So I'm in the process of setting up a small fabrication shop in an
extra garage(as a business) and am currently trying to sort out how
much ventilation I need. Up here in The Great White North of eastern
Ontario, daytime its not getting much warmer than 10* Celcius (50F)
and dropping as low as freezing overnight. We're in the final push to
insulate, drywall, and seal up before the winter, and keeping the
garage door and windows open is no longer an option.
I'm having no luck finding any specific tables or official info re:
how much ventilation is needed. I bought a wall mount fan made by
CanArm that can suck out 1850 CFM. I didn't notice till I got it to
the shop, but the box had a chart on it that gave various examples of
times req'd for total air exchange. The example calculation was for a
garage 36x36x10, so 12960 cubic feet. The required air exchange time
for a GARAGE was stated to be 5 min.
12960 CF / 5 min = 2592 CFM.
Look up the model that draws equal to or more than 2600 CFM and Bob's
The chart on the box suggests that a WELDING SHOP should exchange its
air every 2 min.When the ceiling goes in this week, the volume of the
shop will be 8410 CF (29x29x10). My fan will only do it in 4 and a
half min. For small work I've already built a fume hood over my
2.5x4ft welding table that probably draws about 250CFM.
So the concern is work done in the middle of the shop on trailer
frames etc. --BUT-- I'm the only welder, so the worst case scenario
is me stick welding and my partner MIG tacking things together at the
same time. This is not a production welding shop with rows of welding
booths, each one manned with an arc welder running all the time.
I'm mounting the fan in the attic gable and building a large duct in
the attic to connect the fan directly to the 22x30" opening in what
will be the ceiling(approx. centred in the middle of the shop).
Do I really need to get my air exchange rate down to 2 minutes? Buy
the bigger Fan?
Thanks in advance.
10 years ago