Light spacing in pole horse barn???

[Attono]

I have a monument style barn built that is essentially 36x36 on the inside. I have 3 12x12 stalls along one side, a 12' wide center aisle that is 12' high, 1 12x12 stall, a wash area and 12x12 tack room on the other side. I've got the meter base panel installed and wired (meter not yet installed) and wiring run to the main panel. I need to run 3/4 conduit and think I'm going to just use 12/2 and 12/3 for everything. I'm trying to figure out how far apart I need to put the T8 2 bulb lights across the center aisle and above the stalls.

Based on a few barns I've looked in, I want to say 6' spacing, but don't want to wind up with it looking like the surface of the sun in there. Any advice would be appreciated.

 

[KennyG]

Figure out your target watts per square foot. The 4 foot 2 bulb T8 lights will probably be 64 watts per fixture. I find that 0.75 to 1.0 watts per square foot is good for general work and storage areas. I like closer to 2 watts per square foot over work benches. For an area you just need to get through without running into things, 0.25 to 0.5 watts per square foot is plenty if you can distribute the light.

If you are using the plug in lights, just put plenty of outlet boxes and you can adjust the lighting as you go. For areas that don't need a lot of light you might consider using screw in CFLs also. It makes it easier to get even light at lower levels.

 

[Attono]

I know that the 12' ceiling height will reduce the usable light and figure the working area is about 2-3' high. I think as I was doing some research last night, I ran across something that said 2 watts/ft was the right number for the working area. Using that math, for the center aisle is 432 ft2/64w per light = 6.75 lights x 2 watts/ft = 13.5 lights. So that would give me the approx 6' spacing I was thinking and so I'd do 2 rows at 6' along the center aisle. I'd probably just do 1 row at 6' spacing above the stalls though.

 

[grsthegreat]

I have a 36 x 60 barn, peak of ceiling about 14-15 feet high. I used 5 - 8 foot long light fixtures along the peak and have plenty of light. I spaced mine so there was one fixture between each main truss. the double trusses are 12' on center. this places the lights as such. 2 foot space, 8 foot light, 4 foot space, 8 foot light, 4 foot space, 8 foot light, etc till i reach end.

as i said, plenty of light.

Now i have an open stall system. if you have solid stall walls 8 foot high, then your going to have to have something entirely different. me, i hate enclosed barns. i like the open feel.

in the second pic you can see one of the lights.

 

[KennyG]

2 watts per square foot is the standard for office space. If you are not doing close work, you can get by with a lot less. That's why I said I like 2 watts over the workbenches, but 1 or less is fine for everywhere else.

Looks like grs has less than 0.5/ft2 and it's fine for a barn. Shop space would probably need more.

 

[grsthegreat]

2 watts per square foot is the standard for office space. If you are not doing close work, you can get by with a lot less. That's why I said I like 2 watts over the workbenches, but 1 or less is fine for everywhere else.

Looks like grs has less than 0.5/ft2 and it's fine for a barn. Shop space would probably need more.

i have a program called Visual put out by Lithonia. I use it to design lighting for my customers. Even with my limited barn lighting im getting an average of
16 Footcandles ...which is more than enough for a barn.....not too bad even for a shop

as an example, a bank lobby is generally designed with only 10 footcandles illumination.

 

[Attono]

So can you run it for my barn and tell me the optimum spacing for my lights? I don't know enough about lighting to be conversant in footcandles and such.

 

[grsthegreat]

i could, but i really have no idea as to the interior layout of the barn....such as interior walls, floor cover, etc

 

[Attono]

It's a metal pole barn. 12x36 center aisle with concrete fllor. 3 12x12 stalls on one side with pine tongue and groove. 1 12x12 stall and a 12x12 wash area on the other witha 12x12 enclosed tack room. I sure do appreciate the help!

 

[grsthegreat]

It's a metal pole barn. 12x36 center aisle with concrete fllor. 3 12x12 stalls on one side with pine tongue and groove. 1 12x12 stall and a 12x12 wash area on the other witha 12x12 enclosed tack room. I sure do appreciate the help!

how far are the trusses spaced? no problem, i can run it up tomorrow