Flourescent light spacing

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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
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?
 

Rawls007

Member
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.
 

Buck Parrish

Senior Member
Location
NC & IN
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.
 

ptrip

Senior Member
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.
 

tonyou812

Senior Member
Location
North New Jersey
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.
 

bigjohn67

Senior Member
Lithonia lighting

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.....
 

tom baker

First Chief Moderator
Staff member
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.
 

ptrip

Senior Member
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.....

I have to second this program. I use it all the time and forget that it's available to the "general public"!
 
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