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Thread: Emergency/Egress Illumination Levels

  1. #1
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    Lightbulb Emergency/Egress Illumination Levels

    I am having a hard time understanding to what lighting level should path of egress (corridors, parking garage isles, etc.) need to be lit to. In IBC section 1006.2 it states "not less than 1 footcandle) and in section 1006.4 "at least an average of 1 footcandle". NFPA 101, Life Safety Code has the same verbiage, 7.8.1.3 "at least 1 ft-candle" and 7.9.2.1 "an average of 1 ft-candle".

    Which is it, a minimum or an average of 1 footcandle?

  2. #2
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    Quote Originally Posted by Misha322 View Post
    IBC section 1006.2 it states "not less than 1 footcandle) [1]
    in section 1006.4 "at least an average of 1 footcandle". [2]
    NFPA 101, Life Safety Code has the same verbiage, 7.8.1.3 "at least 1 ft-candle" [3]
    7.9.2.1 "an average of 1 ft-candle". [4]

    Which is it, a minimum or an average of 1 footcandle?
    1 and 3 are equivalent and they mean at least 1 fc.
    4 contradicts 1 half the time, by the definition of average.
    2 contradicts 1 less than or equal to half the time, by the definition of average.

    You're not forbidden to go over 1 fc all the time so that's what I'd do. Try 2 or 3 fc.
    It's easier than getting someone to clarify this issue. The thing decision makers do not want to do is make a decision. In fact a Dilbert cartoon said you shouldn't even be in the same room where and when a decision is made.

  3. #3
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    Quote Originally Posted by G._S._Ohm View Post
    1 and 3 are equivalent and they mean at least 1 fc.
    4 contradicts 1 half the time, by the definition of average.
    2 contradicts 1 less than or equal to half the time, by the definition of average.

    You're not forbidden to go over 1 fc all the time so that's what I'd do. Try 2 or 3 fc.
    It's easier than getting someone to clarify this issue. The thing decision makers do not want to do is make a decision. In fact a Dilbert cartoon said you shouldn't even be in the same room where and when a decision is made.
    GS .......... if you have no clue at all why even answer?

  4. #4
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    Quote Originally Posted by iwire View Post
    GS .......... if you have no clue at all why even answer?
    That's the problem - I don't know that I have no clue.

  5. #5
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    Looking at 101, the way I read it, 7.8 is "Illumination for Means of Egress". So that would cover the normal lighting.

    7.9 is for emergency illumination. So that would apply to unit equipment, or the lighting levels that are required when the power goes out.

    But there is a good chance I'm in the same boat as G.S., and I don't have a clue

  6. #6
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    Let us pray that someone gives us a clue.

  7. #7
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    Quote Originally Posted by Misha322 View Post
    I am having a hard time understanding to what lighting level should path of egress (corridors, parking garage isles, etc.) need to be lit to. In IBC section 1006.2 it states "not less than 1 footcandle) and in section 1006.4 "at least an average of 1 footcandle". NFPA 101, Life Safety Code has the same verbiage, 7.8.1.3 "at least 1 ft-candle" and 7.9.2.1 "an average of 1 ft-candle".

    Which is it, a minimum or an average of 1 footcandle?
    IBC section 1006.2 is for general illumination for the means of egress. So during normal operation the means of egress illumination needs to illuminate the walking surface at not less than 1 foot candle.

    IBC section 1006.4 is dealing with the performance of the emergency lighting system. This section requires that during emergency lighting the initial lighting level shall be at least an average of 1 foot candle and a minimum of .1 foot candle measure along the path of egress at floor level.

    What that means is that for emergency lighting the entire floor level does not need to be illuminated to 1 foot candle only the average needs to be at that level. This permits a farther distance between emergency lighting units then the normal lighting units for the path of egress.

    Chris

  8. #8
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    Quote Originally Posted by Misha322 View Post
    Which is it, a minimum or an average of 1 footcandle?
    Here, it's either, but the minimum sure is easier (and less expensive) to comply with. The averaging requires a lot more work.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  9. #9
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    Quote Originally Posted by raider1 View Post
    IBC section 1006.2 is for general illumination for the means of egress. So during normal operation the means of egress illumination needs to illuminate the walking surface at not less than 1 foot candle.

    IBC section 1006.4 is dealing with the performance of the emergency lighting system. This section requires that during emergency lighting the initial lighting level shall be at least an average of 1 foot candle and a minimum of .1 foot candle measure along the path of egress at floor level.

    What that means is that for emergency lighting the entire floor level does not need to be illuminated to 1 foot candle only the average needs to be at that level. This permits a farther distance between emergency lighting units then the normal lighting units for the path of egress.

    Chris
    This is the way I've always understood it and the way it is typically enforced here in SC.

  10. #10
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    Turns out 0.1 fc is not all that dim, with a full moon being 0.01 fc.

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