I've seen some grain elevators......they are very dusty environments indeed, and explosions do happen (too often)..... The dust concentration is very dense there, due to the closed environment.

If I understand correctly, one of the more common problems with fires/explosions in wood processing is that fires can start in the dust collection systems (a mini grain-elevator like environment???).

You seem to have a good respect for the hazards of your tasks. Opening both doors of your shop is a very good idea. Using a few large, well placed fans to direct the air flow may help. I looked up what i could find on wood dust combustion....minimum temperatures are about 842 F. I don't know what kind of concentration levels there would be in ppm, and if you did know would you be able to recognize it in the shop? My info was from a metric source, and I've no way to substantiate their data, but they stated the combustible concentration level at 20mg/litre. This sounds like it would be approachable in a home shop environment, but then it is hard to say what 20mg/litre would look like in the shop (I wouldn't know 20mg/litre, if it reached out and slapped me). With your ventilation, I can't imagine you'd have a severe fire hazard, but better safe............. *****Rehd definitely has the best idea......GET WITH THE LOCAL EXPERTS. garland

: I work in a shop which is 35 x 40 feet. I have built numerous cedar strip
: canoes etc. etc. I have started building hardwood strip hull & ribbed
: kayaks with treated canvas top, but I'm getting in trouble with WHMIS
: because of the dust. I have been doing this kind of work for over 25
: years.

: I believe in an open door policy which is an 8 x 10 garage door on each end
: of my shop. When I am ripping hardwood both doors are wide open to get rid
: of the dust. I have asked & asked but nobody can give me the parts per
: million before sawdust becomes explosive with the flow through ventilation
: that I have. Why is this not safe?

: Parts per million (what would it look like?) I have no idea, I would like
: some information because I cannot afford a dust extraction system.

: Thank you. Jake