We are building a 30' x 40' x about 11' shop and want to make sure the thing is ventilated properly. I am tired of breathing paint, welding, and cuting fumes.

I am looking into installing a shutter type attic fan in at least one location. We have a vasriety of weather including sub zero to 90's in the summer. With this I could crack a window and exhaust the fumes.

Question: WHAT CFM should I be looking for and is there a better solution than this type of fan?

http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611793280&ccitem=

Thanks

I would probably go with a little bit larger fan. I would aim for an air change every 10 minutes or so, which would be a 1300 CFM fan based on the dimensions you provided.

this is exactly what i plan on putting in my shop this summer. i plan on putting it behind my welding and grinding area to help with the dust and clearing out the shop of fumes. i plan on using a normal hole house fan.

later tj

To build the database -

I orderd two of these: http://www.qcsupply.com/Products/34.aspx A 16" and a 20". The 20" will go up high for the summer and the 16" lower near the area where we will be doing most of the welding. It is hard to find variable speed shutter fans.

You also have to get a seperate variable control unit. The variable speed is important to us because we will paint in there and don't want to much air moving, just enough to do the job. The manufacturer recommended 6600 CFM for welding in a shop 30 x 40 x 11'. It seems like a lot but at least we will be healthy.

It should be somewhere in the range of 1.5 CFM/sq ft. I work in HVAC and that is how we size the exhaust fans we do for auto repair shops.

Anyone have any ideas on how to stop the noise from getting out of the fan when in use? I am going to be going through alot of trouble to sound proof my shop but need a ventilation fan (was looking at these kind of fans). When not in use I can just make a hinged dooor on the inside with soundproofing mat to help keep the noise in, but when its I am making the most noise (blacksmithing) is when I need the fan.

you could always build in a few baffles to a box on the other side of the fan and put egg crate on teh inside panels. kind of like how a muffler works.

really won't matter, any fan with a good draw is going to make a fair amount of noise anyway. Ever try talking near a chickenhouse fan when it's running? You almost have to yell.

i have a 30 x 35 x9 garage and i just popped in a squirrel cage type fan off of a 3 ton central heating and air unit. it works just right with the 12 foot shop door on the opposite end of the garage open about 2 inches. its 110 and even has a low medium and high setting.

Anyone have any ideas on how to stop the noise from getting out of the fan when in use? I am going to be going through alot of trouble to sound proof my shop but need a ventilation fan (was looking at these kind of fans). When not in use I can just make a hinged dooor on the inside with soundproofing mat to help keep the noise in, but when its I am making the most noise (blacksmithing) is when I need the fan.


You can build some ductwork with some bends in it on either side of the fan. I assume you don’t want to hear the fan yourself. The duct will need to have insulation on the inside of it. Typically about 1.5" thick and gulled to the inside of the ductwork. This is what I would do. Bring the ductwork out about 1’-2’ then bend it to the right or left 90 degrees. Then run it another 2’. Then you could end it or put in another 90 degree bend. The idea is to make the air bounce around in the ductwork and the insulation will absorb the noise of the air and fan.