Shop Lighting: What you actulaly need vs what formula says you need?

IQRaceworks · Oct 25, 2012

I’m new to the forums, and I wanted to say hi…and also try to get some information on setting up the lighting in my new shop. The shop is 30’x40’ with a concrete floor, 10’ ceiling w/ wooden rafters, no windows, and the inside walls and ceiling are all white. The building started out as a pole barn, then I recently had the floor poured, and then I ran power to it, and now I’m to the lighting part. I’ve done some research and from the formulas I’ve seen, for a 30x40 shop to have 100 lumens per sq/ft (optimum)….it’s going to take around 85 35w T8 bulbs…WOW, talk about expensive. I think I figured close to $1200 just for the lights and fixtures. I’ve noticed after reading through several good posts on here that lots of you guys are getting away with a lot less lighting than the lighting formulas are calling “optimum”.

For a shop like mine, how would you guys set up the lighting? It will mostly just be a large garage….working on cars every now and then, building motors, stuff like that. I want plenty of light, but I don’t need the entire shop glowing bright if I’m just working in the corner on my work bench.

Any suggestions would be great! Thanks

Gary S · Oct 25, 2012

Whoever made up those fomulas was wacked out on weed or something.

Put up what you need and be happy. You don't need nearly that much.

pattenp · Oct 25, 2012

How are you coming up with 85 T8 tubes? My cals are.... 30X40=1200sqft X 100 Lu = 120000 /2600 = 46 T8 32W tubes or 12 4 tube fixtures. 2600 lumens per 32W T8 tube is about average.

porschedude996TT · Oct 25, 2012

I have a 30' x 40' with 10' walls and a vaulted ceiling. The floor is unpainted at this time and the rest is white. I have 14 fixtures with four T8 tube each fixture. That along with the over bench lighting 13 two T8 tubes in each fixture. That equals 74 tubes and that doesn't count the fixtures in the closets.

I used the 6500k T8's and it is not hard on the eyes.

Gary S · Oct 25, 2012

pattenp said:
How are you coming up with 85 T8 tubes? My cals are.... 30X40=1200sqft X 100 Lu = 120000 /2600 = 46 T8 32W tubes or 12 4 tube fixtures. 2600 lumens per 32W T8 tube is about average.

And, you can cut that in half again and it will still be enough. I have about half what your calculations here say, and I couldn't use more light than I have even with my 60+ year old tired eyes.

larry_g · Oct 25, 2012

When wiring for lights put in junction boxes where you think you need light. Put in the switches to handle 'banks' of lights. Install lights where you are working now. As time goes on and you need more lights then you add fixtures to the system you already have prepared. Me I put switched duplex outlets in the ceiling and to add a fixture I just hang it and plug it in. Pay attention to where you have storage and where you plan to work.

lg
no neat sig line

aka Larry · Oct 25, 2012

I have a 40'x40' with a bright white ceiling and I have (8) T8 fixtures with four tubes each plus (2) more T8 fixtures with four tubes over the work bench. Mine is plenty bright for me.

pattenp · Oct 25, 2012

As you can see you are going to get a lot of opinions of what the needed light level is. It's a very personal choice. I figured my lumens per sqft and it's 107 and I'm happy.

IQRaceworks · Oct 25, 2012

pattenp said:
How are you coming up with 85 T8 tubes? My cals are.... 30X40=1200sqft X 100 Lu = 120000 /2600 = 46 T8 32W tubes or 12 4 tube fixtures. 2600 lumens per 32W T8 tube is about average.

That's the same formula I used...except the fact that in the one I used, it said that only 50% of the light would make it down to the work surface, so you need to double the number of bulbs to compensate for that.

Sounds like the formula I used was put out there by one of the light bulb manufacturers.... :lol:

I may just start off with 6 4-bulb T8 fixtures, or 12 2-bulb fixtures.....just enough to get some light in the shop so I can start using it, and then add lights as time goes on. My work bench is on the corner, and the rest of the shop is pretty much just a storage spot for the ATV's and boat.

Thanks for all the info guys! :thumbup:

By the way...here in the inside of my shop now....minus any lights!

Angelfire · Oct 25, 2012

Don't confuse lumens with Foot Candles. The recommendations made by Jack Lindsey in his article on Sawmill Creek are about FC's. He recommends 100 FC's per SF for older workers and 50 FC/SF for younger ones. He's not talking 100 lumens/SF. He also factors in the 50% loss of light due to dust on the bulbs, loss of light from the fixture itself, etc....

I ran the numbers for my 32x40 shop and ended up with 21 fixtures which I thought was too many. Another online calculator showed the number to be 18 which I can only assume was lower due to less losses were figured in. I ultimately went with 18 as from a layout perspective, that number worked well for me vs. 21.

I haven't gotten them up yet and probably won't for several months but I'm certain there are going to be times when I only need 1/2 of them on and other times when I'll be glad I have them all available.

Falcon67 · Oct 25, 2012

Using the 50% loss deal, 2800 lumens/bulb and with a dark ceiling, here's an estimated 71 lumens sq/ft:

And here is 77 sq/ft

Steevo · Oct 25, 2012

IQ, you don't mention your age, which makes a significant difference in how much light is "just right".
GaryS has good eyes, or he wouldn't be so adamant that you don't need all that many lights to see just fine.

I am 57, my shop is 24x40, has 12' ceilings, white semi-gloss walls and ceilings, and I have 17 four-bulb T8 fixtures in it. That is 68 tubes at 2600 lumens per, or about 180 lumens per square foot. Two fixtures are over my workbench and one is over my lathe, so those are "task" lighting. The rest are all on multiple light switches, so sometimes I only turn on one or two banks of lights, if the door is open and the sun is shining, or I am just doing large work like changing wheels, or such.
When I need to do work that requires visual acuity, such as working with small or fine parts, I turn on all of the lights. I need them, because in less than excellent lighting, my eyesight isn't what it was when I was twenty-something.
Every situation is different, due to ceiling height, reflective qualities of finishes, eyesight differences, etc.

heavypaws23 · Oct 26, 2012

We are building a 16' x 40' addition, I figured I needed 10 T8s with 2 bulbs each. Is that enough? Also, should I use flush mount or hangers? Thanks! Heavypaws

egnorant · Oct 26, 2012

I wired mine with 2 switches controlling a ceiling run of 6 quad boxes.
Each quad box has 2 plugs off each switch.

The plan was that I can choose how I want my lighting to work. Low light or High light, each bay on a switch, regular and Disco lighting if I want.

I noticed yesterday that my barber has as much lighting in his 8 x 16 barbershop as I have in my 27 x 38. But 5 months ago I had a worklight on an extension cord for my shop light.

Bruce

K588 · Oct 26, 2012

I have a 28'x40' with 10.5' ceilings and did 18 4 bulb T8 fixtures. I did 4 rows of 4 and one row of 2, each row has its own switch so I can use what I need for the task at hand. I like having a lot of light when I work and even though I'm only 40 I know my eyes wont get any better in the future. I can't ever remember working on something and complaining about too much light.

ket-tek · Oct 27, 2012

Mine's 28'x38'x12' all sheetrocked and bare concrete, I have x18 dual bulb T8 fixtures using 36 4100k bulbs and the lighting if very good and even, I don't have shadows or a nor hard time working on detailed stuff. All mine are on all the time, I wouldn't want any less.

It cost about $800 for all the bulbs, fixtures, and misc install parts.

85 bulbs would be crazy, never can have too much light but I don't see that many being necessary to see comfortably.. But with a couple switch banks then it would be more practical.

Ray916MN · Oct 27, 2012

I used 88 4' T8 bulbs set in 4 long rows in my 24x48x14 white ceiling and walls, grey floor workshop to get 100 lumens. Formula I used seemed to work well. I've added another 32 4' T8s to light the 80 ft2 of over hung work bench space and about 128 ft2 which is under pallet racking with the bottom row set 7' off the floor (motorcycles are stored above). The bulbs are 6500k. When the lights are on, it is very much like a nice sunny day and when the garage doors are open on a sunny day, the inside doesn't seem dark.

Winters are long here in MN, and I hate working in a dark shop when the weather is nice outside.

Shop Lighting: What you actulaly need vs what formula says you need?

IQRaceworks

Well-known member

Gary S

Well-known member

pattenp

Well-known member

porschedude996TT

Well-known member

Gary S

Well-known member

larry_g

Well-known member

aka Larry

Well-known member

pattenp

Well-known member

IQRaceworks

Well-known member

Angelfire

Well-known member

Falcon67

Well-known member

Steevo

Well-known member

heavypaws23

Member

egnorant

Well-known member

K588

Active member

ket-tek

Well-known member

Ray916MN

Well-known member