cnt LAMP WORKS OF GENERAL ELECTRIC CO. ENGINEERING DEPARTMENT ‘4 : Bulletin 41-D Jone 1, 1928 Second Edition Hlumination Design Data for Industrial and Commercial Interiors By WARD HARRISON AND C. E. WEITZ This bulletin presents a method of illumination design which has become the standard for illuminating engineering work. Through its use tedious calculations of the ‘‘point by point’ method are avoided; the time required is reduced to a few minutes; and even those not experienced in lighting design, by following carefully the steps as outlined, can at once apply these data with confidence. The method of design is known as the “lumen method.” It has the decided advantage that the technical considerations which are important as influencing the result and which require the experienced judgment of the engineer, have been taken into account in the preparation of the charts and tables and therefore automatically receive due allowance in the lighting design. The data apply primarily to interiors where standard types of reflecting equipment are used to obtain general lighting of substantially uniform level. The experienced engineer may temper rule-of-thumb methods with Judgment and secure satisfactory resulis, but, in the final analysis, all short-cut or recipe methods which are effective must be governed by principles as given in this ~ bulletin. For the student, the essence of illuminating engineering will be found in a studied analysis of the factors which make up the tables in their present form. Illumimation Design Data for Industrial and Commercial Interiors A Handbook for Lighting Specialists, Electrical Contractors and Dealers, Engineers, Architects, Students, and Instructors ENGINEERING DEPARTMENT NATIONAL LAMP WORKS of General Electric Co. Sheet Metal Stamping — 20 Foot-Candles The difference between good illumination which cheers the mind and comforts the senses, and poor lighting with its gloom and glare, obviously is nothing more than the difference in results as produced by modern equipment—reflectors and lamps—properly installed, and the results produced by mediocre equipment installed without regard or knowledge of principles and good practice. 9 < MeNOORORDENNOHDODOENURDOONNONDAUAONPOODONONORNOONOGHCOOUOUEDOOONGOSEROSUNCEEOONGHOOOONGOROODUGUCHOOOOCODOOCEEEODEPCOEDOONOUONAUGEOEOOONOUCEOLAONOSOOONEOGUOUNELDOONOHCEOHOEECESOOOOCEDOONTORDORaSoaOoeN DeEoORt ILLUMINATION DESIGN DATA | 3 | for i Industrial and Commercial Interiors Page 1. Location of Outlets—Adequate Wiring 4-5 Spacing-Mounting Height Tables.......... 6-7 eyDICalcLAVOULS womemar. eminent 8-9 Wiring: @apacity-per_ Outletsa,) rere acne 10 Wire size for Branch Circuits), ......5.... 11 2. Foot-Candles Required.............. 12 Recommended Values...... PRE ee 13-18 3. Room Efficiency and Reflector Char- ACTELISLICS Heese ee ie he ee 19-21 Room ndexs) able er eee ee Seer: 22-23 (Zoemcients ots tiizaliOn ss eee ee 24-29 Speciale Units reve ote re, ne eee Oe ele to 28-31 4. Lamp Size—Lumen Output Required Table of Computed Values............... 32-33 Formulasfor;Computation = «en. oe 34. List of Equipment Manufacturers...........:...... 35-36 1. Location of Outlets—Adequate Wiring Lighting standards which we accept today are not only on a better level than those of a few years ago, but studies in light and vision point to even higher standards, which will unquestionably be used in the future. The wiring plan is the foundation of the lighting system and indeed, is the step that should be given the most careful attention. Because the cost of relighting is made up so largely of wiring costs, it is far more economical, in planning a lighting installation, to provide wiring adequate for future as well as present needs. When once outlets are properly installed as regards both spacing and size of wire, a change in type of reflector or in size of lamp, may be made without undue complication; but where the spacing of outlets is too great or the wiring inadequate, satisfactory results can never be obtained without extensive alteration. KOK KOK OK OX The number of outlets to provide for any given area is determined by the maximum allowable spacing between lighting units and is in turn regulated by their height above the floor. The relation between height and spacing is based on the distribution of light to procure a reasonably uniform level of illumination on the working plane. Careful analysis of the accompanying drawings will illustrate the importance of this principle. Strictly speaking, the spacing for uniform illumination on the work depends upon the height of the light source above the surface to be illuminated, but since most work surfaces are from 2% to 3% feet above the floor, the spacing may for practical purposes be considered a function of the mounting height of lamps above the floor. In general, a spacing in feet which does not substantially exceed this mounting height will result in reasonably uniform illumination. See Tables 1 and 2. When lighting units are mounted as high as the ceiling or roof trusses permit, larger and more efficient lamps may be used, while fewer units—to buy, to install, and to maintain—will be necessary. The ceiling height, or rather the height which units may be mounted clear of obstructions, therefore dictates the maximum permissible spacing. 4 LOCATION OF OUTLETS—ADEQUATE WIRING | 0 fect Fig. 1—Units spaced too far apart for their height furnish very uneven illumination, in this case a 4 to 1 variation, and work positions midway between units will be inadequately lighted; harsh shadows will also result. The remedy is to mount the units higher, or if that is impossible, to space them closer as shown in Fig. 2. Fig. 2—It will be noted that if the permissible ratio between spacing and mounting height is not exceeded, uniform illumination will be produced. Note also the overlapping of light which serves to eliminate shadows as the units are brought closer together. With a light source only 8 feet above the floor one unit would be required for each 55 square feet to give reasonably uniform coverage; for a 10-foot height a unit for each 125 square feet; 15-foot height, 325 square feet; 20-foot height, 650 square feet, etc. The arrangement of bays, columns, positions of work, however, often suggests a closer spacing to conform to a symmetrical layout, or a more favorable location with respect to work positions where these are known in advance. Specific data and typical layouts follow. 5 LOCATION OF OUTLETS—ADEQUATE WIRING Spacing of Outlets The location of outlets is determined by the structural features of the interior—in fact in many cases, particularly in new buildings, the wiring is installed even before the type of lighting unit is decided upon. The ceiling height therefore automatically regulates the maximum permissible spacing, assuming the units are mounted as high as possible. The layout of lighting outlets for a large industrial building, indicating the application of data in the table below. The 13-foot clearance allows a spacing of 13 feet. For a symmetrical layout in the bays a 10-foot spacing is adopted. TABLE 1—SPACING OF OUTLETS Ceiling Spacing Between Outlets =p a Oe ide Approximate Height Area per (Or Height in Maximum Aisles or Desks, Work- Outlet the Clear) Usual (For Units at | Storage Next | benches, etc., (At Usual Ceiling) to Wall Against Wall Spacings) (C) (D) (D) (A) (B) (Feet) (Feet) Not more than* Not more than*| (Square Feet) 8 i 7% Usa 3 50-60 9 8 8 y 3 60-70 10 9 9 3% 70-85 ll 10 1014 ae 3% 85-100 12 10-12 12 314-4 100-150 half ee 13 10-12 13 34%-4% 100-150 14 10-13 15 actual 4-5 100-170 9 GE steve 4-5 100-170 -13 19 . 4-6 100-170 18 10-20 21 ee 4-6 100-400 20 18-24 24. between 5-7 300-500 22 20-25 aT 5-7 400-600 24 20-30 30 units 6-8 400-900 26 25-30 ats 8-9 600-900 30 and up 25-30 40 8-10 600-900 * Where it is definitely known that some form of indirect lighting will be used, the maximum spacing between outlets may be increased about two feet, and the distance from the outside outlets to the wall may be increased by one foot. 6 LOCATION OF OUTLETS—ADEQUATE WIRING Mounting Height of Lighting Units When units are spaced less than the maximum permissible distance, they may be dropped from the ceiling for reasons of appearance, ease of cleaning, etc., but in no case should they be dropped below the minimum value shown in column (H) for a given spacing. bE For a 10-foot spacing the units might be dropped to 10 feet above the floor as shown by the dotted outline of a reflector at height H. They are, however, mounted on the trusses 12 feet to minimize glare. TABLE 2—MOUNTING HEIGHT OF LIGHTING UNITS SEMI-INDIRECT AND INDIRECT DIRECT LIGHTING UNITS LIGHTING : Recom- Distance mended ose of Units Desirable Mounting Desirable Mounting Actual | Suspension Reticaen, from eight in Height in | pease Length etween | Floor Industrial Interiors Commercial Interiors etween | (Top of Units | Not Less Units Bowllte Than Ceiling) (D) (AH) (R) (R) (D) (S) F F : F F ; ee ee 12 feet above floor if a : i possible—to avoid ? 8 | 8% | glare, and still be Ee 9 9 Es hires hatren The actual hanging 9 1-3 10 10 stepladder for poe eed is 10 144-3 11 10% cleaning. g I gely 11 2-3 12 11 by panera ePponts 12 2-3 I ance, but particu- va a 1274 : larly in offices and or: aEP 15 be mounted much | minimum values Oe 20 16 more than 12 feet | shown in Column 20 4-5 22 18 it is usually desir- | F{ should not be 22 4-5 24 20 able to mount the | yjolated. 24 4-6 26 21 units at ceiling or %6 A-6 28 929 on roof trusses. 28 oy) 5-7 LOCATION OF OUTLETS—ADEQUATE WIRING | Layouts Suggested for Symmetrical Spacing Where interiors are divided by columns or ceiling beams into bays, it is usually desirable because of appearance to locate the outlets symmetrically with respect to these structural sections. The typical layouts and notes which follow suggest various arrangements of units with respect to bays. Layout A Four Units per Bay—This is the most common system for the square bay of usual dimensions. Layout B Four-Two System—This is equiva- lent to three units per bay and is an alternative to four per bay where permissible spacing allows. Layout C Two Units per Bay—Usually appli- cable only in narrow bays where the width is less than two-thirds the length. Layout E Staggered System—A recourse where one unit per bay is unsatis- factory and where four per bay is unnecessary. Less favorable appear- ance, and certain areas near walls may be inadequately lighted. Often expensive to wire. Layout D One Unit per Bay—A very common practice, but satisfactory only where bay size is no greater than the maxi- mum permissible spacing—an unusual condition. Layout F Interspaced System—A pplicable in rectangular bays where one unit per bay would exceed the permissible spacing in one direction, and where center row will not interfere with future structural arrangements, such as added office partitions. LOCATION OF OUTLETS—ADEQUATE WIRING Layouts for Special Applications The adoption of well-designed general lighting systems elimi- nates the need for a great many “ingenious” lighting devices. However, in certain locations, particularly in manufacturing opera- tions, requiring high machines or peculiar machine grouping, special attention must be given to the layout of the general lighting or to the use of units supplementary to the general system. Warping Machines -Textile Mill Group Lighting Units are arranged with respect to machine groups to give better direction of light and to avoid high machines cutting off light where needed. Usually encoun- tered in standardized industries such as textile, paint, paper, and printing. Craneways Hts = Mount units on truss chords or hang conduit from messenger cable. Stagger units as shown to avoid traveling crane blocking off light from all units in the row parallel to the crane as it travels along. mee Angle Units In erecting shops in high bays, angle units along the walls—20 feet high—will provide additional light for vertical surfaces. Similarly, large high machines or special operations frequently require supplementary units, mounted perhaps on columns close by- Bench Lighting If the general lighting system is well planned, special bench lighting is unneces- sary except where there is fine bench work requiring much higher illumination than is provided throughout the room. TTT Special Purpose Units Some cases require special study because of peculiar requirements. This illustrates the use of special units to spread a high intensity band of light on the vertical surfaces of an automobile body for finishing and inspecting. 9 “LOCATION OF OUTLETS—ADEQUATE WIRING Adequate-Wiring Data WI5 volts Circuit 5 The Underwriters’ Code merely specifies wiring conditions with regard to fire hazard without giving consideration to the economy of operation. The size of wire for a lighting installation may conform strictly to the code and at the same time the circuits be of such length to cause excessive voltage drop. Inadequate wiring is directly responsible for the avoidable waste of electrical energy in overloaded circuits and results in low efficiency of lamps and _ unsatisfactory lighting conditions. 15 volts Circuit 6 7 volts At panel box Wattage Capacity per Outlet—Number of Outlets per Circuit—In order that a higher wattage lamp may be used in each outlet at any future date without necessitating a rearrangement of circuits, it is recommended that the capacity per outlet as given in Table 3 be allowed, and, in general, the number of outlets per circuit as follows: where the capacity is 300 watts or less, not more than 8 per circuit; where 300 to 750 watts per outlet is specified, not more than 4 per circuit; where more than 800 watts per outlet is specified, not over two!'should be on each circuit. TABLE 3 ARCHITECTS’ AND ELECTRICAL CONTRACTORS’ WIRING GUIDE (See Table 4 for Wire Size) CLASS A CLASS B CLASS C CLASS D Actual ite | metainacrions|INSTALLATIONS| NSPAL Tons SEALE RZIONS Area per (Such as Offices, (Such as Stores, |hoodStores,Storage| Areas in Garages Outlet Drafting Rooms, School Rooms) | Areas in Factories*) and Unimportant Factories, etc.) and Basements) Basements) Square Wattage Capacity | Wattage Capacity | Wattage Capacity | Wattage Capacity Feet per Outlet per Outlet per Outlet per Outlet 65-75 300 200 150 100 75-85 300 250 150 100 85-95 350 250 200 100 95-110 400 300 200 100 110-125 450 350 250 150 125-140 500 400 250 150 140-160 600 450 300 150 160-190 700 500 350 200 190-220 800 600 400 200 220-260 950 700 450 250 260-300 1100 800 550 300 300-340 1250 950 650 300 340-390 1450 1100 750 350 390-440 1650 1250 850 400 440—500 dts 1400 950 450 500-560 ce Ne 1600 1050 500 560-630 ae 1800 1200 590 630-710 a oie Lee 1350 650 710-800 Macs SWS 1500 750 800-900 ae ee 1700 850 * In factories it is often desirable to convert storage areas into work places to meet immedi- ate production needs. For this reason, it is recommended that storage areas be wired according to Class B specifications. 10 LOCATION OF OUTLETS—ADEQUATE WIRING Voltage Drop—Wire sizes for all classes of lighting installations should be such that the voltage drop between the panel bor and outlets does not exceed 2 volts, computed for each length of run and for an allowance in capacity per out- let as given in Table 3. Table 4 shows the wire size required for various conditions. TABLE 4—WIRE SIZE REQUIRED (Length of wire for a circuit is double the length of run) WATTS PER CIRCUIT eicieieglieiegiegiegieglieiece eiceielie/sieic Se 30 aly ltal vs loalaalaa lag 14} 14) 14) 14] 14 10} 10} 10) 10} 10 The difference in the cost of an : oie 40 14 iting vite rot aedthead. 14| 14] 14] 14] 12| 12] 12] 10| 10| 10 | 10] 10 vantages generally sufficient, 50 14 that many electrical men 14] 14} 12] 12] 12] 12 specify No. 12 asthe minimum 10] 107 8] 8 60 14 size for branch circuits. 14712] 12) 12410] 10 Sime SeG ES 70 14] 14] 14] 14] 14) 14] 14712) 12] 12] 12710] 10 8] 8 8 6 & 80 114] 14) 14] 14] 14| 14) 12] 12 8| sl 6| 6 = ae ee, = 90 14] 14] 14] 14] 14] 12] 12] 12 6| 6| 6| 6 =) © 100 14] 14} 14] 14] 14,12] 12] 12 6 6] 6 = 110 14| 14) 14] 14 10 6 6] 4 As 120 14] 14) 14) 14 10 6 4) 4 e ey 130 14] 14] 14] 14 10 6 4) 4 | ZI 140 14} 14} 14) 14 10 6 4} 4 & 150 14] 14 | 14 10 4 4) 4 Z 160 14] 14] 14 8 4 4] 4 fe 170 14] 14] 14 8 oe ic) This table shows the wire size required ° 180 14| i4| 14 8 for 115-volt circuits of various lengths of < 9 = run, based on a drop of two volts be- a = tween the panel board and the outlets. cw 190 14 8] 8 It is difficult in branch circuits, at 2} 2 A oe walt Se Aaa meets to use w arger than No. 8 wire because of the =) 200 14 8 iS diioukey of handling in conduit. Where 2) 2 ; the proper wire size‘for a din- . 210 14 8} 8 stallation, ceria’ to dant table: - 2) 2 larger than No. 8, it is usually best either 220 14 8/ 8 to provide more circuits with less load, 2] 2 or to pelocate pear Nata llas . crease lengths of run. e dott i 230 14 8) 8 shows the usual wractical limits for a 2} 1 cuit load and length of run. 240 14 8] 8 ] 250 14 8) 8 1 Note—These recommendations on wiring are based on the allowances of The National Code: i. e. circuits equipped with medium screw sockets limited to 15 amperes and not more than 12 outlets per circuit; mogul sockets—limited to 40 amperes and 8 outlets per circuit. Present wiring practice is usually well within the limit allowed by the code. In some cases it is necessary to meet other requirements of local codes. 11 2. Foot-Candles Required Foot-candle recommendations are 7 based on research studies of vision, on = observations of results in actual installa- tions and, furthermore, on the adequacy of present equipment and methods to provide the desirable standard of illumi- nation with safety and economy. All 2 l : ae Med his ane laboratory data point to the desirability of higher levels of illumination from the standpoint of vision, and practical tests substantiate the economy which results because of increased production, fewer accidents, and similar benefits. But without regard to such factors which are basic considerations of lighting poe ec economics, because of the progress the electric industry has made, tending to lower costs of energy and lamps, 30 foot- candles cost no more today than 3 foot-candles cost twenty-five years ago. 120 100 Foot-Candles 100 (Daylight near windows) LIGHT and TIME required for PERCEPTION oO io} D (oe) 10 Foot-Candles (Artificial light—modern system) Foot-candles of illumination K oO 20 1 2 1 Foot-Candle : . (Artificial light—old style system) Relative time The eye functions over wide range lighting conditions as illustrated by the photographs at the left; the graph at the right is the scientist’s quantitative statement of what everybody has experienced, namely, the eye sees more and sees more quickly as the illumination level is increased. 12 FOOT-CANDLES REQUIRED The foot-candle values given in the following pages correspond to present standards for different classes of industrial operations, offices, stores, etc. They are merely an index to good practice. In most cases, where higher foot-candle values than shown in this table are being used, it is found that the benefits derived more than offset the slightly increased cost. The desirable illumination for any particular installation depends upon actual conditions, such as the accuracy of the operation, the fineness of detail to be observed, the color of the goods worked on or handled, and, in the case of stores, the advertising value resulting from the attractiveness of a well-lighted interior. . TABLE No. 5 Present Standards of Foot-Candles of Illumination for COMMERCIAL INTERIORS Foot-Candles Foot-Candles Recommended Recommended Good = Mini- Good Mini- Practice mum ; Practice mum Armories: Dance Hallsge--neiniesn es 6 4 DrilliShedseenoucim cinerea 10 6 Exhibition Halls......... 12 8 Dental Offices: : Wialtin ci OOnl ene at 6 4 Art Galleries: Operating Office......... 12 8 ede etare Sten ae oe ta ad ae ~ 3 Dental Chairssnee ee 50 25 tings eee — as ay er Depot—Waiting Room..... 8 5 AUICILOTININS ore eee 5 . ; Drafting, Roomy... 22 4 00n 25 15 Automobile Show Rooms... 15 10 Bank: Elevators: eee 10 6 Freight and Passenger... . 6 4 Cages and Offices.:...... 15 10 Fire Engine House: Barbershop aeeeeieeeren: 15 10 eee Aor is turned in. . 8 By Base Ball—Indoor Game... 15 10 BY O thes Bins ete a Y a Basket Boll seees ae eae ee 15 10 co timer ier aces - ; : rage—Dead.......... Bowling: Lives eae ; 8 5 OnAlley, RunwayandSeats 8 5 Repair Dept. and Washing 15 10 Oni Pins: 3s sore eee 25 15 2 Billigede. Goal 6 A Gymnasiums: Leer Nie ante eae RE ODS Main Exercising Floor.... 12 8 On Table........ a a Swimming Pool.......... 8 5 Cars: Side oe Lae niaenee 6 4 ps Ce cker FROOMS i. co ene 6 4 paee ae posh odes 8 el Fencing, Boxing, Wrestling 12 8 Mail: , en ee 12 g_——“Hialls, Passageways in Ine aia Cases iar caess 8 a BS aay torage............ yee Handball oercermsre ces oe ele 25 1 Street Railway and Subway 10 6 oe? Hospitals: Churches: * Andi tori see ities 3 2 Robby end Beopucn Room ° . Sunday aeuoe) Room..... ‘ 5 OLFFIGOLIS. cee esc ccc cc ces Pulpit or Rostrum....... 2 8 : : oo Art Glass Windows... ... 25-50 15 bile het ie ban wun = 47 ; Club R : Private Rooms.......... 8 D lee : : Night Mumination.....-. onto oe Be a a oe ate a a perating Ol Mesatetternre 00-200 7 Reading Room.......... We = Operating Room......... 15 10 Court Rooms sysc- resets 10 6 Laboratoriesneny eee ee 15 10 FOOT-CANDLES REQUIRED TABLE No. 5 (Continued) Present Standards of Foot-Candles of Illumination for COMMERCIAL INTERIORS (Continued) Foot-Candles Foot-Candles Recommended Recommended Good Mini- Good Mini- Practice mum Practice mum Hotels: Two to four Lobby ene eee 8 5 Show) Cases tactic times that of Dining Roomeree eee 6 4 store proper Kitchens eee cero ee 10 6 Show Windows: Bed Rooms............. 8 5 Large Cities— Gorridors can ancaaees c 3 2 Brightly Lighted District. 150 100 Writing Room........... 12 8 Secondary Business Loca- . F UONo cs souadcoaanoucodar 165) 50 cash to haces 13 , Neighborhood Stores. .... 50 30 elegance pee xe) edium Cities— Stacks Roome seer eee 6 4 Brightly Lighted District. 15 50 De ek, ACI 6 4 eighborhood Stores... .. 50 30 EEE SOUS Small Cities and Towns... 50 30 hunch # Roommate 12 8 Lighting to Reduce Day- Market 2 8 light Window Reflections. 200-1000 ae gh Ser es Stores—Department and Moving Picture Theatre: Lara eore ee: ae During Intermission...... 5 3 Manu BlOOrsssceieeeaiene 15 10 During Pictures......... 0.1 Others loorsse eee 12 8 Musou: Basement Store.......... 15 10 General S33 cee ee 8 5 Stores—Medium Size: Special Exhibits......... 25-100 10 Art marci acne eee net 12 8 Office Buildings: puremelae Supplye erie 1 ; eShopsceeeenrreor onc Private and General Offices— Books eee 12 8 @loses Works ea eenere 15 10 Chita oe eee a. 12 8 No Close Work.......... 10 8 Cigars eee ae 15 10 Eile oom Fete ees : A nee lls SOREN ae RSS ie 10 OE OnreCHIONEry enone 2 8 Reception Room......... 6 4 Dairy Products.......... 12 8 Post Office: Perortoe x cieats sea nia ertene ie # Lobby. ja = 22022 s0 loam. Dry Goods..00000000)11) 1B Soran Matt ise ts ge a Sletten uspty at Bit Private and General Offices 15 10 Ponte, Pe ae a ee ie ‘ File Room and Vault..... 6 4 Grocery Scns tie ne 12 8 Corridors and Stairways. . 3 2 Haberdashery........... 15 10 Railway: Hardware jit s- eco 12 8 Depot—Waiting Room... 8 5 vat aoa, Gh elena cotenemer oyna 15 10 (ticket. Ofiices wee eee 12 8 pe PES ae q 15 10 Rest Room, Smoking Room 8 5 Teonka’ OS eo 12 Baggage Checking Office. . 12 8 Me: DPD SORE Gib Baba C 12 8 Storage cae eee 6 4 Main FORD tO AO AOS 15 ib Goncourse® 2756 one 6 4 Masa CSO 5 22RD 12 : 5 ee VLUSIOS eet ite ace Train Platform.......--. 9 ia INGtiOnS Senet ieee eee 12 8 Restaurants 3.0 scone cure 8 5 viene Bastin Pe Oe 12 8 OG Hitcoec at ore scote phocontee 15 10 Racquet 2:2 eo okinennle 25 15 Sporting Goods.......... 12 8 Schools: ‘Tailor =p er eere ee 15 10 INGOT ENN, on omcounbE 8 5 lObaCCOMma rete ite 15 10 Class Rooms, Library and Variety Store nee eee 15 10 CON een ices eee yettete 12 8 Telephone Exchanges: eee: and Stairways. . ee i poarlna learns a Yeas ove att 8 5 Laboratories...........- 12 8 Gi hlec\antcetaes ae =e 6 | Manual Training........ 12 8 a Ee meee Sewing Rooms... 25 15 ennis (indoor) erate ene 25-50 15 Study Room—Desks and Theatres: Blackboards. . 12 8 AUdItOriUIn acer 3 2 Skating Rink eee Ue 8 5 kes ee a ic P Squash oi. sey iacte eres 25 15 Toilet and Washrooms.... . 6 4 14 FOOT-CANDLES REQUIRED TABLE No. 5 (Continued) Present Standards of Foot-Candles of Illumination for INDUSTRIAL INTERIORS Aisles, Stairways, Passage- Automobile Manufacturing: Automatic Screw Machines Assembly Line.......... Frame Assembly......... ‘LooliMaking= ee cme Body Manufacturing— Assembly, Finishing and Inspecting’. -cictoeren eine Bakeries Sercctesssieicicle on revere Book Binding: Folding, Assembling, Past- Ing ).etCte oon oak aoe Cutting, Punching and Stitching 7. eee re Himbossing ys .102 2 cienals ei Gandy, Making yeeieris)essrels Canning and Preserving... . Chemical Works: Hand Furnaces, Boiling Tanks, Stationary Driers, Stationary or Gravity Crys- tallizinge een es eee Mechanical Furnaces, Gen- erators and Stills, Mechan- ical Driers, Evaporators, Filtration, Mechanical Crystallizing, Bleaching. . Tanks for Cooking, Ex- tractors, Percolators, Ni- trators, Electrolytic Cells. Clay Products and Cements: Grinding, Filter Presses, Kiln. Rooms san aero Molding, Pressing, Clean- ing and Trimming....... Enameling?..2. eee eric Color and Glazing. ...... Cloth Products: Cutting, Inspecting, Sew- ing— Paght Goods. terrier DarkiGoods\ecn ae. use aes Pressing, Cloth Treating (Oil Cloth, etc.)— Light Goods............ Darke Goods ).ceet ee Coal Breaking and Washing, Screening: 390s. hiaae ses Foot-Candles Recommended Good Mini- Practice mum 3 2 8 5 12 8 20 12 50-100 25 15 10 15 10 12 8 20 12 50-100 25 12 8 8 5 12 8 15 10 12 8 12 8 5 3 6 4 10 6 5 3 8 5 10 6 15 10 15 10 50-100 25 12 8 20 12 5 3 15 Construction— Indoor General.......... Dairy Products s--e-e eee Electric Manufacturing: Storage Battery, Molding of Grids, Charging Room. . Coil and Armature Wind- ing, Mica Working, Insu- lating Processes.......... Elevator—Freight and Pas- Engraving. ieee ere Forge Shops and Welding... Foundries: Charging Floor, Tumbling, Cleaning, Pouring and Shalang.Outpeeeeeeee Rough Molding and Core Making: etscse cme ae ee Fine Molding and Core Making vec a... eee ae Garage—Automobiles: borseces Dead Slaetecice Repair Deptacd Washing Glass Works: Mix and Furnace Rooms, Pressing and Lehr, Glass Blowing Machines. ...... Grinding, Cutting Glass to Sizejoilveringeeeeeen ee Fine Grinding, Polishing, Beveling, Inspection, Etch- ing and Decorating...... Glass Cutting nie less) Inspecting Fine.. Glove ee poe Light Goods— Cutting, Pressing, Knitting Sorting, Stitching, Trim- ming and Inspecting..... Dark Goods— Cutting, Pressing, Knitting Sorting, Stitching, Trim- ming and Inspecting..... Hat Manufacturing: , Dyeing, Stiffening, Braid- ing, Cleaning and Refin- Forming, Sizing, Pouncing, Flanging, Finishing, L[ron- Foot-Candles Recommended Good Mini- Practice mum 5 3 12 8 10 6 20 12 8 5 50-100 25 10 6 8 5 10 6 15 10 3 2 8 5 15 lu 10 6 12 8 15 10 25-50 15 12 8 15 10 15 10 50-100 25 10 6 15 10 12 8 15 10 15 10 50-100 25 TABLE No. 5 (Continued) Present Standards of Foot-Candles of Illumination for INDUSTRIAL INTERIORS (Continued) Foot-Candles Recommended Good Mini- Practice mum Ice Making: Engine and Compressor Roont nee seein ae ace 10 6 Inspecting: Rough .caccceo es cect 10 6 Mediuiaiiinic « otisuewesiere oe ss 15 10 Fine «06 os Su omaaton 25 15 Extra Wines. acc .cet ce oe 50-100 25 Usually requires glint reflections Polished Surfaces........ from specially located light source Jewelry and Watch Manu- facturing). dase ene oe 50-100 25 Laundries and Dry Cleaning 12 8 Leather Manufacturing: WatsAcarciecte cmearhee tenets: 5 3 Cleaning, Tanning and Stretching ase eeoeee eee 6 4 Cutting, Fleshing and Stuff- ING sek eee 10 6 Finishing and Scarfing... . 15 10 Leather Working: Pressing, Winding and Glazing— La ght 5.) ascaccthon atatshe ote 12 8 Darkane cc aero 15 10 Grading, Matching, Cut- ting, Scarfing, Sewing— Lightnin ee ae 15 10 Dark ayicins 6 sontinen ae 50-100 25 Locker Rooms............. 6 4 Machine Shops: Rough Bench and Machine Work?) Syn Se ae 10 6 Medium Bench and Ma- chine Work, Ordinary Auto matic Machines, Rough Grinding, Medium Buffing and Polishing. ......... 15 10 Fine Bench and Machine Work, Fine Automatic Ma- chines, Medium Grinding, Fine Buffing and Polishing 20 12 Extra Fine Bench and Ma- chine Work, Grinding (Fine Wiorktecae. ccm ee. 50-100 25 Meat Packing: Slaughtering............ 8 5 Cleaning, Cutting, Cook- ing, Grinding, Canning, Packing ici Sere ote 12 8 Milling—Grain Foods: Cleaning, Grinding and Rolling Sis -creen eee Baking or Roasting...... Flour Grading........... Offices: Private and General— Close Work............. Packing: Crating 3.47 eee eee Boxing jenn eee ee Paint Manufacturing....... Paint Shops: Dipping, Spraying, Firing. Rubbing, Ordinary Hand Painting and Finishing. . . Fine Hand Painting and Minishin see eee Extra Fine Hand Painting and Finishing (Automobile Bodies, Piano Cases, etc.) . Paper Box Manufacturing: Paper Manufacturing: Beaters, Machine, Grinding @alendering=)eee eee Finishing, Cutting and (rimming seer eee Polishing and Burnishing.. . Power Plants, Engine Rooms, Boilers: Boilers, Coal and Ash Handling, Storage Battery Roomszereea noe cee Auxiliary Equipment, Oil Switches and Transformers Switchboard, Engines, Gen- erators, Blowers, Compres- SOPS sees cece eee ee Printing Industries: Matrixing and Casting, Miscellaneous Machines, Presses #96. pe ee Proof Reading, Lithograph- ing, Electrotyping....... Linotype, Monotype,T ype- setting, Imposing Stone, Engraving so eee Receiving and Shipping 16 Foot-Candles Recommended Good Mini- Practice mum 8 5 12 8 25 15 15 10 10 8 25 15 6 4 10 6 10 8 5 12 8 15 10 50-100 25 10 6 12 8 5 3 6 4 10 6 12 8 8 5 12 8 5 3 8 5 10 6 12 8 15 10 50-100 25 6 4 FOOT-CANDLES REQUIRED TABLE No. 5 (Continued) Present Standards of Foot-Candles of Illumination for INDUSTRIAL INTERIORS (Continued) Rubber Manufacturing and Products: Calendars, Compounding Mills, Fabric Preparation, Stock Cutting, Tubing Ma- chines, Solid Tire Opera- tions, Mechanical Goods Building, Vulcanizing.... Bead Building, Pneumatic Tire Building and Finish- ing, Inner Tube Operation, Mechanical Goods Trim- ming; CLreading>..-04- Sheet Metal Works: Miscellaneous Machines, Ordinary Bench Work.... Punches, Presses, Shears, Stamps, Welders, Spinning, Fine Bench Wor Shoe Manufacturing: Hand Turning, Miscella- neous Bench and Machine Inspecting and Sorting Raw Material, Cutting, Lasting and Welting (Light)...... Inspecting and Sorting Raw Material, Cutting, Stitch- img) (Dark) eee eer ee Soap Manufacturing: Kettle Houses, Cutting, Soap Chip and Powder... Stamping, Wrapping and Packing, Filling and Pack- ing Soap Powder.. : Steel and Iron Mills, Bar, Sheet and Wire Products: Soaking Pits and Reheating Wurnacessnnace seria Floo: Muck’ and Heavy Rolling, Shearing, rough by gauge, Pickling and Cleaning... . Plate Inspection, Chipping Automatic Machines, Red, Light and Cold Rolling, Wire Dravine phowine, fine by line.. ee StoneCrushingandScreening: Belt Conveyor Tubes. Main Line Shafting, Spaces, Chute Rooms, In- side of Bins:5.. 3. foes Primary Breaker Room, Auxiliary Breakers under ime RI OS ee OCR ODI Foot-Candles Recommended Good Mini- Practice mum 12 8 15 10 12 8 15 10 25 15 12 8 15 10 50-100 25 8 5 10 6 3 2 6 4 8 5 25 15 12 8 3 2 5 3 8 5 Ly Foot-Candles Recommended Good Mini- Practice mum Store and Stock Rooms: Rough bulky material... . 3 2 Medium or fine material requiring car6...)) 0. 8 5 Structural Steel Fabrica- tion te Ae este ae 10 6 Sugar Grading* see 25 15 Testing: Roughss.cush cee 8 5 Fine aie Mae nee 15 10 Extra Fine Instruments, Scales etedie ras 50-100 25 Textile Mills: (Cotton) — Opening and Lapping, Carding, Drawing-frame, Roving, Dyeing.. 8 5 Spooling, Spinning, Draw- ing-in, Warping, Weaving, Quilling, Inspecting, Knit- ting, Slashing (over beam 00d) eee eae: eae 12 8 (Silk )— ee Throwing, Dye- er Meche of ashe baaee ip, 8 Quilting’ Warping, Weav- ing and Finishing— LightiGoods Seeman 15 10 Dark Goods............. 20 15 (Woolen)— Carding, Picking, Washing and Combing ian 6 4 Twisting and Dyeing..... 10 6 Drawing-in, Warping— Light.Goods mena entans 10 6 DarkGoods incu aoe 15 10 Weaving— LightiGoods See eeee ee 12 8 DarkiGoodss.ncsneneee: 20 12 Knitting Machines...... . 15 10 Tobacco Products: Drying, Stripping, General 3 2 Grading and Sorting..... 25 15 Toilet and Wash Rooms.... 6 4 Upholstering: Automobile, Coach and Hurnittire ss arene 15 10 Warehouse seria citer ec: 3 be Woodworking: Rough Sawing and Bench ‘Worker eee ee 8 5: Sizing, Planing, Rough Sanding, Medium Machine and Bench Work, Gluing, Veneering, Cooperage wotaen 12 8 Fine Bench and Machine Working, Fine Sanding and Minish since eee 15 10 FOOT-CANDLES REQUIRED TABLE No. 5 (Continued) Foot-Candles Illumination for OUTDOOR LIGHTING These values are included for reference purposes although the special considerations of design are not covered in this bulletin. Foot-Candles Foot-Candles Recommended Recommended Good Mini- Good Mini- Practice mum Practice mum G : ae at Automobile Parking Spaces. 1 0.5 epee oe, fer 15 10 Baseball Diamond (Indoor Yard and Driveways..... 4 2 Game).......--..-+..+5-- 10 9 Horseshoe Pitching........ 6 4 Basket; Ball jcc). enone ree 6 4 loe Hockey 8 5 Bathing Beaches........... 1 0.5 Loading Docks............ 3 2 Bulletin and Poster Boards: umbersY ards. eee 1 0.5 Bright Surroundings— Sha ttag rn Light Surface........... 30 20 SUNITA ts boo como dimooae 3 2 DarkiSurtacc eae 50 30 Track eee 15 10 Dark Surroundings— Monuments (See Building Light Surface........... 15 10 Exteriors) Darky ouriacesceeeia 30 20 oats . reight (See Loading Bicese De A ACH ees Nell eae 3 2 Docks) Ring eee een 80 50 Passenger... sine ae verte 4 2 Building: Play grounds2.. nee 4 73 Construction Work...... 6 4 Polo eee nese a= ees 8 i Excavation. ............ . : Prison: Vardar 3 2 omits Heoie apa Mon- Protective Industrial....... 1 0.5 Bright Surroundings— Quarries - 0.2 2 Sener se 3 2 Paghtiouriace errr 10 6 Railway Yards: Dark purtacess. eer 20 15 General eh @cecer ecee 0.25 0.15 Dark Surroundings— Scale: Housesa.s eee ee 3 2 ight) Surtace anise 6 4 Roque ase sci teeta eionpet 6 4 DarkjSuarfaces. sae 12 8 Signs—Painted (See Poster Church Windows (Art Glass) 25-50 5S Boards) ee ‘ Ship Yard Construction.... 6 4 EVES esate tert ot ricoh val clke yey = nos 2 - Kconeat ee ee 10 6 Skating .c-ceont cee ae 2 1 Storage.Y ards. eee 1 0.5 Glock’ Golfse cn aceeee kee 10 6 é A Croquet Staetiws-irdes atte 6 4 Swimming 2001s eae a : ‘ iLarget shooting see 20 15 Dredging as oes ne see 2 1 eas ‘Vennis!| Courts. eee 25-50 15 Drill Pields*otee eee 3 2 Tob Slid 2 1 Flags—Floodlighted........ 25-50 15 eas Seger 0 Fg Football (lrattic Officers race te 20 10 Practica ean ne 6 4 Trap Shooting........ Bete 15 10 Gramesigyies setepre sacha 12 8 Volley: Ball 82.0. 15 10 STREETS AND THOROUGHFARES Lamp Lumens per Linear Foot of ates Street Business District: White Way—Large, City car a0%0 Aare oe ee ee CTE RE ree ares eee 500-2000 Small Citys. shane <-.c e e er aee 200-500 Park: Boulevards sie 2 Sees oie: Sal Se ae et re Boe ao, Se Ce See 50-100 Thoroughfares and Wholesale Districts .......................00000 eeu 50-200 Residence Streetal. orcictees o ctelecsecavers. 5 peer vera Mek yer SoMa nite ee ba ene tree ae 20—40 Outlying: Districtsiand/Alleys snes. 5 he eee ee ee : 5-10 Phi ghiweaye ftebe vars ojscoveneie oeyeisee hehetire: 8 o.oo a SR Me ee Ae rent en a 10-20 stil) Reflection Factors The proportion of light reflected by walls and ceilings of various colors, that is, their Reflection Factors, has an important bearing on both the natural and the artificial lighting. The proportion reflected will depend somewhat upon the color of the incident light. The figures here given show what proportion of No. 1 White Papert 80% No. 2 C* Gat aft ; 67% €-) N OF 83 urrg Gray ’ 60% Gray i i i nee ; hy. . oe ss ics re Ne No. 4 & 2 ey a S oe! : ps a o ee) 549, No. 5 Gray 39% No. 6 French Gray 38% No. 7 Gray 28% No. 8 Gray 17% No. 9 Ivory White 78% No. 10 Caen Stone 73% No. 11 Ivory 71% No. 12 Ivory Tan 64% No. 13 Primrose 70% No. 14 Lichen Gray 69% No. 15 Pearl Gray 74% No. 16 Silver Gray and Caen Stone 57% of Colored Surfaces the light of Mazpa lamps these painted surfaces reflect. Reflection Factors are of special usefulness in determining the Coefficient of Utilization (ratio of light de- livered at the work to total light of lamps) applicable to an interior. The Re- flection Factor of any colored surface can be approximated by comparing it with these samples. No. 17 | No. 25 Buff Stone | marcar aac oe Green ure 36% 18% No. 26 Ae Je Olive Green 54% ae No. 19 No. 27 | ‘ Buff Stone Ley ue iy 42% $30, | No. 28 ve Pale Azure a) iva 38% iy No. 29 Sky Blue 35% Sa oe No. 30 ' we Shell Pink P. Green 5 ) in) 61% | re 49% No. 23 Bright Sage No. 31 and Ivory Pink an 49% 53% No. 32 Cardinal e 18% $1712 E27 794 Buik 3. Room Efficiency and Reflector Characteristics In order to specify the lamp size necessary to provide the foot-candles desired, the first step is to determine the percentage of light emitted by the lamp that actually gets down and is useful on the working plane. This percentage is called the Coefficient of Utilization for the particular installation. A simple “watts per square foot’’ specification is unreliable unless applied with the benefit of experienced judgment of various factors which affect the result. Interior finish, size and proportions of the room, the type of reflector, and maintenance conditions are variables which must be taken into account. Unless due allowance is made for each of these the results vary, in many cases 5 to 1; in other words, the same wattage per square foot might produce 15 foot-candles under certain conditions and only 3 foot-candles under a combination of unfavorable conditions. Coefficient of Utilization Tables, Pages 24 to 29, give the net efficiency result with due regard for the important variables noted below. Interior Finish—The paint samples show the percentage of light from Mazpa Lamps reflected by various colors; the holes in each sample permit convenient comparison with actual interior finishes. It will be noted that the influence of the interior finish is least important with opaque direct lighting reflectors, more pro- nounced with translucent glass units and a major consideration with semi-indirect and totally indirect luminaires. Room Proportions (Room Index)—In general, large rooms use light more efficiently than do small rooms because there is less wall area to absorb light in proportion to floor space. Raising the light source tends to increase the proportion of wall area to floor area, thus reducing the relative efficiency of high bay installa- tions. It will be observed that a room 10 feet square with a 10-foot ceiling has a Room Index of 1. Room Index values are computed with a unit room of this character as the basis. The effect of room proportions on illumination efficiency, and its importance in actual design problems will be noted by comparing the Coefficient of Utilization for example, for a room having a Room Index of 0.6 against one of 5.0, other factors remaining constant. 19 ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS Reflector Characteristics*—The selection of a suitable type of lighting unit depends not only upon its efficiency, the proper distribution of light and the requirements of the work, but, in the case of indirect units, upon the construction of the room and color of ceiling and walls. Decorative appearance frequently is an impor- tant item. A lighting installation may be judged by seven fundamentals described on page 21, and in Table 7 various lighting units are rated in accordance with these criteria. AT pBxcetten B. Good Gu rain _ B- ; < B 1 perv Good C 7 per Fair D_ Unsatisfactory The relative importance of these ratings should be carefully weighed with respect to the particular application at hand. For instance, in an office the criteria of major importance would rank: (1) Direct Glare, (2) Reflected Glare, (3) Shadows; (4) Illumination on Horizontal. On the other hand, ina foundry with lamps mounted high the order of importance would be: (1) Illumination on Horizontal, (2) Vertical Illumination, (3) Maintenance. A rating of D under Reflected Glare would not disqualify a unit except for use above polished metal or other highly glazed surfaces. Procedure To Determine the Coefficient of Utilization for the Installation Refer to Table 6—Room Index, which classifies the room according to its proportions. From this table find the Room Index which corresponds most nearly to the dimensions of the installation. Apply this in the use of Table 7. Refer to Table 7—Coefficients of Utilization, which gives the proportion of the generated light from the lamps which reaches the plane of work. The Coefficient of Utilization for the installation of the type of lighting unit selected will be found in the proper column of wall and ceiling color, opposite the correct Room Index. *Note: It is important that good reflecting equipment be installed. The luminaires shown in Table 7 illustrate common types under which most reflectors on the market can be classified for purposes of design calculations. For example, No. 8 is a unit of a general type of which there are a great variety made by various manufacturers. Of two or more units of the same type the choice should be governed by considerations of brightness, diffusion, absorption, appearance and cost, but not by cost alone. Of two samples of glass enclosing globes, out- wardly identical, one may absorb 30% of the light and the other only 15% for the same degree of diffusion. The safest plan is to choose products of reliable manufacturers. 20 ‘ROOM EFFICIENCY AND REFLECTOR CHARACTERIS ICS Illumination on Horizontal Surfaces is a prime requisite in offices, drafting rooms and those shops where the problem is to provide the best illumination for sustained vision of flat surfaces on the horizontal or slightly oblique planes in which papers, books and other flat objects are usually examined. For relative performance of various units compare coefficients of utilization for any given condition. Illumination on Vertical Surfaces is essential in many industrial operations where working surfaces are in vertical or oblique planes. It is likewise important in stores with vertical shelving, rug racks, etc., in art museums, library stock rooms, office file rooms. Without supple- mentary units, the illumination on vertical surfaces from ordinary general lighting units is of the order of one-half to one-third of the horizontal illumination values. Appearance of Lighted Room refers only to the general or casual effect produced by the complete system, and is not intended to rate the unit as to satisfaction from the standpoint of good vision or freedom from eye fatigue. Direct Glare is the most frequent and serious cause of bad lighting. It results among other things from unshaded or inadequately shaded light sources located within the field of vision, or from too great contrast between the bright light source and a dark background or adjacent surfaces. Glare should be avoided by the use of proper reflecting and diffusing equipment. Reflected Glare from polished working surfaces is particularly annoying because of the necessity of directing the eyes toward those surfaces, and further because the eyes are by nature especially sensitive to light rays from below. The harmful effects of this specular reflection can be minimized by properly shielding from below or diffusing the source. Shadows, that is, differences in brightness of surfaces, are essential in observing objects in their three dimensions, but are of little or no value in the observation of flat surfaces. Where shadows are desirable, they should be soft and luminous, not so sharp and dense as to confuse the object with its shadow. Maintenance Requirements depend upon contour of reflector, construction of fixture, and average maintenance conditions. The rating is based upon the likelihood of breakage, the labor involved in maintaining the units at comparable degrees of efficiency, and indication given of need of cleaning. 21 FEET TABLE 6 ROOM INDEX FOR NARROW AND AVERAGE ROOMS ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS ° ° Hs Hs ee 6 PELLICLE D/OooMAclomaooolmrnoonnlooammunloammun 19 6° si oo SSSSSRISSOCRHRRISC CH ARR RP SHR RSI RHR RRS a g 2 & ° ° ream om es Orwre] Cowon CLRAAANALSOANNIRIONAMINM|ARROSS mncess o aN Se) ooo SSR SAI OCR SARIS RRR RRNA ARAN © © nN at i - ee i] 0] ° ° ° 5 & Ss es C0000 6 0 cS BLSA aa Sooqawnwirannce|mncece|moonmnmn! 2 B reN aye A oooo CRS SSSI R eee SAA NAIRS RNAI ANNAN Nd © =~ Las | I = ¢ 4 Z s Sss 5 Sos mt JOWWRMMO/oLwnooS SAAWMMOINKROSSSSOIMMNSSSOloHMNNNH Sacsess| & so ea] on ooococors SSSA NIRS NNN NR RNAS ANNANAAINAM MOON coh! |e! tatanll PPS a |! fa) = © ARS ew a CALSSAIRLASOANW AMMESS[MSSOHUH/CoMnMMNN|MHSESSS weosessicscsessc as ao Scocdnie AAAANANAAANAAINANA A Alaa sola en en oslo i ai al a Ss Bee RASAANWISSANIMN IMIBOOCSwMISowmmmMunNjouunos|[rososo essssesisssss on BS COs s=s=—— ARANNANINNANANANINAN AMD NOD OD OD OD OD | OD OD OD SA SH SH SH HID ae c-) Eos ee SSAAWSIAANIIIROS SarwwwMopowwWoocoimosoosl[socoscco Ssessssissssse ao an addenda AAAAAMIAANMMS|NMM NN Olsaotdaal(saainwmwinhswmwwis a é pe! —“ ——. ra ” ~ ° ° ° 2° rR) ° oS 80 = ED leowcen & Nes Noneot Honsos Wnco SS Mn cs SS Heo SSA Onsen Seer Oo IIIT RIES s ISS TT FSS AS aSSA8 5 2 ol aioe gE |jeotoon SSSSISSISSSGSsessiesxesssienesssinssd iD m.o| | saans OHOSAADAOABIAGHSAG/ MH SRSS RAESATS|HSAS —— mr To 8 = | oe TE S) »* | o O om of ~ = ~ — ie i | o aA ‘8 aN a a — = x ° x0 ue ES a S ” a q =O) g ar — ot San a N a oO? q0 AS | cs S a0 ay Na ot oo be cl ho = aw 6 a ro] nN C) 6 o } ice) a an) aa) ~- ~~ ote 60 68/8 * . y a g ts a x ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS TABLE 6 ROOM INDEX FOR LARGE HIGH ROOMS 37 to 50 ° bal =) nor) br) ° ° a) ©o rio earl br) N ° ° Po sm mi O19 me N = & 3) —| 3/— | 9 mH! o bad —) C=) 19 rN Nn I oe os a“ | | 38 Se S-s oa as S38 Ss x= 1) ———GN —_— we 2 ga ge rep Sheed - ae) Ia) bo C.-C ce ae og »'S Oc o S| 4s| = oy 33 om © 4 aS m Oo im © ov OD a=) a aooslaoan Cee s|COnRK Sopa Le ee oe ee Ae ee ee Bel naw c|agce SS SNS RNIN EEN Sg SS ee SAANIN AAA onnnlemce ACINANINA SM ROOM INDEX noos|oose NI OD Of) OD | OD OD SH OH SSSS|SSSS C9 oF oD 3 | i i ooosl|ooes bo nl feed tel te) (Feet) (Feet) Room Width |Room Length TABLE No. 7 A GUIDE TO THE SELECTION OF REFLECTING EQUIPMENT RELATIVE FOOT- CANDLES FORAGIVEN| appear. LAMP SIZE ANCE OF | piRECcT | _, RE: MAIN- LIGHTING UNIT LIGHTED | GLARE | FLECTED | SHADOWS) teWaNce ROOM On Horizontal | Vertical Direct Lighting—General Industrial Reflectors RLM A B Be iB) BeBe eA White Bowl Lamp Excellent} Good Good Very Good Very Very 90° to 180°—0% Good Good Good 0° to 90°—66% Glassteel Diffuser B + A B i ey Very |Excellent] Good 90° to 180°—7% Good 0° to 90°—60% ee | A+ Excellent 3 RLM Dome Dust-tight Cover 90° to 180°—0% 0° to 90 °—54% Satis- RLM Dome factory Excellent Clear Lamp above 20-foot mount- ing Height 90° to 180°—0% 0° to 90 °—76% D Concentrated Prismatic Reflector Aluminum Cover Clear Lamp 90° to 180°—5% 0° to 90 °—72% 6 Mirrored Glass Reflector Clear Lamp 90° to 180°—3% 0° to 90°—73% tse |) 4 Excellent} Good Excellent C A Fair | Excellent Excellent! Good Good ee Oxidized Aluminum Excellent} Good Good Very | Unsatis-| Fair Very Reflector Fair factory Good Clear Lamp above Polished 90° to 180°—0% 0° to 90°72 of Surfaces 24 TABLE No. 7 AND COEFFICIENTS OF UTILIZATION PROBABLE AVERAGE ILLUMI- | CEILING NATION—AS FRACTION VERY LIGHT (70%) FAIRLY LIGHT (50%) | FAIRLY DARK (30%) FAIRLY | FAIRLY VERY FAIRLY | FAIRLY | VERY FAIRLY VERY OF INITIAL ILLUMINATION | Watts] LIGHT | DARK | DARK | LIGHT | DARK | DARK | DARK | DARK (50%) | (30%) | (10%) | (50%) | (30%) | (10%) | (30%) | (10%) Clean Average Dirty ROOM Conditions | Conditions | Conditions | 1/5 py COEFFICIENTS OF UTILIZATION Calculation Data—General Units 0.6 32 28 25 sos 28 25 27 25 8 A 0 2 5 0 aD 0 0 0 6 8 .0 2 =D 0 5 0 0 0 SuUboee NN Bee oS Vipwpn se moclaaes ecoooeouc AUNoOanococou Calculation Data—High Bay Units 0 42 39 38 Al 39 38 40 37 0 50 48 47 49 AT 46 AT 45 1 54 53 52 93 02 51 51 50 1. 58 7 56 56 .09 54 54 53 1. 61 59 57 58 oT 56 a7 55 Se OS Ce wh bh wre SSONS UNOeRNSSONS UbOeS ViPWNN =—=SS le -6 8 0 2 5 -0 5 -0 0 0 25 TABLE No. 7 (Continued) A GUIDE TO THE SELECTION OF REFLECTING EQUIPMENT RELATIVE FOOT- CANDLES FORA GIVEN| appear. LAMP SIZE ANCE OF| piRECT | ,, RE- MAIN- GLARE ROOM On On Horizontal | Vertical Store and General Utility Enclosing Units 8 Flattened B+ |} B+ A AaB e White Glass € Enclosing Globe > Excellent Very Very 90° to 180 °—35% Good Good 0° to 90°—45% 9 Prismatic Glass Enclosing Unit 90° to 180 °—27% 0° to 90 °—53% A B B-— B Excellent} Good Very Good Good Fair Good 10 Enclosed Semi-Indirect Enameled Bottom Etched Top Skeleton Glass Holder 90° to 180°—50% 0° to 90 °—27% i 2 Excellent Good Enclosed Semi-Indirect Enameled Bottom Etched Top 90° to 180 °—48% 0° to 90°—32% Good | Excellent Fair 12 Enclosed Semi-Indirect A — A B Enameled Bottom Etched Top Excellent] Excellent Excellent] Good (Close Ceiling Only) 90° to 180 °—53% 0° to 90 °—22% 13 Enclosed Semi-Indirect a C ae C a A B =; Cased-Glass Bottom Very Etched Top Fair 90° to 180°—51% 0° to 90°—21% 14 Enclosed Very Very |Excellent| Excellent] Excellent] Excellent Fair Fair Semi-Indirect S Prismatic Glass . 90° to 180 °—69% 0° to 90°—17% Excellent] Excellent] Excellent| Excellent] Good TABLE No. 7 (Continued) AND COEFFICIENTS OF UTILIZATION PROBABLE AVERAGE ILLUMI- CEILING NATION—AS FRACTION OF INITIAL ILLUMINATION | WALLS Clean Average Dirty Open Diffusing Bowl +4 ° 90°—609/" ee ete of Utilization slightly higher than those given for nit No, 8. ment, silk, AZ 21 £3 Enclosing Unit Large Decorative Shade 90° to 180°—21% 0° to 90°—56% 28 TABLE No. 7 (Continued) AND COEFFICIENT OF UTILIZATION PROBABLE AVERAGE ILLUMI- | CEILING VERY LIGHT (70%) FAIRLY LIGHT (50%) |FAIRLY DARK(30%) NATION—AS FRACTION FAIRLY | FAIRLY | VERY | FAIRLY | FAIRLY | VERY | FAIRLY | VERY OF INITIAL ILLUMINATION | Waiig | LIGHT | DARK | DARK | LIGHT | DARK | DARK | DARK | DARK (50%) | (0%) | (10%) | (50%) | (30%) | (10%) | (0%) | (10%) Clean Average Dirty* ROOM ‘ondition | Condition | Condition | joey COEFFICIENTS OF UTILIZATION 0.6 18 a5 13 15 12 10 10 08 0.8 22 19 17 19 16 14 ‘13 VW 1.0 "25 ‘99 20 21 ‘18 16 5 13 1.2 28 "35 ‘29 24 ‘21 19 16 15 70 | .60 15 31 27 ‘24 26 32 21 17 16 2.0 34 31 28 28 25 24 20 19 2.5 37 34 32 30 28 26 "29 2] 3.0 39 36 34 32 29 28 33 "22 4.0 37 34 5.0 40 36 0.6 14 abl 10 ai 09 07 06 05 0.8 18 14 ‘13 ‘14 at 10 ‘07 ‘06 1.0 ‘20 17 15 15 13 VW ‘09 ‘07 1.2 33 20 17 ‘18 15 13 10 ‘09 75 | .65 is 26 "39 19 20 17 ‘15 at 10 2.0 29 26 23 22 19 17 13 12 25 31 28 26 ‘34 21 20 14 3B 3.0 34 31 28 "25 "23 "21 ‘15 ‘14 4.0 37 34 32 ‘27 26 24 ‘17 16 5.0 39 36 34 30 27 26 18 17 0.6 15 12 10 ll 09 07 05 04 0.8 18 ie 13 13 id ‘09 ‘07 ‘06 1.0 22 19 16 15 13 ah 08 ‘07 1.2 25 29 ‘19 18 15 13 09 ‘08 70 | .60 i 27 24 21 20 ‘17 15 10 "09 2.0 30 27 25 22 19 17 J 10 2:5 34 31 28 24 29 20 13 ‘12 3.0 36 30 26 34 "22 14 13 4.0 "40 34 28 26 24 15 5.0 37 30 28 26 ‘17 SPECIAL UNITS FOR COMMERCIAL INTERIORS 22 m Units of this design have the same character of distribution <= as open types, with cover plate serving to exclude the dust Enclosed PEE TE and dirt from the lamp and reflecting surfaces of the unit. They have the decided advantage from the standpoint of ante per paene cleaning accompanied, however, by considerable sacrifice in the PehediGlasetlon total light output of the unit. 90° to 180°—48% Coefficients of Utilization about 20% less than open top 0° to 90°—10% units of the same design. Lanterns of period designs to conform architecturally to interiors, are frequently used in public buildings, notably churches. Reflectors inside of the ornamental housing increase the lighting efficiency and if made of glass may be made to 23 Ornamental Lantern Art Glass Panels Diffusing transmit varying amounts of light to illuminate the side panels. Bottom Plate Subject to a variety of design in which distribution ranges Internal from direct to totally indirect lighting. Reflector Coefficients of Utilization for the type of unit illustrated 90° to 180°—8% 0° to 90°—40% will average about two-thirds of the values given for Unit No 2. Multi-light clusters are in favor as decorative elements in public buildings and other monumental interiors. When mounted high with a large number of low wattage lamps, the result is not unsatisfactory. However, when mounted low, the uncontrolled distribution of light and the glare from the unshielded sources, spoils what would otherwise be an artistic effect. Lighting efficiency about 50% lower than same wattage in single lamp unit. 24 Multiple Light Clusters Smali Frosted Lamps The application of shades to multi-light units will, in many instances, raise the over-all effectiveness of the installa- tion. On the other hand, the illuminating qualities of large decoration designs can be materially improved if the decorative 25 Large Main lamp clusters are built around a central large-lamp unit Unit either of the indirect type or of dense enclosing glassware. Small Decorative A combination of this sort offers a greater flexibility in control Lamps of lighting effects, and, in most cases, will allow the illumination level to be raised by the use of a larger lamp in the main unit at any time if the occasion requires. 29 TABLE No. 7 (Continued) SPECIAL PURPOSE INDUSTRIAL UNITS 26 ‘ Generally inferior to RLM Dome with white-bowl lamp j because of lower efficiency, sharp shadows, and reflected glare Deep Bowl when used above shiny surfaces. Contrary to a common impression the light at any angle from a deep bowl steel reflector “paper cake is generally less than that from the RLM Standard Dome, 90° to 180°—0% Coefficients of Utilization average about 15% lower than 0° to 90°—65% those given for Unit No. 4. Highly efficient reflector which, by modification in design, can be made to give extensive, broad, or narrow light distribu- tion characteristics. With clear lamps it is difficult to avoid sharp shadows and reflected glare, and these factors are serious handicaps to a more general use of this type of unit, particularly at usual mounting heights. White-bowl lamps, properly 27 Prismatic Reflector Clear Lamp positioned, help these factors, although their use sacrifices, to 90° to 180 °—20% some extent, accurate control of light distribution as well as 0° to 90°—74% the efficiency. Coefficients of Utilization about 15% higher than those given for Unit No. 9. This unit like all deep-bowl types has a large shielding angle 28 to protect against direct glare; it likewise has the disadvantage in that it does not protect against reflected glare nor does it Mirrored Glass avoid sharp shadows when used with clear lamps. The use of Reflector white-bowl lamps lowers the efficiency of the unit about 20%, Clear Lamp due iy the light being potted up in the reflector, and, in 90° to 180°—0% general, are not recommended. ° oe; Coefficients of Utilization are about 10% lower than those OR tO 002 70 given for Unit No. 4. A : This unit has an aluminum reflector inside of a dust tight 29 ‘ housing. The reflector insert gives a concentrated distribution P i and a consequent higher utilization factor in high narrow Concentrating ———=4 interiors than would be the case with Unit No. 3. Its lower Aluminum Reflector efficiency, compared to Unit No. 7, limits the use of this unit Dust-tight Housing to locations where excessive dirt and smoke prevail. 90° to 180 —0% Coefficients of Utilization average about 20% lower than 0° to 90°—57% those given for Unit No. 7. 30 pial Designed for locations where corrosive vapor, inflammable pe, gases, or explosive dusts are likely to be encountered. In oe cares ar yi moisture laden atmospheres such as canning processes, engine popor Bross ae (ial, NN rooms, shower baths; also where gases and vapors from such Reflectonith 44) processes as oil refining, varnish making, spray lacquer painting Glass Enclosing and the like are present, units of this character are recom- Globe mended. See also Unit No, 31. 90° to 180°—0% Coefficients of Utilization about 10 to 15% lower than 0° to 90°—68% for an open reflector. 31 Vapor-proof Fitting ed Applications same as for Unit No, 30; the glass reflector is usually not subject to corrosive action and holders are obtainable in a variety of metals and compositions to withstand corrosion from acid vapors of chemical plants. Recommended also in grain elevators, spice, flour and feed mills, in the manu- facture of powdered sugar, cornstarch, sulphur, etc., where explosive dusts are present. Coefficients of Utilization about the same as for Unit No. 9. Prismatic Enclosing Globe 90° to 180 °—28% 0° to 90°—57% 3 2 Often used in craneways mounted below cranerail to supple- ment general pak te system in building up illumination on ateral surfaces. sed also to light individual machines where es epee pines demand special distribution or direction of light. = pecial care must be taken in locating units to avoid glare: in Output 74% general, they should be placed high. To supplement general lighting where operations require high levels of illumination of the order of 50 to 100 foot-candles where general lighting of at least 10 foot-candles is provided. Local lamps are subject to much handling and for this reason 33 Local Lighting Unit Se pores glass cover plates are recommended to protect reflecting © elac on surface from grease and dirt; construction must be substantial; reflectors should not be supported by socket shell. 25 to 60-watt inside frosted lamps will generally provide the level of illumination required. Cover Plate Output 45-55% 30 COLOR QUALITY—APPLICATION OF ARTIFICIAL DAYLIGHT A few years ago discussions of artificial daylight were centered about units built on theoretical lines and of somewhat uncertain performance. Today, good practical units are being marketed and consequently the field for such units has broadened beyond the original conception of limited applications in stores and textile industries. The duplication of natural daylight is confined largely to those industrial and commercial applications involving accurate color discrimination or color rendition in varying degree, depending upon the specific require- ments. Even in this field difficulties arise because the colorist has been accustomed, perhaps through years of habit, to a specific daylight quality peculiar to his location. It is practical and expedient, however, to provide exact reproductions of daylight for any given requirement with the attendant advantage of constancy and 24-hour availability. Although color quality is accurately specified by color temperature designations, equipments for reproducing daylight for working purposes may be grouped roughly into (1) skylight units, (2) sunlight units, and (3) units which provide a whiter light than the common types of general lighting equipment, but not so white as those listed under (1) and (2). Equipments of this character employ accurately correcting filters by means of which it is possible to duplicate the color of outdoor daylight. Generally designed for localized lighting over counters in stores, for small areas or special operations in industrial plants where precision in color identification, grading, and other color inspection is required. Illumination of the order of 100 foot-candles is desirable for this sort of work. Color factories, paint and dye mixing, art studios, chemical analysis, dental mechanics, surgery, textile and cigar sorting and grading are examples suggesting the application of skylight reproducing equipment. As compared to unmodified artificial light, from 6 to 8 times the wattage is required for the same foot-candle values. 34 Skylight Quality Special Color Filter Clear Lamp the inside modify the light from a lamp to approximate the color of direct sunlight at noon. Their applications are to some extent the same as skylight units, the actual choice depending on specific requirements; in general, noon sunlight equipment is used for less exacting color discrimination. For example, ink and dye mixing, and inspection may be done locally under skylight quality, and a general system of noon sunlight equipment may be installed in certain rooms or over small areas restricted to manufacturing operations requiring clear color rendition—such, for example, as lithographing processes, color printing and the like. A\\ so aé ail 35 M_|\\ Sunlight Quality Reflector and Color Correcting Globe Clear Lamp As compared to unmodified artificial light, from 2 to 3 Enclosing globes of special crystal blue glass frosted on times the wattage is required for the same foot-candle values. “Daylight” lamps, emit a whiter light which is but a partial step toward daylight whiteness. In many instances of color rendition, their use gives sufficient color correction to be of considerable advantage over the warmer tones of unmodified light. For example, they are widely used in stores and show windows to improve the display of merchandise. Again the light blends well with natural daylight; in fact in many cases it is about the same color as the daylight which one gets 36 Ordinary 2 5 fj h 1 4 Equipment indoors taking into account the prevalence of warm tones in window shades. walls and hangings; for this reason the use Blue Bulb of daylight lamps in offices and many other places will be found to correct an unsatisfactory mixture of ordinary artificial light and inadequate daylight. The next larger size of lamp will be required to produce approximately the foot-candle level as computed for a clear lamp of a given size. They are used in all common types of equipment. Daylight Lamps Enclosing globes with slight bluish ingredient do not appreciably modify the color quality of illumination for utilitarian purposes, but have a considerable field of applica- tion by virtue of their whiter appearance. Such equipment is correct. for the yellowish tone usually noticeable with ordinary opal glassware. These usually give far less color correction than Mazpa Daylight lamps. The units are very pleasing, 37 Color Modifying Globes appear white and clean, and are often more satisfactory than Cl r units of yellowish tone, particularly when supplementing eis TEA natural daylight. The spectral quality of illumination is usually not far from that of a clear bulb Mazp, C lamp. Coefficients of Utilization will be about 10% to 30% less Lamps with blue bulbs, commercially known as Mazpa than the values given for Unit No. 8. 31 Lamp Size—Lumen Output Required 4. TABLE 8—COMPUTED ILLUMINATION VALUES In this table the actual foot-candles have been worked out for man initial y different ice to be 70 per cent of the the average foot-candles In serv COEFFICIENT OF UTILIZATION a |e eo Ae bal 5 1) g§ o |S 5-5 AN a ne a |e =| | £3 4 0] com) gE gi § § © .Aa8 a= we O om ANON wowr ANDO wowrvo Othe reno oncom SHoHt | SSnd |uracn Tce a co RECT: [et Cee CN a Sore Rai somnn | onnr |oodte | MOND | wrndh oe orl eel Ce | Oe | mN ee eet ON en | ee ae determined, AQIS U Omran KIN ronmn Fores Ataeeo racow SAN nero AON SnuN AMON Caan wore IN HOw monn | Feds tren o Mooer | MowWN wnaANS FON | HMO Cama | mono | Frown asec Lo} ein). Lo | aN ie CMON | ataw rere no MADN | CODW in co SN ANtS | Omot ail | ee wom | co LNLD AWA mowew wn COLn oD sear SREND | POMS MINSCO | NAS FON Ss eo) moo | Mana trow | t#oam aN mn ns | ae ee C eo oe _ Smenm | Ooon | nouns AAnn | Corr ANBWO }]|onos Anew | reretr | morta onon NM-NDA | reono wens | FreAn | FreND Mmonrr | moore CUDA | HCO ODS sreHo | moot | Monn wmeaE | HOD | MINOM mN mn ae ac Cm = ee ae meme pa HO | RAE | SRA | Nine | CONS Sey SER [AAS PSeme | MAD | OABN | IAMS aenae|sone |mork awwow | muadt | ator Sra | aso | muan mine | ROAM | mice | ord aN [on ama ae Llama cal Cl Coal eo Shee |RaaS | SOSs | FANN [awonm | waren HOSE [OMA | Smma [rane SADA | HAOH [Ors occ moor |anow e018 Ost ooo oD age mood | moa | mmo |agro | HOO COLD tm HFOS —-—— OHO’ metres | CAD COON | ONOC Are | MANS one Oran | tors NNO | CHRO | HRAN MmNSO | MINA cmc CUSTiCoIGN Ate NS mina | mince NERS | NAODN MNrKA | MAOS | AMNOD oe izes of lamps can be obtained directly LUMEN OUTPUT REQUIRED e and the coefficient of utilization COEFFICIENT OF UTILIZATION FOOT-CANDLES SND | ARINAN | OMAR | FONN AEE | one | ances or ore Aaa |S RON | MONS | RAAN | MOMS COL AS NPFOM (ASN iS bore NMOS | AMA | Noo NEKO | NAOD | NMS MAOS | AANA | NMC DEMS | MWANCHD | MAH OFS | OMAN ODN | CONN Mana | Kran | ann OMAO | SrMM | ANON aeom |ANAEeR | NMOS QoS AMA | AAW SS ES NAFOD | NMS | RK oMwe APFOHD | AMINO | ANSE = we ot | AreS | eK teH Amoe | ONAN WooM |nANSo | orerr DOMAN | CHOW sown |AmMmom | ano Cl SUES AMCS | AMOD | AmMMe aan | ANSE | ANBOD Nene | emer | AANHO NANO | AMA | AANAHO Qi-es | oot | acne raAnmo|ounm SOND | Keon Hares eoww DEAD | ANAY | HONS rore AROS AMON | eens eNO | RANE HNO |AMNS | AMMe amdto | Renan | ANSE AaHOoO | AN WH 16 18 | .20 | .22| (25 | .28 | .32 | .36 | .40 | .45| .50 | .55 | .60 | .65 | .70 duced by various s -14 | has been mad LAMP SIZE TABLE 8—COMPUTED ILLUMINATION VALUES table. Size of Lamp After the layout e foot-candles pro from this Lamp th | | a | | cs a | | ——— OOOO Oe | oo ————SS OO | wl coooleocoecoiococoeo ccooci;eocesc cccoo |;eoeeo coco loosce |oooeo cooolecesoiooceo eeseissoo!iseoce esesoi;ooeceo ecess;essoes;ecosce eesselesoqoliococee2 escoo |;oooeo AmMne | AMMO | AMNS Gissine | gimme | Nu MHEO|MNODS|MNAS mnrneaso|maceo|;wece nooo OIDAH | MINA | MAS IDA | MIAH ODA | WAS | WAS DAS | WAG | ARMAS AtAaM | ata e Lal e Cl Ll e aN mN aN mN Ca orl aN mNO ee a ed reed Watts! Lumens 200 220 LAMP SIZE— LUMEN OUTPUT REQUIRED Formulas for Computing Lamp Size After the outlets have been located on the plan, the size of lamp to be used may be determined by the following calculation: (A) Area in Square F. eet _ Total Floor Area in Square Feet per Outlet Number of Outlets Lamp Lumens (BMH ec dined pene Foot-Candles Ss Foot Coefficient Probable Average Illumination So madden of >< in Per Cent of Initial Utilization Illumination Lamp Lumens Area in Square Feet Lamp Lumens Required (C) Required per = per Outlet x per Square Foot Outlet (From A) (From B) Having determined the lamp lumens required per outlet by the above calculations, the wattage of Mazpa lamps to be used may be found by reference to Table 9, below, which lists the lumen output rating for each size of Mazpa clear and Mazpa Daylight lamps. Locate in this table the size of lamp of the desired type which most nearly meets the requirements of lumen output. When the lamp lumens required fall nearly midway between two sizes, it will usually be found best to choose the larger size. TABLE 9—LUMEN OUTPUT OF MULTIPLE MAZDA LAMPS Subject to change without notice 110-115-120 Volt 110-115-120 Volt 220-230-240-250 Volt Standard Lighting Service | Standard Lighting Service Service Clear Lamps Mazpa Daylight Lamps Clear Lamps Size of Size of Size of Lamp in Lumen Lamp in Lumen Lamp in Lumen Watts Output Watts Output Watts Output 100 1350 100 900 100 1040 150 2300 150 1500 se pene ee ae 200 3200 200 2100 200 2700 300 5300 300 3500 300 4300 500 9500 200 6200 500 8100 750 14800 oe we ee See 750 13000 1000 21000 t Saas HN pie een 1000 18200 1500 33000 sey eeu as sae 1500 27300 34 LIST OF MANUFACTURERS MANUFACTURER TRADE NAME OF UNIT Unit No. 1 (60 to 1500 watts) *Benjamin Electric Manufacturing Co. ze *Tvanhoe Division of the Miller Co. - - pe ceunenonee eee ae Manufacturing Co. *Wheeler Manufacturing Co. - = = *National Screw and Manufacturing Co. - RLM Standard Dome Overbagh and Ayres Manufacturing Co. - Quadrangle Manufacturing Co. - -~— - Central States G. E. Supply Co.- -~— - Unit No. 2 (150 to 500 watts) Manufacturers marked (*) under Unit No.1 - Glassteel Diffuser Unit No. 3 (60 to 500 watts) Ivanhoe Division of the Miller Co. - -~ - Benjamin Electric Manufacturing Co. - - }RLM Dust-tight Wheeler Reflector Co. - - -~ - = - Unit No. 4 (60 to 1500 watts) Same as for Unit No.1- - - - - - RLM Standard Dome Unit No. 5 (500 to 1500 watts) Holophane Glass Co. - - - - - - Holophane Unit No. 6. (750 to 1500 watts) Pittsburgh Reflector Co. Curtis Lighting, Inc. - Unit No. 7 (750 to 1500 watts) Ivanhoe Division of the Miller Co. Unit No. 8 (100 to 500 watts) Flattened globes of this character are made by most lighting glassware manufacturers and marketed under various trade names. The best quality will have a light output of about 80% and yet be sufficiently diffusing that the globe is of uniform brightness. The-minimum diameter of globe for a given lamp wattage is as follows: Permaflector Big Boy Industrial Flood US O0nw atts eee 12-inch 300 watts. ........ 16-inch ANOLE, oo Goood 14-inch SOO kwatts eee 18-inch Unit No. 9 (100 to 500 watts) Holophane Glass Co. - - - = 7 - RR (Reflector-Refractor) Unit No. 10 (100 to 500 watts) Goodrich Electric Co. - - - - - - Beardslee Chandelier Co. -~— - = 4 - Clear Top Henkel and Best Co. - -— - - - - Unit No. 11 (100 to 500 watts) Graybar Electric Co.,Inc. - - - - - 99 Reflex Unit No. 12 (100 to 300 watts) Wakefield Brass Co. - - - - -. - Red Spot Office Unit Unit No. 13 (150 to 500 watts) Ivanhoe Division of the Miller Co. - - - Keldon Unit No. 14 (100 to 500 watts) Holophane Glass Co. =< - - - - - Filterlite Unit No. 15 (100 to 1500 watts) Duplexalite Division of the Miller Co. - - Duplexalite Unit No. 16 (200 to 500 watts) Curtis Lighting, Inc. - - - - - Winall 35 LIST OF MANUFACTURERS MANUFACTURER TRADE NAME OF UNIT Unit No. 17 (100 to 1500 watts) Curtis Lighting, Inc. - - - - - - £=X-Ray Unit No. 18 (25 to 150 watts) Made by most Lighting Glassware Manufacturers. Unit No. 19 (60 to 1000 watts) Made by most Lighting Glassware Manufacturers. Unit No. 20 (100 to 500 watts) Planetlite Company, IGG - - - - - Planetlite Edwin F. Guth - - - - = = Brascolite Unit No. 21 (100 to 500 watts) Art stores and studios, in general, make a specialty of executing designs in silk, parchment, and other suitable shade materials. Unit No. 22 (100 to 500 watts) The Duplexalite Division of the Miller Company Duplexalite Units Nos. 23, 24, 25 Specifically designed ornamental equipments will be made up according to specification by a considerable number of lighting fixture manufacturers. Unit No. 26 (25 to 1500 watts) Same as list for Unit No. 1 - - - = Deep Bowl Steel Unit No. 27 (100 to 500 watts) Holophane Glass Co. - - - - - - Holophane Prismatic Unit No. 28 (100 to 500 watts) Curtis Lighting, Inc. - - - - = - Unit No. 29 (200 to 500 watts) Ivanhoe Division of the Miller Co. Unit No. 30 (60 to 500 watts) Benjamin Electric Manufacturing Co. - - Ivanhoe Division of the Miller es - - - ¢Vapor Proof Wheeler Reflector Co. - — - Stes SS Unit No. 31 (40 to 200 watts) Industrial Floodlight Holophane Glass Co. - - - - - - Vapor Proof Unit No. 32 (25 to 1500 watts) Same as list for Unit No. 1 - - - - Angle Type Unit No. 33 (10 to 50 watts) Ivanhoe Division of the Miller Co. - -~ - Benjamin Electric Manufacturing Co. - - Unit No. 34 (150 to 1000 watts and in multiple units) MacBeth Daylighting Co. - - - = MacBeth Ivanhoe Division of the Miller Ce eee rutine Unit No. 35 (200 to 1000 watts) Ivanhoe Division of the Miller Co. - - - Noon Sunlight Unit No. 36 (60 to 500 watts) Mazpa Lamp Manufacturers - - - - Mazpa Daylight Lamp Unit No. 37 (100 to 750 watts) Gleason-Tiebout Glass Co. - - - - - Celestialite Glass 36 3 | BULLETINS OF THE NATIONAL LAMP WORKS b| ~7D—Fundamentals of Illumination This bulletin presents the principles of light—its measurement, its control and distribution—together with essentials of illuminatien design—60 vages. Illumination Terms, a supplement to Bulletin 7D, is a dictionary of light- ing terms.—56 pages. 33C—Picture Projection with Mazpa Lamps ' A practical discussion of the principles of Mazpa lamp projection and their if, application.—54 pages. 41D—MIlumination Design Data for Commercial and Industrial Interiors This bulletin presents a simple method of illumination design adapted to ' general lighting systems where standard equipment is to be used. Charts and 4 tables simplify the method and make for accuracy in the design.—36 pages. * 42B—Factory Lighting Designs : Ready-made illumination plans for the more common bay sizes found in industrial interiors are presented in this bulletin—48 pages. 44A—Incandescent Lamp Temperatures Data on operating temperatures of lamps, wiring parts, and fixtures.— 36 pages. 45A—Lighting Designs for Stores Presents lighting recipes for a number of typical store interiors, with designs and notes on lighting of the display windows——48 pages. A46A—Street Lighting Designs 5 Simple recipes are given for the lighting of business, thoroughfare, and residence streets for cities of various sizes.—20 pages. “47A—Home Lighting Fundamentals A practical guide for lighting the home, replete with sketches illustrating the use of various types of lighting fixtures to obtain desirable lighting effecis Al in the different. rooms.—32 ‘pages. 50A—Electrical Advertising—lIts Forms, Characteristics, and Design This bulletin contains a discussion of the requirements, characteristics, and adaptabilities of the principal forms of electrical advertising, and simple approximate rules to guide the sign user and builder.—48 pages. 51—Night Lighting for Outdoor Sports This bulletin discusses the various types-of equipment and gives compre- hensive lighting plans for tennis, volley ball, race tracks, bathing beaches, and a number of other common outdoor recreations.—24 pages. ' 52—Photographic Lighting with Mazpa Lamps Analyzes the requirements, describes the equipment, and illustrates the results obtained with Mazpa lamps in portrait and commercial photography.—64 pages. 53—Farm Lighting Pertinent to the general interest and widespread activities in farm electrifica- tion, this bulletin presents lighting recommendations which are practical and satisfactory for the various farm buildings and the farm home.—36 pages. 54—Floodlighting ‘ Presents a comprehensive design procedure together with suggestions on floodlighting effects, equipment, and equipment location—48 pages. Many other publications are available, dealing with specific phases of lighting —schools, hotels, stages, printing plants, cotton mills, automobile headlighting, Christmas lighting, maintenance, airway roof signs, etc. When requesting pub- lications, please state the subjects in which you are interested. THE SALES ORGANIZATION OF THE NATIONAL LAMP WORKS OF GENERAL ELECTRIC CO, ALLEGHENY DIVISION ATLANTIC-FEDERAL DIVISION BUCKEYE DIVISION . CONTINENTAL DIVISION EMPIRE DIVISION MICHIGAN DIVISION MIDLAND-FEDERAL DIVISION MISSISSIPPI YALLEY DIVISION . NEW ENGLAND DIVISION NORTHERN DIVISION PACIFIC DIVISION SOUTHERN DIVISION SOUTHWESTERN DIVISION SUNBEAM DIVISION. SUNBEAM DIVISION . PITTSBURGH, PA. NEW YORK, N. Y. CLEVELAND, OHIO - PHILADELPHIA, PA. . BUFFALO, N. Y. . DETROIT, MICH. CHICAGO, ILL. ST. LOUIS, MO. . BOSTON, MASS. MINNEAPOLIS, MINN. OAKLAND, CALIF. ATLANTA, GA. KANSAS CITY, MO. NEW YORK. N. Y. CHICAGO, ILL. AT EACH OF THESE OFFICES A LIGHTING ENGINEER IS AT YOUR SERVICE { \ y i ENGINEERING DEPARTMENT NATIONAL LAMP WORKS OF GENERAL ELECTRIC CO. @ NELA PARK, CLEVELAND