How much cfm/fans to ventilate Painting Room?
12-02-2013, 01:02 AM,
How much cfm/fans to ventilate Painting Room?
Hey There, I'm spray painting with cans of paint in a 12' by 20' one car garage with a 7.5' high ceiling. The fumes are quite toxic and need to be removed!

I've read that you take your all 3 measurements and multiple them together to get your cfm for the room. Then buy a fan according to the cfm of your room so it has enough power to exhaust your room. I live in British Columbia so its very cold here in the winter to open the garage door to paint because the paint doesnt dry when it is cold.

I have one 2.5' by 2.5' to vent out and 8" opening in the wall opposite to the window that i could put a intake fan. I have a polyed off 20" box fan in the window right now but its not moving that much air through the room. Some say box fans push around 2500cfm and other says they push around 250cfm. But this obviously isnt working well enough because its only strongly pulling air/smoke about 2' away from the fan.

So my question is what would be the most efficient way to properly vent my garage

- Without spending a excessive amount of money?

- How much cfm do i really need?

- Possibly 2 fans for exhaust and 1 for intake?

Here is a few options ive been considering:

First 2 links i was thinking buying 2 or each and 3 link i was just going to purchase the one because its more expensive.

Please let me know what you think and suggestions

Thank you
12-02-2013, 01:25 PM,
RE: How much cfm/fans to ventilate Painting Room?
We are specialists in powders flame spray, Metal dusts- and vapors may be toxic and result in health problems, Suck-in- and filter devices must be dimensioned sufficiently, and this must be done by specialist, so I recomend you to contact who design special spray booth for paint, take care of your healthy first of all.

Best regards
12-02-2013, 05:03 PM,
RE: How much cfm/fans to ventilate Painting Room?
Here in the USA, ventilation requirements are defined by OSHA in Standard 1910.94©. Air should have a minimum velocity (feet per minute) to entrain particles and a minimum volume (cubic feet per minute) to dilute solvent vapors to at least 25% less than the minimum explosive concentration. Canadian standards will be somewhat different, but a quick internet search should help you turn up design requirements. Note, air velocity is calculated based on the cross-sectional area of your booth.
12-02-2013, 11:10 PM,
RE: How much cfm/fans to ventilate Painting Room?
So your saying that my cfm 1800. I would need at least that much power to keep my air 25% below the igniting/explosive stage. Also when you say cross-sectional area do you mean the whereabouts of my the intake and outtake fans are? They are cross the room from each other and on the opposite walls.
12-03-2013, 02:55 PM,
RE: How much cfm/fans to ventilate Painting Room?
You should read the spec to determine how to calculate air flow.
12-05-2013, 05:12 AM,
RE: How much cfm/fans to ventilate Painting Room?
The normal rule of thumb is to have 20 to 40 air changes per minute for this type of application, So depending on your paint spray booth volume decide capacity of the exaust.
12-06-2013, 09:38 AM, (This post was last modified: 12-06-2013, 09:48 AM by kschewe.)
RE: How much cfm/fans to ventilate Painting Room?
Hi from Manitoba...
Go to princess auto, there are all over Canada and buy a proper vent fan and respirator. Either paint right beside it or you will have to get a paint booth. Using a regular fan probably wont do it.
The one at home hardware are good for hobby painting and some shops use a couple of them for painting cars. Ones with enclosed motor for explosion protection.
That's cheap as you can get. Otherwise you will need a booth with exhaust and a makeup air unit with a gas heater for cold climates like it is here today at -25c

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