1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lighting Requirements, Industrial/Commercial.

  1. Jun 30, 2009 #1
    Are the lighting requirements stated in lux? Also, where would I go to find out the requirements for various settings? I looked around in the NEC book but didn't really find anything.

    Thanks for the help.
  2. jcsd
  3. Jun 30, 2009 #2


    User Avatar
    Science Advisor

    Local building codes should tell you what type of lighting is required for various buildings as well as CFR and OSHA.

    The requirements are typically given in foot-candles.

    Here is a link from OSHA which should point you in the right direction:


    Last edited by a moderator: Apr 24, 2017
  4. Jul 1, 2009 #3
    For most fixtures, there is some type of polished thin white metal above the lamp used as a reflector. About what would it's hemispherical spectral reflectivity be?

    It is more or less a speculur reflector right?

    Assuming the reflectivity is high, and the upper hemisphere is blocked by this metal, can I double the lumens being emitted in the lower hemisphere, getting Candella*4pi=x Lumens ?
  5. Jul 1, 2009 #4
    For a lamp that is stated to have x lumens, is that x lumens total, or x lumens per steradian?
  6. Jul 1, 2009 #5
    While we are at it, could someone explain to me what a Candella is? I am not really getting it.

    Okay, so it is a Watt/Steradian. Okay.

    Lets say that when we get a flux of 100 photons passing through a surface per second, that that is equal to one watt.

    So if we have, lets say 50 Candella, we have a flux of 5000 photons passing through a surface whose area equals r^2 per second.

    What I do not get, is, if the Candella is defined this way, then doesn't that mean that the candella is dependent on r? If I were to double r, then i am quadrupling the surface area, and therefore my Candella will go down to a quarter its previous value.

    So what does it mean, when you say a lamp has a candella rating of X, without giving the r that was used to determine that?

    I mean, if I choose a big enough R, I could get the sun to have a candella of 1E-1000
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook