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Thread: Flourescent light spacing

  1. #1

    Flourescent light spacing

    Is there a general recommendation for how far apart 2x4 flourescent lights should be in a commercial building?

  2. #2
    Join Date
    May 2005
    Location
    Richmond, Virginia
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    Quote Originally Posted by Rawls007 View Post
    Is there a general recommendation for how far apart 2x4 flourescent lights should be in a commercial building?
    It really sepends on how much light you want, in the lumens-per-square-foot sense.

    Often, though, it's the layout pattern that looks the best that wins out.

    Is this a large open area? Are there natural boundaries, like aisles or partitions?

    Is this for general illumination or task lighting?
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  3. #3
    Basically just general lighting. One is the dining area for a catfish shack type of place with open ceilings and the other is for the kitchen with a ceiling grid.

  4. #4
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    Quote Originally Posted by Rawls007 View Post
    Basically just general lighting. One is the dining area for a catfish shack type of place with open ceilings and the other is for the kitchen with a ceiling grid.

    The health dept. will require the minimum amount of light allowed. They have a method to measure the candle power. Or something like that. Esspecially over food prep tables.

  5. #5
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    Nov 2006
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    North New Jersey
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    how many bulbs per light? 2,3 4 ?

  6. #6
    Join Date
    Dec 2008
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    146
    The "Rule of Thumb" I use is 8'-0" on center. This is generally done with a 3-lamp fixture on a "standard" ceiling height for offices/classrooms.

    Now ... there are 2-lamp fixture out nowadays that will give out similar lights as the 3 lampers. And not all fixtures are created equal.

    I will generally utilize a direct/indirect fixture in an open ceiling application. Seems like a waste to light the ceiling, but it will feel more open and less like a black hole that way. 10% uplight is sufficient.

    Food prep areas will require closed/gasketed fixtures.

    Lean on your light fixture manufacturer reps. They can run footcandle calculations for you to make sure what you're installing will work. This is actually required in a lot of localities for food prep areas.

  7. #7
    Quote Originally Posted by tonyou812 View Post
    how many bulbs per light? 2,3 4 ?

    Not real sure exactly. It's kind of open for me to decide on the lighting system. Let's just say 3 for example's sake.

  8. #8
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    Nov 2006
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    North New Jersey
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    I would probably go with 3 lampers and space them as evenly as possible using the 8' on center rule. I would make sure that the kitchen has ample lighting.

  9. #9
    Join Date
    Jun 2003
    Posts
    291

    Lithonia lighting

    Lithonia's website has a program you can download.
    The light level you want in general is 50 foot candles.
    The program tells you how far apart to place the lights you intend to use.

    There are some variable you must enter in relation to reflective of surfaces.

    We use it all the time to design lighting and it is awesome one you learn to use it.


    **This post is not an advertisment for Lithonia, rather a great tool.....

  10. #10
    Join Date
    Feb 2003
    Location
    Bremerton, Washington
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    6,606
    The Lithonia program would be the simplest way to lay out your luminaires

    The work type determines the footcandles needed, eg hallways are 20 FC, offices typically are 50.
    Each lamp puts out a certain amount of light, in footcandles or lumens. You add up the lumens and divide into the work space square footage, factors affecting are room cavity ratio, floor and ceiling reflectance. Also there is a lamp loss and dirt depreciation factor.

    Its a well established system, no harder than voltage drop.
    Moderator-Washington State
    Ancora Imparo

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