Paint Booth Exhaust Help

[mlg567]

I purchased a used paint booth. It came with a 30 inch fan. However 30 inch exhaust ducting is super expensive. I can save $500 by reducing to 24 inch using a 30-24 reducer. Is this advisable. Will booth pull overspray properly

 

[James-W]

I can't answer that, but I do know that around here there are strict laws when it comes to paint booths. I would try to get a copy of the laws governing paint booths for your area and read up on it.

 

[cvairwerks]

It's almost a 40% reduction in area. It will definitely have an effect on how the booth flows. What you cut in cost by going to 24" exhaust duct is probably going to swamped by the cost for the required changes in fan speed to get the necessary flow.
Flow requirements vary depending on what style booth you bought. There are some quick calculations out there, but they do not consider duct size, only total flow rate. You would need to jump into duct calculations in addition to get a correct total answer.

 

[matt_i]

Its probably more dependent on the total length of the duct and the number of turns.

The smaller dia will cause some restriction but what that will do to the final result of pulling out the overspray is hard to predict. The manufacturer of the booth would probably be best to speak to if they will take your calll.

Absent that, you decide on 24" and it doesn't work right. So now its 2x your original investment plus a $500 penalty. Instinct says do it once and do it right, its part of the cost of doing business.

 

[ScottsGT]

Cry once.....
As mentioned, check local laws since these rules are constantly changing due to environmental laws. If you're a business, no getting around it. A hobbiest with your own booth, not as strict.

 

[sberry]

Did the original have 30 inch duct?

 

[6768rogues]

A substantial size reduction like you mentioned will reduce flow and will put more load on the fan motor, making it use more electricity and shortening its life. Get a price for an equivalent square or rectangular duct, it might be cheaper. If you know anyone with a brake, you can buy flat stock and form your own square duct. 27x27 or 25x30 would work, but if you need a corner piece it should have turning vanes in it.

 

[Barnabas]

Have you considered two smaller ducts that would have the same flow as a single 30" duct? Might cost less.

 

[sberry]

I bet smaller reduces load on the motor, it's doing less work

 

[PWC Repair]

Have you considered two smaller ducts that would have the same flow as a single 30" duct? Might cost less.

It will still be expensive as the 2 smaller ones will still be larger than common residential size round duct.
How far to the outside for the exhaust? Could you build an enclosed plenum above the booth to the outside wall? Simple 2x4's and 26ga sheetmetal would work.

 

[ZRX61]

I can't answer that, but I do know that around here there are strict laws when it comes to paint booths. I would try to get a copy of the laws governing paint booths for your area and read up on it.

...Anonymously....

 

[James-W]

...Anonymously....

That would unquestionably be a good idea.