exhaust fan venting

[Kram02]

Hello,
I just had a 40x48x16 pole barn built and I am currently in the insulation phase. It will have heat and a/c. I will be doing a lot of welding/cutting and have exhaust fumes I will need to get out. im trying to get some ideas for ventilation. which will not sacrifice the heat too much in the winter and wont let cold air in when its not running. thank you

 

[peter2772000]

I installed a 600 CFM in-line fan which draws air through a grille in the middle of the ceiling of my 25' x 25' garage. I have a speed controller on it and can dial down the capacity to about 200 CFM. So far, been pretty pleased over the last 15 yrs.

Keep in mind, evacuating that much air means your dropping your garage into a negative pressure. My garage is attached, so in winter, I just crack the adjoining door open and allow the fan to steal air from the house. Summer's a no-brainer, just open a window in the garage. Otherwise, the fan's going to run outta air to exhaust and air starts infiltrating from the strangest places.

 

[rattle_snake]

I think a dedicated welding fume extractor is what you would want as apposed to a whole building exhaust fan. They can be very pricey.

I have a variable speed exhaust fan with dedicated inlets. It clears the smoke out of the air fairly quickly and doesn't really change the interior temperature if run only for a short time. There is a lot of mass in the building so it takes hours of fan running to make a significant difference. Yes the air temp inside will change but as soon as the fan shuts off it will go back to that of all the stuff inside.

 

[peter2772000]

+/- $300 for an 800 CFM in-line. Not expensive at all. Only reason I suggested a centralized exhaust is that the OP mentioned welding and exhaust fumes. Otherwise, I would have recommended a flexible-arm welding station exhaust system.