Planning my next shop - an interior spray room (not "booth")

[Todd Burch]

Has anyone done this? I'm planning on allocating quite a bit of floor space to a spray room. I figure I have to buy all the air filtering and handling equipment anyway, so if I had to take a shortcut, might as well use 2X4 walls instead of metal prefab. If I wanted to convert the room to something else in the future, it's just a "room" at that point and not a big metal box sitting on the floor.

I am thinking I would have double doors at the entrance (at least). Not sure what lighting and I'm not familiar with the whole "explosion proof" requirements yet (if any). The room will be for occasional advanced hobbiest use. Maybe 12' wide and 20' deep. This would be inside a larger enclosed workshop. Doors large enough to drive a car into would be nice too. ;)

I imagine I would have some shelving here and there, and cabinets for spray materials. I would be spraying both solvent and water based materials. Hooks for hoses and guns too.

I don't know what kind of air moving requirements I would have, or outside venting, or filtration either - I'm just getting started here.

All input is appreciated.

[Doug Herzberg]

Todd, something like this is in my long range plans. I imagined a lean to shed on the side of my shop, about the same size as you're proposing. Thinking about a separate entrance just to eliminate that source of sawdust. Some thoughts: You will need to be able to seal the entry doors so you can control the filtration of the air entering the finishing room; Shelves and other horizontal surfaces will collect what dust there is and need to be cleaned - maybe cabinets with doors; Ability to hose down the entire room with water to eliminate dust; fire safe cabinet for flammable liquids; My compressor will be outside with air piped in to a regulator and filter, then around the room.

I haven't looked into the explosive issues yet, either. Keep us posted if you go forward. I'm certainly interested.

[Steve Jenkins]

Quite a few years ago I built a 20'x30'x8' spray room.
for lighting I used wire reinforced glass panels held to the ceiling with aluminum frames and layed 8' daylight flourescents on top of the glass. That was approved by the local firemarshal. It didn't give the low raking light that is the most desirable for finishing but it worked pretty well and I didn't have to buy the really expensive explosion proof lights. You don't want any electrical outlets in the room.

[Michael W. Clark]

Todd,
I'm in the same boat as Doug in that I would like to include a separate room for finishing in my future shop. Among the other things mentioned, I think it would be good to have a utility sink with laminante or SS counter top for cleaning spray guns, brushes, etc. If you are going to make it conform to building codes and you plan to use finishes and stains that are flammable, it will be expensive with all the X-Proof items required (its not just the fixtures, it is also the electrical installation). If you can keep the combustibles limit below a certain concentration, then normal electrical wiring and fixtures may be sufficient.

I think the ventilation is important and can dictate the room layout. I think a good setup would be to pull air from the rest of the shop through filtered openings in the walls or doors of the finish room (may not be good if someone else is working in the shop). If you heat or cool your shop, the air in it will likely be a little closer to the temperature you want for the finish room, reducing utility costs. Also, I think it would be good to have a PTAC unit (hotel room heat pump) dedicated for the room to control the temperature more precisely. Exhaust can be accomplised with a tubeaxial fan located to draw through filters. There is no such thing as an X-proof fan, don't let anyone tell you different. The safest bet is AMCA spark resistant construction with a belt drive motor located out of the airstream. That's what industrial paint booths use.

[John Coloccia]

There is no such thing as an X-proof fan, don't let anyone tell you different.

What does this mean?

For example:

http://www.industrialfansdirect.com/IND-FA-HL-CD/LFI-AX12-4.html

And it doesn't even have the motor out of the air stream. On the other hand, you can have a tubeaxial fan with the motor out of the airstream that is NOT safe to use in a spray booth because it doesn't have non-sparking blades.

There is no reason to have any electrical at all in the room. In my booth, we made the ceiling out of plexiglass, and the regular fluorescent fixtures are on the other side of the plexi. The walls are metal studs with sheet metal instead of drywall. The fan is a proper fan designed for a spray booth and sized for my opening. I built it with with a friend who has experience building automotive spray booths. The light on the other side of the plexiglass is a really common way these things are built to keep costs down but still be safe. The light is just simply not in the room.

[Brian Backner]

If it were me, I'd check local auctions and see if a finishing "booth" was coming up. I just went to preview the auction of a very large cabinet shop (I'm talking 100,000 sf +++ of space - these guys were running 4" air lines and multiple 36" diameter dust collector trunks) and there were several spray rooms available. All could have easily fit all but the biggest pickup truck inside. They are all modular and have every conceivable safety feature that OSHA could ever want - the ones I looked at yesterday even had an internet hookup that would automatically call the local fire department if some internal sensor tripped. In the recent past, I've seen these things go for $4-6k. That would probably be on par for what a home built version would cost and it would be MUCH better quality. It would probably take three or four guys a day to take down and transport and then another couple of days to set up. If I had the room for one, I'd have set one up years ago.

Brian
Taxachusetts

[Michael W. Clark]

John, Please see this article from Greenheck:
http://www.greenheck.com/media/articles/Product_guide/src.pdf

I think X-proof fans are a misnomer from some fan markerters and manufacturers. My understanding is the X-proof devices such as motors and electrical boxes are designed to contain an explosion if it occurs within them. I don't see how a fan can do this since it is open on both ends. Mounting the lights outside the booth as suggested is a great idea and is seen in industrial applications. If you also mount the fan outside the room, then the motor could be a belt drive outside the airstream and avoid the X-proof motor. That's what I intended to say. Sorry if I confused someone.

[Todd Burch]

I've started reading NFPA 33: STANDARD FOR SPRAY APPLICATION USING FLAMMABLE OR COMBUSTIBLE MATERIALS. Not sure if it will tell me what I want to know, but all info is good info. It's a start. This standard also applies to water based/water borne materials as well.

Todd

[Jeff Nelson7]

So I have the same desire for a dedicated spray area large enough to do a vehical if I ever wanted. I have not looked into this but what about local codes? Some resisdential areas are not to keen on a home shop with a flammable material being used. Just thinking that I would make sure all is legal, for when or if the neighbors complain about the smell being pumped out of the booth.

[Todd Burch]

You are correct - some areas have pretty strict codes. Where I live, there are no building codes, and where I'm moving - even less! When I lived in San Jose,CA, and did auto-work for folks at my home, my neighbors called the Fire Department on me and the FD came over, big truck and all, and told me to "cease and desist", as I was performing "hazardous activities" in a residential area. After a long talk with them, I learned that even changing my own motor oil was against the law, but then he put it into perspective and said "Hey, if no one complains..." However, when you have a few cars in the driveway, and one is without hood, and you have an engine hoist pulling out the engine, and this activity was dead-on-center out of my neighbor's dining room window... well, someone complained.

I was more discreet after that.

Go ask your local fire department. Take a few rings of sausage for cooking on the grill with you too. ;)