Lighting layout

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dnbob

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Location
Rochester, MN
I am working on a lighting layout for our new shop. The warehouse portion of the shop is 16,000 sq. ft., all of which is open with 17' ceilings. All (most) storage will be against exterior walls. I am wondering if 18 - 250 watt metal halide low bay lights will be adequate. The area is used primarily for storage and loading trucks in the mornings.

Thanks, Bob
 
Re: Lighting layout

You need to determine what the FC level you need in this environment. This is not a guessing game.
Suggest you get someone who is knowledgeable in this area. Your lighting distributor may be able to help.
 
Re: Lighting layout

There are many rules-of-thumb that will get you in the ballpark. But the manufacturer or his rep will usually help you pick a footcandle level & lay them out for you on paper. Ask your supplier.

You need some help though, like bob says, this is not a guessing game.

By the way, (18) 250WMH totals about 5625VA.
That would be only .35 VA per square foot.
Gonna be pretty dark in there.
 
Re: Lighting layout

dnbob
I ran a typical whse thru my LitePro program. It is a lighting calculator provided by my Hubbell rep. I used the following assumptions, which shouldn't make a big difference, 125'x125', mount low bays at 16', white backed insulation ceiling, cluttered walls, concrete floor. One factor I didn't consider would be sky lights in the roof, however if you want to load trucks early in the morning, don't count on sky lights.
For most whse applications, 25 footcandles is enough.
Using 18 250w Hubell lowbays I get an average of 12 fc.
I used 18 400w lowbays and got 23 fc.
I think that 400w is probably closer to what you need.
Jim T
 
Re: Lighting layout

I would look into high output T-5 Fluorescents.

A Four lamp fixture with 54-W T-5 HO lamps produces the light of a 400 watt metal halide and consumes less power to do so.

MH 400 = 465 watts

4 lamp T-5 HO = 234 watts

They also take up much less vertical space.
T-5 HO Info

We have retrofitted a few places with these and they work great, even higher than 17'

As far as the layout get a sales rep to help.

Bob

[ December 19, 2004, 10:58 AM: Message edited by: iwire ]
 
Re: Lighting layout

To echo Bob's comment, metal halide high/low bays are quickly going the way of the dinosaur with the advent of t-5 lamps in the U.S. They have been around in Europe for a long time.

The drawback to t-5 is that they are metric, so you can't retofit old fixtures. You need a new fixture.
 
Re: Lighting layout

A big advantage of the T-5s is they can be switched on and off. HID's are normally left on.
Your POCO may have grant money to install the T-5's. Several companies make center stem hung T-5 fixtures.
 
Re: Lighting layout

I agree the T-5's are a better choice in many instances but not all. Around here, a low-bay is $120 or so, and a T-5 high bay is $320.00 or so. At $.10/KWH, if you burn the lights for 3 hours a day, 5 days a week, 52 weeks a year, you have about a 10 year simple payback. If you burn them 8 hours, you have a 4-5 year payback. The high bay T-5's are still a tough sell around here unless you are a school district, or something like that.
Jim T
 
Re: Lighting layout

Thanks for all of the responses. I am not sure why I wrote 18 lights, we are using 24 - 250 watt m/h. I spoke to my supplier this morning and we should have about 30 f.c. so I think we'll be fine. Thanks again!
 
Re: Lighting layout

I spoke to my supplier this morning and we should have about 30 f.c. so I think we'll be fine.
Click to expand...
I hope he knows what he is doing. I just ran it and came out with 42 250 WMH 30FC and
30 250 WMH for 20FC.
 
Re: Lighting layout

I do lighting design as well, but there are a lot of things to consider here....

Your:

room size
wall reflectances
type of lighting fixture
the type of space
how high the ceiling is
and how clean or dirty the space is

Either get a lighting rep, or get the visual program by lithonia, and plug in the ies values and catalog number of the light fixture and it will give it to you. Just tell them the catalog number, type of fixtures, space size (sq ft), and the ceiling height I can give you an estimate.

[ December 21, 2004, 11:49 AM: Message edited by: lady sparks lover ]
 
Re: Lighting layout

lady spark lover
I was the first one to run the point by point in this example, and here's what I used,
125'x125'
.8,.5,.2 reflectances, clg,wall,floor
250 watt lowbay
warehouse
17' clg, 16' fixture height
medium dirty, .75 depreciation
You are right, these are all important factors and should be included in any serious layout analysis.
Jim T
 
Re: Lighting layout

Originally posted by jtester:
lady spark lover
I was the first one to run the point by point in this example, and here's what I used,
125'x125'
.8,.5,.2 reflectances, clg,wall,floor
250 watt lowbay
warehouse
17' clg, 16' fixture height
medium dirty, .75 depreciation
You are right, these are all important factors and should be included in any serious layout analysis.
Jim T
Click to expand...
Got to argree with you , Jim!
 
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