After reading the recent posts regarding the unhealthy aspects of wood dust, I’ve decided to do everything I can to rid it from my shop (garage). I’m adding a dust collector and have already built a down draft sanding table. I also use a box fan with a furnace filter on the intake side. Since I live in Arizona I can leave the garage doors open year round with another fan pointed outside in an effort to blow
anything else out. This is sometimes useless depending on the wind direction.
This brings me to my question. My garage has on the wall opposite the doors 2 vents, 1 at ceiling height and 1 near the floor. These are to provide ventilation for the gas water heater that I unfortunately share workspace with. I was able to get a small squirlcage blower and motor. I want to use this to blow any remaining dust outside. Since most air filters are placed near the ceiling, should I use the upper
vent? However, I would really prefer to use the lower one.
Appreciate any thoughts regarding this.
Replies
Beach Bum,
It probably makes little or no difference, and being that dust will eventually settle towards the floor, there is probably some advantage to the floor vent. Most ventilation is set high because you are typically trying to vent hot moist air from a living area and that rises to the high points of a living space. The air filter units made for shops are ceiling hung mostly to get them out of the way and to allow free air circulation around them, they are not up high because that is where most of the dust is.
Concerning the gas heater, if you create a negative pressure in the garage because of the suction of the fans you could back draft the gas heater, which will pull air down the chimney, possibly blowing out the pilot, wasting fuel, and potentially creating a carbon monoxide risk. As long as you have the garage doors open to provide make-up air you won't have a back draft problem, but don't run the vent fans with the doors closed. Units like the down draft table which exhaust the filtered air back into the room won't create a problem, only fans that vent to the outside will cause a back draft.
Enclosing the heater in an air tight closet with air intake vent to the outside would be a good idea, a better idea would be to get it out of the garage altogether. I never liked the idea of any open flame appliance sitting in the same room as a car with gallons of gas just a few feet away. I know of several explosions and fires resulting from gasoline leaks being ignited by gas furnaces and heaters in garages. I suspect that in some areas it wouldn't be legal to have a gas appliance in a garage.
Hope this helps, John W.
Beach Bum,
Here is a link to one of my previous posts regarding dust collectors. In it, I give a full description as well as drawings and schematics for building your own air scrubber. Since you already have the squirrel cage blower, you're already half way there!
http://forums.taunton.com/tp-knots/messages?msg=11626.1
If you have any questions, please feel free to ask!
Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.
Edited 11/20/2003 10:35:06 PM ET by Jackie Chan
I'd vote for the upper vent. The light, super-fine dust is what you want to be most concerned about, and if you live in AZ, I assume it's pretty warm a good part of the year, so that fine stuff is gonna float. Same reason for placing the air cleaners up high.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
BeachBum,
A Gas Company repair man once told me one set of vents are for natural gas and the others are for gasoline fumes. One rises and the other falls. In Orange Co., CA, where I live, it depends on the individual city's building code as to whether and outside closet is required for the water heater. Mine doesn't - bummer.
Ken
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