Exhaust Blower for Basement

[Ephriam]

My basement dimensions are about 30’ X 50’ X 8’, a volume of 12,000 cf. How big a blower is needed to exhaust dust so that little gets upstairs into the house? I’m not overly concerned about personal safety when working in the basement because I wear a mask when I sand. It’s my wife who has COPD that I’m worried about. Windows located at one end of the basement and stairs at the other should provide enough air flow to keep the upstairs clean. Is there an advantage to installing two blowers such as reduced noise? Advice will be greatly appreciated. Thank you.

Fred from Rhode Island

[stevem]

exhausting air outside from your house is not a good idea.

you will create a negative pressure inside the house forcing air to infiltrate from somewhere else typically down the chimney which will create a CO problem in the house

the dusty air will have to be filtered somehow, dust collector, air cleaner what ever works

if its a really bad problem, then its time to move the workshop or at least the dusty operations like sanding

[Rick Thom]

Hi Fred, welcome aboard! I'm not 100% sure but you may be our first member from the State of Rhode Island, but certainly not our only member from U.S. Perhaps you could provide us more details concerning your shop, the type of woodworking you plan to do, the equipment you use, any details about dust collection currently in place and so forth. We would also need to know a bit about your homes HVAC system and local seasonal climate. Maybe seems like we are picking your brain (and we are), but that's some of what we may need to understand your situation and provide an appropriate recommendation.
It may not come as too big a surprise that many of us have basement shops so we face similar dust issues, but most of us also have seasonal heating requirements because of our cold winters that have to be factored into account in our solutions.

[billh]

Hi Fred,
I have an exhaust fan that is made from an old furnace blower - it also doubles as an air filter but I can direct the exhaust out of the house or back into the shop. (I should say, I was able to do this but I'm doing a bit of a rework so it isn't operational right now.)

I have an electric furnace so I don't have the chimney issue and the fireplace never ran during the day when I was in the shop so that wasn't an issue.

Regardless, any air that goes out of the house has to be made up and it will come in through the window/door cracks, etc. By using windows, you can exercise some control on the primary air entrance from outside. I think you can use this to your advantage by providing the path of least resistance say upstairs such that the air-flow is from the living area into the shop which should help keep the dust downstairs.

Of course, how well a lot of this works depends on the air temperature outside when you exhausting the shop. Note that in the summer you will be blowing your cool air-conditioned air (if you use an A/C) out of the house so this isn't just a winter issue.

If you have a forced air furnace with ducts, you can help keep dust out of the living area upstairs by sealing all the joints in the air-return basement ductwork so they can't draw dust into the system. I used aluminum duct tape. Consider upgrading the furnace filter to a better one. The fiber-glass ones are not very good but be careful going to a real fine one since it may throttle your air-circulation too much.

All the dust you can capture at the source is less dust to go through the house. Use a good DC; a cyclone with a good filter would be better than a regular DC. Use a shop air-cleaner and let it run for some period of time after you are finished in the shop. Keep the shop door closed and consider changing out of your clothes before you come upstairs.

An advantage of multiple fans is that you can move air around shop and eliminate dead spots. You don't need to have both/all fans exhausting to outdoors, you can set them up to feed the fan that is doing the exterior exhausting. The air cleaner fans could also perform this function. The usual recommendation is to set them up "race-track" style. One on one side of the shop and the other on the opposite side so the air flow blows around the shop like a race-track.

billh

[Ephriam]

Thank you stevem, Rick Thom and billh for responding. I thought I was aware of the safety issues relating to dust in the workshop but the level of concern that you’ve expressed has certainly raised mine a notch. The CO danger posed by negative pressure is something I wasn’t aware of before.

OK, it’s time to fess up. Everything I wrote above is so but I left a bit out. Go back in time to last summer when the orangeburg sewer pipe under my cellar flooor collapsed. A crew sawed a diagonal trench across the floor and installed plastic pipe which I trust will outlive me. They didn’t use a wet saw but tried to keep the dust down with spray from a hose. It helped some but I’ll never see the last of the concrete dust. Half the basement floor had been covered with asphalt tile (previous owner, forty plus years old) all of which I pried up leaving behind a pattern of cured black bonding agent in neat squares bordered by raw concrete. The other half of the floor was coated (again forty plus years ago) with paint which is now showing concrete in patches. The bottom line is I want to coat the floor with something that will keep it from flaking and I figured that whatever I use will require immediate exhaust to keep fumes from getting up into the house.

I figure that with the cellar door and the adjacent back door open, I can run the blower(s) and exhaust the fumes out the cellar windows at the other end. I would now only do this on a mild spring day. My wife would be safely stowed at my sons house until the fumes cleared.

Aside from the question of blower size, I don’t know what I can effectively use on the floor. Maybe nothing. But if I install an exhaust blower, at least I could unlimber an electric leafblower in the basement to lift the accumulated dust and hopefully move it outside (while wearing a canister mask and goggles).

I have a single stage dust collector and a JDS hanging filter unit but they’re no match for concrete dust. I wonder what that dust has done for the life expectancy of my power tools.

Thanks again for the advice.

Rick Thom – I will post more info on my shop in future. Thanks.

Fred from Rhode Island