What does the NEC consider "Illumination"

[RussellH]

Is there a set standard or how many lumens it has to be, to be considered Illuminated? Example, there is a light well above a stairway with about a 20 watt bulb that really does not illuminate anything. Is there a standard to what the NEC considered "Illuminated".

 

[mgookin]

Is there a set standard or how many lumens it has to be, to be considered Illuminated? Example, there is a light well above a stairway with about a 20 watt bulb that really does not illuminate anything. Is there a standard to what the NEC considered "Illuminated".

Chapter 10 of your building code will tell you what light levels need to be where along a means of egress.

Welcome to the forum.

 

[steve66]

Lumens is a measure of how much light a fixture or lamp puts out. "Illumination" is measured in footcandles, and its a measure of how much light hits the surface of an object.

We normally calculate (actually, its more like an estimate) footcandles based on the lumen output of the fixture, how far away it is, and other details.

The IBC generally requires 10 footcandles average at the floor for normal lighting in the means of egress, and 1 footcandle on the floor for emergency lighting (when the normal power fails).