lighting layout question

[Matt Neil]

I'm working on the layout of lights in my future workshop space. It's approximately 23' x 28'. In the picture, you can see that the right wall is the 23' length and will have a counter along it. 8' 8" from the wall is a steel I-beam that runs parallel to the wall. It's drop is about 8" from the ceiling. There's about 11' of open ceiling space to the left of that and then another I-beam off the left of the picture with about 8' 8" between that I-beam and the left wall. My idea is to run the flourescent lights parallel to the I-beams, with 4 rows of lights. The spacing has me concerned. Can I place one row of lights between the I-beams and the walls and 2 rows of lights between the I-beams and still get good coverage? Do any of you have suggestions of other layout options? I've read Jack's articles and will try to get 40-48 bulbs in.

Additionally, I know some of you place each row on it's own switch. Are you happy with that or do you wish you had more of a staggered layout?

[Don Jarvie]

I suggest you cover the ceiling with drywall or plywood and paint it flat white. The light will reflect much better and the shop will be brighter. I would insulate and strap (1x3s 90 degrees to the joists) the ceiling and put up the dry wall. 1/4 drywall would work great and its light.

The add T8 lights 90 degrees to the I beam say every 3 to 4 feet. You will probably get 5 lights per side. When you finish the walls paint the a light color and you should have plenty of light.

[Jim Neeley]

Matt,

I recommend that you start out by deciding how bright you want the room in your shop (based on your age, eyesight, how much detail work you do, and how much you want to depend on "task lights" in specific areas of the shop. This and knowing what kind of lights you wish to use (for example 4' T-8 fluorescent bulbs) will let you get a ballpark number of bulbs to install.

There is a great sticky at the top of this forum that lets you calculate the number of bulbs / fixtures you will need to provide a certain average level of light. As you will see from the article, the guideline is 50 foot-candles (fc) if you're young and 100 fc's as we get up into our 50's and 60's. Obviously we can go lower than this if we either have very good eyes, like working in dim light or make extensive use of individual or portable lights in your shop.

On the upper end of intensity, for a 23' x 28' shop, to give you 100fc with 2800 lumen 48" t-8 bulbs, it would take 46 bulbs. This could be made up by using 23 two-light fixtures or 11 4-light fixtures and a two-light. If you went with the 8' strip fixtures with 4 bulbs per fixture, you would have 11-12 fixtures. If you want 50fc, go with half that. Once you get a ballpark of how many fixtures you want, then look at layout.

I'm suggesting this approach because when I did it for my shop I found out (before I started my upgrade) that I'd need more than I thought I'd need. This fed into my planning and layout. For example you could choose to start with 50fc but lay out the strips with an eye to where you would add more in the future if you decide you'd want to. This can help you end up with the bast overall lighting placement.

Just my $0.02.. from an electrical engineer (me) who has validated the "rule of thumb" calculations in the article. YMMV.

Also, there's a lighting quality lot to be gained by starting with a white, flat ceiling.

[Lee Schierer]

I agree with Matt, use the calculator or many electrical supply houses will do the calculations for you. Once you determine the desired light level, the layout gets easier. The new t-5 lamps are very bright and you would need less of them.

[Jack Lindsey]

Matt - I think the layout you are proposing will work fine with the following: drywall the ceiling or cover it with drywall, and paint it white. If you can't drywall at least paint the ceiling and the joists white. Also, paint the beams white. The white paint is critical. You're going to need a lot more fixtures without it. Use 4 rows of 5 two lamp fixtures per row as you have described. Locate the fixtures in the side bays 3 1/2' from the walls (5' from the I beams), and locate the rows in the center bay 2' from the I beams with 7' between the rows. This is a few fixtures less than I would normally recommend but you can compensate by washing the lamps and fixtures when the lighting levels drop due to the factors I discussed in the article.

I wouldn't recommend T5 lamps due to the brightness of the lamps combined with your low ceiling height.

Hope this helps.

Jack

[Matt Neil]

Jack, I was hoping you would notice this thread and weigh in. I just wasn't sure how much light those beams would block if the fixtures were 2' from them. The help you've provided the hobbyist both here and in your articles has been tremendous.

[Jack Lindsey]

Jack, I was hoping you would notice this thread and weigh in. I just wasn't sure how much light those beams would block if the fixtures were 2' from them. The help you've provided the hobbyist both here and in your articles has been tremendous.

Matt, the impact of the beam won't be significant as long as it is painted a light color such as white. Yes, some light will be blocked but most of the light that strikes the beam will be reflected. The use of a flat paint (not glossy) will help even out the lighting in the space. With a white ceiling and the layout you propose the entire ceiling will to some extent act as one big light fixture so the lighting in your shop should be pretty uniform.

[Mark Shirley]

I would insulate and strap (1x3s 90 degrees to the joists) the ceiling and put up the dry wall. 1/4 drywall would work great and its light.

While I second the recommendation for drywall the ceiling, 1/4 is the WRONG way to go on the ceiling. They use 5/8 rather than 1/2 on the ceiling to keep it from sagging. Years ago I helped my dad install 3/8 on his shop ceiling and it's now sagging badly. it looks terrible. If you want light, go with a steel liner panel. 3-rib steel is $2/linear ft. That's about 67 cents a square ft.

[Julie Moriarty]

When it comes to fluorescent lighting there are lots of options that affect illumination. Besides the T12, T8 and T5 lamps you also have color temperature and lumen output. On the color temperature you'll be looking for a number followed by a K (Kelvin). 4500K will look dull next to a 6500K lamp, which is a bright white. I recently replaced 12 of my 40W 4500K lamps with the 6500K lamps and it brightened up my shop a lot, plus I like the color better. The other half of my shop has 96" HO lamps in 2-lamp fixtures. "HO" is high output. There's also VHO and SHO, the last being the highest lumen output. And, depending on the mounting height and spacing, you may want to consider shades for the fixtures to reflect the most light downward.

Figure the most light for where you'll do the most work and take into consideration shadowing. You don't want the light to cast a shadow on whatever it is you're working on, like when you're at the workbench.

My shop is about 12'x24' and I have (3) 96" T12 2-lamp HO fluorescents, (3) 96" T12 4-lamp fluorescents and (1) 48" T12 2-lamp fluorescent. Also, over the workbench and under some shelves I have a 60" T5 2 lamp fluorescent. Each of the 3 bank fixtures are on their own switch but it's rare that I have only one on. The 48" T12 is over the lathe and on its own switch and the workbench fixture is on its own switch but is always on when I'm in the shop. I like a well lit shop. It makes me forget the shop is in the basement and with the new 6500K lamps makes it feel more like I'm getting in some sunlight. When the HO lamps need replacing I'm going with the 6500K for them too.

When you're running the power for the lighting, remember to figure sufficient power for whatever you think you may have, now and in the future, for power tools. I put the dust collector on a dedicated 15A circuit and installed switching throughout the shop to turn it on, no matter where I am. I just used 3-way and 4-way switches mounted in with the duplex receptacles in 1900 boxes with 2 gang drywall rings. Then I ran two 20A circuits, alternating them along the walls, for the receptacles. I thought I had more than enough (there's about 20 duplex receptacles total) but there have been times I wished I had more, especially at the work bench areas.

I'm with the others on the drywall thickness, if you intend to drywall the ceiling. Code here says 1/2" for 16" O.C. joists and 5/8" for 24" O.C. joists. You can get lightweight drywall that seems as stiff as the old standard and is a lot easier to handle.

I saw one shop that didn't need ceiling insulation and the owner stapled a white parachute to the ceiling and it cast back a lot of light. From your picture, if you leave the ceiling as is, you'll lose a lot of light.

Post some pictures when you're done!