weatherby460
Well-known member
30x40x12
Will 12 - 8' fluorescent lights be enough?
Will 12 - 8' fluorescent lights be enough?
Will 12 - 8' lights be enough in a 30x40?
- Thread starter weatherby460
- Start date
Steevo
Well-known member
No
You will need more.
In my 24' x 40' x 12' I used 17 eight foot fixtures, each with 4x 4 T8 bulbs.
You will need more.
In my 24' x 40' x 12' I used 17 eight foot fixtures, each with 4x 4 T8 bulbs.
OP
weatherby460
Well-known member
darn
laser3kw
Well-known member
I have about 12, 8ft in half of my 30 x 40. plan on doing the other half this winter.
dcmus
Well-known member
I sure won't dispute Steveo's comment. Great shop and great execution. I have a 28x31 and local electrical house recommends six, 6 bulb 4 ft, T5 fixtures and I planned on area lighting to take care of the shadows. Did they mislead me?
Falcon67
Well-known member
I've got 13 in a 24x40 and except for the work room, its the minimum. There are 8 in the 24x28 section and it could really use 3 more.
Nope.
30 ft x 40 ft = 1200 ft^2
At a lighting level of 100 lumens/ft^2 (on the 'low' end of the recommended amount of light for semi-detailed 'task' lighting, not night lights but not full up OperatingRoom lighting), you are looking at a 'need' for 120,000 lumens altogether.
F96T12 tubes, 87 CRI and 4100K color temperature (decent IMHO, not the 'best' though, personal pref is to get the CRI over 90 if possible and put the color temp at 5000K especially if there is a mix of sunlight and 'artificial' light so you don't get that jarring color temp mismatch)
https://www.1000bulbs.com/product/6353/F-96T12CWX.html
Initial lumen rating of 4400 lumens, mean lumens rating of 3872 lumens.
120,000 lumens needed / 3872 lumens/tube = 30.992 tubes needed
Actual 'need' is higher than that, as we have not included a fixture 'loss' (efficiency rating correction factor) of approximately 80% (due to a 'dirty' fixture, or the light that is absorbed or otherwise lost in the baffles or diffuser/lens or the painted part of the upper fixture, etc).
30.992 tubes / 0.80 'correction' factor = 38.4 tubes needed.
At a lighting level of 150 lumens/ft^2, the numbers go to
1200 ft^2 x 150 lumens/ft^2 = 180,000 lumens needed
180,000 lumens / 3872 lumens/tube = 46.5 tubes
46.5 tubes/ 0.80 'correction' factor = 58.1 tubes
If you are using a different bulb/tube, run the math yourself.
ex 4 ft T8 5000k and 98 CRI
https://www.1000bulbs.com/product/152921/PHILIPS-209056.html
mean lumens = 1860 lumens/tube
at the 100 lumens/ft^2 lighting level, that means you would need 80.6 of those 4 ft tubes.
At the 150 lumens/ft^2 lighting level, that means you would need 120.97 of those 4 ft tubes.
Yes, that is a lot of tubes. Yes, if you want that rather large space lit up all over so that it is all nice and bright you will need that many tubes.
Your call. But 12 8' tubes will make the space lit only rather dimly (lighting level there for the 12 8' T12 3872 lumen tubes would be 38.72 lumens/ft^2 'raw', and only 30.976 lumens/ft^2 'corrected' for fixture light losses). That would be lit, but nowhere near the light required to be 'well lit'. IMNSHO.
You may not want or need all the tubes to be on altogether or all the time, so put them on several banks of tubes/fixtures. But when you do need or want to have the area well-lit, you can turn on all the lights.
I have a 'small' 250 ft^2 workspace lit to the approximately 100-150 lumens/ft^2 level with three fixtures each with four 4 ft T8 tubes , and with wall and fixture 'losses' and fixture spacing I could use another one or two fixtures. No, it is not 'overly' bright.
OP
weatherby460
Well-known member
So what is a good fixture?
laser3kw
Well-known member
I have these (link below) in half of a 30 x 40 x12. Decent price, electronic ballast, uses (4) 4ft T8 tubes (I have 4500º and are nice color), been good so far. In cold weather. Illinois, 0º day, no heat, flip switch, lights on a little dimmer but go full bright in a couple of minutes. Mounted to sheet rock ceiling, conduit and hard wired. I spent $600 for fixtures, bulbs and wire last year and will probably spend another $400 this year to finish.
8ft tandem T8 fixture link
8ft tandem T8 fixture link
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OP
weatherby460
Well-known member
Thanks....I will go with them.....
DpSyChO
Well-known member
The fixture from HD linked above is what I have. It may or may not make a difference but I liked how the actual fixture was wider than same price range offering from Lowes. To me the bulbs having some separation with the wider fixture was a advantage. I would buy them again.
ForceFed70
Well-known member
So I guess we're all just assuming that these are single lamp fixtures?
And that they are non-HO?
I've got 9 x 4' fixtures in my 32x40 and they provide plenty of light.
And that they are non-HO?
I've got 9 x 4' fixtures in my 32x40 and they provide plenty of light.
xtremek
Well-known member
I must be getting old. I have eight 4' 2 bulb T-8 fixtures in one corner of the barn (30x40), and it's just barely enough. My plan for right now is a total of 36 4' fixtures plus 8 big "pineapple" size CFL's.
ForceFed70
Well-known member
My fixtures are 4 lamp.
Lighting company I bought the fixtures from tried to talk me into only using 6 as their design app said 6 was the optimal configuration. I went with 9 and am glad I did but 6 probably would have been enough.
Honestly, when you get to spaces this big, the smarter approach is to look at the lighting requirements of each area. Do you really need all that light in the mezzanine or store areas, etc. I'm happy with the light level I have and most people who see my garage for the 1st time comment on how bright it is. If I ever do need more light, It'll be task lighting - above the workbenches, etc.
People also need to consider the environment. My walls and ceiling are drywalled and painted white. Gives me WAY more light than if the walls and ceiling were unfinished. Kinda frustrates me with this forum - we all tell the OP what he needs without actually gathering the relevant information.
bloomingtonmike
Well-known member
Are T5HO an option?
pattenp
Well-known member
If you are asking about 8' four lamp F32T8 fixtures, I think 12 fixtures will give you good over-all lighting. You're talking 48 lamps at approx 2600LU per lamp which is 124800 LU or 104 LU per sqft un-adjusted. Unless you need very bright light for detailed work then in my humble opinion 12 fixtures is a good starting point.
OP
weatherby460
Well-known member
I am thinking about doing 12 or 15...for a total of 48 or 60 4' tubes.
laser3kw
Well-known member
ps:
the tubes are sold separately. I got these:
t8 tube 30 pack link
4100 color is a nice white, not yellowish, not blueish.
the tubes are sold separately. I got these:
t8 tube 30 pack link
4100 color is a nice white, not yellowish, not blueish.
east_tn_emc
Well-known member
I have eleven in my 30x42x10.....,nine running in three rows over the main garage space and two tangent to them and over the workbench.....been very pleased with it.
I have 40x40x12 i purchased a couple of 4 ft 4 bulb t8 lamps today home depot had on sale for $39.97 each! I originally thought of putting 4 rows of 4 evenly spaced but the first two i put up is spaced for 5 rows of 5
Do you think 25 4 ft 4 bulb t8 is way to much?
Do you think 25 4 ft 4 bulb t8 is way to much?
bczygan
Well-known member
Between half again as many, and twice as many, depending on area covered by overhead doors and mounting height and ceiling finish.
Bluer color temp makes things seem brighter and crisper and cleaner, but also harsher.
My less than 200SF garage gets eight 2 tube 4' lights with 6500K daylight bulbs hung at 9'.
At that rate, you would have 48 of the same fixture or 24 of the 8 foot 2 tube ones.
Bluer color temp makes things seem brighter and crisper and cleaner, but also harsher.
My less than 200SF garage gets eight 2 tube 4' lights with 6500K daylight bulbs hung at 9'.
At that rate, you would have 48 of the same fixture or 24 of the 8 foot 2 tube ones.
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PhantomEB
Well-known member
I am going with 12 4' 4 bulb t8ho sunken style in a 24x24 which I think will be perfect. Plans are to have provisions for under cupboard lighting as well to eliminate shadows.
philofab
Well-known member
You always think you have enough light until you add more fixtures, then you ask yourself how you ever made due before you added them.
More light is always better. Although your intended use and the time in which you will use it does affect what you need. Also, shops that are more cluttered need more light.
Split the circuits if you can so you don't HAVE to turn them all on. I split the front half of the garage and the rear so during the day I only need the rear of the garage on.
More light is always better. Although your intended use and the time in which you will use it does affect what you need. Also, shops that are more cluttered need more light.
Split the circuits if you can so you don't HAVE to turn them all on. I split the front half of the garage and the rear so during the day I only need the rear of the garage on.