220 234 248 261 275 289 302 330 5 X 6 240 255 270 285 300 315 330 360 5 X 6% 260 276 293 308 325 341 357 390 5 X 7 280 297 315 332 350 368 3S5 420 5 X 7V6 300 319 338 358 375 394 412 450 5 X 8 320 340 360 380 400 420 440 480 5 X sy 2 340 361 3S3 403 425 446 467 510 5 X 9 360 382 405 427 450 473 495 540 5 X % 380 404 428 451 475 499 522 570 6 X 10 400 425 450 475 500 525 550 600 5% X 5% 242 257 272 287 303 318 332 363 5% X' 6 264 281 297 313 330 347 363 396 5tf X 6% 286 304 322 339 358 375 393 429 5% * 7 308 327 347 365 385 404 423 462 5% 7% 330 351 371 391 413 433 453 495 5y 2 X 8 352 374 396 418 440 462 4S4 523 5% X % 374 397 421 444 468 491 514 561 sy 3 X r 396 421 446 470 495 520 544 504 5% X 9% 418 444 470 496 523 549 574 627 MISCELLANEOUS TABLES 259 CUBICAL CONTENTS OF ROOMS HAVING CEILINGS OF THR FOLLOWING HEIGHTS Floor Area 8 ft. 8% ft. 9ft. 9% ft. 10ft. 10% ft lift. 12ft. 5% X 10 440 468 495 522 550 578 605 660 5% X 10% 462 491 520 548 578 606 635 693 5% X 11 4&4 514 545 574 605 635 665 726 6 X 6 288 306 324 342 360 378 396 432 6 X 6% 312 332 351 370 390 410 429 468 6 X 7 336 357 378 399 420 441 462 604 6 X 7% 360 383 405 427 450 473 495 540 6 X 8 384 408 432 456 480 504 528 576 6 X 8% 408 434 459 484 510 536 561 612 6 X 9 432 459 486 513 540 567 594 648 6 X 9% 456 485 513 541 570 599 627 684 6 X 10 480 510 540 570 600 630 660 720 6 X 10 y 3 504 536 567 598 630 662 693 756 G X 11 528 561 594 627 660 693 726 792 6 X 11% 552 587 621 655 690 725 759 828 6 X 12 576 612 648 684 720 756 792 864 6% X 6% 338 359 380 401 423 444 464 507 6% X 7 364 387 410 432 455 478 500 546 6% X 7% 390 414 439 463 488 512 636 685 0% X 8 416 442 468 494 520 546 572 624 6y 2 X 8% 442 470 497 524 553 580 607 663 6% X 9 468 497 527 555 585 615 643 702 6% X 9% 494 525 556 586 618 648 679 741 6% X 10 520 553 585 617- 650 683 715 780 6% X 10 y 2 546 580 614 648 683 717 750 19 6% X 11 572 608 644 679 715 751 786 S58 6% X 11% 598 035 673 710 748 785 822 897 6% X 12 624 663 702 741 780 819 858 956 6% X i2y 2 650 691 731 771 813 853 893 975 ey 2 X 13 676 718 761 802 845 887 929 1014 7 X 7 392 417 441 465 490 515 539 588 7 X 7% 420 446 473 498 525 651 677 630 7 X 8 . 448 476 504 532 560 688 616 672 7 X 8% 476 506 536 5.65 50G 25 654 714 7 X 9 504 536 557 59-8 630 662 693 756 7 X 9% 532 565 599 631 665 698 731 798 7 X 10 560 595 630 665 700 736 770 840 7 X 10% 588 625 662 698 735 772 808 882 7 X 11 616 655 693 731 770 809 847 924 7 X 11% 644 684 725 764 806 845 885 966 7 X 12 672 714 756 798 840 882 924 1008 7 X 12% 700 744 788 831 875 919 962 1050 7 X 13 728 774 819 864 910 956 1001 1092 7 X 13% 756 803 851 97 945 992 1039 1134 7 X 14 784 833 882 931 980 .029 1078 1176 7% X T% 450 478 506 534 563 591 618 675 7% X 8 480 510 540 670 600 630 660 720 7% 8% 510 642 574 005 638 669 701 766 7% 9 540 574 608 641 675 709 742 810 7% 9% 570 606 641 676 713 748 783 855 7% 10 600 638 675 712 750 788 825 900 7% 10% 630 669 709 748 788 827 866 945 7% 11 660 701 743 783 825 866 907 990 7% 11% 690 733 776 819 863 906 948 1035 260 MISCELLANEOUS TABLES CUBICAL CONTENTS OF ROOMS HAVING CEILINGS OF THE FOLLOWING HEIGHTS Floor Area 8 ft. 8V^ ft. 9 ft. 9Vfe ft. 10 ft. 10% ft. lift. 12ft. % X 12 720 765 810 855 900 945 990 1080 K x 12% 750 797 844 890 938 984 1031 1125 % X 13 780 829 878 926 975 1024 1072 1170 % 31 13 1/ 2 810 861 911 961 1013 1063 1113 1215 l/o X 14 840 893 945 997 1050 1103 1155 1260 l /2 X 14%, 870 924 979 1033 1088 1142 1196 1305 V 2 X 15 000 956 1013 1068 1125 1181 1237 1350 8 X 8 512 544 576 608 640 672 704 768 8 X 8y 3 544 578 612 646 680 714 748 816 8 X 9 576 612 648 684 720 756 792 864 8 X 9% 608 646 684 722 760 798 836 912 8 X 10 640 680 720 760 800 840 880 960 8 X ioy 2 672 714 756 798 840 882 924 1008 8 X 11 704 748 792 836 880 924 968 1056 8 X 11 /2 736 782 828 874 920 966 1012 1104 8 X 12 768 816 864 912 960 1008 1056 1152 8 X 12% 800 850 900 950 1000 1050 1100 1200 8 X 13 832 884 936 988 1040 1092 1144 1248 8 X is y 2 864 918 972 1026 1080 1134 1188 1296 8 X 14 896 952 1008 1064 1120 1176 1232 1344 8 X 14% 928 986 1044 1102 1160 1218 1276 1392 8 X 15 960 1020 1080 1140 1200 1260 1320 1440 8 X is y 2 992 1054 111G 1178 1240 1302 1364 1488 8 X 16 1024 1088 1152 1216 1280 1344 1408 1536 s% X 8% 578 614 650 686 723 759 794 867 8% X 9 612 650 689 726 765 803 841 918 8% X 9% 646 686 727 767 808 848 888 969 8% X 10 680 723 765 807 850 893 935 1020 8y 2 X iov 714 759 803 847 893 937 981 1071 8% X 11 748 795 842 888 935 982 1028 1122 8% X 11% 782 831 880 928 978 1026 1075 1173 8y 4 X 12 816 867 918 969 1020 1071 1122 1224 8V 2 X 12% 850 903 95$ 1009 1063 1116 1168 1275 8V 2 X 13 884 939 995 1049 1105 1160 1215 1326 8% X 13% 918 975 1033 1090 1148 1205 1262 1377 sy 2 X 14 952 1012 1071 1130 1190 1250 1309 1428 sy 2 X 14% 986 1048 1109 1170 1233 1294 1355 1479 sy 2 X 15 1020 1084 1148 1211 1275 1339 1402 1530 sy 2 X 15% 1054 1120 1186 1251 1318 1383 1449 1581 sy 2 X 16 1088 1156 1224 1292 1360 1428 1496 1632 8y 2 X 16% 1122 1192 1262 1332 1403 1473 1542 1683 sy 2 X 17 1156 1228 1301 1372 1445 1517 1589 1734 9 X 9 648 689 729 769 810 851 891 972 9 X 9% 684 727 770 812 855 898 940 1026 9 X 10 720 765 810 855 900 945 990 1080 9 X 10% 756 803 851 897 945 992 1039 1134 9 X 11 792 842 891 940 990 1040 1089 1188 9 X 11% 828 880 932 982 1035 1087 1138 1242 9 X 12 864 918 972 1026 1080 1134 1188 1296 9 X 12% 900 956 1013 1068 1125 1181 1237 1350 9 z 13 936 995 1053 1111 1170 1229 1287 1404 9 X 13% 972: 1033 1094 1154 1215 1276 1336 1458 9 i 14 1008 1071 1134 1197 1260 1323 1386 1512 9 X 14% 1044 1109 1175 1239 1305 1370 1435 1666 MISCELLANEOUS TABLES 261 CUBICAL CONTENTS OF ROOMS HAVING CEILINGS OF THE FOLLOWING HEIGHTS Floor Area 8 ft. 8% ft. 9 ft. 9& ft. 10 ft. 10 Vz ft. H ft. 12 ft. 9 X 13 1080 1148 1215 1282 1350 1418 1485 1620 9 X 15 % 1116 1186 1256 1325 1395 1465 1534 1674 9 X 16 1152 1224 1296 1368 1440 1512 15S4 1728 9 X ioy a 1188 1262 1337 1410 1485 1559 1633 I7t>2 9 X 17 1224 1301 1377 1453 1530 1607 1683 1836 9 X 17 y a 1200 1339 1418 1496 1575 1654 1732 1890 9 X 18 1206 1377 1458 1539 1620 1701 1782 1944 9% X 9y 2 722 767 812 857 903 948 992 1083 9% X 10 760 808 855 902 950 998 1045 1140 9y 2 X 10 y 2 798 848 898 947 998 1047 1097 1197 9% X 11 836 888 940 992 1045 1097 1149 1254 9y 2 x; 11% 874 929 983 1038 1093 1147 1201 1311 9y, X 12 912 969 1026 1083 1140 1197 1254 1368 9% X 12 y 2 950 1009 1069 1128 11S8 1247 1306 1425 9% X 13 988 1050 1111 1173 1235 1297 1358 1482 9V 2 X i3y a 1026 1090 1154 1218 1283 1347 1410 1539 9% X 14 1064 1131 1197 1263 1330 1397 1463 1596 9y 2 X 14 y 2 1102 1171 1240 1308 1378 1446 1515 1653 9% X 15 1140 1211 1282 1353 1425 1496 1567 1710 9% 15% 1178 1252 1325 1398 1473 1546 1619 1767 9% 16 1216 1292 1368 1444 1520 1596 1672 1824 9y 2 16 y a 1254 1332 1411 1489 1568 1646 1724 1881 9y 2 17 1292 1373 1453 1534 1615 1696 1776 1938 9v 2 17% 1330 1413 1496 1579 1663 1746 1828 1995 9y 2 18 1368 1454 1539 1624 1710 1796 1S81 2052 9y 2 X 18Va 1406 1494 1582 1669 1758 1845 1933 2109 9y 2 X 19 1444 1534 J.625 1714 1805 1895 1985 2160 10 X 10 800 850 900 950 1000 1050 1100 1200 10 X 10% 840 893 945 997 1050 1103 1155 1260 10 X 11 880 935 990 1045 1100 1155 1210 1320 10 X 11% 920 978 1035 1092 1150 1208 1265 1380 10 12 960 1020 1080 1140 1200 1260 1320 1440 10 i2y a 1000 1063 1125 1187 1250 1313 1375 1500 10 13 1040 1105 1170 1235 1300 1365 1430 1560 10 13% 1080 1148 1215 1282 1350 1418 14H5 1620 10 14 1120 1190 1260 1330 1400 1470 15*40 1680 10 14% 1160 1233 1305 1377 1450 1523 1595 1740 10 X 15 1200 1275 1350 1425 1500 1575 1650 1800 10 X 15 y a 1240 1318 1395 1472 issa 1628 1705 1800 10 X 16 1280 1360 1440 1520 1600 1680 1760 1920 10 X 16% 1320 1403 14S5 1567 1650 1733 1815 1980 10 X 17 1360 1445 1530 1615 1700 1785 1870 2040 10 X 17 y 2 1400 148S 1575 1662 1750 1838 1925 2100 10 X 18 1440 1530 1620 1710 1800 1890 1980 2160 10 X 18% 1480 1573 1665 1757 1850 1943 2035 2220 10 X 19 1520 1615 1710 1805 1900 1995 2090 2280 10 X 19% 1560 1658 1755 1852 1950 2048 2145 2340 10 X 20 1600 1700 1800 1900 2000 2100 2200 2400 11 X 11 968 1029 1089 1149 1210 1271 1331 1452 11 X 12 1056 1122 1188 1254 1320 1386 1452 1584 11 z 13 1144 1216 1287 1358 1430 1502 1573 1716 11 X 14 1232 1309 1386 1463 1540 1617 1694 1848 Hi X IS 1320 1403 1485 1567 1650 1733 1815 1980 11 z 16 1408 1496 1584 1672 1760 1848 1936 2112 262 MISCELLANEOUS TABLES CUBICAL CONTENTS OF ROOMS HAVING CEILINGS OF THE FOLLOWING HEIGHTS Floor Area 8 ft. sy 2 ft. 9ft. 9% ft. 10ft. 10% ft. 11 ft. 12ft. 11 X 17 1496 1590 1683 1776 1870 1964 2057 2244 11 X 18 1584 1683 1782 1881 1980 2079 2178 2376 11 X 19 1672 1777 1881 1986 2090 2195 2299 2508 11 X 20 1760 1870 1980 2090 2200 2310 2420 2640 11 X 21 1848 1964 2079 2194 2310 2426 2541 2772 11 X 22 1936 2057 2178 2299 2420 2541 2662 2904 12 X 12 1152 1224 i29e 1368 1440 1512 1584 1728 12 X 13 1248 1326 1404 1482 1560 1638 1716 1872 12 X 14 1344 1428 1512 1596 1680 1764 1848 2016 12 X 15 1440 1530 1620 1710 1800 1890 1980 2160 12 X 16 1536 1632 1728 1824 1920 2016 2112 2304 12 X 17 1632 1734 1836 1938 2040 2142 2244 244S 12 X 18 1728 1836 1944 2052 2160 2268 2376 2592 12 X 19 1824 1938 2052 2166 2280 2394 2508 2736 12 X 20 1920 2040 2160 2280 2400 2520 2640 2880 12 X 21 2016 2142 2268 5394 2520 2646 2772 3024 12 X 22 2112 2244 2376 -2508 2640 2772 2904 3168 12 X 23 2208 2346 2484 2622 2760 2898 3036 3312 12 X 24 2304 2448 2592 2736 2880 3024 3168 3456 13 X 13 1352 1437 1521 1605 1690 1775 1859 2028 13 X 14 1456 1547 1638 1729 1820 1911 2002 2184 13 X 15 1560 1658 1755 1852 1950 2048 2145 2340 13 X 16 1664 1768 1872 1976 2080 2184 2288 2496 13 X 17 1768 1879 1989 2099 2210 2321 2431 2652 13 X 18 1872 1989 2106 2223 2340 2457 2574 2808 13 X 19 1976 2100 2223 2346 2470 2594 2717 2964 13 X 20 2080 2210 2340 2470 2600 2730 2860 3120 13 X 21 2184 2321 2457 2593 2730 2867 3003 3276 13 X 22 2288 2431 2574 2717 2860 3003 3146 3432 13 X 23 2392 2542 2961 2840 2990 3140 3289 3588 13 X 24 2496 2652 2808 2964 3120 3276 3432 3744 13 X 25 2600 2763 2925 3087 3250 3413 3575 3900 13 X 26 2704 2873 3042 3211 3380 3549 3718 4056 14 X 14 1568 1666 1764 1862 1960 2058 2156 2352 14 X 15 1680 1785 1890 1995 2100 22J05 2310 2520 14 X 16 1792 1904 2016 2128 2240 2352 2464 2688 14 X 17 1904 2023 2142 2261 2380 2499 2618 2856 14 X 18 2016 2142 2268 2394 2520 2646 2772 3024 14 X 19 2128 2261 2394 2527 2660 2793 2926 3192 14 X 20 2240 230 2520 2660 2800 2940 3080 3360 14 X 21 2352 2499 2646 2793 2940 3087 3234 3528 14 X 22 2464 2618 2772 2926 3080 3234 3388 3696 14 X 23 2576 2737 2898 3059 3220 3381 3542 3864 14 X 24 2688 2856 3024 3192 3360 3528 3696 4032 14 X 25 2800 2975 3150 3325 3500 3675 3850 4200 14 X 26 2912 3094 3276 3458 3640 3822 4004 4368 14 X 27 3024 3213 3402 3591 3780 3969 4158 4536 14 X 28 3136 3332 3528 3724 3920 4116 4312 4704 15 X 15 1800 1913 2025 2137 2250 2363 2475 2700 15 X 16 1920 2040 2160 2280 2400 2520 2640 2880 15 X 17 2040 2168 2295 2422 2550 2678 2805 3060 15 X 18 2160 2295 2430 2565 2700 2835 2970 3240 15 X 19 2280 2423 2565 2707 2850 2993 3135 3420 15 I 20 2400 2550 2700 2850 3000 3150 3300 3600 MISCELLANEOUS TABLES CUBICAL CONTENTS OF ROOMS HAVING CEILINGS OF THE FOLLOWING HEIGHTS Floor Area 8 ft. 8V6 ft. 9 ft. 9% ft. 10 ft. 10% ft. 11 ft. 12 ft. 15 I 21 2520 2678 2835 2992 3150 330& 3465 3780 15 X 22 2640 2805 2970 3135 3300 3465 3630 3960 15 X 23 2760 2933 3105 3277 3450 3623 3795 4140 15 X 24 2880 3060 3240 3420 3600 3780 3960 4320 in X 25 3000 3188 3375 3562 3750 938 4123 4500 15 X 26 3120 3315 3510 3705 3900 4095 4290 4680 15 X 27 3240 3443 3645 3847 4050 4253 4455 4860 15 X 28 3360 3570 3780 3990 4200 4410 4620 5040 15 X 29 3480 3698 3915 4132 4350 4568 4785 5220 15 X 30 3600 3825 4050 4275 4500 4725 4950 5400 16 X 16 2048 2176 2304 2432 2560 2688 2816 3072 16 X 17 2176 2312 2448 2584 2726 2856 2992 3264 16 X 18 2304 2448 2592 2736 2880 3024 3168 3456 16 X 19 2432 2584 2736 2888 3040 3192 3344 3648 16 X 20 2560 . 2720 2880 3040 3200 3360 3520 3840 16 X 21 2688 2856 3024 3192 3360 3528 3696 4032 10 X 22 2816 2992 3168 3344 3520 3696 3872 4224 16 X 23 2944 3128 3312 3496 3680 3864 4048 4416 16 X 24 3072 3264 3456 3648 3840 4032 4224 4608 16 X 25 3200 3400 3600 3800 4000 4200 4400 4800 16 X 26 3328 3536 3744 3952 4160 4368 4576 4992 16 X 27 3456 3672 3888 4104 4320 4536 4752 5184 16 X 28 3584 3808 4032 4256 4480 4704 4928 5376 16 X 29 3712 3944 4176 4408 4640 4872 5104 5568 16 X 30 3840 4080 4320 4560 4800 5040 6280 5760 16 X 31 3968 4216 4464 4712 4960 5208 5456 5952 16 X 32 4096 4352 4806 4864 5120 53T6 ,'5632 6144 18 X 18 2592 2754 2916 3078 3240 3402 3564 3888 18 X 20 2880 3060 3240 3420 3600 3780 3960 4320 18 X 22 3169 3366 .3564 3762 3960 4158 4356 4752 18 X 24 3456 3672 3888 4104 4320 4536 4752 5184 18 X 26 3744 3978 4212 4446 4680 4914 5148 5616 18 X 28 4032, 4284 4536 4788 5040 5292 5544 6048 18 X 30 4320 4590 4860 5130 5400 5670 5940 6480 18 X 32 4608 4896 5184 5472 5760 6048 6336 6912 18 r 34 4896 5202 5508 5814 6120 ,6426 6732 7344 18 X 36 5184 5508 5832 6156 6480 6804 7128 7776 20 X 20 3200 3400 3600 3800 4000 4200 4400 4800 20 X 22 3520 3740 3960 4180 4400 4620 4840 5280 20 X 24 3840 4080 4320 4560 4800 5040 5280 5760 20 X 26 4160 4420 4680 4940 5200 5460 5720 6240 20 X 28 4480 4760 5040 5320 5600 5880 6160 6720 20 X 30 4800 5100 5400 5700 COOO 6300 6600 7200 20 X 32 5120 5440 5760 60SO 6400 6720 7040 7680 20 z 34 5440 5780 6120 6460 6800 7140 7480 8160 20 X 36 5760 6120 6480 6840 7210 7560 7920 8640 20 X 38 6080 6460 6840 7220 7600 7980 8360 9120 20 X 40 6400 6800 7200 7600 8000 8400 8800 9600 264 CHAPTER XX RECIPES AND MISCELLANEOUS DATA To Clean Brass. Mix in a stone jar one part of nitric acid, and one-half part of sulphuric acid. Dip the brasswork into this mixture, wash it off with water, and dry with sawdust. If greasy, dip the work into a strong mixture of potash, soda and water, to re- move the grease, and wash it off with water. To Clean Zinc. Dissolve a teaspoonful of oxalic acid in a half pint of water, and wash the zinc with the solution, after which the zinc should be washed off with water, and polished witha woolen cloth and dry whiting. To Clean Out Water Front That is Filled With Rust. Take the water front out and place it in a forge or in a furnace, and heat it. This will bake the deposit that has col- lected in the water front, and will loosen much of it. After being sufficiently heated, it should be removed, and tapped with a hammer to dislodge the rust that clings to the surface. In this way the water front may be entirely cleaned. To Remove Lime Deposit in a Water Front. After disconnecting the range, take out the water front, and immerse it in muriatic acid, where it should remain two or three hours, according to the amount of deposit and the strength of the acid. On removing the water front from the acid, plunge it into water and wash thoroughly. Government Recipe for Cleaning Brass. The following is said to be the method used in government arsenals for cleaning brass. Use two parts of common nitric acid to one part of sulphuric acid. The acid should be kept in a stone jar. Articles that are to be cleaned should be first dipped into the acid, then into clear water, and then dried with sawdust. This cleaning process will change the brass at once to a brilliant color. If the metal to be cleaned is RECIPES 265 greasy, the grease should be first removed, by dipping the article in a strong solution of potash and soda in warm water. To Prevent Rusting of Iron and Steel. Cover the surface with a mixture made of I Ib. melted lard, I oz. camphor, and black lead to give it the desired color. By covering the surface with this mixture, the metal will be protected for an indefinite length of time, and it may be cleaned off with naptha or benzine. To Prevent Polished Iron From Rusting. Cut a small amount of beeswax with benzine, and supply it to the surface of the polished iron. This has long been in use in protecting Russia iron through the damp season, and has been found very effective. To Clean Zinc. Zinc is generally cleaned by scouring it with fine sand and pumice. A bath of two parts of nitric acid, and one part sulphuric acid will also give results. The bath should be followed by a water bath. After cleaning zinc, a permanent bright surface may be obtained by giving it a coat of transparent varnish. How to Clean Steel Tapes. Cover the tape with crude oil and rub down with No. O steel wool. This will clean the rust from the tape without injury to the etching. If the tape is not very rusty it may be brightened up by rubbing with powdered pumice or dry cement. To Paint Galvanized Iron. There is very often difficulty in making paint stick to gal- vanized iron. The galvanized iron should first be cleaned with a solution of ammonia and water. When the iron has dried off, it is ready for the paint, which will then adhere without any difficulty. To Keep Plaster of Paris From Setting Too Quickly. Sift the plaster into the water, allowing it to soak up the water, without stirring, which would admit air and cause the plaster to set quickly. If desired to keep the plaster soft for a much longer time, add to every quart of water, one-half teaspoonful of common cooking soda. This will gain all the time necessary. 266 RECIPES To Solder Galvanized Iron. Be sure to have a very hot soldering copper in soldering galvanized iron, even though it has to be returned often. When the copper is not sufficiently hot, it simply solders to the surface of the zinc, which is liable to peel off. In having the iron hot, the soldering gets to the iron, and the solder and zinc are more thoroughly fused together and to the iron. A Flux for Tin Roofing. A good roofing flux is made of two parts of binnacle oil, and one part of rosin. Rosin, cut with alcohol, and applied with a swab, also is very satisfactory. Fluxes for Various Metals. For cast and malleable iron and steel, borax and sal-am- moniac. For brass, gun metal and copper, chloride of zinc, sal-ammoniac or rosin. For zinc, chloride of zinc. For tinned iron, chloride of zinc or rosin. For lead, tallow for coarse solder, and rosin for fine solder. For pewter, gallipoli oil. To Keep Soldering Coppers in Order While Soldering With Acid. In a pint of water dissolve a piece of sal-ammoniac about the size of a walnut. Whenever the copper is taken from the fire, dip the point into the liquid, and the zinc taken from the acid will run to the point of the copper and can then be shaken off, leaving the copper bright. A Good Soldering Acid. In i Ib. muriatic acid, dissolve all the zinc it will take up, thereby forming zinc chloride. Add to the zinc chloride I ounce of sal-ammoniac. Reduce with the same amount of water there is of the acid. A Non-Corrosive Soldering Paste. An excellent paste for soldering purposes can be made of one part by weight, of chloride of zinc, and sixteen parts of some such grease as vaseline, thoroughly mixed together. The chloride of zinc is known to every tinsmith, and is made by dissolving in muriatic acid, as much zinc as the acid will eat up. RECIPES 267 Waterproof Glue. Use one part India rubber, and three parts gum shellac, by weight. Dissolve each in separate vessels, in ether, and under a mild heat. After being completely dissolved, mix the two, and keep in an air-tight vessel. This mixture will withstand both hot and cold water, and nearly all kinds of acids. Common glue, mixed with varnish or linseed oil, applied to the parts to be glued after they have been warmed, will be permanent and with stand water. How to Make Putty. Mix dry whiting with raw linseed oil. For glazing, add about 10 per cent, of white lead to increase durability. In hot climates a little cottonseed oil should be added to prevent the putty from drying too quickly. Fireproof Cement for Furnaces. A cement or mortar that will close up cracks in furnaces to keep the gas from escaping can be made as follows: Mix together seventy-five parts of wet fire clay, three parts of black oride manganese, three parts of white sand and one part of powdered asbestos. Thoroughly mix by adding enough water to make a smooth paste. Apply over the cracks and when dry it will be as hard as iron and stick like glue. Rust Joints. To make a good rust joint, use 5 Ibs. iron filings, and I oz. each of sal-ammoniac and flour of sulphur. Do not use a greater amount of sal-ammoniac as it is likely to generate heat, and thereby cause expansion. A stronger but slower setting cement may be made by using the following propor- tions of ingredients: 12 Ibs. iron filings, 2 ozs. sal-ammoniac, and i oz. flour of sulphur. Friction of Water in Passing Through Pipes. Friction of Water in pipes is approximately equal to the square of the velocity at which it is flowing. Therefore the greater the velocity, the greater the friction will be. The friction of water in passing a 90 degree bend is as great as the friction of a length of such pipe 38 times as great as the diameter. The friction of water in small pipes is much greater than in large pipes, as in the small pipe a much larger proportion of the water comes in contact with the sides of the pipe. 268 RECIPES Heating Capacity of Stove and Furnace Coils. When a stove or furnace heating coil is so placed as to be covered by the fire, it is estimated that it will take about one square foot of heating surface in the coil to heat fifteen gallons of water in the boiler. If the coil is to be of J4 inch pipe, it will require 45 inches of pipe for each 15 gallons of tank capacity. If a I inch coil is to be used, it will require 3 feet of pipe for 15 gallons. In the case of furnace coils that are placed in the combus- tion chamber, above the fire, the heating power of the coil will not be so great, for the reason that when the feed door is opened, or fresh coal is thrown onto the fire, the heating of the coil is checked. Under these circumstances it would not generally be safe to figure on heating much over 10 gal- lons per square foot of heating surface. INDEX I Furnace Heating Air, Amount Required for Ventilation Ill Air, Amount Moved by Fan 115 Air, Composition of 109 Air Filter 55 Air Moistening and Humidity 121 Air Moistening, Investigation of Results Obtained 124 Air Moistening, Methods of 125-129 Air Moistening, Methods of Testing 129 Air Moistening, Reduction of Fuel 123 Air, Recirculation of 132 Air, Vitiation of no Apparatus for Controlling Drafts 161 Application of Heating Rules 80 Appliances for Fuel Saving 147 Area and Height of Chimney Flue 12-14 Area of Cold Air Duct 32, 33 Automatic Air Damper 82, 83, 84 Automatic Draft Regulators 159 Auxiliary Heaters, Types of 140 Auxiliary Heating, Arrangement of 141-143 Auxiliary Heating from Furnaces 138 Auxiliary Heating, Methods of 139-145 Auxiliary Heating, Methods of Installation 144 Bends 100 Black Sheets, Weights of 239 Boiling Point of Fluids 249 Brass, Government Recipe for Cleaning 264 Brass, To Clean 264 Capacity of Exhaust Fans 1 18 Carbonic Acid Gas, Parts in the Air 109, in Casing and Top of Furnace 24- 26, 98 Cement Construction, Determining Quantities 176 270 FURNACE HEATING Cement Construction for Furnace Men 173 Cement Construction, Methods Used 177 Cement Construction, Tools Required 175 Cement for Furnaces, Fire-Proof 267 Character and Size of Chimney Flue 9 Character and Size of Furnace 23, 24 Chimney Flue 9 Chimney Flue, Area and Height 12, 14 Chimney Flue, Character and Size 9 Chimney Flue, Construction 10, 1 1, 12 Chimney Flue, Draft Gauge 15, 16 Chimney Flues, Location 17, 18 Chimney Flues, Sources of Trouble 18, 19 Chimney Flues, Table of Sizes 17 Chimney Flue, Table of Velocities 16 Chimney Flue, Tests of 15, 17 Chimney Flue Troubles 19, 20 Circle, Areas of 256 Circle, Circumferences of 256 Circle, Rules Relative to -. 257 Coal, Composition of 165 Coal, The Universal Fuel 171 Coke Air Moistener 125 Coke, How Produced 165 Cold Air, Methods of Supplying 29 Cold Air Duct, Area of 32, 33 Cold Air Filter 31 Cold Air Pit for Furnace 27 Cold Air Supply for Furnaces 29, 33 Combustion of Fuel 163 Composition of Air 109 Composition of Coal 165 Concrete Mixtures 173 Conductors, Table of Sizes 251 Construction of Chimney Flue 10, 1 1, 12 Construction, Practical Methods of 85 Correct Tests of Chimney Flue IS" 1 / Cost of Hard Firing 101 Cost of Heat Regulation 156 FURNACE HEATING 271 Cubical Contents of Rooms 258-263 Draft Gauge for Testing Chimney Flue 15, 16 Draft Regulators 159 Ducts for Recirculation of Air, Method of Connecting. . . 136 Dust Discharge 97 Effect of High Winds 135 Efficiency of Exhaust Fans 117 Estimate, Form for 77, 78 Estimating Furnace Work 70, 77, 79 Estimating Sizes of Pipe 47 Example of Good Furnace Work 103, 107 Exhaust Fans, Efficiency of 117 Exhaust Fans, Horse Power Required 1 18 Exhaust Fans, Speed and Capacity 1 18 Exhaust Fans, Table of Capacities 119 Expansion Tank, Size and Location 144 Factors of Good Furnace Work 97 Fan-Blast Heating 61 Fan-Blast Heating with Trunk Line Piping 65 Filter for Cold Air 31 Filtering Chamber 55 Fittings for Furnace Heating 37, 38 Flues, Location of 42 Fluids, Boiling Points of 249 Fractions and Decimals 255 Fuel 163 Fuel, Air Required for Combustion 166 Fuel, Analysis of 165 Fuel, Chemical Components and Combustion 163 Fuel Saving Devices 146 Furnace, Auxiliary Heating from 138 Furnace Casing and Top 24, 26, 98 Furnace, Character and Size 23, 24 Furnace, Coil in Fire Pot 139 Furnace Coils, Heating Capacity of s 268 Furnace, Cold Air Pit 27 Furnace, Cold Air Supply 29, 33 Furnace Fittings 37, 38 Furnace, Foundation for 97 272 FURNACE HEATING Furnace Heating, Arguments for 22, 23 Furnace, Heating Surface 101 Furnace Heating, History of 21 Furnace, Installation of 44 Furnace, Location of 26 Furnace, Methods of Setting 26, 30 Furnace Pipe 36, 37, 99 Furnace Ratings 34, 35 Furnace, Size Required 33~35 Furnace, The 21 Furnace Work, Estimating 70 Furnace Work, Factors of Good 97 Furnace Work, Importance of High Class IO2 Galvanized Iron, to Solder 266 Galvanized Iron, to Paint 265 Galvanized Pipe and Elbows, Weights of 242 Galvanized Sheets, Gauges and Weights 240 Glue, Water Proof 267 Grates, Diameter of 251 Grates, Square Feet of Surface 251 Heater Pipes, Stock Sizes of Tin for 244 Heating, Fan-Blast 61 Heating Rules, Intelligent Application of 80 Heating, Trunk Line 57 Heat Regulation, Cost of 156 Herr Humidifier 126 High Class Work, Importance of IO2 History of Furnace Heating 21 Horse Power Required for Exhaust Fans Il8 Humidity and Air Moistening 121 Hygrometer, The 129 Importance of High Class Furnace Work IO2 Installation of the Furnace 44 Iron, to Prevent Rusting 265 Location for Rotating Register ioo Location of Chimney Flue 17, 18 Location of Furnace 26 Location of Registers 40, 41 Melting Points of Metals. -. 249 FURNACE HEATING 273 Metals, Fluxes for 266 Metals, Melting Points of 249 Method of Estimating Furnace Work 70 Methods of Setting Furnace 26, 30 Methods of Ventilating ill Millimeters and Decimals 253 Miscellaneous Data and Recipes 264-268 Mixing Concrete 174 Opposition to Re-circulation of Air 134 Origin of Thermostats 148 Plaster of Paris, To keep from Setting 265 Practical Methods of Construction 85 Propeller Fan, Use for Ventilation 114 Putty, How to Make 267 Radiator, Size of 138 Ratings of Furnaces 34, 35 Recipes and Miscellaneous Data 264-268 Re-circulation of Air 132 Re-circulation of Air, Method of Connecting Ducts for. 136 Rectangular Tanks, Capacities in U. S. Gallons 245 Registers, Dimensions oi ...._, 250 Registers, Location of 40, 41 Registers, Side Wall 38, 39 Registers, Size of 42, 43 Registers, Table of Standard Sizes 250 Regulators, Electric 149 Regulators, How to Attach 156 Regulators, Non-Electric 150 Rooms, Cubical Contents of 258-263 Rotating Register, Location of 100 Round Tanks, Capacities in Gallons 246 Rules, Tables and Information 237 Rust Joints, How to Make 267 School House Warming and Ventilating 91 Sheet Copper, Weights and Thickness . : 241 Sheet Zinc, Weight of 242 Side Wall Registers 38, 39 Size of Furnace Required 33, 35 Size of Registers 42, 43 274 FURNACE HEATING r Size of Warm Air Pipes 40 Soldering Acid 266 Soldering Coppers. To Keep in Order 266 Soldering Paste 266 Speed of Exhaust Fans 118 Stack for Ventilating 1 12, 1 13 Standing Seam Roofing, Table of Costs 243 Standing Seam Roofing ; Tin Required 244 Steel Sheets, Weights of 238 Steel Tapes, To Clean 265 Steel, To Prevent Rusting 265 Stove Coils, Heating Capacity of 268 TABLES : Air Moved by Propeller Fan 115 Areas and Circumferences of Circles 256 Cost for Standing Seam Roofing 243 Diameters of Wire 247-248 Gallons in Round Tanks 246 Gauges and Weights of Black Sheets 239 Gauges and Weights of Galvanized Sheets 240 Horse Power of Belting 254 Exposures 74 Common Fractions and Decimals 255 Millimeters and Decimals 253 Chimney Flues, Sizes 17 Pipes, Flues and Registers, Sizes 74 Weights and Measures 252 Size of Conductors 251 Size of Registers 43 Stock Sizes Tin for Heater Pipes 244 Tin Required for Standing Seam Roofing 244 U. S. Gallons in Rectangular Tanks 245 Weights of Copper Sheets 241 Weights of Galvanized Pipe and Elbows 242 Weights of Sheet Zinc 242 Weights of Steel 238 Weight of Tin Plates 243 Weight, Strength and Size of Wire 249 Wire, Diameters of 247-248 FURNACE HEATING 275 Tanks, Capacity in Gallons and Barrels 253 Temperature Regulation 146 Temperature Regulation, Cost of 156 Temperature Regulation, Electric Regulators 149 Temperature Regulation, Non-Electric Regulators 150 Temperature Regulation, Value of 154 Thermostats, How to Sell 155 Thermostats, Method of Attaching 156 Thermostats, Origin of 148 Tin Plates, Weight Per Box 243 Tin Roofing, Flux for 266 Trunk Line Heating 57 Velocity in Chimney Flues 16 Ventilation 22, 23, 108 Ventilation by Use of Propeller Fan 144 Ventilation, Fresh Air Required in Ventilation, Methods of 1 1 1 Ventilating Stack 1 12, 1 13 Warm Air Pipes, Size of 40 Warming and Ventilating School Houses 91 Water, Friction in Passing through Pipes 267 Water Front, to Clean Out Rust 264 Water Front, to Remove Lime Deposit 264 Weights and Measures, Table of 252 Weights of Black Sheets 239 Weights of Galvanized Pipe and Elbows 242 Weights of Galvanized Sheets 240 Weights of Sheet Copper 241 Weights of Sheet Zinc 242 Weights of Steel 238 Weight of Tin Plates per Box 243 Wire, Diameters of 247, 248 Wire, Weight, Strength and Size 249 Zinc, To Clean 264, 265 INDEX II Furnace Fittings Adjustable Elbows, Positions for Setting 186 Air Tight Joints in Wall Pipes 217 Angle of Collar Determined by Deflector 179 Angles in Warm Air Elbows, Methods of Finding. . . .232-236 Area in Wall Pipes, How it is Decreased 217 Areas of Round Pipes and Registers, Table of 203 Asbestos Covering in Wall Pipe, Protecting 217 Bonnet and Deflector 179 Bonnets or Hoods, Conical 179 Boots, Offset 21 i -216 Boots or Wall Pipe Starters 207 Box-Shaped Starter Connecting Two Registers 207 Box-Shaped Starters, Nine Styles of 208 Casings, Furnace 180, 181 Casing Rings, Spacing - 180 Cast Iron Shoe for Cold Air Connection 199 Circular Joints, Locking , . . . 189 Circular Joints, Seaming 188 Cold Air Duct Elbows, Finding True Angles in 231 Cold Air Duct Elbows, Frictionless 201 Cold Air Duct Elbows, Seaming 202 Cold Air Shoe Connection, Cast Iron for 199 Cold Air Shoe for Inside Air Connection 198 Cold Air Shoes 196 Collars Joining a Flat Top Casing 180 Collar on Pitched Bonnet 181 Collar on Straight Bonnet 184 Collar to Register Box, Joining 204 Collars, Various Styles of 181 Collar Joining a Straight Bonnet 180 Combination Header on Register Box 206 Compound Wall Pipe Offsets 220222 FURNACE FITTINGS 277 Conical Bonnets or Hoods 179 Connecting Sheet Metal Shoe Casing 199 Connecting Shoes to Center of Furnace 198 Connecting Shoes to Round Cold Air Pipes 197 Covering Wall Pipes with Paper 217 Deflector on Conical Bonnet 179 Degree of Miter Line for Four-Piece Elbow 187 Determining Size of Register Box 203 Diameter of Main Pipe, Determining Unknown 224 Double Offset 220, 222 Double Wall Pipes 218 Elbow, Frictionless Cold Air Duct 201 Elbow, Oval, on the Flat 189 Elbow, Oval, Three-Piece on the Sharp 189 Elbow Patterns, Methods Employed 232 Elbow, Reducing 190 Elbows 185, 186, 187 Elbows, Cold Air Duct, Finding True Angles in 231 Elbows Less Than Right Angles 188 Elbows, Oval 188 Elbows, True Angles in, Finding 232-236 Equal Fork in Trunk Line Fitting 224 Fastening Collar to Straight Bonnet 184 Finding True Angles in Cold Air Duct Elbows 231 Finished Collar for Flat Casing Top 185 Finished Collar for Pitched Bonnet 185 Fittings for Trunk Line Heating Systems 223 Fittings Used in Furnace Piping 218 Flat Casing Top, Finished Collar for 185 Flat Top Casing, Collars Joining 180 Floor Register Box in Four Pieces 204 Floor Register Box in One Piece 204 Floor Register Boxes 203 Flues, Metal, in Brick Walls 218 Fork, Equal, in Trunk Line Fitting 224 Fork of Equal Prongs in Trunk Line System 225 Fork, Unequal, in Trunk Line Fittings 226 Forks for Trunk Line Systems 224-231 Four-Piece 90 Degrees Elbow, Rule for 186 278 FURNACE FITTINGS Frictionless Cold Air Duct Elbows 201 Frictionless Starters 207-212 Furnace Casings 181 Furnace Fittings, Single Wall, Twenty-Six Styles of... 219 Furnace Piping, Fittings Used in 218 Header, Combination, on Register Box 206 Header, Round 193 Joining Collar to Register Box 204 Locking Circular Joints 189 Metal Flues in Brick Walls 218 Methods of Finding True Angles in Cold Air Elbows. . .232-236 Miter Line for Four-Piece Elbow, Finding Degree of. 187 Obtaining Radii for Curves 201 Offset Boots 211-216 Offset, Double 220, 222 Oval Elbow on the Sharp, Three-Piece 189 Oval Elbows 188 Pitched Bonnet, Collar for 181, 185 Positions for Setting Four-Piece Adjustable Elbow 186 Pronged Fork, Three Equal in Trunk Line System 228, 230 Pronged Fork, Three Unequal in Trunk Line System... 229 Protecting Asbestos Covering in Wall Pipe 217 Radii for Curves, Rule for Obtaining 201 Reducing Elbow 190 Reducing Joint, Short Rule for . . 223 Reducing T, Riveting 197 Reducing T-Joint 195 Register Box, Determining Size of 203 Register Box, Floor, in One Piece 204 Register Box, Floor, in Four Pieces 204 Register Boxes 206 Risers, Wall Pipes or 217 Riveted Joints in Tees 196 Riveting Reducing T 197 Round Header 193 Round Pipes and Registers, Table of 203 Round to Oval Frictionless Starter 207 Rule for Developing Four-Pieced 90 Degree Elbow 186 Rule for Reducing Joint 223 FURNACE FITTINGS 279 Seaming Circular Joints 188 Seaming Cold Air Duct Elbows 202 Setting Four-Piece Adjustable Elbows 186 Shoe, Cast Iron, for Cold Air Connection 199 Shoe, Cold Air, for Inside Air Connection 198 Shoe Connecting to One Side of Furnace 19^) Shoe, Sheet Metal for Rectangular Pipe 198 Shoes, Cold Air 196-201 Shoes, Connecting to Furnace Casing 199 Shoes, Connecting to Center of Furnace 198 Shoes for Round Cold Air Pipes, Connecting 197-198 Short Rule for Reducing Joint 223 Single Wall Furnace Fittings, Twenty-Six Styles of. . 219 Straight Bonnet, Collar on 184 Spacing the Casing Rings 180 Starter, Box Shaped, Connecting Two Registers 207 Straight Bonnet, Collars Joining 180 Straight Bonnet, Fastening Collar on 184 T-Joint Between Pipes of Equal Diameter 192 T- Joint Between Pipes of Unequal Diameter 193, 194 T-Joint, Reducing 195 Table of Areas of Round Pipes and Registers 2*03 Tees, Riveted Joints in 196 Three Equal Pronged Fork in Trunk Line System 228 Three-Piece Oval Elbow on the Flat 189 Three-Piece Oval Elbow on the Sharp 189 True Angles in Cold Air Duct Elbows, Finding 231 True Angles in Warm Air Elbows, Finding 232-236 True Angles in Warm Air Elbows, Finding with Line and Bevel 235 Trunk Line Fittings, Equal Fork in 224 Trunk Line Fittings, Unequal Fork in 226 Trunk Line Heating Systems, Fittings for 223 Two-Pronged Fork for Trunk Line System 225 Two-Pronged Fork, Unequal, Determining the Unknown Diameter in 227 Unequal Fork in Trunk Line Fittings 226 Unequal Three-Pronged Fork in Trunk Line System. . . . 229 Unknown Diameter of Main Pipe, Determining 224 280 FURNACE FITTINGS Wall Pipe Offsets, Compound 220-222 Wall Pipe Starters 207 Wall Pipes, Covering with Paper 217 Wall Pipes, How Area is Decreased in 217 Wall Pipes or Risers 217 Wall Pipes, Securing Air Tight Joints in 217 SHEET METAL PUBLISHED MONTHLY A specialised journal, accepted and approved as the authorita- tive organ of its field in which it enjoys a universal circulation. It deals exclusively with the various branches of modern sheet metal work, including the mechanical and business problems of the trade. It is a superior magazine presenting an unequalled variety and quality of reading matter for sheet metal workers, each number containing interesting and valuable expositions of modern methods. Briefly stated, there are included among the leading subjects considered: Constructive Practice in the Various Departments of Sheet Metal Work. Cornice and Skylight Making, Metal Roofing. The Construction and Installation of Heating, Ventilating, Blower and Exhaust Systems. Expert Demonstrations of Problems in Pattern Cutting. The Plainest and Most Practical Articles on Warm Air Fur- nace Heating. These Practical Discussions are Supplemented by the Latest Sheet Metal Trade News, Market Reports, and Reliable Current Price Lists of Materials. SHEET METAL is Designed for Practical Purposes in the Office, the Shop and (or Home Reference and Study. ONE DOLLAR A YEAR SHEET METAL PUBLICATION COMPANY Tribune Building, New York. Practical Exhaust and Blow Piping A Treatise of the Planning: and Installation of Fan Piping in all its Branches BY WILLIAM H. HAYES. At the present time no depart- ment of sheet metal work offers a more profitable field of opportunity for sheet metal workers than ex- haust and blow pipe work. Every operator should be qualified with a practical knowledge of the correct design and installation of fan pip- ing systems. This book was written by an ex- pert of long and varied experience in the field as a foreman and super- intendent and the treatment is based on practical daily work. It is re- liable, easily understood and ap- plied, covering the essentials of efficient construction very clearly. Contains Sixteen Sections Each treating a leading department of blower work and compre- hending specific information of construction, installation and cost. General Rules. Connecting Dust Separator and Feeder. Piping for Automatic Firing System of Boilers. Constructing the Feeder Nozzle and Switch. Piping System for a Planing Mill. Pipe Connections for a Flooring Machine. Designs for Hoods and Sweepers. Hoods for Special Machines. Proper Construction of the Separator. Efficiency of the Exhaust Fan. Use of the Two-Way Mixing Valve and the Automatic Damper. Piping a Forge Shop, including the Blast and Suction Systems. "Don'ts" and "Don't Forgets" for Blow Pipe Men. Correspondence Relating to Special Problems. Hints on Installing an Exhaust System. Hints on Estimating the Cost of an Exhaust System. Comprising 160 pages, 51 illustrations. Printed on heavy paper, durably bound in cloth Price, $2.00 SHEET METAL PUBLICATION COMPANY Tribune Building, New York Practical Sheet Metal Work and Demonstrated Patterns . O G H U I E * E 3 R w w L&X ' f T V * I Y L P 6 N . E R H S J T H n I A > p A w v o b L R R K K Here is comprised a sheet metal workers library in 12 large volumes. Each volume is devoted to pattern cutting, shop and erection methods as applied to a given branch of the trade, all being well classified and in- dexed for ready reference. The methods are the out- growth of actual practice and the patterns are among the most practical and useful in print. The text is very freely illustrated, up- ward of 2,500 engravings being contained in the series. As aids to rapid and accurate work, this entire set of books or selections of the volumes will prove an in- valuable possession to the oper- ator. LIST OF VOLUMES. I Leaders and Leader Heads 113 pages, 150 figures. 2 Gutters and Roof Outlets 116 pages, 194 figures. 3 Roofing 138 pages, 207 figures. 4 Ridging and Corrugated Iron Work 132 pages, 239 figures. 5 Cornice Patterns 119 pages, 195 figures. 6 Circular Cornice Work 126 pages, 194 figures. 7 Practical Cornice Work 139 pages, 237 figures. 8 Skylights 122 pages, 260 figures. 9 Furnace and Tin Shop Work 145 pages, 239 figures. 10 Piping and Heavy Metal Work 144 pages, 259 figures. ii Automobile and Sheet Metal Boats 137 pages, 193 figures. 12 Special Problems 144 pages, 150 figures. Size of volumes, 11x8^2 inches. Substantially bound in cloth. Price of Set (Twelve Volumes). $15.00. Price of Single or Selected Volumes, each, $1.50 SHEET METAL PUBLICATION COMPANY Tribune Building, New York New Metal Worker Pattern Book A Treatise on the Principles and Practice of Pattern Cutting as Applied to All Branches of Sheet Metal Work By GEORGE W. KITTREDGE A LARGE QUARTO VOLUME Containing 744 Illustrations and Diagrams This is the universally used compendium of sheet metal pattern problems. It may be consulted for guidance in laying out every form of work that comes up in the shop, demonstrating as it does, 218 distinct problems covering every example of work of probable occurrence, or related ex- amples in which their principles are involved. Hence it may be said that all forms of work are here compre- hended in the pattern problems sec- tion,, from pages 96 to 429. The preliminary chapters com- prised in pages i to 96 provide a reference section covering all es- sential study required by the drafts- man in acquiring a mastery of sheet metal pattern cutting. ARRANGEMENT OF CONTENTS. Chapter i. Terms and Definitions 15 pages. Chapter II. Drawing Instruments and Materials 13 pages. Chapter III. Linear Drawing 6 pages. Chapter IV. Geometrical Problems 35 pages. Chapter V. Principles of Pattern Cutting 25 pages. Cutting. 2. Flaring Work. 3. Triangulation. Chapter VI. Pattern Problems (3 Sections) 325 pages, i. Miter 430 Pages, Size 10x13 Inches. Heavily Bound in Cloth. Price, $5.00. SHEET METAL PUBLICATION COMPANY Tribune Building, New York IE NEW J- J- METALWORKER PATTERN BOOK Elbow Patterns for all Forms of Pipe A treatise upon the elbow pattern explaining the most simple and accurate methods for obtaining the patterns for elbows in all forms of pipe made from sheet metal With Useful Mathematical Rules and Tables By F. S. KIDDER One of the first and most important considerations for the sheet metal worker is to be possessed of a method for securing the patterns for elbows in the least possible time consistent with ac- curacy. To meet the popular demand and provide a means by which unnecessary expenditure of time and labor may be avoided, the author presents here a method for laying out elbows with accuracy and despatch, Without Resort to Geometrical Display. With the service of this handbook, the mechanic will be enabled to quickly produce the patterns for elbows in round pipe of any size, angle or number of pieces, by the simple employment of a pair of compasses and a straightedge. Size 4 l /2 x &/ 2 inches (for the pocket), 73 pages, 35 figures, cloth bound. PRICE, $1.00 SHEET METAL PUBLICATION COMPANY Tribune Building, New York Sheet Metal Work A Practical Manual for Sheet Metal Workers, Treating Cornice and Skylight Work, Metal Roofing, Pattern Drafting, Etc. BY WILLIAM NEUBECKER This is a first class book on shop and construction work, covering all of the ordinary practice in architec- tural and general sheet metal work. It is a valuable shop reference book, and a reliable guide for mechanics who are aiming for a mastery of the most essential problems of sheet metal construction and pattern cutting. The General Divisions of This Vol- ume Are as Follows: Tools and Methods of Obtaining Pattern 3-26 Workshop Problems 26-132 Skylights 133-157 Roofing 158-192 Cornice Work 193-262 Index 263-267 267 Pages; 358 Illustrations (6 l /2 x 9^4 inches); Half Morrocco Binding Price, $3.00 SHEET METAL PUBLICATION COMPANY Tribune Building, New York THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $I.OO ON THE SEVENTH DAY OVERDUE. LD 21-100m-8,'34 . /L 12855