exhaust fan question

[Greg Stanford]

Setting up a new shop (new house, new shop, everything's a mess) which is 16' x 30' - unfinished inside. I'm in south mississippi, I'm not going to heat or cool the space so it will be well ventilated. There's a double door at one end, 4 small windows, & I want to put an exhaust fan at the other end. Table saw will go in front of the double doors (outfeed will actually be through the doors when necessary - save some space) & the lathe will go in front of the fan. Assorted tools in between. No dust collection. Exhaust fan is to get dust out of the air, particularly at the lathe. Sanding (except for turned pieces) is done outside, finishing is done elsewhere. My question is how much fan do I need? Is 2600 CFM enough? 3200 CFM? 5460? As always, I greatly appreciate the help. You guys are a wealth of information.

[Rob Will]

I have owned several ventilation fans similar to those mentioned.

In retrospect, the fans that were the nicest to be around were those that had wide paddle-style blades that ran at low RPM.

On the high end of things there are variable speed fans.

Next there are two and three-speed fans. That would plobably be my choice.

As far as size goes, I would probably get at least a 24". That way, you can run it on slow most of the time.

Some squirrel cage fans that can operate at low static pressure might also also be ok.

Rob

[Greg Stanford]

Thanks. What I ended up ordering is a 3200 CFM, 1650 RPM exhaust fan w/ 20" blade diam. I think it will move enough air & hopefully won't make too much noise.

[Rob Will]

Greg,
Since you are in MS and this post is about ventilation, I have an off-the-wall question.

In the South, do you see a lot of reflective foil insulation in the attic of buildings? I have used a fair amount here in KY and found it to really reduce heat gain from the roof. I'm sort of surprised we don't see more.

Anyway your post about the non heated non A/C shop made me want to ask the question. Seems like it could make many buildings a lot more comfortable (?).

Thanks,
Rob

[Lee Hingle]

Greg,
Gulfport MS? I'm just a stone's throw over in Picayune. Glad to see a fellow Mississippian over here. My 30X40 shop has no central a/c or heat as well. I have a BIG 48" box fan which keeps it bearable in the summer and a 220V electric heater for the winter. My bldg is well insulated, and I think that is the key. As for the fan, the bigger the better. You will want to evacuate as much dust as possible as quickly as you can with no dust collection.

Good luck,
Lee

[Don Hein]

Is the 20" exhaust fan going in a window hole, or will a new hole be framed? In your search did you run across anything decent in 110V that would install between existing studs 16" on center? Reading this thread from the beginning, I was hoping to learn of an exhaust fan which would fit between existing studs and provide a partial--not complete--ventilation function in my 24x28 shop.

[Rob Will]

Is the 20" exhaust fan going in a window hole, or will a new hole be framed? In your search did you run across anything decent in 110V that would install between existing studs 16" on center? Reading this thread from the beginning, I was hoping to learn of an exhaust fan which would fit between existing studs and provide a partial--not complete--ventilation function in my 24x28 shop.

I would try Grainger.com

Rob

[Greg Stanford]

Rob, don't see the foil, rarely see anything but the blown in anymore.

Don, I'm framing a new opening, I ordered from Triangle Engineering out of Arkansas & the smallest they have is 17".

& hello to Lee, good to see MS woodworkers! Don't think it's quite the hobby/vocation in the south that it is "up north", don't know why. Had a fella tell me it's because everybody's out hunting instead of home in their shops. Guess you could do both.

Thanks everybody.

g

[Lee Schierer]

For a fan that large, you will also need to provide an air inlet for it to be effective. There will be some gaps around the doors, but not nearly enough to satisfy the fan. Better plan on an open window or louver somewhere else in the shop.

[Rob Will]

For a fan that large, you will also need to provide an air inlet for it to be effective. There will be some gaps around the doors, but not nearly enough to satisfy the fan. Better plan on an open window or louver somewhere else in the shop.

Good point Lee.

[Greg Stanford]

Plan is to have the double doors open at one end of the shop & the fan blowing out at the other. Winters here are mild, on the few days it really is too cold I'll just have to find something else to do.

g

[Bill White]

Well let me chime in 'cause I'm way up here in Tupelo. My exhaust fan is ceiling mounted to draw air from the windows and out thru the ceiling (9'). Used a squirrel cage, and it has a filter to keep the dust out of the attic.
Bill