Quick lumen question

[Greg5OH]

I gots me a 32x32 concrete floor pole barn, 11 feet to the rafters. I do plan on insulating it. Drywall or similar, once all the wiring and ducting is complete. I plan on having approx 12' ceiling height by reworking the rafters (seperate thread). This will be a fab shop and service bay. I am thinking to have a total 12 t 8 fixtures, with some 4500k high cri bulbs (have 3 t8 fixtures with open rafters with some philips cool white bulbs, its not enough, but it is what it is for now).

I once saw a great total lumen needed calculator, cant find it any more.

do you guys think 12 twin tube t8 fixtures are adequate or should I go with 16?

they would be approx 8 feet apart width wise, 10 feet lengthwise using 12, or 8 feet length using 16 total.

sorry for the messy thread. Im hashing out ideas. Its basically a clean bare 32x32 pole barn. Want to put a 2 post lift in, dedicating weldgin corner with good ventilation, heated and insulated.

 

[BoostAddiction]

It may be more complex than "how many T8 fixtures." Different fixtures with identical bulbs can have very different amount of usable light, depending on whether or not they have filters and reflectors (painted vs polished, or nothing at all). And of course, usable light will vary based on install height, as well as distribution throughout the room.

Bulbs vary tremendously in terms of color temp and output as well. I have some bulbs that appear to be much brighter than the "same" bulb in the same fixture.

 

[pattenp]

I think 100LU per sqft is a good light level. One F32T8 lamp outputs 2600-2800LU. That's about 18 two lamp F32T8 fixtures for your 1024 sqft. I think the 16 fixtures is better than 12.

 

[happy2rv]

I've come to believe that there's no such thing as too much light. OK at some point there probably is, but with 12' ceilings I don't think you would reach that point if you "carpeted" the ceiling with two or even 4 lamp T-8's. I know reason and cost have to factor in, but there are options that are inexpensive that allow you to plan ahead. The amount of light needed will vary by task, so think about how you use the space both overall and task areas.

I have a 26x32 garage with 12' ceilings I wanted put lots of 4 tube fixtures up, but by the time I got to that portion of the build I was over budget. So, I compromised with the future in mind. I bought 6 2 tube fixtures and put them up over the work bench area then I installed ceiling boxes 6 ft apart on the rest of the ceiling and installed "key" fixtures on them with 100 or 120watt equivalent compact fluorescent bulbs. I also put the lights on multiple switches, so I can turn on half of them at a time. This arrangement works pretty well, worked out to about 3 or 4 bucks a fixture including the bulbs, and allows me the option to improve in the future without rewiring.

 

[DC73]

I have about the same area as you in the workshop I'm building but my ceilings will only be 10'. The online calculator I used showed about 18 2-lamp T8 fixtures to get 100 foot-candles at work bench height. I plan to use 4 switches so I can control the light level as needed.

DC

 

[BoostAddiction]

I've come to believe that there's no such thing as too much light.

I agree. And the older you get, the more important it is, as older eyes apparently need more light.

I recently installed a new flow-through style tile floor in black and gray over a light gray epoxy floor that had been in place for about 10 years.

The difference in reflectance with the new floor is noticeable, and I think I will have to add more lighting somehow.

I have a lot of 4' 4-bulb T12s in the garage now, and am looking at eitherconverting them to LED, or just going with new ballasts and brighter T8s.