SO fts, TING GAS-FITTING. THIRD EDITION, WM. PAUL GERHABD, C ; ; Consulting Eny iiutr f'tr H(i2i < Sanii .' \r) , M ' ' - ." I, .D. VAN NOSTRAND COMPANY, PUBLISHERS. 1904. THE VAM MnQTDA No. 11. THEORY OF ARCHES. By Prof. W. Allan. No. 12. THEORY OP VOUSSOIR ARCHES. By Prof. Wm. Cain. Third edition, revised and enlarged. THIC VAX NOSTRAND SClKNCK SERIES. No. 13. GASES MET WITH IN COAL. MIMOS. By J. J. Atkinson. Third edition, rcvis^l and enlarged, to which is added The Action of Coal Dusts by Edward H. Williams, Jr. No. 14. FRICTION OF AIR IN MINES. By J. J. Atkinson. Second American edition. No. 15. SKEW ARCHES. By Prof. K. W. Hyde, C.E. Illustrated. Second edition. No. 10. GRAPHIC METHOD FOR SOLVING Certain Questions in Arithmetic or Algebra. By Prof. G. L. Vose. Second edition. No. 17. WATER AND WATER- SUPPLY. By Prof.'W. H. Corfield, of the University Col- lege, London. Second American edition. No. 18. SEWERAGE AND SEWAGE PURIPI- cation. By M. N. Baker, Associate Editor "Engineering News." Second edition, re- vised and enlarged. No. 11). STRENGTH OF BEAMS UNDER Transverse Loads. By Prof. W. Allan, author of "Theory of Arches." Second edi- tion, revised. No. 20. BRIDGE AND TUNNEL CENTRES. By John B. McMaster, C.E. Second edition. No. 21. SAFETY VALVES. By Richard H. Buel, C.E. Third edition. No. 22. HIGH MASONRY DAMS. By E. Sherman Gould, M. Am. Soc. C. E. Second Edition. No. 23. THE FATIGUE OF METALS UNDER Repeated Strains. With various Tables of Jesuits and Experiments. From the Ger- man of Prof. Ludwig Spangenburg, with a Preface by S. H. Shreve, A.M. No. 24. A PRACTICAL TREATISE ON THE Teeth of Wheels. By Prof. S. W. Robinson. 3d edition, revised, with additions. No. 25. THEORY AND CALCULATION OF Cantilever Bridges. By R. M. Wilcox. No. 26. PRACTICAL TREATISE ON THE PROP- erties of Continuous Bridges. By Charles Bender, C.E. No. 27. BOILER INCRUSTATION AND CORRO- sion. By F. J. Rowan. Now edition. Re- vised and partly rewritten by F. E. Idell. No. 28. TRANSMISSION OF POWER BY WIRE 1 lopes. By Albert W. Stahl, U.S.N. Fourth edition, revised. VAN NOSTRAND SCIENCE SERIES. No. 29. STEAM INJECTORS, THEIR THEORY and Use. Translated from the French by M. Leon Pochet. No. 30. MAGNETISM OF IRON VESSELS AND Terrestrial Magnetism. By Prof. Fairman Rogers. No. 31. THE SANITARY CONDITION OF CITY and Country Dwelling-houses. By George E. Waring, Jr. Second edition, revised. No. 32. CABLE-MAKING FOR SUSPENSION Bridges. B. W. Hildenbrand, C.E. No. 33. MECHANICS OF VENTILATION. By George W. Rafter, C.E. . Second edition, re- vised. No. 34. FOUNDATIONS. By Prof. Jules Gaurtarrt, C.E. Translated from the French. Second edition. No. 35. THE ANEROID BAROMETER: ITS Construction and Use. Compiled by George W. Plympton. Tenth edition, revised and enlarged. No. 36. MATTER AND MOTION. By J. Clerk Maxwell, M.A. Second American edition. No. 37. GEOGRAPHICAL SURVEYING: ITS Uses, Methods, and Results. By Frank De Yeaux Carpenter, C.E. No. 3S. MAXIMUM STRESSES IN FRAMED Bridges. By Prof. William Cain, A.M., C.E. New and revised edition. No. 39. A HANDBOOK OF THE ELECTRO- Magnetic Telegraph. By A. E. Loring. Fourth edition, revised. No. 40. TRANSMISSION OF POWER BY COM- pressed Air. By Robert Zahner, M.E. New edition, in press. No. 41. STRENGTH OF MATERIALS. By Wil- liam Kent, C.E., Asspc. Editor "Engineering News." Second edition. No. 42. THEORY OF STEEL-CONCRETE Arches, and of Vaulted Structures. By Prof. Wm. Cain. Fourth edition, thoroughly re- vised. No. 43. WAVE AND VORTEX MOTION. By Dr. Thomas Craig, of Johns Hopkins University. No. 44. TURBINE WHEELS. By Prof. W. P. Trowbridge, Columbia College. Second edi- tion. Revised. BY THE SAME AUTHOR: HOUSE DRAINAGE AND SANITARY PLUMBING. (Science Series No. 63.) Tenth Edition, revised and enlarged. With Illustrations. 1903. RECENT PRACTICE IN THE SANITARY DRAINAGE OF BUILDINGS. (Science Series No. 93.) Second Edition, revised and enlarged. THE DISPOSAL OF HOUSEHOLD WASTES. (Science Series No. 97.) Second Edition. 1904. Price, post-paid, 5O cents each. GAS-LIGHTING AND GAS-FITTING, A POCKET BOOK FOE GAS COMPANIES, GAS ENGINEERS AND GAS FITTERS, FOR MANU- FACTURERS OF GAS FIXTURES AND DEALERS IN GAS APPLIANCES, FOR GAS CONSUMERS, ARCHITECTS AND BUILDERS, HEALTH OFFICERS AND SANITARY INSPECTORS. THIRD EDITION. BY WM. PAUL GERHARD, C.E., Consulting Engineer for Hydraulic and Sanitary Works, New York City. NEW YORK: D. VAN NOSTRAND COMPANY, 23 MURRAY AND 27 WARREN STREETS. 1904. COPYRIGHT, 1894. D. VAN NOSTRAND COMPANY. PREFACE. The following " Notes on Gas Lighting and Gas Fitting " were first published by the author in 1887. In 1892 he prepared a special pamphlet containing " Hints to Gas Consumers," of which over 5,000 copies were bought and distributed by gas companies. It has been the author's intention to re- write the entire matter and to publish I I. * v a larger manual on the subject of the domestic uses of ^ coal gas, but the press- ing demands upon his time of a large and constantly increasing practice in the field of domestic engineering and of house sanitation in (particular, have prevented the autnor^so far from carrying out his plan " 26849.1 The larger book is, however, in actual preparation, and pending the publication of the same, it was deemed desirable to supply the demand for a small guide on the subject, written from an American standpoint, by issuing this little volume, which in addition to the two articles mentioned above, contains an introduc- tory article on "Artificial Illumination, Historical Notes on Gas Lighting, and on the Advantages of Gas" first published in the American Architect, an article on " Gas for Cooking and Heating Par- poses" published first in Domestic Engin- eering, and the admirable "Rules and Regulations on Gas" issued by the Munic- ipal Department of the City of Munich, translated by the writer. WM. PAUL *GERHAKD. NEW YORK, December, 1893, 36 Union Square. GAS-LIGHTING m GAS-FITTING. AKTIFICIAX ILLUMINATION. Numerous and varied are the methods employed at the present day for obtain- ing artificial illumination. Leaving out of consideration the electric light which occupies a position by itself, we may, broadly speaking, distinguish between solid, liquid and gaseous illuminants, of which the candle, the oil-lamp and the gas-flame are representative forms. It would be interesting and instructive to trace the history of the different kinds of artificial light employed both in domes- tic and in street lighting at various periods of history, and to follow the successive im- provements in lighting introduced by men of talent and inventive genius. It seems indeed a gigantic step forward from the crude methods of lighting employed by 8 the ancients to the gas-light and the elec- tric-light of the nineteenth century. But the glow of the camp-fire, the light from blazing logs, or from torches made of splin- ters of resinous wood, as exclusively em- ployed by our forefathers, may even now- adays be found in use by the Indians and other uncivilized tribes. It may, therefore, be said that the means for artificial illumi- nation employed at the present time are an indication of the more or less advanced state of civilization of a nation. The burning log and the blazing resinous pine torch are the oldest and crudest methods of lighting. Oil was burnt by the Phoenicians, the Greeks and the Romans in primitive forms of open-vase lamps, into which a cotton or flax wick dipped. The Romans used the first candles in the form of rushes covered with wax or tallow, or of rope saturated with pitch or resin. These candles were gradually improved and formed, during the Middle Ages, the principal means of church illumination, and were likewise used in castles at court festi- 9 vals. Later on, the smoky and ill-smell- ing tallow candle was replaced by the better forms of drawn or cast candles, made from sperm, paraffine, wax and stearine. The modern improved candle differs from the candles employed in the last century principally in the method of manufacturing the wick, which as the candle grows shorter in burning, is con- sumed and reduced to ashes, thus render- ing the use of the " snuffers " of our grandfathers, which many of us still may remember, unnecessary. The rude forms of lamps employed by the Romans and Etruscans have been gradually displaced by lamps of improved construction, with closed oil-reservoirs, improved wicks and variously shaped burners. Argand invented and developed the round form of burner and wick, the oil ascending from the reservoir into the wick and to the tip of the burner by capil- lary attraction. Carcel made further im- provements by placing the oil-reservoir at the bottom of the lamp, where it would not throw a disagreeable shadow. In this 10 form of lamp the oil has to be forced up to the wick by means of a pump, or in the later " moderator " lamp, by a spring act- ing upon a leather plunger. The liquid illuminant employed in these lamps was either colza oil, olive oil or some other vegetable oil. Still later, and belonging to the present century, came the use of kerosene or min- eral oil in lamps, this illuminant being a liquid improved by distillation and refin- ing, which operations remove the more volatile, highly inflammable and, there- fore, dangerous ingredients of the oil. Equally as varied as the means employed for domestic illumination have been those in use at different periods of history for the lighting of streets, highways and public squares. In the larger cities the darkness of the evening hours was at first dispelled in a measure by the use of flaming torch-lights, of fire-baskets and of candles burnt in glass-lanterns, which were either carried by hand or hung out from windows. Later on, the candle-lanterns were replaced by oil-lamps, with wick and reflector, and 11 these in turn were superseded by the intro- duction, at the beginning of this century, of coal-gas burnt in street-lanterns, while to the gas-light now so universally em- ployed, both for domestic and street light- ing, a formidable rival has during the past ten years arisen in the electric arc-light and the incandescent electric glow-lamp. HISTOEICAL NOTES ON GAS LIGHTING. Wonderful as have been the many and rapid improvements made in this last form of illumination, viz., the electric-light, it must be admitted that the progress of gas- lighting has been no less astounding. The present generation who have wit- nessed the advent of the electric-light have become so accustomed to the use of the ever- ready gas-flame, that few are probably aware of the difficulties which beset the path of the talented men of science who created and introduced lighting by gas. It is a matter of historical record that when Murdock, one of the pioneers of gas- lighting, appeared in 1809 before the 12 House of Commons Committee, he was asked by one of the members of the Com- mittee, " Do you mean to tell us that it will be possible to have a light without a wick?" and upon his replying, " Yes, I do indeed," the same person replied, " Ah, my friend, you are trying to prove too much." We are also informed that Samuel Clegg, an engineer to whom the world is indebted for many important improve- ments in gas-manufacture and gas-distribu- tion, was sarcastically asked by Sir Hum- phrey Davy, who considered the idea of public gas-lighting ridiculous, if Mr. Clegg intended to take the Dome of St. Paul's for a gasometer. The great Napoleon laughingly remarked of gas-lighting, " C^est une grandefolie" and Sir Walter Scott considered it a vision- ary scheme and expressed fears that "Lon- don would be on fire by it from Hackney Gate, to Tyburn " [east and west extremi- ties, then, of London]. Indeed, when the House of Commons was first lighted by gas, the astonished 13 citizens of London were in such fear of burning their fingers when touching the gas-pipes for the conveyance of gas that they first carefully put on their gloves. When Westminister Bridge was first fitted up for illumination by gas-lamps, the lamplighters refused to light the lamps. In 1815, the London Fire Insur- ance Companies refused to insure build- ings lighted with gas. To overcome their prejudices, Samuel Clegg invited the Un- derwriters to inspect the gas-works, and after explaining to them the process of gas- manufacture, and the method of stor- ing the gas at the gasometer, he quickly took a pick and cutting a hole in the dome of the gas-holder, lighted the escaping gas without danger or explosion, and thus demonstrated to their satisfaction the com parative safety of the new light. ADVANTAGES OF GAS. Many are the advantages of gas for household purposes, and its disadvantages are comparatively few, and for this reason 14 It is prooably more used in houses at the present day than any other form of artificial illumination. Gas-light is relatively cheap, although kerosene oil per se, is probably cheaper. But, in comparing gas and oil, one should not forget the additional cost caused by wear and tear and breakage of oil-cans, glass-chimneys and shades of oil-lamps. Gas-light is convenient, and saves domes- tic labor by being always ready for instant lighting, whereas lamps require preparation in filling and in trimming the wicks, while time and labor are consumed in procuring candles or oil. GasJight is superior in point of cleanli- ness to oil-lamps and candles, because there is no spilling of oil, no dropping of candle- grease, no greasy or oily hands from the cleaning of lamps; there is no smoking of candles and no offensive odor such as attaches to oils and fats. Gas-light is brilliant, yet easily con- trolled, readily increased or diminished, and not difficult to manage by persons of ordinary intelligence. 15 Gas-light is comparatively much safer than candles or lamps in which colza oil or kerosene is burned. The carrying about of candles or lamps, with the unavoidable danger from fire or from lamp explosions, is rendered unnecessary, as only a match is required to light the gas at the burner. Gas-light, finally, creates in proportion to the light developed less disagreeable heat and is less unhealthful than candles or oil-lamps, where proper ventilation of rooms is provided. The increased illumi- nation by gas-light in our streets, squares and parks, as compared with the former semi-darkness, has been a great protection to property and life, and the parks and alleys of our cities are not so much as formerly the haunts of the vicious and the criminals, for efficient public lighting is the best safeguard against the commit- ment of crimes. With the advent of gas-light an entire revolution in social life has taken place, and civilization owes not a little of its progress to the increased illumination of 16 the streets as well as of buildings for amusement, worship and education. Incidentally I would call attention to the many other uses to which coal or illuminating gas has in recent years been put. Gas is used for heating rooms, heat- ing sadirons, heating water; gas is em- ployed for cooking, roasting, baking, steam- ing, frying, boiling and broiling; gas is adopted as fuel to drive small domestic motors, gas-engines of various kinds, gas and caloric pumping-engines, also for heat- ing soldering-irons, and for various other industrial purposes, and, finally, it is ex- tensively employed for artificial ventilation by means of gas-jets burning in exhaust- flues, or by the use of sun-burners. More recently, with the arrival of the incandescent electric glow-lamp, much has been said about the injurious influence of gas-lights upon health, of the vitiation of the atmosphere of rooms, and of the des- tructive effects of gas, when imperfectly consumed, upon the furniture and decora- tions of a room, to say nothing of the smoking-up of ceilings and walls. E But notwithstanding the rapid develop- ment of domestic electric-lighting, and not- withstanding also the recent return in dwellings to the use of oil-lamps, which on account of their softer and steadier light, are by many preferred for reading and sewing, and to the use of extensive and costly paraffine and wax candles in luxu- rious gilt or silver candelabras and sconces, a use dictated by the ruling fashion on account of the beautiful soft and mellow illumination obtained, the use of gas in dwelling-houses, offices and stores is un- doubtedly so convenient and comparatively safe, that for many years to come it will constitute the chief means of artificial illumination. To quote from R. H. Patterson's article on " Gas-burners and the Principles of Gas Illumination " in King's " Treatise on Gas ": " Any one who learns from the ex- perience of human customs and affairs, will feel assured that gas-light, although perhaps with shorn honors, has still a long career of usefulness before it, and that the admirable improvements in its ap- 18 pliances made within the last twelve 01 fourteen years, will not be robbed of their usefulness by a shunting aside of the illu- minant to which they have given a new economy and additional brilliance, and which still, as of yore, is of such vast and ever-ready service to mankind. " Gas-lighting has undoubtedly been the most beautiful, arid well-nigh the most useful triumph which human invention has yet achieved in the present century. For marvellousness it cannot vie with the electric telegraph ; for utilitarian value it cannot rank with the steam locomotive and railways. Nevertheless, but for its com- monness, even poetic genius would find a congenial theme in the process which evokes the * spirit of coal,' and, convert- ing it into a spirit of light, conveys it as an invisible fluid under our streets rising from below, wherever required, in pil- lared jets, to displace the darkness of the night hours, and flood our roads and streets with a warm and comely radiance. No spirit of the mine, even in fairy tale, has so blessed mankind. Passing from our 19 streets it enters our dwellings, both rich and poor, as an ever welcome and valued visitor, giving to the word * home ' a new attraction, brightening the dwelling, and enabling us to pursue our work, and to taste the enjoyments of common life, as it we could cpmmand the sweet daylight to attend us at our pleasure. Thanks to gas- light, there is no night in our dwellings save such as we choose for our own com- fort. It has illumined the former darkness of our halls and crooked staircases. From the gaselier in the dining-room it has made sparkling the glass and silver on the fes- tive board, and lit up the kind and jovial faces of the company, making banquet or homely board lightsome and merry ; while in drawing-room or * assembly' it has flooded the room or hall with a radiance but for which the dance would lose much of its gaiety, and beauty with its bright costumes would be shorn of its brilliance. In the bed-room, too, still more where there is helpless infancy or sickness where child has to be watched, or some sore-pained and weary-hearted invalid has 20 to be tended, longing at times for light to break the dull, drear monotony of night's darkness there, too, has the ' spirit of coal ' been a priceless boon ; existing when not wanted, as a mere speck of light with- in the mellowed globe through which it shows softly as a spot of luminous haze; yet ever ready, on the mere turning of a tap, to spring instantaneously into full illu- mination " I do not propose to treat in these pages of the various processes used in the manu- facture of coal or illuminating gas, nor of the proper distribution of gas through the streets of a city, nor shall I discuss the public lighting of streets, alleys, squares and parks. I shall take up the subject of gas from the point when it is brought to the con- sumers' premises, and shall endeavor to explain how gas may advantageously be employed in the illumination of our dwell- ings, incidentally mentioning other do- mestic uses of coal gas. My book will not give detailed technical or workshop instruction regarding the 21 practical work of the gas fitter in piping a house for gas, from the gas-fitter's point of view only. The following pages are intended chiefly for the instruction of the gas consumer, the householder, but incidentally they will contain much information useful to those contemplating the building of a house, and to architects, builders, gas engineers and gas-fitters as well as sanitary inspectors, enabling them to acquire a better knowl- edge as to how best to introduce, dis- tribute and utilize gas and gas-lights in buildings. USUAL DEFECTS OF GAS-LIGHTING AND GAS PIPING. It is, unfortunately, true that, as a rule, not much attention is paid by architects and builders in the erection of new build- ings to the means required for artificial lighting by gas. In the case of ordinary dwelling houses and stores the whole matter of gas distribution is left to the gas-fitters, many of whom employ either incompetent, inexperienced or careless mechanics, the architect concerning himself chiefly with the selection of ornamental gas fixtures which form a part of the interior house decora- tion. The details of gas-piping and gas- fitting are seldom looked into, except in the case of large and important structures, such as churches, halls of audience and theatres. Wherever gas-light illumination is de- ficient, laymen are generally inclined to grumble about the gas-works, attributing the cause to the poor quality of the gas furnished by gas companies or to lack of pressure in the pipe system. There is, of course, occasionally good reason for the complaint that the gas supplied to con- sumers falls far below the standard, but in the majority of cases the chief causes of bad illumination may be looked for in the gas apparatus of dwellings, in other words, in defective gas-fixtures, gas-burners, gas- globes and gas-piping. The general public is usually ignorant and indifferent about the subject. The gas companies, with few exceptions, do not 23 keep the householder or gas consumer in- formed about the ic mysteries" of the subject, although it would be to their in- terest, without doubt, to enlighten the public, and to help them in every way possible to get the maximum amount of light and illumination from the consump- tion of a given quantity of gas. Next to plumbing, heating and ventila- tion, there is no part of interior house con- struction requiring as much attention as the gas piping and gas fitting. Gas piping in buildings should be done according to carefully drawn specifications, experienced gas fitters should be employed in the work, no part of the work should be "skimped," and the distribution system with its numerous connections should re- ceive a proper amount of attention on the part of the superintendent of the building in order to insure that the gas fitting is done right and that there are no defects. The gas fitter should work from a carefully drawn sketch plan, showing the run and distribu- tion of all gas service pipes in the build- ing, showing location of the gas meter, or the several gas meters (where the building is subdivided into suites of rooms, each suite having its separate meter,) also the location of the main gas cock, or of the several shut offs, in the case of large build- ings. The plan should also indicate the precise location of the gas risers, and the size of the same, and in each room and in the halls the side or bracket lights and the drop or centre lights should be clearly marked. The number of outlets on each floor, the number of burners at each out- let and the sizes of pipes should also be indicated, and the superintendent should allow no deviation from the sizes specified. But, let us inquire what the usual prac- tice in this respect is ? A brief specifica- tion calls for "the house to be piped for gas in the best manner, and according to the rules and regulations of the gas com- pany which is to furnish the gas to the house." The work is, as a rule, given out by contract to the lowest bidder. In the majority of cases the gas fitting of a build- ing is included in the plumber's work, and in estimating for both plumbing and gas 25 fitting a small amount is usually allowed for the gas fitting work. If the contractor has put in a low bid for the whole work to cut out more honest competitors, the gas fitting work is usually the feature most readily neglected. Gas companies do not, nowadays, exercise a general supervision over the piping, and rarely send a gas in- spector when the pressure test is being ap- plied. The gas fitting is not looked after by the architect, and in order not to lose money on his contract, the contractor buys an inferior quality of gas pipes and fittings, reduces the sizes of all service pipes and puts in a much larger amount of the smaller sizes of pipes than is allowed. The jointing is done in a slovenly manner, and the whole work is usually put up in a great hurry, the gas fitter being notified at the last moment that the lather and plasterer are waiting. The pipes are covered up, permanently hidden from sight, and buried in plastering as soon as put in place. The testing of the pipes cannot be done in a thorough manner, because the gas fitter is hurried, and the result is necessarily that 26 instead of obtaining a system of gas pipes of proper size, properly run, properly graded, and perfectly tightened, the work is more or less defective, containing pipes of too small calibre, which soon choke up with rust and obstruct the flow of gas, split pipes, fittings full of sand holes, loose and leaky pipe joints, drops taken out from the bottom of running lines, bracket lights run from overhead instead of from below, condensation running into fixtures instead of into risers, nipples not at right angles to the wall or ceiling from which they project, distributing pipes trapped by sag- ging, etc. All such errors in the gas pip- ing often lead to an inadequate supply of gas and subsequent trouble with bad light. Of course, it is supposed to be the archi- tect's or superintendent's duty to see that all this does not happen, but there are in house-building so many other important matters of detail to be looked after, that the gas fitter is allowed to do as he pleases, except as to the exact location of side lights and chandeliers, which are laid out by the architect. Even where a careful gas-fitting specification has been drawn, irresponsible gas fitters will pay little at- tention to its requirements, unless carefully and continually watched. Since there is no official inspection of gas piping in most cities, smaller towns, villages and particularly in the case of iso- lated country residences, the house owner has to rely almost entirely upon the honesty of the gas fitter, hence there is wisdom in employing only first-class firms in this work. Aside from the obvious necessity of doing gas piping in the best manner in order to obtain good illumination, defects in gas piping should be avoided to guard against unhealthf ul influences, such as gas leaks, to which we shall refer hereafter. A strict inspection and supervision is, therefore, much to be desired from a health point of view, and the whole subject is properly deserving the attention of those who make a specialty of sanitary house construction. 28 GAS SERVICE PIPES AND GAS METERS. The gas service pipe by which gas is " laid on to a house " is always put in by the gas company. The size of the service pipe is governed by the number of burners to be supplied, but the rule should be laid down that no service, even for the smallest house should be less than one inch inside diameter. While this size is slightly larger than called for by the requirements of small dwellings, it will prove more satis- factory in the end, as such pipe is not so liable to stoppages, and the cost of using the larger pipe is but a trifle more. Be- sides, it often happens that additions are subsequently built to the house, and the pipes of such houses often become insuf- ficient and inadequate for the service which they have to perform unless allow- ance is made in the beginning for a pos- sible increase in the number of lights. In determining the sizes of service pipes and this refers to the distributing pipes in the house as well it should be borne in mind that where water gas or naphtha gas is used, the sizes should be increased 15 to 20 per cent, over those required for coal gas. The material for the main service pipes from the street into the house is either lead or wrought iron. Cast iron pipes with lead caulked joints are used only for very large buildings, i. e., those requiring gas pipes, four inches in diameter and up- ward. As a rule, wrought iron screw- jointed service pipe is preferred to lead, at least in America, probably because lead pipe is liable to sag in the trench and thus create dips in the pipe, which would accu- mulate water of condensation and thereby become the cause of the flickering of lights, or may even cause the gas to cease flow- ing. Certain precautions must, however, be observed, in the use of wrought iron service pipes, such as laying the pipes in trenches with a firm bottom and protect- ing the outside of the pipes with asphalt or coal tar, where they are laid in soils containing acid or alkaline residues, or mixed with ashes, cinders, furnace slag or chemical refuse, which cause a quick cor- rosion and destruction of the pipe. 30 The service pipe should preferably rise from the street gas main toward the house, in order to allow all condensation to run back into the mains. This, however, cannot always be accomplished, owing to the rela- tive levels of the street main and the gas meter in the house. The latter should be placed in a cool, easily accessible and well- lighted place at the lowest point at which gas is to be burned, usually the cellar, which in city houses is below the level of the street gas main. It, therefore, be- comes necessary to carry the service pipe in a descending line towards the house, and a drip pipe, usually called a " siphon " by gas-fitters, is put in the cellar, and left capped. When water accumulates at this point, the cap is removed and the pipe drained. Under no circumstances should there be a trapped gas service pipe between the house and the street main. The gas company supplies and sets the gas meter, usually a " dry " meter, which is preferred in America, because it registers more accurately, requires less attention and is not as liable to be injured or deranged in 31 frosty weather than a wet meter. The dry meter is apt to give trouble only where the gas is very impure and contains large amounts of naphthaline, causing the dia- phragm in the dry meter to stick. Tlie size of the meter must, of course, be in proportion to the total number of lights supplied, and it is well to obtain a gas meter of ample capacity. Occasionally the cause of bad illumination may be found in a gas meter of insufficient capacity. The gas company usually places a stop cock or valve turned by a long key on the service pipe near the curb, in order to be able to control and shut off the gas from each building separately. This is always done on service pipes IK inches and larger, and it is insisted on by building laws in the case of theatres, but it is well not to omit the shut off, even in the use of smaller services. The meter is connected with both the service pipe and the main house pipe by means of short connections of extra heavy lead pipe. A gas cock is placed near the meter, and in large buildings this is 32 arranged so that a lock may be attached to it, when the gas is shut off, the com- pany retaining the key to the lock. Globe valves as well as stop cocks do not open to the full capacity of the service pipe, hence straight- way or gate valves on gas service pipes which give an unrestricted flow of gas are much to be preferred. GAS DISTRIBUTING PIPES. The gas pipes inside of a house are, as a rule, wrought iron pipes, except where carried exposed in offices, or on walls lined with enameled brick or tiles, when copper or polished brass pipes are sometimes used. In England and on the Continent lead and composition pipes are much used, occasionally even block tin pipes, but in America, all soft metal pipes are considered objectionable for the same reasons which in plumbing work govern the preference of heavy iron to lead soil and waste pipes. All soft metal pipes, if used for gas, are liable to sag and have depres- sions, accumulating water of condensation. When carried under floors or buried in 33 walls or in partitions, they are very liable to have picture or other nails driven into them by careless workmen. In places acessible to, or frequented by rats, exposed lead pipes are liable to be gnawed, and finally they melt quickly during a fire, thus adding fuel to the flames. The chief requirements of plain wrought iron pipes for distributing gas are that they are carefully welded and that they are perfectly round and regular in section. The fact that gas pipes often split in cut- ting or threading them on the pipe bench, and that in testing gas piping, lengths are occasionally found with flaws at the weld, will be better understood when it is con- sidered how such wrought iron pipes are manufactured at the mills. Long strips of wrought iron varying slightly in thickness and of different widths corresponding to the diameter of the pipes, are bent into a circle. When the two ends or butts of the iron meet, the same are, while still hot, welded together under pressure. It is, therefore, apparent that the weld is the weakest part of the 34 pipe and that it must be done with partic- ular care and skill. Where pipes are re- quired to stand a great internal pressure, as when used to convey water or steam under pressure, the welding is rendered stronger by overlapping one butt over the other, and the pipe is accordingly called " lapwelded " pipe. Gas pipes are not re- quired to withstand any strong internal pressure; nevertheless the welding should be perfect, and hence it is better to use, at least for sizes above \/i inch, lapwelded gas pipe. The smaller sizes, from % inch up to 1/4 inch are buttwelded. Pipes should be examined for such defects by hammer test and sounding. The other requirement, namely that the pipe should be perfectly circular in sec- tion, is equally important. All gas pipes are put together with screw joints, a thread being cut upon the outside of the pipe. Where the pipe contour is irregular the threading will be more or less imper- fect, and as a result there will be defective joints. A good gas-fitter must, therefore, examine all gas pipes as delivered at the 35 building, and observe either by the eye or by means of calipers the regularity of the section. In some cases it is advisable to cut test threads. All defective pipe, whether imperfect in welding or in con- tour, should be rejected and at once re- moved from the building. In this as in so many other matters, the contractor can protect himself, at least to a certain extent, by buying his pipe from reputable firms only, who are known to be reliable, and by insisting that all pipes be tested under hydrostatic pressure at the pipe mills be- fore being delivered at the building. Plain wrought, iron pipe is liable to corrode and to rust on the inside, especially where the gas supplied is imperfectly puri- fied, and the smaller sizes are particularly liable to become obstructed. At the foot of vertical risers and branches the iron scale is very apt to lodge, and hence it may be advisable to use, under certain conditions, pipes made rustless, either by the Bower-Barff process or by galvanizing in the best possible manner. In practice it is found that the danger of rust is confined 36 to the smaller sizes, hence it is not neces- sary to use pipes protected against rust, for the main riser and the larger distribu- tion pipes. Still, where economy is no object, it seems to me to be preferable to use rustless gas pipes throughout, and I have had many first-class residences piped in this manner with the best results. PIPE FITTINGS AND PIPE JOINTS. In joining together lengths of wrought iron gas pipes, certain fittings are used, for instance sockets or couplings for straight runs, and elbows, tees and crosses for changes of direction and for taking out branch pipes. Other fittings not so ex- tensively used, are the union, the flange union, the running socket and the right and left couplings, the latter used whers pipes can be sprung. These fittings are either of cast iron, or of malleable iron, the latter preferred for the smaller sizes. Fit- tings may be galvanized or made rustless by the Bower-Barff process, and it is par- ticularly necessary that sandholes be avoided in all cast fittings. 37 In making pipe joints the gas fitter should make use of red lead or red and white lead mixed on all joints to make up for any possible imperfections in the threads; but I may here remark that I consider the dipping into, or filling of fittings with, red lead objectionable as having a tendency to reduce the full bore of the pipe. The use of gas fitters' cement on pipe joints should be absolutely pro- hibited. It is also important that each length should be screwed entirely home before the next length is put on. It is al- ways a wise precaution, in putting the gas-piping together, to examine every length of pipe carefully to make sure against any obstructions on the inside of the pipe. How TO RUN GAS PIPES IN BUILDINGS. The proper manner of running the gas distributing pipes in a building is suf- ficiently explained in a subjoined " Spec- ification for Gas Piping," and a few hints given here may suffice. 38 It should be the rule to keep all large gas risers exposed, instead of burying them in the walls or plaster, and to arrange the piping as much as possible so as to be readily got at. All horizontal distributing pipes must run with an even, though slight pitch toward the riser, and all depressions in such pipes must be avoided as tending to collect water and forming traps, hence pipes should be firmly supported at fre- quent intervals, particularly the smaller sizes which are not as stiff and easily sag or bend in the middle. Floor boards over all horizontal gas pipes should prefera- bly be fastened down with brass screws to admit of easy removal for alterations, inspections or repairs. When it becomes unavoidable to trap a pipe, a drip with drain cock must be put in, but this should be avoided under floors, and always put in an accessible position, for occasional re- moval of the condensed water or deposit of pitch which collect in the drip. The gas litter must use his best judgment in substituting at suitable points cross pieces instead of Tee branches, and closing the 39 opening of the cross opposite the branch by means of a plug forming a cleaning cap. All these precautions are particularly necessary where the gas is apt to leave de- posits of tarry matter or naphthaline in the pipes which cause obstructions and re- quire in their removal the use of a force pump. The proper size for all distribution pipes should be regulated by a table of sizes, one of which is given in the appended specification, while another may be found in the Munich gas rules at the end of the book. Both tables, which the writer has applied in many cases in his own practice, give sizes slightly larger than required for coal gas, but it is always poor economy to use pipes of too small calibre, which soon become insufficient to furnish the quantity of gas required at burners, particularly at chandeliers and Argand burners. It should be a rule that no pipe for a drop light should be less than ^ inch in diameter, and no pipe for side lights less than % inch. 40 TESTING GAS PIPES. As soon as the gas piping is completed it should be tested by means of a as fit- J o ter's pump and manometer or mercury gauge. Before proceeding with the pipe testing all deviations from the true position of nipples for brackets or centre lights must be rectified. In the case of large buildings, the gas fitter should preferably test the pipe system in sections, one iioor at the time, and afterwards, when all floors are connected with the main riser or risers, the whole system should be subjected to a final strong test in the presence of the architect, engineer or a gas company's in- spector, who furnishes a certificate to the owner. All leakage reveale.d by the test should be at once repaired, avoiding en- tirely the use of gas fitter's cement, which cracks and breaks off very easily, or melts from heat where gas-pipes are located in close proximity to steam-pipes. The test must then be repeated until the whole sys- tem is perfectly air tight under an air pres- sure of from 15 to 20 inches of mercury. This testing of gas-pipes is of the utmost importance to prevent subsequent annoy- ance, trouble and danger from gas leaks, resulting from pin holes in pipes, sand holes in fittings, split pipe, loose joints, im- perfect threads, or outlets carelessly left without capping. Regarding the careful proving of gas- piping in buildings in course of erection, as well as in buildings already completed and occupied, I cannot do better than quote the following clear description, given in the Sanitary Engineer and Building Rec- ord, Vol. XL, May 14, 1885: " If the house is in progress of construc- tion, see that all the outlets are carefully closed with caps, and that the foot of the rising line is stopped. Then at any con- venient side-light attach the ordinary gas- fitters' pump, which is simply an air-pump. To the same side-light, or an adjacent one, attach the mercury-column gauge used by gas-fitters with a column from fifteen to twenty inches in length. " Great care must be now taken to prove that there are no leaks in the gauge or its connections or cock, and in the pump and hose connection, and a good cock should be used between the permanent gas-pipe and any temporary connections to pump, so that it may be closed immediately after the pumping stops, to prevent back-leak- age of air through the pump-valves or hose-joints. . " When all is complete, pump the pipe system in the house full of air until the mercury rises at least twelve inches. Then close the intermediate cock before men- tioned, and should the mercury column be found to " stand " for five minutes, it is reasonable to assume that the pipes are sufficiently air and gas tight for any pres- sure they can afterwards be subjected to. But it is the rule in the most carefully done gas-pipe work to find the mercury will not " stand," as there will be leaks that would escape the most careful work- man, it is necessary then to locate them. " Should there prove to be a very large leak, it will be apparent at once, as it will be impossible to get a pressure worth con- 43 sidering, the mercury simply bobbing up and down in the tube. "It may be an outlet that has been neglected to be closed, or it may be a long split in the pipe. If the former, and very close to the pump, the mercury will not respond; but should it be far away, with considerable length of pipe to cause resist- ance, the mercury will jump and return as suddenly. But should there be a split pipe ov an aggregation of small leaks, the mer- cury will run back steadily, though slower than it rises, between the strokes of the pump. Should it rise well in the glass and sink at the rate of about one inch in five seconds, small leaks only in fittings or joints may then be anticipated. Of course? there are exceptions to these rules, which are only for general guidance. " To locate a leak, then, that cannot be heard blowing, strong soap water applied with a brush or sponge may be used. The liquid is rubbed over suspected joints or fittings and air-bubbles are blown by the escaping air. 44 " Sometimes it becomes necessary to use ether in the pipes in locating leaks, if the pipes are under floors or in partitions. The ether is put into a bend of the hose or into a cup attached to the pipe and blown into the pipes with the air. By following the lines of the pipes the approximate position of a leak may then be determined by the odor of escaping ether. " In very large work it is well to prove a floor at a time, and when all are done, connect them with the riser and prove as a whole. u The best thing for making pipes tight for coal-gas is gas-fitters' cement, which is a common grade of sealing-wax. The threads of the pipes should be immersed in it when warm and let drain, and the fittings also are sometimes so treated. To put the pipes and fittings together both are warmed and screwed tightly and allowed to cool. Porous places incidental to malleable iron or shrinkage-cracks in malleable iron fittings are generally stopped with this cement, but a split or 45 crack should never be so mended, as it will be an element of danger.* " For naphtha-gases some of the heavy body asphaltum varnishes are considered best, such as black air-drying japan, or black baking japan, but paraffirie varnish should not be used. To use the japans both threads of pipes and fittings should be dipped in them and drained, and the japan should be applied with a brush when putting them together, the same as using lead. Red and white lead are also good, but are with more difficulty made air-tight. " If the house is an old one, or has been finished, and you have to test for leaks, take off the meter and cap the bottom of the riser; also unhang the gas-fixtures and remove the brackets, and cap all outlets carefully. Then use ether and locate leaks before tearing up floors or breaking plaster. * The author cannot endorse this recommendation of the use of gas-fitters' cement. He, on the contrary, con- sult rs it a dangerous practice, which should be prohibited strictly, for such cement is liable to crack and break when cold, and when exposed to the heat of steam-pipes it is apt to melt at any time, and hence joints made tight with gas- fitters' cement cannot be relied upon to remain so. 46 " The mercury should be made to stand remain stationary in the glass if pos- sible, before the work is passed, but a fall of one inch of mercury in an hour would indicate a comparatively tight job. " Occasionally, when a gas-fitter cannot get a job tight, there is a possibility he may cut off the part or floor of the build- ing he cannot get sufficiently tight to suit the inspector's idea of perfection. The in- spector can only prove such practice by re- moving or slacking off a cap here or there about the house if he suspects such an at- tempt. If no air escapes, then he has the dead end." Mr. William Eassie, the well known English sanitary expert, writes on this sub- ject in his " Sanitary Arrangements of Dwellings " as follows : " In England as a rule, we are culpably careless about our gas supply. A gas com- pany, for instance, receives notice that the service of such and such a house is ready to be connected with their main, and when they have obtained a signed agreement setting forth who is responsible for pay- ment, the meter is connected forthwith, and there is an end of it. The gasfitter may have done many things badly, and not done some things at all, but the gas company seldom, very rarely ever, exer- cises any jurisdiction. The gasfitter next sends in his account, which is paid, and when the smell of escaped gas from some faulty portion of the pipes has become un- bearable, he is sent for to remedy it, and charges for the rectification. The work- man may be thoroughly incompetent, as gasfitting is not, as it should be, a separate trade. Indeed, the artisan who performed the work may be a blacksmith, whitesmith, glazier, brazier, plumber, bellhanger, and gasfitter all rolled into one. " A gas-titter who is a gas-fitter, and who understands his business, will never take leave of a house until he has tested the pipes for leakage. Where this trouble is taken, the ordinary practice among us is as follows: When the pipes have been laid throughout the house, and the company's main connected to the meter, a temporary burner is fixed to each floor of the house, 48 and the gas is turned on. The gas is now- ignited at these trial jets and allowed to burn for some little time. The main is then turned off, and at the same time the exact reading of the index is taken. When the gas left in the pipes has burnt uut, the taps of the experimental lights are turned off, and if, after the lapse of an hour or so, the dial of the meter continues to indicate a consumption of gas, it is plain that it somewhere escapes, and the leak is searched for by the sense of smell, &c., and remed- ied." The same writer describes his own prac- tice of testing gaspipes as follows : " Before the gas-fitter asks the gas com- pany to make the connection with their main, he sets about proving the pipes. He stops up, with one exception, all the out- lets which have been left for brackets and pendants with plugs or with screwed caps. On the one not so stopped he attaches a force-pump, into the interior of which has been put a few drops of sulphuric ether. This pump is now connected with a gauge, and it is then set to work, generally until 49 a high pressure is registered. A high pressure in a gas-pipe at first appears un- necessary, but gasfitters know very well that iron pipes have many latent weak- nesses, so to speak seams just ready to open, pinholes filled with grease,