TK 4161 CM 1919 General Lighting Safety Orders UC-NRLF Issued by the Industrial Accident Commission of the State of California 525 MARKET STREET, SAN FRANCISCO Effective December 1, 1919 CALIFORNIA STATE PRINTING OJTIC1 SACRAMENTO 1919 General Lighting Safety Orders Issued by the Industrial Accident Commission of the State of California 525 MARKET STREET, SAN FRANCISCO Effective December 1, 1919 CALIFORNIA STATE PRINTING OFFICE SACRAMENTO 1919 (7800 INDUSTRIAL ACCIDENT COMMISSION OF THE STATE OF CALIFORNIA 525 Market Street, San Francisco 423 Union League Building, Los Angeles , Chairman. A. H. NAFTZGER, Commissioners. H. M. WOLFLIN, Superintendent of Safety. SUMMARY OF THE SAFETY PROVISIONS of the Workmen's Compensation, Insurance and Safety Act. Being Chapter 176 of the Laws of 1913 as Amended by Chapter 607 of the Laws of 1915, and Chapter 586 of the Laws of 1917. Sections 33 to 54, inclusive, of the Workmen's Compensation, Insur- ance and Safety Act give the Industrial Accident Commission power to make and enforce safety orders, rules and regulations, to prescribe safety devices, and to fix safety standards. It also empowers the Commission to appoint advisers who shall, without compensation, assist the Com- mission in establishing standards of safety. The Commission may adopt and incorporate in its general orders such safety recommendations as it may receive from such advisers. The Commission, carrying out its plan of obtaining the best practical ideas to incorporate in its Safety Orders, asked various interests to serve on a committee to draft Tentative General Lighting Safety Orders. COMMITTEE ON GENERAL LIGHTING SAFETY OEDEBS. ROMAINE W. MYERS (chairman), consulting engineer (electrical and illuminating), representing the National Council of Defense, Divis- ional Committee on Lighting. L. E. VOTER (vice chairman), illuminating engineer, General Electric Company, representing the Association of Electrical Manufacturers and the Lighting Fixture Association. W. W. HANSCOM, electrical and mechanical engineer, representing the National Electric Light Association, Pacific Coast Section. SMITH O'BRIEN, architect, representing the American Institute of Architects. R. H. FENKHAUSEN, electrical engineer, Bethlehem Shipbuilding Corpo- ration, Union Plant, representing the American Institute of Electrical Engineers. DANIEL C. MURPHY, president California State Federation of Labor. PAUL SCHARREXBERG, secretary-treasurer California State Federation of Labor. R. S. PRUSSIA, illuminating engineer, Westinghouse Lamp Company, representing the Association of Electrical Manufacturers. MILES F. STEEL, Benjamin Electric Manufacturing Company, repre- senting the Association of Electrical Manufacturers. S. J. LISBERGER, Engineer, San Francisco District, Pacific Gas and Electric Company, representing the Pacific Coast Gas Association. CHAS. M. MASSON, illuminating engineer, Southern California Edison Company, representing the Illuminating Engineering Society. CONSTANT MEESE, Meese & Gottfried Company, representing the San Francisco Chamber of Commerce. F. DOHRMANN, JR., Nathan-Dohrmann Company, representing the San Francisco Chamber of Commerce. HARRY GORMAN, field agent, representing the Bureau of Labor Statistics. H. B. WOODILL, president Woodill & Hulse Electric C9mpany, Inc., representing the Merchants and Manufacturers Association of Los Angeles. W. A. CHOWEN, manager California Inspection Rating Bureau, repre- senting the Casualty Underwriters Board of California. D. AYRE, superintendent inspection department, California Inspection Rating Bureau, representing the Casualty Underwriters Board of California. HAROLD MESTRE, representing the Industrial Welfare Commission. ROBT. L. ELTRINGHAM, electrical engineer, representing the Indus- trial Accident Commission. JOHN R. BROWNELL (secretary), superintendent of safety, Industrial Accident Commission. Acknowledgment is made of the assistance rendered by the Illuminating Engineering Society in the preparation of these General Lighting Safety Orders, and for the use of the various cuts which they kindly loaned. M48977 GENERAL LIGHTING SAFETY ORDERS. Order 1500. Definitions. (a) Candle (or candlepower) means the unit of luminous intensity maintained by the national laboratories of the United States, France and Great Britain. (b) Lumen means the unit of luminous flux, and is the quantity of light necessary to produce an average intensity of illumination of one foot-candle over an area of one square foot. (c) Foot-candle means the unit of illumination equal to one lumen per square foot. It is the lighting effect produced upon an object by a lamp of one candlepower at a distance of one foot. (d) Photometer means a standardized instrument suitable for making illumination measurements. (e) Lamp means that part of the lighting equipment from which the light originates. (/) Local lamps (or lighting) means lighting units located close to the work, and intended to illuminate only a limited area about the work. (g) Overhead lamps (or lighting) means lighting units installed above ordinary head-level to secure a general illumi- nation over a considerable area. (h) Brightness means the intensity of light per unit area emitted from, or reflected by, a body ; and in these Orders is expressed in candlepower per square inch. (i) Glare means any brightness within the field of vision of such a character as to cause discomfort, annoyance, interfer- ence with vision, or eye fatigue. (j) Eyestrain means a physiological condition of the eye resulting in discomfort, poor vision, or fatigue. (k) Shaded means that the lamp is equipped with a reflector, shade, enclosing globe, or other accessory for reducing the brightness in certain directions, or otherwise altering or chang- ing the distribution of light from the lamp. (I) Illumination means the quantity of light received upon a surface ; it is measured in foot-candles or in lumens per square foot of area. (m) Intensity of illumination means the quantity of light received upon a surface, expressed in foot-candles or in lumens per square foot of area. GENERAL LIGHTING SAFETY ORDERS. 5 (n) Foot-candles at the work means the intensity of illumi- nation on the object upon which work is being performed. (0) Foot-candles at floor-level means the intensity of illumi- nation on the floor of the space specified. Order 1501. General Requirements. (a) Working or traversed spaces in buildings or grounds of places of employment shall be supplied during the time of use, with either natural or artificial light in accordance with the following Orders (1502-1509). Order 1502. Natural Lighting. (a) Windows, skylights or other roof-lighting construction of buildings shall be arranged with the glass area so appor- tioned that at the darkest part of any working space, when normal exterior daylight conditions obtain (sky brightness of 1.50 candlepower per square inch) there will be available a minimum intensity equal to twice that of Order 1503, other- wise artificial light of intensities specified in Order 1503 shall be provided. (&) Awnings, shades, diffusive or refractive window glass shall be used for the purpose of improving daylight conditions or for the avoidance of eyestrain wherever the location of the work is such that the worker must face large window areas through which excessively bright light may at times enter the building. NOTE. The intensity requirements for adequate day lighting are much higher than those for adequate night lighting, because in general under daylight conditions the light reaching the eye from all surroundings in the field of vision is much brighter than at night, and hence a correspondingly more intense light must fall on the object viewed. Order 1503. Artificial Light. (a) When the natural light is less than twice the minimum permissible intensities of illumination set forth in the following table, artificial light shall be supplied and maintained in accordance with the table. NOTE. See Appendix for intensities recommended for best working conditions. Foot-candles at the floor level 1. Roadways and yard thoroughfares 0.02 2. Storage spaces, stairs, stairways, halls, hallways, passageways, aisles, exits and elevator en- trances 0.25 3. Water-closet compartments, toilet rooms, wash- rooms, dressing rooms and elevator cars 0.50 b GENERAL LIGHTING SAFETY ORDERS. Foot-candles at the work 4. Work not requiring discrimination of detail, such as handling material of a coarse nature, and performing operations not requiring close visual application 0.50 5. Eough manufacturing requiring discrimination of detail, such as rough machining, rough assem- bling, rough bench work, also work in base- ments of mercantile establishments requiring discrimination of detail 1.00 6. Rough manufacturing requiring closer discrim- ination of detail, such as machining, assembly and bench work, also work in basements of mercantile establishments requiring closer dis- crimination of detail, intermediate between 5 and 7 2.00 7. Fine manufacturing, such as fine lathe work, pat- tern and tool making, also office work, such as accounting and typewriting 3.00 8. Special cases of fine work, such as watchmaking, engraving and drafting 5.00 9. Processes otherwise safeguarded in which light is detrimental i 0.00 NOTE. Some exceptions to the intensity rule : (a) There are some operations that are performed in compar- ative darkness, as for example, photographic processes in the dark room. (6) There are some operations that are best observed by their own light, as in parts of the process of working glass. (c) Some^ operations are best observed by the "silhouette" method of lighting in which the work is seen against a lighted background in a comparatively dark room, as in some processes of working with dark threads and lamp filaments. In all such cases in which work is of necessity carried on in comparative darkness, special precautions should be taken to properly safeguard the workmen. Order 1504. Measurements. (a) For the purpose of light measurements, a standardized photometer, certified by the Industrial Accident Commission of the State of California, shall be used, and such measurements shall be made at the locations specified in the table. Order 1505. Shading of Lamps for Overhead Lighting. (a) Lamps suspended at elevations above eye level less than one-quarter their distance from any positions at which work is performed, or where places are traversed, must be shaded in such a manner that the intensity of the brightest one-quarter square inch of visible light source shall not exceed seventy-five candlepower per square inch. GENERAL LIGHTING SAFETY ORDERS. 7 NOTE. The following diagram illustrates the application of the above rule, the distances being explanatory and representing the ratio between the height of the lamp above the eye level and its horizontal distance from the eye. L /nz -7 L a/npj be/o w the l/rr?/ there shown ft 02 td/s fa/rt must" be 3O -shaded thaf the. Casrd/e Power o fthe brtghfes t 3
-47f
10 GENERAL LIGHTING SAFETY ORDERS.
APPENDIX.
GENERAL INFORMATION AND SUGGESTIONS.
1. The foregoing orders give in the briefest possible form the
minimum requirements of lighting in factories, mills and other
work places to insure reasonable safety to workmen from
accident and injurious eyestrain. General information with
detailed discussion of the methods of applying the orders and
of obtaining adequate illumination to insure efficient production
are 'presented in this Appendix.
2. When adequate and satisfactory illumination is substi-
tuted for the all too prevalent poor illumination in factories,
mills and other work places, the results obtained are mutually
beneficial to the employees, the employers, and the country as
a whole. Under proper illumination conditions, the health,
contentedness, safety and skill of the employees are maintained
at a high standard, the output is increased in quantity and
improved in quality, while there is a proportional reduction in
the cost of each unit of finished products when it reaches the
public.
3. While it is desirable to have adequate light over the
working areas, it is absolutely essential for the proper results
to eliminate or minimize the light which otherwise would pass
directly from the lamps to the eyes of the workers ; that is, one
must avoid glare which is not only fatiguing to the eye but
also conducive to the incorrect estimation of sizes and locations
of objects in the field of view.
4. Glare effects may be caused not only by the light reaching
the eye directly from the sources having a brightness greatly
in excess of that of the objects viewed, but they may be pro-
duced by excessive reflection from the objects within view. In
factory lighting each lamp should be so located that the eye
does not see it in the ordinary course of work, and so shaded
or covered that brilliant reflections are avoided. The desired
result can be obtained by putting over the lamp an open shade
which screens it and reflects downward much of the light which
would otherwise be of either no value or actually detrimental.
Another way of accomplishing the same result is to surround
the lamp with a diffusing globe dense enough not to reveal the
form of the actual light source within, but to give the effect of
GENERAL LIGHTING SAFETY ORDERS. 11
the light pouring from the globe as a whole. Specific sugges-
tions for various locations are contained in this Appendix.
5. In the following descriptive matter may be found the
elements of good illumination versed in such manner that it
can be understood readily by the nontechnical mind. A
perusal of this subject will convince one that, aside from the
humanitarian standpoint, the expense incurred in obtaining
satisfactory lighting will, in practically all cases, result in good
financial returns.
6. Minimum and desirable illumination. The minimum
foot-candles in Order 1503 specify the lowest illumination with
which the employee can be properly safeguarded against acci-
dent. It is to the advantage of the employer to provide the cor-
responding intensities of modern practice listed in the follow-
ing table of desirable illumination, as such provision results in
reduced eyestrain, greater accuracy of workmanship, increased
production and less spoilage.
Desirable Illumination.
Foot-candles
at floor level Corresponding
modern minimum
practice Order 1503
1. Roadways and yard thor-
oughfares 0.05 to 0.25 0.02
2. Storage spaces 0.50 to 1.00 0.25
3. Stairs, stairways, halls, hall-
ways, passageways, aisles,
exits, elevator entrances
and elevator cars 1.00 to 2.00 0.25-0.50
4. Work not requiring discrim-
ination of detail 1.00 to 2.00 0.50
5. Rough manufacturing re-
quiring discrimination of
detail 2.00 to 4.00 1.00
6. Rough manufacturing re-
quiring closer discrimina-
tion of detail 3.00 to 6.00 2.00
7. Fine manufacturing, ac-
counting, typewriting 4.00 to 8.00 3.00
8. Special cases of fine work___ 7.00 to 15.00 5.00
12 GENERAL LIGHTING SAFETY ORDERS.
7. Table of Recommended Intensities for Detailed Operations and
Processes. (Expressed in foot-candles.)
Classification.
Assembling.
Rough assembling 2-6
Medium assembling 3-9
Fine assembling 4-12
Extra fine assembling 7-15
Automobile manufacturing.
(See machine shops, paint shops, woodworking shops, etc.)
Bakeries.
Mixing and baking 3-9
Banks.
Clerical and private offices 4-12
Desk and cage lighting 4-12
General illumination 1-3
Barber shops 4-12
Boiler, engine rooms and power houses.
Boiler rooms 2-4
Coal and ash handling 2_4
Engine rooms 3-9
Auxiliary equipment 2-6
Oil switch and transformer rooms 3-9
Switchboards 3-9
Storage battery rooms 2-6
Brewing, distilling and bottling.
Beer boiling 2-6
Bottling 3-9
Clearing or resting and fermenting 1-3
Cool ship 1-3
Keg washing 3-9
Keg filling 3-9
Buffing and polishing.
Medium work 3-9
Fine work 4-12
Button manufacturing.
Grading machines, wet and dry polishing 1-3
Grinding machines, cutting blanks and shells, card-
ing buttons, hand turning, automatic machines 3-9
Sorting of waste, sorting for thickness 3-9
Grading for color and defects 7-15
GENERAL LIGHTING SAFETY ORDERS. 13
Classification.
Candy making.
Cooking over furnaces 3-9
Cooling slabs 3-9
Cream beater machines 3-9
Dipping (hand) 3-9
Dipping (machine) 3-9
Moulding 3-9
Revolving pan 3-9
Spinning bench 3-9
AWights and measures 3-9
Wrapping and packing 3-9
('ii'inng and preserving.
Cooking 3-9
Assorting, cleaning, cutting and peeling 3-9
Hand filling .__ 3-9
Machine filling 3-9
Chemical works.
Furnaces 2-6
Tanks or cooking, extractors, percolators, nitrators- 3-9
Generators and stills 2-6
Drying 2-4
Evaporators 3-6
Filtration 3-6
Grinding 3-9
Crystallizing 3-6
Bleaching 3-6
Electrolytic cells 3-9
Clay products and cements.
Enameling 3_9
Grinding 2-4
Filter press rooms 2-4
Moulding and pressing 3-6
Cleaning and trimming 3-6
Coloring and glazing 4-12
Kiln rooms 2-4
Kiln yards -J-2
Cloth products. fif &*
Cutting 4-12 7-15
Sewing (machine) 4-12 7-15
Si-wing (hand) 4^-12 7-15
Pressing __^ 4-12 7-15
Inspecting 4-12 7-15
Cl>th treating (oilcloth, etc.) 3-9 4-12
14 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Construction Building, railway, tunneling, etc.
Indoor 1-3
Outdoor -2
Dairy products.
Separators, evaporators, churns, moulds and presses 3-9
Pasteurizing 3-9
Bottling, canning and labeling 3-9
Ice cream freezers 3-9
Depots.
Baggage rooms 1-2
Dining rooms 3-6
General offices 4-8
Waiting rooms 2-4
Loading platforms 1-2
Draughting rooms 7-15
Electric manufacturing.
Coil and armature winding 4-12
Mica working 4-12
Insulation moulding 4-12
Other insulating processes 4-12
Storage battery moulding of grids 3-9
Lamp manufacturing 7-15
Wire insulating 4-12
Elevators.
Freight and passenger 1-3
Fertilizer manufacturing.
Cookers, pressers, fertilizer dryers, fertilizer mills- 2-6
Forge shops and welding.
Rough forging 2-6
Fine forging 3-9
Drop forging 3-9
Foundries.
Rough moulding 2-6
Fine moulding 3-9
Core making 3-9
Charging floor 2-4
Tumbling and cleaning 2-6
GENERAL LIGHTING SAFETY ORDERS. 15
Classification.
Glass works.
Mix room 2-6
Furnace room 2-6
Casting and lehr 2-6
Grinding 3-9
Fine grinding and polishing 4-12
Glass-blowing machines 39
Cutting glass to size 3-9
Glass cutting (cut glass) 7-15
Beveling 4-12
Silvering 3-9
Inspecting 7-15
Etching and decorating 4-12
Glove manufacturing. goods. goods.
Sorting 1 4-12 7-15
Cutting 3-9 4-12
Stitching 4-12 7-15
Trimming and inspecting 4-12 7-15
Pressing 3-9 4-12
Knitting 3-9 4-12
Grinding, buffing and polishing.
Rough work 2-6
Medium work 3-9
Fine work 4^-12
Halls, stairways, passageways and aisles 1-2
Eat manufacturing.
Forming, sizing, pouncing, flanging, finish-
ing and ironing 3-9 4-12
Dyeing and stiffening 2-6 3-9
Braiding 2-6 3-9
Cleaning and refining 2-6 3-9
Sewing 4-12 7-15
Hospitals.
Corridors 0.5
"Wards, general (supplemented by local) 0.5
Wards, with no local lighting 1-3
Laboratories , 3-6
Operating tables 25-40
(See boiler and engine rooms, laundries, kitchens,
dining rooms, storage spaces, etc.)
16 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Hotels.
Kitchens 2-6
Dining rooms 3-6
(See engine and boiler rooms, offices, storage spaces,
stairways, passageways, laundries, etc.)
Ice making 2-6
Inspecting.
Rough inspecting 2-6
Medium inspecting 3-9
Fine inspecting 412
Extra fine inspecting 7-15
Jewelry and watch manufacturing.
Bench work and extra fine machine work 715
Machine work 715
Stamping 7-15
Engraving 7-15
Jewel working 7-15
Laundries and dry cleaning.
Sorting and marking 3-9
Washing 2-6
Mangles and machine ironing 3-9
Pressing and hand ironing 39
Dry and steam cleaning 3-9
Leather manufacturing.
Cleaning, tanning, stretching, etc 2-6
Cutting, fleshing and stuffing 3-9
Finishing and scarfing 4-12
Vats 1-3
Leather working. * *
Grading and matching 412 7-15
Cutting and scarfing 4r-12 4-8
Sewing 4-12 7-15
Pressing and winding 3-9 4r-12
Libraries 3-6
(See other classifications relating to corresponding
quarters. )
Locker, toilet and wash rooms^^ : - 2-4
GENERAL LIGHTING SAFETY ORDERS. It
Classification.
Machine shops.
Rough bench and machine work 2-6
Medium bench and machine work 3-9
Fine bench and machine work 412
Extra fine bench and machine work 715
Automatic machines (ordinary) 3-9
Automatic machines (fine) 4-12
Grinding, buffing and polishing, rough work 3-9
Grinding, buffing and polishing, medium work 4-12
Grinding, buffing and polishing, fine work 7-15
Meat packing.
Slaughtering 2-6
Cleaning and cutting 3-9
Cooking 3-9
Grinding and packing ^ 3-9
Canning 3-9
Milling and grain food products.
Cleaning 2-6
Grinding or rolling 2-6
Baking or roasting 3-9
Mining.
(See boiler and engine rooms, power houses, halls,
stairways and passageways, roadways, yard thor-
oughfares, etc.)
Offices 4-12
Oil refining.
(See boiler and engine rooms, power houses, road-
ways, yard thoroughfares, chemical works, etc.)
Packing.
Rough 2-6
Medium 3-9
Fine 4-12
Paint manufacturing 2-6
Paint shops.
Dipping or spraying 3-9
Rubbing 3-9
Firing 2-6
Hand painting and finishing, ordinary 3-9
Hand painting and finishing, fine 4^12
Hand painting and finishing, extra fine (automobile
bodies, piano cases, etc.) 7-15
3-47806
18 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Paper 'box manufacturing. &>oas. goods.
Cutting 2-6 3-9
Machine folding 2-6 3-9
Hand folding 2-6 3-9
Pasting and assembling 2-6 3-9
Paper manufacturing.
Beaters 2-6
Calendering 3-9
Machine 3-6
Grinding 2-6
Finishing, cutting and trimming 4-12
Plating.
Plating 3-9
Polishing and burnishing 3-9
Printing industries.
Linotype and monotype 7-15
Typesetting 7-15
Composing stone 7-15
Matrix and casting 3-9
Miscellaneous machines 3-9
Proofreading 4-12
Presses, job and small automatic 3-9
Presses, rotary, flat-bed, etc 3-9
Lithographing 4-12
Electrotyping 4-12
Engraving 7-15
Receiving and shipping 2-6
Restaurants (see hotels).
Roadways and yard thoroughfares 0.05-0.25
Rubber manufacturing and products.
Calendering 3-9
Grinding 3-6
Vulcanizing 3-6
Washing and compounding rolls 3-9
Schools.
Auditoriums 2-4
Blackboards 3-5
Classrooms, study rooms, libraries, laboratories 3-9
Gymnasiums '. 3-6
Sewing, drafting 7-15
Shop work (rough) 2-6
Shop work (fine) 4-12
Stairways, corridors, toilets, hat and cloakrooms, etc. 1-2
Storage spaces 0.5-1
GENERAL LIGHTING SAFETY ORDERS. 19
Classification.
Sheet metal working.
Bench work, ordinary 3-9
Bench work, fine 4-12
Punches, presses, shears, stamps and welders 4-12
Spinning 4r-12
Miscellaneous machines 3-9
Shipbuilding.
( See machine shops, sheet metal working, roadways,
yard thoroughares, woodworking, assembling, etc.)
07 , Light Dark
Shoe manuactunng. goods, goods.
Inspecting and sorting raw material 4-12 7-15
Cutting 4-12 4-8
Stitching, machine 7-15 7-15
Stitching, hand 4-12 7-15
Lasting and welding 4-12 4-8
Hand turning 3-9 3-9
Miscellaneous bench and machine work 3-9 4-12
Soap manufacturing.
Kettle houses 2-6
Framing 1-3
Cutting 2-6
Stamping, wrapping and packing 3-9
Soap chip 2-6
Soap powder 2-6
Filling and packing soap powder 3-9
Stairways (see halls) .
Steel and iron mills, bar, sheet and wire products.
Automatic machines 3-9
Charging floor 2-4
Casting floor 2-4
Soaking pits and reheating furnaces 2-4
Rolling mills 3-9
Shears, presses, punches and riveters 3-9
Rod mill 3-9
Wire drawing, coarse 3-9
Wire drawing, fine 4-12
Pickling and cleaning 2-6
Stone cutting.
Machine cutting 2-6
Hand cutting 2-6
Carving 3-9
Polishing 3-9
20 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Store and stock rooms.
Rough stock 2-6
Medium stock 3-9
Fine stock 4r-12
Stores.
(Satisfactory store lighting requires that considera-
tion be given so many different factors, such as
location, color of finish, size and shape, location
and character of displays, as to make it impossible
to compile a complete list. The following tabu-
lation is general, only, and it is recommended that
expert advice be obtained where any doubt exists
as to the proper allowances to be made.)
Automobile showrooms - 3-9
Art (light on exhibits) 5-10
Book 3-9
Baker 2-6
Butcher 2-6
China 3-9
Cigar 4-6
Clothing 4-12
Cloak and suit 4-12
Candy 3-6
Confectionery 3-6
Decorator 4r-12
Department (see each department).
Drug 2-6
Dry goods 4-12
Florist 2-6
Furniture 3-9
Furrier 4-12
Grocery 26
Haberdasher (men's furnishings) 4-12
Hardware 2-6
Hat 4-12
Jewelry 4-12
Millinery 4-12
Music 2-6
Notions 3-9
Piano 3-9
Rug racks 10-20
Shoe 2-6
Stationery 2-6
Tailor 4-12
Tobacco (see cigars).
GENERAL LIGHTING SAFETY ORDERS. 21
Classification.
Sugar refining.
(See boiler and engine rooms, power houses, halls,
passageways, chemical works, etc.)
Telegraph.
Operating __ 4-12
Telephone.
Automatic exchanges 4-12
Manual exchanges 3-9
Testing.
Rough 2-6
Medium 3-9
Fine 4-12
Extra fine 7-15
Textile mills.
n Light Dark
OOttOn goods. goods.
Opening and lapping 2-6 2-6
Carding 2-6 2-6
Drawing frame - 26 26
Roving, spooling, spinning, etc 3-9 3-9
Warping 2-6 2-6
Slashing 2-6 2-6
Drawing in 3-9 3-9
Weaving 3-9 3-9
Dyeing 3-9 3-9
Silk
Winding 3-9 3-9
Throwing 3-9 3-9
Quilling and warping 3-9 4-12
Weaving 3-9 4-12
Dyeing 3-9 3-9
Finishing 3-9 4-12
Woolen
Picking 3-9 3-9
Washing and combing 3-9 3-9
Carding 2-6 2-6
Twisting 3-9 3-9
Dyeing 3-9 3-9
Drawing in 3-9 4-12
Warping 3-9 4-12
Weaving 4-12 7-15
Perching 7-15 7-15
Knitting machines, ordinary and nappers 3-9 3-9
Knitting machines, flat and others 4-12 4-12
Cordage mills __, 3-9 3-9
22 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Tin can manufacture.
(See sheet metal working, machine shops, etc.)
Tobacco products all operations 3-9
Warehouses 2-4
(See other classifications.)
Woodworking.
Rough sawing (sawmills) 2-6
Sizing, planing, rough sanding, etc 3-9
Machine woodworking, medium 3-9
Machine woodworking, fine 4-12
Bench work, medium 3-9
Bench work, fine 4-12
Fine sanding and finishing 4-12
Gluing and veneering 3-9
Cooperage 3-9
DAYLIGHT.
8. Importance of daylight. Adequate daylight facilities
through large window areas, together with light, cheerful
surroundings, are highly desirable and necessary features in
every work place, and they should be supplied through the
necessary channels not only from the humane standpoint, but
also from the point of view of maximum plant efficiency. The
unusual attention to gas and electric lighting in factories, mills
and other work places during the past few years ; the perfection
of various lamps and auxiliaries by means of which an improved
quality and quantity of lighting effects are obtained; and the
care which has been devoted to increasing the efficiency in
various industrial operations all go to emphasize the many
advantages and economies that result from suitable and ade-
quate window space as a means for daylight in the proper
quantities and in the right directions during those portions of
the day when it is available.
9. Three considerations. Three important considerations of
any lighting method are sufficiency, continuity and diffusion.
With respect to the daylight illumination of interiors, suffi-
ciency demands adequate window area; continuity requires
(a) large enough window area for use on reasonably dark days,
(6) means for reducing the illumination when excessive, due to
direct sunshine, and (c) supplementary lighting equipment for
GENERAL LIGHTING SAFETY ORDERS. 23
use on particularly dark days and especially toward the close
of winter days; diffusion demands interior decorations that are
as light in color as practicable for ceilings and upper portions
of walls, and of a dull or mat finish in order that the light
which enters the windows or that which is produced by lamps,
may not be absorbed and lost on the first object that it strikes,
but that it may be returned by reflection and thus be used over
and over again. Diffusion also requires that the various sources
of light, whether windows, skylights or lamps, be well distrib-
uted about the space to be lighted. Light colored surroundings
as here suggested result in marked economy, but their main
object is perhaps not so much economy as to obtain a result
that will be satisfactory to the human eye.
10. Requirements. The following requirements may now be
listed for natural lighting:
1. The light should be adequate for each employee.
2. The windows should be so spaced and located that daylight
conditions are fairly uniform over the working area.
3. The intensities of daylight should be such that artificial
light will be required only during those portions of the day
when it would naturally be considered necessary.
4. The windows should provide a quality of daylight which
will avoid a glare due to the sun's rays and light from the sky
shining directly into the eye, or where this does not prove to
be the case at all parts of the day, window shades or other
means should be available to make this end possible.
5. Ceilings and upper portions of walls should be maintained
a light color to increase the effectiveness of the lighting facil-
ities from window areas. The lower portions of walls should
be somewhat darker in tone to render the lighting restful to the
eye. Factory green or other medium colors may be used to
good effect.
11. Classification. Means for natural lighting may be
classed under three broad divisions as follows :
(a) That case in which the windows are located on the sides
of the building or in the framework of saw-tooth construction
where diffused light from the sky reaches the work during a
large portion of the day.
(&) That case in which windows are located overhead on a
horizontal or nearly horizontal plane in the form of skylights,
24 GENERAL LIGHTING SAFETY ORDERS.
thus furnishing direct light from the sky during a large portion
of the day.
(c) That case in which prismatic glass takes up the direct
light from the sky and redirects it into the working space.
Method (a) is, of course, the most common of the three, and
it may be noted that the saw-tooth or other roof -lighting con-
structions have become very popular and result in an excellent
quality and quantity of light for given window areas, provided
the size and location of windows are in accord with modern
practice.
12. Increasing the value of floor space. Adequate and well
distributed natural light means that certain portions of the
floor space which ordinarily would not be available for work,
are converted into valuable manufacturing space. In a gen-
eral way, therefore, the average factory, mill or other work
place, if properly designed, should possess natural lighting
facilities which produce the best practicable distribution of
daylight illumination.
13. Wide aisles. With low ceilings and very wide aisles,
workmen located at the central portion of the building must
sometimes depend for their natural light on windows located
at a considerable distance away from their working position.
In these cases it may be possible, in general, to depend alto-
gether on daylight over an entire floor space, even at those
times of the day when daylight conditions would be entirely
adequate under other circumstances. This statement applies
to side windows rather than to skylights or to saw-tooth con-
struction. Fig. 1 illustrates this feature.
14. Varying conditions. In a case of this kind, employees
located next to the windows are furnished with suitable day-
light in the early morning and towards the latter part of the
afternoon, the upper portions of the windows being particu-
larly serviceable in lighting areas at some distance away from
the windows. A southern exposure, however, results in such
excessive light from the sky during the middle of the day, that
heavy shades are nearly always pulled down so as to cover the
entire window area. This plan makes it necessary to use arti-
ficial light throughout the larger part of the office during the
brightest portion of the day, and reduces the daylight at those
points where it would supposedly be the best, namely, near the
GENERAL LIGHTING SAFETY ORDERS.
25
windows. Here the location of the windows is a large factor
in the excellence of the daylight conditions, but the manipula-
tion of the shades is perhaps even more important. To avoid
such difficulty, adjustable translucent upper window shades
with adjustable opaque lower shades might be employed.
REGION OFCOM-
PARITIVE ABSENCE
OF DAYLIGHT. ARTI-
FICIAL DAYLIGHT
REQUIRED NEARLY
ALL DA.Y
ELEVATION
/DESKS-,
000
O
O
-50'
000
PLAN
FIG. 1. Diagram of a large office
with windows on one
side only.
15. Upper portions of windows. It should be further noted
in this illustration that the upper portions of the windows give
a reduced illumination in proportion to their areas, to the floor
space near them. In rooms of moderate size, therefore, the
windows should be placed as near the ceiling as practicable.
When the sun shines* through windows so located, the direct
light must be reduced or diffused. This may be accomplished
by the use of ribbed glass in ordinary factory and mill build-
ings, and in offices by the use of translucent sunshades or
awnings.
16. Tempering the light. The light due to the sunshine on
such shades and awnings will be as bright as ordinary skylight
if the shade is well chosen, and the ribbed glass will be still
brighter. If the windows are large, the illumination is likely
4 478C6
26
GENERAL. LIGHTING SAFETY ORDERS.
to be too great near the windows as previously pointed out and
it should be reduced. This should not be done, however, by
pulling down an opaque shade over the top of the windows
because the top portion of the window is the part that is par-
ticularly needed to give light to the interior of the room. The
better scheme is to employ an opaque shade which should be
raised from the bottom of the window. This will reduce the
illumination near the window without affecting it over the
interior of the room to any marked degree.
17. Bench locations. Fig. 2 shows how benches are com-
monly located with respect to windows, so that the light received
on the work may be most satisfactory. This sets a certain
< CEILING-* | 7Q .
BENCH SURFACE- ] ASSEMBLY WORK;
^^~" \
"1 /
},>;;,, '<
ELEVATION
'!
1
"VBENCH-I -i - u
li
I
+ J
(
!
1]
1
* -
V -BENCH-, 1 -
* l
1
///S//SS/S/////J//)
PLAN
FIG. 2. Diagram showing benches located
with respect to the windows so
as to receive the natural light
advantageously.
limitation upon the possible arrangement of the work over
the floor space, depending on the way daylight is furnished to
the floor area. This limitation can be eliminated almost com-
pletely in the case of artificial light through a uniform dis-
tribution of lamps overhead. This statement applies to those
cases where natural light is transmitted through side windows,
and includes a feature specially noticeable in buildings of more
than one story. In contrast, the work may be arranged almost
independently of the natural light in buildings where the
natural light is furnished by overhead windows or through
the means of saw-tooth construction.
18. Window glasses. Both translucent and clear glass are
employed for factory and mill windows. There is a slight
reduction in the transmitted light through ordinary translucent
GENERAL LIGHTING SAFETY ORDERS. 27
vvire glass, but it is often required by insurance regulations
for a deduction in the fire risk where a given building is located
in close proximity to other buildings. Wire glass is also used
quite generally with steel window frames, here being an added
protection from the standpoint of fire risk. Wire glass may
be obtained in clear form, but its expense in contrast to the
translucent form is such as ordinarily to prohibit its use for
industrial purposes.
19. Wire glass. Wire glass, also known as ribbed glass,
should be used and is advocated for practically all factory and
mill windows where prisms are not required. Wires of rather
open mesh cause so little reduction in light as to warrant no
mention of this .feature. Special care should be taken to get
such glass as is smooth both on the flat side and on the ribbed
side to facilitate cleaning. Wire or ribbed glass gives better
diffusion than plain glass.
20. Prism glass. Where the sky outside of the windows is
obstructed by buildings, prism glass is recommended if the room
is deep. Different kinds of prisms can not be used to advan-
tage interchangeably. The amount of prism glass required
in any case depends much upon the surroundings and to obtain
excellent results, of which such glass is capable, it must be
used intelligently.
21. Skylights. Skylights are sometimes installed in long
narrow continuous strips in a sloping roof. The ribs of the
ribbed glass are generally so arranged that it is convenient
to make them at right angles to the length of the strips. The
result is that the sunshine is diffused by the ribs over a narrow
area parallel to the strip of skylight, thus lighting one part
of the room much more brilliantly than the remainder. If the
ribs are installed to run parallel to the strips, they will give
a much more general distribution of the sunlight. In the
foregoing, the word strip refers to the long belt of skylight and
not to the individual sheet of glass. Ribbed glass in vertical
windows should generally be placed with the ribs horizontal.
They thus roughly fulfill some of the functions of prisms.
22. Dirt accumulations. While translucent wire or ribbed
glass reduces the amount of light transmitted through the
windows, the roughness of the outside surface of such glass
often causes accumulations of dust and dirt, which are more
28 GENERAL LIGHTING SAFETY ORDERS.
to blame for the reduction of transmitted light in some cases
than the translucent nature of the glass itself. Remedies of
this difficulty are to secure smooth glass and to resort to
frequent cleaning.
23. Wire glass as a safeguard. Wire glass for skylights is,
of course, a practical necessity as a safeguard against accidents
due to accidental breakage of the glass or due to objects falling
on top of the glass.
24. Sunshine not desirable. In all the work of providing
natural light, it should be kept in mind that direct sunshine
in itself, from the illumination standpoint, but irrespective of
sanitary conditions, is not wanted. The idea that sunshine is
the important item is a common but an erroneous impression.
For example, in saw-tooth construction, the windows do not
face the south to get all the sunshine possible, but they face
the north to exclude the sunshine. Ordinarily windows, on
the other hand, face all directions because not enough light
can be distributed to interiors from north windows alone.
Windows on the other than north fronts admit sunshine to be
sure, and this makes sun shades and awnings necessary to
exclude the excessive brightness.
VALUE OF ADEQUATE ILLUMINATION.
25. Factory and mill owners are concerned in the matter
of securing the largest output for a given manufacturing
expense. An improved machine tool capable of increasing
the product for given labor costs is most attractive, provided
its first cost is within returnable limits out of the larger profits.
Improved small tools, better methods of handling material,
adequate crane service, fire protection, good shop floors,
accurate and efficient timekeeping methods, and similar items,
vitally concern the shop manager ; money is expended to realize
excellence in these features because they afford increased
economies and protection, thus resulting in a higher efficiency
of the plant.
26. Energy consumption a minor item. Many arguments
leading to the sale of gas and electric lamps for use in factory
and mill buildings are based on reducing the lamp operation
cost of substituting a new for an older system. Arguments
of this kind are of value, however, only when such a reduction
GENERAL LIGHTING SAFETY ORDERS. 29
in operation cost can be effected without sacrifice in the ade-
quacy of the illumination. It would be a poor policy, in the
extreme, to argue a saving in energy consumption by the sub-
stitution of one type of lamp for another on a basis of equal
candlepower in both old and new systems.
27. Effect of good light on production. Arguments of a
convincing nature, which insure to the factory or mill man-
ager an increased output through improved illumination
service, are of importance and even greater at times than
reductions in the cost of illumination for the same quantities
of light. In view of the fact that resulting advantages of
superior illumination on increased output are apt greatly to
exceed economies in operation cost as regards the lighting
system, it is a distinct advantage to direct and hold the atten-
tion on the former rather than on the latter. This statement
will be more apparent when interpreted into definite items
as follows:
28. Advantages of good light. While the necessity of good
natural and artificial light is so evident that a list of its effects
may seem commonplace, these same effects are of such great
importance in their relation to factory and mill management,
that they are well worth careful attention. The effects of good
light, both natural and artificial, and of bright and cheerful
interior surroundings, include the following items:
1. Reduction of accidents.
2. Greater accuracy in workmanship.
3. Increased production for the same labor cost.
4. Less eyestrain.
5. Promote better working and living conditions.
6. Greater contentment of the workmen.
7. More order and neatness in the plant.
8. Supervision of the men made easier.
In this list it will be noted that items 4, 5, 6, 7 and 8 all have
a bearing on accident prevention.
29. Interpreting the advantages of good light. While the
major consideration in the eyes of the factory or mill owner
is undoubtedly and quite naturally the money value of good
light in the larger return of both quantity and quality of work
which may result from the installation of a superior as com-
pared with an inferior lighting system, it should be noted that
it is very difficult to interpret into dollars and cents the value
30 GENERAL LIGHTING SAFETY ORDERS.
of good light made possible by such returns. This difficulty
is due to the necessity of keeping all conditions in a factory or
mill section absolutely constant while varying the amount of
illumination from poor to good conditions, in an effort to
determine the output and its dependency on the light facilities.
As accurate data becomes available, giving the increases in
production for certain specific improvements in artificial light-
ing, it will doubtless prove helpful to a proper interpretation
of adequate light and its worth to any plant.
The eight foregoing points are emphasized as forming the
most important features in the problem of good lighting.
Although difficult to interpret into money values, and some-
what intangible, they are indisputable arguments in favor of
the best available illumination from the standpoint of the
factory or mill owner.
30. Practical example. Continuing from the manufacturer 's
point of view, it may be said that certain assumptions as to
energy cost, cleaning, interest and depreciation, show that the
annual operation and maintenance cost for the illumination
of a typical shop bay of 640 square feet area, may be taken
at $50.00. If five workmen are employed in such a bay at an
average wage of say 25 cents per hour, the gross wages of the
men in such a bay, plus the cost of superintendence and indi-
rect shop expense, may equal from $5,000 to $7,000 per annum.
In a case of this kind, therefore, the lighting will cost from
fa to 1 per cent of the wages, or the equivalent of less than
4 to 6 minutes per day. We may roughly say that a poor
lighting system will cost at least one-half this amount (some-
times even more through the use of inefficient lamps and a poor
arrangement of lamps), or the equivalent of say 2 to 3 minutes
per day. Nearly all factories and mills have at least some
artificial light, hence, in general, if good light enables a man
to do better or more work to the extent of from 2 to 3 minutes
per day, the installation of good lighting will easily pay for
the difference between good and bad light, through the time
saved for the workmen.
31. Actual losses. Superintendents have stated in actual
instances, that due to poor light their workmen have lost much
time, sometimes as much as from one to two hours per day on
certain days. If good light will add an average of say one-
half an hour per day to the output, these 30 additional effective
GENERAL LIGHTING SAFETY ORDERS. 31
minutes represent an increase in output of 5 per cent, brought
about through an expenditure equal to \ of 1 per cent of the
wages for improved lighting, or a saving equal to ten times the
expense.
OLD AND NEW LAMPS.
32. The inadequate means available for illumination by
artificial methods in the past have contributed to the slowness
of an appreciation of the features of artificial light which
influence the working efficiency of the eye. Open flame gas
burners, carbon incandescent and arc lamps, practically the
only illuminants available ten years or so ago, play but a
small part in the present approved methods of factory and
mill lighting.
33. New lamps. The large variety of comparatively new
lamps available for factory and mill lighting includes the
mercury vapor, tungsten, gas-filled tungsten, metallic flame
or magnetic arc, the flame carbon arc, the quartz mercury
vapor, and various types of gas arc lamps. Remarkable
improvements have thus been made in both the electric and
gas lighting fields, the same general rules of applying the
lamps covering both of these fields. Possibilities in factory
and mill lighting are now attainable which, before the intro-
duction of these new lamps, were either unthought of or
impossible. Consideration of the eye as a delicate organ,
together with the new ideas of the items which affect its comfort
and efficiency, have resulted in establishing certain principles
in illumination work, and have directed attention naturally
and in a growing manner to the proper use and application of
these new lamps.
EFFECTS ON FACTORY AND MILL LIGHTING PRODUCED
BY MODERN LAMPS.
34. With the introduction of these new gas and electric
lamps, broader possibilities have been presented in factory
and mill lighting. The use of units of sizes adapted to the
purposes, allows results which it has been hitherto impossible
to obtain satisfactorily, either by the arc lamp, carbon filament
or open flame gas burner, formerly available.
32 GENERAL LIGHTING SAFETY ORDERS.
35. New possibilities. It is evident that the introduction of
the many new lamps has made possible what may be termed
a new era in industrial illumination, a distinctive feature of
which is the scientific installation of the lighting units, suiting
each to the location and class of work for which it is best
adapted. Before the availability in recent years of medium
sized gas and electric units the choice of the size of unit for
a given location was often no choice at all. In many cases, due
to small clearance between cranes and ceilings, or other con-
ditions making it necessary to mount the lamps very high above
the floor, but one size or type of unit was available, the carbon
filament or open flame gas burner in the former, and the arc
lamp in the latter case.
36. Low ceilings. For low ceilings, up to 18 feet, the use
either of carbon filament, open flame gas burner, or arc lamps
resulted usually in anything but uniform light over the work-
ing plane, and often produced merely a low general light
which was practically useless for the individual machine. In
such instances, individual lamps had to be placed over and close
to the machines. With this arrangement, a relatively small
area is lighted by each lamp and the metal shades usually
employed serve only to accentuate the "spot lighting" effect.
Such a form of illumination for factory and mill work is
unsatisfactory and inefficient, but, as stated, was in the past
in many cases the only available scheme. The absence of
lamps of the proper size is no longer an excuse for the exist-
ence of such conditions in industrial plants.
GENERAL REQUIREMENTS OF ARTIFICIAL LIGHTING.
37. The following requirements for factory and mill lighting
are made all the more important by the peculiar limitations and
the wide variety of conditions to be found in factory and mill
buildings and in factory and mill work :
1. Sufficient illumination should usually be provided for
each workman irrespective of his position on the floor
space.
2. The lamps should be installed and selected so as to
avoid eyestrain to the workmen.
3. The lamps should be operated from sources of supply
which will insure reliable illumination results, particularly
on account of the demoralizing effect by intermittent
service, just when the light may be most needed.
GENERAL LIGHTING SAFETY ORDERS. 33
4. Adequate illumination should be provided from over-
head lamps so that sharp shadows may be prevented as
much as possible, and in such measure that individual
lamps close to the work may be unnecessary except in
special cases.
5. The type and size of lamp should be adapted to the
particular ceiling height and class of work in question.
6. In addition to the illumination provided by overhead
lamps, individual lamps should be placed close to the work
if they are absolutely necessary in the eyes of a lighting
expert, and in such cases the lamps should be provided
with suitable opaque reflectors.
These requirements may now be met by means of the new
types of gas and electric lamps, one type of which can usually
be found for practically each factory and mill location, espe-
cially adapted to the general physical conditions of the location
as typified by the clearance between cranes and ceiling and
other similar items.
OVERHEAD AND SPECIFIC METHODS OF ARTIFICIAL
LIGHTING.
38. Factory and mill lighting may be classified under two
general divisions: First, distributed illumination furnished
from lamps mounted overhead ; and second, distributed illumi-
nation furnished by individual lamps located close to the work.
For practical purposes this classification is sufficient. In
numerous cases a combination of these two methods becomes
necessary.
39. Mounting the lamps high. Where the lamps are high
enough to be out of the line of ordinary vision, and are of a
size and so spaced as to furnish illumination at any position
on the floor where work may be carried on, the system is
referred to as the overhead method of lighting. This method
has many advantages. Its general adoption, which has been
somewhat slow, has increased with the appearance of the many
new types of lamps and with the growing appreciation of the
value of good lighting.
40. Where a small amount of general or overhead lighting
is coupled with specific lighting from. individual lamps, a large
part of the floor space in many shops is in relative darkness,
and much dependence must be placed on the hand lamps close
to the work. The small number of overhead lamps generally
34 GENERAL LIGHTING SAFETY ORDERS.
used in such cases furnishes merely a small amount of addi-
tional illumination over the floor space which is not sufficient
to be of much value. However, where sufficient intensity is
provided by general illumination, this is often a very effective
means of lighting a large workroom.
41. Low ceiling. Locations with low ceilings, until recently,
have been lighted by the individual hand lamp method, because
the old carbon filament lamps, being of low candlepower, could
not well be used close to the ceiling, while the old type of arc
lamp was often impracticable, due to its large physical size,
as well as its relatively high candlepower. This statement is
subject to some modification, because low candlepower units
have sometimes been used in clusters for low ceilings as a com-
promise between a single small or a single large unit, this
scheme being, however, usually insufficient and unsatisfactory
in comparison with modern methods of lighting. In a partic-
ular manner, therefore, suitable illumination has been difficult
with low ceilings.
42. New types of gas and electric lamps have a range of
candlepower from very low to very high values, and the over-
head system with the elimination of individual lamps is thus
possible ; in other words, a size of gas or electric lamp may now
be selected from a large available list of sizes for nearly every
factory or mill condition.
VARIOUS LOCATIONS ILLUSTRATED.*
43. Figs. 3 to 12 inclusive are given to indicate how the
problem of adequate illumination has been solved in a number
of actual instances, and the following notes apply to some of
the considerations involved.
There are two main items to consider in deciding for or
against high candlepower lamps for the factory or mill. First,
how high are the lamps to be mounted; and second, will the
light at any given point on the machines or other operations
be satisfactory if it comes from a few lamps or should it come
from many sources? If the ceiling or overhead construction
is under 16 feet, lamps of high candlepower can hardly be
used in sufficient numbers to produce uniform illumination
over the floor space. If they are to be mounted at a height
*Figs. 8 to 12 inclusive are, in general, arranged in the order of their
mounting heights. The low mounting heights are shown in the earlier
illustrations and the higher mountings in the later views.
GENERAL LIGHTING SAFETY ORDERS. 35
between 16 and 25 feet, it is largely a question of whether
light from a relatively few lamps will produce satisfactory
results. For mounting heights over 25 feet, lamps of high
candlepower possess some advantages, chief of which is their
large volume of light for given energy consumed, always pro-
vided the light is effectively directed towards the floor.
44. Three groupings. These three groupings by mounting
heights are conveniently shown in Figs. 15, 16, 17 and 18. In
Fig. 15, a single shop bay with a ceiling height of 12 feet is
shown as typical of the first grouping. The single high candle-
power lamp furnishes approximately the same amount of light
to the machines as do the eight small lamps. Note, however,
that the illumination from the large lamp is not nearly as
uniform as that from the small lamps, although the spacing
of both the small and the large lamps as represented in this
illustration is typical of many actual installations. Note also
that the shadows cast by the large lamp at certain portions of
the floor space must be so marked as to make the illumination
it furnishes very inferior in this respect to the illumination
from the smaller lamps, because of their larger number.
Here, if the number of large lamps for the given floor area
be increased in an endeavor to make the illumination more uni-
form and to reduce the shadows, the expense as compared with
that for smaller lamps, makes the large lamps a very unfavor-
able proposition. These two features are the basis for stating
that in general large lamps are not desirable for mounting
under 16 feet, and an analysis of conditions, together with
a. careful and unbiased comparison with the illumination
produced by smaller lamps, will nearly always bear out this
conclusion.
45. Second grouping. In Fig. 17, a 20-foot ceiling has been
selected as typical of the second grouping, a single shop bay
being shown. Here the work is assumed to be rough assembly,
mostly on horizontal surfaces, and the single high candlepower
lamp, besides giving more nearly uniform illumination, because
the light is distributed more broadly due to the increased
height, is correspondingly more satisfactory as to shadows
produced by the large lamp in the preceding illustration
(Fig. 15), on account of the improved direction in which much
of the light reaches the work. In this case, the arrangement
36 GENERAL LIGHTING SAFETY ORDERS.
of both large and small lamps is typical of many existing
installations.
46. In Fig. 16, however, although the height is the same as
in Fig. 17, the work is quite different, being conducted on the
inside of large vertical tanks. It would obviously be impos-
sible to perform this work by the light from the single large
lamp as Well as with that from the larger number of medium
sized lamps, even if the actual amount of light from each was
the same, on account of the poor direction of the light at cer-
tain positions of the work from a single unit in such a case.
The medium sized lamps furnish approximately the same
quantity of light and yet no matter where the tanks may be
placed, they will receive considerable light from the medium
sized lamps directly over or nearly over them, at least far more
than is apt to reach them from a single unit in every other
bay (the assumed arrangement of the large lamps).
47. For this second grouping of mounting heights, then, the
large lamps may or may not be adapted, depending on whether
the reduction of shadows is of much importance, as is the case
in Fig. 16. The large lamp is, however, more likely to be
satisfactory here than in the first case (Fig. 15), because of
the better distribution of the light due to the higher mounting,
a fact made evident in Figs. 15 and 17 on account of the
decreased number of small lamps and the increase in their
size made possible in Fig. 17 as compared with Fig. 15, where
the mounting is lower. By the same line of argument, it can
be shown that for higher mountings, large lamps are still more
likely to prove satisfactory.
48. In Fig. 16, the number of large lamps might have been
increased for the given floor area, but to have done so would
mean that the cost for the energy and upkeep to maintain
them would be excessive in comparison with the smaller types
of lamps.
GENERAL LIGHTING SAFETY ORDERS.
37
FIG 3 Night view of a rather low factory section showing tungsten lamps
of the 100-watt size in bowl reflectors mounted 13 feet above the
iloor.
FiG. 4. Night view showing lighting in low store section, 400-watt tungsten
lamp in 18-Inch dense semi-indirect bowls. Ceiling height 13 feet.
Note the comparative absence ef shadows.
38
GENERAL LIGHTING SAFETY ORDERS.
FIG. 5. An example of yard or alleyway lighting, 200-watt tungsten lamps in
reflectors with a mounting height of 20 feet. Note the evenness of
illumination and the absence of shadows. Twenty-five per cent of
the accidents in manufacturing plants are due to poor illumination.
6. Night view of a planing mill showing an installation of 250-watt
tungsten lamps with a 16 -foot mounting. Note the excellent dis-
tribution of the light and the comparative absence of shadows. This
is an example of the overhead method of lighting.
GENERAL LIGHTING SAFETY ORDERS.
39
FIG. 7.
Night view of factory section, 400-watt bowl type reflectors with
29-foot mounting height.
FIG. 8.
Night view of open hearth pouring floor with 750-watt reflectors,
35-foot mounting height and 40-foot spacing.
40
GENERAL LIGHTING SAFETY ORDERS.
FIG. 9. Night view of factory section with relatively high mounting of
250-watt tungsten lamps. The lamps are 20 feet above the floor.
Note the excellent distribution of the light and the shielding effect
of the girders which serve to reduce the glare as one looks down
the aisle.
FIG. 10.
Night view of arc lamp installation with 40-foot mounting at center
of picture and 20-foot at sides. Excellent distribution.
GENERAL LIGHTING SAFETY ORDERS.
41
FIG. 11. Day view of relatively high stin, showing a system of gas lighting.
FIG. 12.
High section showing a system of mercury-vapor lamps. Note the
excellent distribution o f . light over the floor area.
42
GENERAL LIGHTING SAFETY ORDERS.
FIG. 13.
Bad lighting. Bare lamps produce a glare which Is harmful and
renders the Illumination very ineffective. Compare with Fig. 14.
Fio. 14. Example of good tungsten lighting.
GENERAL LIGHTING SAFETY ORDERS.
43
)W POWER
UNITS
HIGH POWER UNIT
ELEVATION
PLAN
FIG. 15. Diagram showing alternate
schemes for lighting a
low factory section.
This contrasts the use
of large and small
lamps for a mounting
height of 12 feet.
ELEVATION
'.LOW
POWER UNlTi
^ 4*
JHIGH POWER UNIT
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PLAN
FIG. 16. Diagram contrasting the
use of large and medium
sized lamps for mount-
ing height of 20 feet.
PLAN
FIG. 17. Diagram of same factory
space shown in Fig. 16,
but with a different class
of work. This view con-
trasts the use of large
and medium sized lamps
for a 20-foot mounting.
44
GENERAL LIGHTING SAFETY ORDERS.
49. Third grouping. In Fig. 18, the third grouping of
mounting heights is shown with the lamps about 50 feet above
the floor. In this illustration the distribution of the light
from the large lamps will be far more satisfactory, both for
flat and tall work than in the two preceding cases. It will be
noted further that the increased height of the lamp causes the
light to fall in such directions as to distribute it evenly over
CRANE RUN-WAY-
MACHINE TOOLS AND HEAVY ASSEMBLY
WORK LOCATED ON THIS FLOOR AREA'^
ELEVATION
[HIGH POWER UNIT
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-l6'-6"--->K 33-0"--
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'HIGH POWER UNIT
*-$ PLAN
FIG. 18. Diagram showing the use of large lamps
for a mounting height of 50 feet.
the entire floor space taken care of by this one lamp in much
better shape than for the lower mounting heights. (See also
Pigs. 19 to 23, inclusive.)
LIGHTING CIRCUITS FOR ELECTRIC LAMPS AND SUPPLY
MAINS FOR GAS LAMPS.
50. The question of lighting circuits is mentioned here with
particular reference to factory and mill conditions, where
motor loads are apt to be large in comparison to the energy
GENERAL LIGHTING SAFETY ORDERS.
45
consumption of electric lamps which are in service. In some
cases; the proportion of motor load to lighting .load is in the
ratio of 10 to 1, in others 7 to 1, and so on, and the varying
demands on the circuits by motors may greatly affect the lamps.
Hence it is important to maintain strictly separate supply
circuits for the lamps in order to avoid varying voltage which
is apt to result if the motors are connected to the same circuits
with the lamps.
MEZZANINE
FLOOR '
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PLAN
FIG. 19. This shows a v e r y
poor arrangement
of artificial light-
ing by means of
large lamps mount-
ed too close to the
floor. Compare
this poor lighting
scheme with the
improved plan in
Fig. 20.
ELEVATION
40'-0"---.
; TBENCH:
=0
csi TBENCH
PLAN
FIG. 20. This illustration is
to be compared
with Fig. 19. It
Indicates an im-
proved scheme over
that shown in
Fig. 19 ; made pos-
sible by the use of
smaller lamps.
51. Constant voltage. In addition to the superior illumina-
tion resulting 'from lamps supplied from constant voltage
mains, some types operate with longer life or very much better
mechanically when supplied with constant voltage than other-
wise. These features will therefore generally more than offset
the somewhat greater cost of maintaining separate circuits for
each class of service. In like manner and for similar reasons,
it is advisable to place gas lamps on supply lines separate from
those delivering gas for power purposes.
CONTROL OF LAMPS AND ARRANGEMENT OF SWITCHES.
52. The control of lamps in factory and mill lighting is
important in all cases, but specially so where a large number
of lamps is used in preference to a small number for a given
46
GENERAL LIGHTING SAFETY ORDERS.
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