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Need some help on new shop lighting

olytdi

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Olympia, Washington
This is another "help me out" thread with lighting only because I find the hundreds of previous threads on this either outdated, lacking application to my situation, or simply contradictory. I understand the basics of lighting in terms of intensity falling off over distance and the need to not pack all of your lumens in a few small packages!

In my previous 28x28 square shop build, there were two interior trusses dividing the box into three equal sections. The truss bottom chords were 11 ft from the floor. I had put up two fluorescent fixtures longways on each truss bottom (each fixture was 8 ft long and had 4) 4ft t8 lamps), and I put another 8 ft 4 tube fixture at 90 degrees perpendicular midway from each of the trusses toward the outer walls. So, 6 fixtures in total, each with 4 tubes = 24 tubes at 2600 lumens per tube, mounted at 11 ft above the floor. This comes to about 62,400 lumens applied at 11 ft off the floor. The walls were flat white -- I don't know what that means in terms of reflectance but the lighting was pretty good in my opinion but probably could be better.

I now have a new 36x36 building that is very similar in design to the 28x28 in that it's a square building and is similarly trisected by two interior trusses, the bottom chords of which are also 11 ft from the floor. Also similarly, the walls are somewhat white given the insulation wrap and I'll probably end up with white walls once completed. The 36x36 is about 55% larger in area than the 28x28. I will use the new building for projects, hobbies, wrenching, etc.

My question is about LED fixtures, of course. Given my satisfaction with my previous flourescent setup, is there any reason not to stick to the layout I used previously but increase the number of LED fixtures such that the total number of lumen output is proportionate? So perhaps 10 fixtures total with similar output, 3 each on the truss bottoms and another two each perpendicular to the walls? I'm uncertain how LEDs will perform vs the T8 tubes in a direct comparison.

Another question involves fixture type -- I would think long and narrow is best (better coverage/fewer shadows) and that a reflector of some sort and diffuser lens would have positive effects(?).

Lastly, I would assume that if I over do it, I can always bail out with a dimmer switch?

BTW, I did try some of the online calculators but I'm not understanding some of the input terminology and sometimes they have a "pick your application" but it's not clear what application from their list would be analogous to mine (grocery store/show room/class room/etc.).

Anyway, thanks up front for any tips and suggestions. This doesn't have to be perfect and brighter has always seemed better to these aging eyes. It's the shadows, light "harshness," and glare from the fixtures that I worry about. I don't like glare and shadows!

Eric
 
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cybrdyke

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Some lighting software that's directed at the general public asks for appliction because the first thing that any software needs to know is how much light (in foot-candles) you need. Whatever application you choose tells the software what target to shoot for. Obviously, this is dumbed-down because the common person doesn't know what foot-candle levels he needs.
Your first move should be to try to determine this. Common well-lit hobby shop should be around 50fc. If your work is more detailed, small parts, then more is better. The best pro auto shops are lit from 75-100 fc., but that's a ton of light and complete overkill for most people.
One mistake you're making is using the figure of "total lumens". This figure has no meaning and isn't helpful to what you're trying to do. I get a great big belly laugh at all the YouTube knuckleheads shouting about how many total lumens they have. If they only knew how much they were embarrassing themselves, they'd be ashamed.
Your assumption that linear lights will provide more even light with better shadow fills and less contrast is correct. Continue with this plan.
Your T8 lamps didn't emit 2600 lumens. That's a common mistake. They were on a ballast that only produced 87% of the full capability of the lamp. Then, they were in a fixture that only lets about 70% of the light out of the fixture. That's only about 1600 lumens per lamp. You can use that figure to start to calculate your LED fixture requirements.
Here's the process...
Pick your light level in foot-candles. Doesn't have to be exact.
Pick a fixture style that you like that's linear. Reflectors aren't necessary. Lenses are optional. They can help diffuse some of the harshness of a bare LED.
Do a layout on the online software to see how many of your chosen fixtures you need (and how they should be arranged) to get to your target. If you intend to buy these online, some of the online sites will do this for you. Take advantage of that.
Good luck,
CD
 

nadogail

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Coronado, CA
I let my eyes be the judge; if it looks dark, I add more light. I switched to the screw in LED converters that are about $35 a pair.
 
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olytdi

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Joined
Dec 3, 2011
Messages
2,202
Location
Olympia, Washington
Some lighting software that's directed at the general public asks for appliction because the first thing that any software needs to know is how much light (in foot-candles) you need. Whatever application you choose tells the software what target to shoot for. Obviously, this is dumbed-down because the common person doesn't know what foot-candle levels he needs.
Your first move should be to try to determine this. Common well-lit hobby shop should be around 50fc. If your work is more detailed, small parts, then more is better. The best pro auto shops are lit from 75-100 fc., but that's a ton of light and complete overkill for most people.
One mistake you're making is using the figure of "total lumens". This figure has no meaning and isn't helpful to what you're trying to do. I get a great big belly laugh at all the YouTube knuckleheads shouting about how many total lumens they have. If they only knew how much they were embarrassing themselves, they'd be ashamed.
Your assumption that linear lights will provide more even light with better shadow fills and less contrast is correct. Continue with this plan.
Your T8 lamps didn't emit 2600 lumens. That's a common mistake. They were on a ballast that only produced 87% of the full capability of the lamp. Then, they were in a fixture that only lets about 70% of the light out of the fixture. That's only about 1600 lumens per lamp. You can use that figure to start to calculate your LED fixture requirements.
Here's the process...
Pick your light level in foot-candles. Doesn't have to be exact.
Pick a fixture style that you like that's linear. Reflectors aren't necessary. Lenses are optional. They can help diffuse some of the harshness of a bare LED.
Do a layout on the online software to see how many of your chosen fixtures you need (and how they should be arranged) to get to your target. If you intend to buy these online, some of the online sites will do this for you. Take advantage of that.
Good luck,
CD
That's very helpful, CD. I appreciate your input. So I will start with the 50fc figure and work from there. I can provide a layout to whomever I use to do a "plan," I guess. I'll also proof it with calculating the previous setup at 1600 lumens and extrapolate that to the new building as the ceiling height and layout are the same -- only a larger foot print. I'd like to keep the fixtures on the trusses and the boards I install perpendicular to the trusses for the outer areas. Trying to keep is simple.

Yes, I'm leaning toward one of the commercial lighting outfits in that I'm just not confident in any of the Amazon stuff I see written about. I'd rather pay more up front for a setup that's reliable but I have a lot of research to do figuring out which brands to go with.
 
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olytdi

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I let my eyes be the judge; if it looks dark, I add more light. I switched to the screw in LED converters that are about $35 a pair.
I'm not sure that I understand the latter half of your post. I'm installing in a new build; what are the converters to which you refer?
 
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olytdi

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Olympia, Washington
I'll update here in case anyone ever stumbles on this and is interested.

I purchased 10 of these from warehouse-lighting.com:

8FT LED Strip, 65 watt, 8320 Lumens, 120-277V, 4000K, Comparable to 2 8ft T12 or 4 4ft T8 Lamp Fixtures​


They had done an analysis for me and this should get me 40fc at waist height when mounted at 11 ft above the floor. In my experience, it should be plenty bright with task light added if needed.
 
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olytdi

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Olympia, Washington
Here's the update: I installed the 10, 8-ft fixtures in two banks in my new 36x36 shop. In total there are six fixtures along the two truss bottoms and 4 hanging perpendicular to those trusses. Five fixtures on each switch dividing the shop in two halves.

Nice and bright, all fixtures work well. I see no need for dimmers. Diffuser lenses help a lot with shadow fill as there is no shadow annoyance whatsoever.

So far very happy with these fixtures and the light level at table height for these 63 year-old eyes. I might add that my walls are white painted plywood panels between the posts and attached to the girts. Lots of excellent reflectivity from that and it undoubtedly also helps with shadow fill.
 

cybrdyke

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Great to hear. You did it right...thoughtful process, a good bit of research, ask a few questions and dont over-think it.
Well done!
CD
 
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