Show SOME ELECTRIC LAMP FACTS in estimating the illumination required for a room A times C equals total candle power where A equals area of floor space in square feet and C Is a constant found in the accompany ing table the constant depending on the color of th the e walls in each case i to secure a uniform distribution of 0 this light judgment must be exercised however in selecting the size of units and their location class of foot const C walls service candles candies dark light reading heading 20 oo 00 0 SO OIO O IO theartres theatres The atres 20 20 05 0 aylo churches 35 general store 33 35 OSO 0 desk illuminata 35 bookkeeping 40 clothing 33 55 window this table is to be used only the light units aro are equipped with good reflectors example A room 70 teet feet by feet with light walls to lo be lighted to give good reading illumination to table two foot candles are required constant for light walls area 70 feet by tet iet I t et square teet feet times equals candles it if twelve units three rows of four each have been decided upon divided by 12 equals candles per unit unil or ff a unit containing live 60 watt mazda lamps has been decided upon 5 times 48 49 equals 24 0 candles cand lis then dividing by 14 units total candle power multiplied by efficiency fici ency of lamps watt per candle power gives total watts consumed it if mazda lamps are used multiply by 1 20 filament 25 now used carbon 33 38 the following table compares energy used and energy sav d by using different class of lamps to produce same candle power lamp f energy energy used saved 10 W P C mazda 1 97 W P C tantalum W P 11 C iba 2 97 NAT P C carbon 12 3 W P a carbon GA AV p C carbon 00 |