Exhaust fan

[hybred355]

I am planning my new 32x40 pole barn garage.I am thinking i should put an exhaust fan in now,better now than trying to cut it in latter.Floor heat and walls and ceiling all insulated. Fan would be to get out welding smoke and car exhaust. 12 foot ceiling any advice here? I know car would not be running very long or I would open the doors. Thanks Larry

 

[ChevyIINova]

Ditto....... I'd also like to hear info/opinions.

 

[aka Larry]

Ditto....... I'd also like to hear info/opinions.

X2.

My 40'x 40' has a 10' ceiling and I need an exhaust fan too. I'm thinking hopefully it will create a draft when the doors are open as it gets hot as hell here in NC in the summer.

 

[hughfree]

Check this link...

http://www.garagejournal.com/forum/showthread.php?p=2937308#post2937308

 

[Rigpig]

I put one in my shop just as the walls were going up. I think its about 32"x32" or so. My shop is 31'x36' deep with 13' walls. I also ran a seperate circuit for it on a switch just below it. Think there's a photo of it in my shop build thread on here.
Cheers!

 

[jimindm]

You need to figure out how much air you want to exhaust. Think of this as how fast to you want to recycle the air in your building. keep in mind that what goes out must come back in. If you start exhausting to much, then you will need an inlet air supply.

Overhead garage doors are a great example. Depending on exhaust fan size, you have a huge inlet. What if you do not want the doors open? Also keep in mind that the airflow inside of a building will be between the inlet and outlet. So if they are centered in the room, exhausting the air out of a corner may still need a fan to get it circulating.

You need to decide what the use of an exhaust fan would be. Design it into the building for the way you want to use it. If it just to cool it off in the hot summer, OK. If it is to vent a task that you are doing, then do it right.

I know when I got a home occupaion permit to work on cars at home for a business, the city required one that moved 1.5 CF of air, for every square foot of floor space. I am in Iowa and have a very insulated garage with force air heat. They did not require an inlet. To this day I do not turn it on if the resnor is running in the corner. The chimney does work very well for a fresh air vent, if doors are not open.

 

[samert111]

Here's what I put in the back wall.

http://www.globalindustrial.com/p/hvac/exhaust-fans/exhaust-and-supply/14-exhaust-fan-shutter-mounted

 

[ultgar]

I am planning my new 32x40 pole barn garage.I am thinking i should put an exhaust fan in now,better now than trying to cut it in latter.Floor heat and walls and ceiling all insulated. Fan would be to get out welding smoke and car exhaust. 12 foot ceiling any advice here? I know car would not be running very long or I would open the doors. Thanks Larry

For fume extraction for auto and welding in a conditioned workspace, you want "source capture".

 

[aka Larry]

Here's what I put in the back wall.

http://www.globalindustrial.com/p/hvac/exhaust-fans/exhaust-and-supply/14-exhaust-fan-shutter-mounted

Do you have any installed pics?

 

[samert111]

Do you have any installed pics?

Sorry, nothing close up or during the install, just the finished install. I framed in between the post, studs 24" OC so I selected a size that fit nicely between the studs. If my calculations are correct, the fan on high speed can change out the air in the building every 12 minutes or so.

 

[Chaznsc]

I think of I was exhausting air, I'd want to bring fresh air in as well.

 

[Gary S]

If you live in a mild climate, an exhaust fan might have value. If you live in an extreme climate, an exhaust fan is just another hole in the wall to add or lose heat.
I have only a month or so each year where I could use an exhaust fan. The rest of they year, the weather is too hot or too cold to let in outside air. I have heaters for winter and A/C for summer. My garage stays closed. On those rare days I want outside air in the garage, I open a door
The rest of the time, a big fan hole would defeat my heating and cooling.

 

[hybred355]

okay then, thanks guys.I do plan on putting in another vent that should open when the exhaust fan comes on. I will wire it with a seperate switch. I have used this setup before in a horse barn but that was to get rid of all the moisture in the air. Thanks Larry

 

[kbs2244]

A fan in the wall is great for ventilation.

But the problem with a fan in the wall for fume and dust exhausting is that as it ***** the dust toward it a lot settles out and covers things along the way.

That is the big advantage of “at the source” pick up with hoses.

 

[sberry]

It needs to be locared in a corner so the place could be divided if needed.

 

[D rock]

I put a 36" max air exhaust fan in the gabel of my shop. It works great.

 

[wssix99]

If you live in a mild climate, an exhaust fan might have value. If you live in an extreme climate, an exhaust fan is just another hole in the wall to add or lose heat.

Since the space is heated, I'd recommend spending a little bit more and putting in a HRV. I'm doing this in a new garage to provide code-required ventilation without loosing my heat.

"2011 ASHRAE Handbook - HVAC Applications (SI); Chapter 15 - Enclosed Vehicular Facilities; Parking Garages" gives the calculations for vent rates required. This will cover the exhaust for cars coming and going and running for short periods of time. If you want to run the car for longer periods, you'll need a system like ultgar pointed out.

 

[ormachine]

I put a 36" max air exhaust fan in the gabel of my shop. It works great.

Is your shop insulated below your fan?

Ron