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see photometryphotometry
, branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light such a source may cast on a surface area.
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A unit of measurement for the average light on a surface; 1 foot-candle equals 1 lumen per square foot.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Illuminance is the density of light on a surface, and it is measured in units of lumens per square meter (lux, abbreviated lx) or lumens per square foot (foot-candles, abbreviated fc).
In general, the study found that sites with lighting levels below three foot-candles were given low security ratings, usually between -4 and 1.
Guidelines established by the USDA (5) for meat and poultry are similar; all areas where utensils are produced, packaged or washed must meet a minimum of 30 foot-candles. However, inspection stations must be either 50 or 200 foot-candles depending upon the type of inspection area.
The new court lighting package delivers light levels of more than 16 foot-candles across the full playing area, while achieving extremely even light levels, a max/min ratio of only 2.71.
Light is measured in foot-candles -- the amount of light cast on a square foot area by a candle at 1 foot distance -- and the sun on a clear summer day can bathe us in 10,000 foot-candles.
When I converted foot-candles to lux, I noticed how
The UV-B (312nm) intensity of the Bi-O-Vision can be adjusted without preset stops--its ranges go from 6,000 to 3,000 [micro]W/[cm.sup.2] and the white light output can be regulated to fall between 1,000 and 2,000 foot-candles (93 to 186 lux).
The UV-B (312 nm) intensity of the series can be varied without preset stops, from 6,000 to 3,000 [micro]W/[cm.sup.2], and the white light output can be adjusted from 2,000 to 1,000 foot-candles (186 to 93 lux).
For example in Normal Mode, 170,000 LUX or 17,000 foot-candles of light is available, while in Turbo Mode, illumination can be increased to 220,000 LUX or 22,000 foot-candles.
The lamp's visible light emission is less than two foot-candles, and it easily meets MIL and ASTM specs for FPI and MPI.