Anyone ever tried indirect lighting fluorescent fixtures?

[Logan William]

Well while pondering my light scheme for the garage/workshop I started wondering about using indirect fluorescent light fixtures that point upwards, like the ones commonly found in libraries, office buildings etc. A local building is being renovated and thats including replacing fixtures so I have a chance to get 8' long, 4 bulb T5/T8 fixtures for basically the same price as your standard 4' long, 4 bulb shop fixture from the BORG.

My shop is an oversized 2 car, roughly 25' square with white ceiling, white walls and 9' ceilings, I'd hang them pretty close to the ceiling to prevent from losing too much ceiling height, but I would lose probably 8-10" which might be stretching what I can live with. My other thought is to buy one and see how much work it'll be to flip it so its more like a standard, direct lighting fixture just without a diffuser.

Has anyone tried this or used these in a workshop environment? Would love to hear any feedback before I buy as I'm on the fence. The picture below is representative of what it would look like.

[Josiah Bartlett]

How are you going to keep them from filling up with sawdust?

[Bob Winkler]

Overhead clearance is important to me. I'd would hate banging a lowered fixture. Also make sure they are ballasted for 120V- I think some industrial fixture are 240V or more.

If it were me, I'd stick with new and conventional.

Bob

[Logan William]

They are ballasted for 120V, thankfully it was a small office complex about a year old that they're gutting. Far as cleaning they have small perforations on the bottom side so I'd probably hit them at the end of the day with the air hose and also bend up a copper blow pipe into a J so I can blow them out from the top side periodically.

The dust is one thing that really makes me want to pick one up and try and redo the mounting so that it lights like a direct lighting fixture. Not having a diffuser to make cleaning easier will be a downside, but they're a pretty darn good price for 8' long 4 bulb fixtures. What I don't know yet is if they're cold start ballasts....doubtful but the garage will be fully insulated by the next heating season so shouldn't be much of an issue.

[Jim Terrill]

They look nice, but you could probably get 5 direct fluorescent fixtures for what one of those costs. If the cost is irrelevant to you and you have the ceiling height for drop fixtures, go for it, but I decided that I would rather have a whole lot of fixtures rather than just a few nice onces, and I definitely don't have the ceiling height in my shop for any drop fixtures.

[Bruce King]

Just make sure you get the electronic type for flicker free quick starting.

[Matt Meiser]

I worked in an office once that had those. I always felt like it was dark in there. It wasn't, but that was the effect.

[David Prince]

The dust issue and having to clean them is going to be a PITA. I would avoid them for that reason alone.

[Doug Hobkirk]

I have 8 indirect T5 fixtures with electronic ballasts in my 1 1/2 car garage. Each has 2 bulbs, most have 4100 "daylight" bulbs (note the difference in color between the near unit and the far unit with convention cool white. Mine have a perforated housing that allows some light to filter down directly. They work very well, although at 64 I always want more light, so I might install a couple more. I haven't had much problem with sawdust, but they can be dusted or blown out. Dead bugs is more of a problem - you can see some of the debris in the pictures. I've had them up for over a year and have yet to dust them.

I was very lucky - I got about 30 of these units, all in excellent shape and most equipped with the 4100 bulbs, for $40! I had planned on buying 3 or 4, but the seller wanted them gone. It took me several hours to disconnect them from each other and pack them into my Chrysler T&C to get them home. I still haven't figured out what to do with the other approx. 20 fixtures so they just sit in the attic above my shop.

[Jack Lindsey]

Without knowing the photometrics of the fixture you have pictured I can't make a firm judgement but based on what it appears to be I don't think it is a good choice for a woodworking shop for several reasons.

Indirect lighting is typically used in offices and school classrooms where uniform, shadow free lighting is desired, and reflected glare in computer screens must be minimized. Visual tasks in these environments differ greatly from those in manufacturing facilities and the characteristics that make indirect systems desirable in an office, such as the absence of reflected glare which is used for inspection of newly applied finishes, may make them poorly suited to your shop.

Indirect systems must be suspended below the ceiling, generally at least a foot with 18" to 24" preferred for most luminaires. That doesn't work well with a 9' ceiling height.

The light output of indirect systems is significantly reduced in dirty environments - typical of wood shops. And the efficiency drops off rapidly as the ceiling becomes dirty. This means regular cleaning of lamps and fixtures. At least once a year.

The photos of Doug Hoskirk's shop show a direct/indirect fixture which has a greatly different light distribution that what I expect would be provided by the fixture you have shown. I can provide a better opinion, though, if you can post photometrics.

The bottom line - you can use whatever fixture you want to use. It's your shop. That said, I think a bare lamp strip mounted directly to the ceiling is a far better choice.

[Logan William]

These fixtures would look very similar to the ones Doug posted(thanks!) as these are also full perforation models, major difference would be these are 4 bulb and his are 2.

Jack: I've attached the photometic information for these fixtures, I'd love to hear your feedback on it, I've got a general idea on what the information means but don't have the background info to put it into context

I'm also still debating on flipping them 180 and hanging them close to the ceiling so they provide the more conventional direct lighting. These are cheaper than (2) 8' long 2 bulb strip light fixtures, but thats not accounting for my time/labor/frustration in rehanging them.

[Tom Vanzant]

Matt,
I also once worked in an office that used indirect lighting, but in this case, the lamps were aircraft landing lights in 6-foot tall columns, shining on 10-foot flat-white ceilings. The light was so dim that everyone had one or more high-intensity lamps at their desks. At the time, a 100 candle-power light level at the work surface was considered necessary for close work, and the ceiling fixtures fell far short of that.
In a shop invironment, I would think dust accumulation in indirect fixtures would be a problem. No shop is that dust-free.
Tom

[Ian Steven]

I can't find a picture, but I remember seeing someone hang pegboard (painted white) below standard fluorescent fixtures, which allows reflected light off the ceiling as well as some direct light through the holes.

[Thomas Bank]

Weighing in as an architect, I prefer indirect lighting in areas where you will then have task lighting. It gives a very nice, uniform light without glare. For a workshop, I'm not sure that I'd use it.

Typically, there is a minimum distance that an indirect light must be hung from the ceiling to properly disperse the lighting. Your idea of hanging them 8~10" down seems closer than what it should be.

As others have said, collecting dust would be another issue that would concern me.

[Jack Lindsey]

Thanks for posting the photometrics. The fixture is classified as an indirect fixture since less than 6% of the light emitted from the fixture is below the horizontal. The downward component is negligible in terms of providing light on the workplane. It does have a fairly wide distribution so the suspension length could be shortened, especially since the uniformity of brightness of the ceiling isn't particularly important in a woodshop.

The fixtures Doug Hoskirk shows appear to have a lens below the lamps which will cause the fixture to have a significantly larger downward component. Yours is quite a bit different.

The efficiency of the system will be greatly impacted by the reflectivity of the ceiling and how well that reflectivity is maintained. That means regular washing and repainting of the ceiling, which probably isn't going to happen. Note also that you should use a flat paint which provides a more diffuse reflective surface than a high gloss paint will provide. The downside to the flat paint is that it is more difficult to clean.

Based on assumed reflectances of 70% ceiling, 50% wall, and 20% floor you can expect something in the neighborhood of 50% to 54% of the light exiting the fixture to reach the workplane.

And note that the amount of light exiting the fixture will decrease over time due dirt build up in the fixture, and that indirect fixtures are much more affected by dirt than direct fixtures like the strips I suggest you use.

I see far more negatives than pluses for an indirect system in your shop. More fixtures required to produce an equivalent lighting level, higher power costs and relamping costs, and increased cleaning labor needed. I can't think of a single logical reason to install the indirect system.

You have to be happy with your system, though, so do what you want.