Outside Venting? Be Careful!

[jck53151]

New to the forum.  Wow!  What a wealth of information in these pages.  First of all, God bless you Phil for your time and energy creating such an ingenious product that has changed dust collection forever.  I think it's pathetic how companies are robbing you of your idea because of your patent woes.  Keep the faith, brother!

I was reading a post - can't for the life of me find it again - and got me thinking about a danger that some of you may be putting yourselves in to.  Where are most home shops located?  Unless you are one of the few to convince your spouse/family that the living room is appropriate, it is probably either the basement or garage, right?  Basement - don't we usually try to button up out shop doors to contain the dust?  We don't want the entire house infected, so we make sure our door(s) are sealed.  Garage - In northern climates we heat them. In order to keep the heat in we insulate:  Drywall, insulated door, weatherstripping - anything to keep the cold out.

Now comes the problem.  Does your basement shop have any combustible appliances like a furnace or hot water heater?  Does your garage have a wall mounted or a nice ceiling mounted Modine type heater?  If so, then venting your DC to the outside can cause an extremely dangerous carbon monoxide situation!!  Add one of those ceiling mounted air scrubbers vented outside and you are doubling the problem.

Even if your garage is buttoned up good, there is still enough make-up air for the heater to draw from.  However, add a DC system vented outside, and you are using that make-up air.  There is not enough air available for the flue to work effectively, so the combustible gases are drawn into the garage.  Same in the basement.  Venting to the outside can suck the gases out of the flue for the hot water heater for sure, and maybe the furnace although those are usually sealed up better.  This is why the UBC (Uniform Building Code) specifies a certain distance that a cold air return must be placed away from the combustion source.  If too close. the furnace will draw it's air from the closest source (the hole you just cut into the return) and will create an air current that will pull the gases right out of the hot water heater flue.

I know this does not apply to all shops.  Many don't have these appliances in them, Southern climates don't heat garages or use a furnace often, etc.  But everyone has a hot water heater, right?  Just saying - plan how your make-up air will flow when thinking about venting outside.

John

[phil (admin)]

A worthwhile warning.  Any shop heated via by the combustion of anything (gas, wood, etc.) NEEDS A CARBON MONOXIDE (CO) detector, whether you exhaust your DC outside, or not.

[Bruce Seidner]

I had not thought of a CO detector and will get one soon. I am in the temperate South and even in winter opening the garage door a few inches across its expanse has always seemed fine for someone who vents outdoors. But a CO monitor is a very good investment to have mounted near the gas furnace that shares my garage shop.

Thanks