footcandle


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Related to footcandle: lumen

footcandle

[′fu̇t ‚kand·əl]
(optics)
A unit of illumination, equal to the illumination of a surface, 1 square foot in area, on which there is a luminous flux of 1 lumen uniformly distributed, or equal to the illumination of a surface all points of which are at a distance of 1 foot from a uniform point source of 1 candela; equal to approximately 10.7639 lux. Abbreviated ftc.

illuminance

The density of luminous power, also called illumination. One lumen of luminous flux, uniformly incident on 1 square foot of area, produces an illuminance of 1 footcandle; in SI units, one lumen of luminous flux, uniformly incident on 1 square meter of area, produces an illuminance of 1 lux.
References in periodicals archive ?
Maintaining good color recognition from high-pressure sodium lamps, Bullough says, can be achieved by using at least 3 footcandles of illumination.
Since the American Standard Recommendation prescribes illumination in terms of footcandles on the horizontal plane and emphasizes reduced glare, there has been a tendency to use luminaires with sharp cutoffs of the main beam, which directs the light predominantly down onto the pavement surface.
For championship play, 35 footcandles or over maintained evenly distributed - within 10 percent - and measured with a light meter about 42 in.
The amount of illumination is expressed in a footcandles rating as read by the testing method described.
1 footcandles (a 109% increase) and uniformity at an average/minimum ratio of 4.
You don't need the same type of lamps in every area--for example, in Research & Development, we need 72 footcandles at the desktop because they do fine work, but we don't need 72 footcandles at the floor level in the warehouse.
I could have three different apps to check footcandle levels and they'll give me three separate results that could be significantly different from each other," explains Fedoruk.
Although the light offers excellent efficiency when it comes to overall footcandle output, it is weak in the area of distribution and overall uniformity.
The built environment is created for people and therefore the light in a space should serve their needs and desires, not just be engineered to a predetermined footcandle level," Berrigan said in an LD+A interview in 2013.
IES issues guidelines for the recommended footcandle level for different applications--visual tasks with small detail and high contrast can require as much as 50 fc, while the same job with low contrast could require up to 100 fc, according to Mark Havira, director of national accounts for Efficient Lighting Consultants.
The remainder of the tunnel maintains a 10 footcandle level using conventional fluorescent fixtures.
If you have five fixtures with the lamps burned out, that could pose a problem because now you're not meeting the required footcandle levels," Dixon says.