My Workshop
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16 August 2018 at 1:58 pm #550277
What type of particle counter were you using Ed, and what particulate concentration levels were you able to measure? I would like to make those measurements in my shop.
I have a Dylos DC1100-PRO . It’s been a couple years, so there may be other options.
I need to be careful about specific claims or assertions. What I’ve done is informal. The topic is complicated. The manufacturer is cautious about applying the meter and interpreting the data. There is a sticker on the meter that says, “Air Quality Chart 0.5 micron, Small count reading” and then tabulates:
3000+ = very poor
1050-3000 = poor
300-1050 = fair
150-300 = good
75-150 = very good
0-75 = excellentA couple sweeps with a broom produced counts over 10,000. This was true on our kitchen floor as well as on the cement basement / shop floor. No degree of “sweep gently” was able to keep the count from going high.
16 August 2018 at 4:10 pm #550281Those particle counts don’t mean very much to me. What I’m used to are actual particulate concentrations for PM10 or PM2.5 measured in ug/m3. It’s really the PM2.5 and sub-micron stuff that is the bigger potential health risk. Some of the meters I’ve seen are calibrated to read concentrations that way as opposed to just a raw count.
I wonder what particle count you would get if you made that same measurement just before you turn on your shopvac and again just after. I’m curious about how much effect the exhaust from the vacuum might be having in stirring up the air in the room and the dust that’s laying on top of things that the shopvac’s exhaust is aimed at. That might be worse than the broom. I know that mine is pretty effective at blowing dust around – in fact I often open the garage door and use the exhaust as a blower.
I completely understand what you mean. I wish the result was reported in ug/m3. This is what I mean by the manufacturer being guarded. What I can suggest is that you research the product, research the correlations that are shown between this device and others. Examine what people say in various professional forums regarding this meter vs. more typical instruments. From that, form an opinion. From an engineering point of view, an instrument generates a response to a signal. The response is then calibrated. As long as there is sensitivity, there is hope to get information. My opinion / speculation is that the manufacturer is reluctant to cross that final bridge and state results in ug/m3 because it may have liability implications they are not willing to take. Dig around and see what conclusions you reach.
I’m thinking of putting a vacuum cleaner port in the wall between my woodshop and garage, then open the outer garage door to vent it out. Another thought would be venting into the attic, which is open at the top and eaves (would the post-HEPA fines from the shopvac output be enough to become a fire hazard near the furnace?). One pro I talked to said he does all his work, then at lunch and at the end of the day he opens both sides of his shop and turns on a set of industrial fans to make a wind tunnel.
16 August 2018 at 5:30 pm #550284I don’t think I would vent it into the attic space. Over time, you could see an accumulation of dust up there just because your blower won’t produce enough volume to maintain an air flow velocity sufficient to keep the larger particles suspended. That could indeed become a fire hazard. I like the wind tunnel approach. I only have a normal garage door but from time to time, my electric leaf blower comes out and within a couple of minutes, most of the dust, some of the spiders and a few of the smaller rodents are out in the driveway. Just remember to pick up all the sandpaper and chisel guards first or they’ll be out there too.
Keep in mind that, if you move air from space A to space B, you can backdraft combustion sources like furnaces and fireplaces in space A. Also, if you open a “port” to exhaust A into B and B happens to be at positive pressure, you may get the opposite of what you expect. I’m not sure that a garage with it’s door open will vent air vs. draw air in.
16 August 2018 at 7:48 pm #550289It won’t do either without some wind or a fan blowing and in either case, equal amounts of air have to come in and go out through different parts of that one opening.
It’s not as simple as that. Air can be warmed in the house, rise, and exit near the top of the structure. As you say, air must come in to make up what went out. This can lead to infiltration at the basement (and elsewhere). The house acts like a chimney. In my house, in cooler months, no fan is needed to have air gushing in at windows in the basement. Brian was considering exhausting to the garage and then opening the garage door. I would not count on the air exhausted to the garage going out the garage door vs. swirling about until the dust settles or vs. being drawn back into the structure.
@Ed – Yes, wherever the output goes will likely accumulate the unwanted fine particles. Maybe I’ll figure a way to vent it directly outdoors or do some variation of the leaf blower method (there are a lot of spiders I wouldn’t mind sending away). Currently I’ve just been doing slow sweeping, because the shopvac blows everything around due to the output, that and the shopvac itself is covered in static charged dust so wrestling it around the shop releases some of that onto whatever it touches, mostly my clothing. That all being said, there has been a lot less dust since switching to planes vs sanding and power-routing!
16 August 2018 at 9:55 pm #550294No, it really is that simple unless you just want to try and complicate it. Exhausting into the garage will not work. The dust will stay largely in the garage even if the door is open unless there is a way to provide air flow through the garage and at a velocity sufficient to keep the particles suspended in the flow stream. That is a function of the size of the particles. I designed industrial and utility air pollution control systems for 46 years so you might say that I have a little experience with air flow. In industrial ductwork the standard velocity used to avoid dust dropout is 3600 ft/min which is about 40mph. I doubt Brian wants a 40mph wind blowing through his garage and I guarantee you he wouldn’t want the power bill associated with a fan that large. This has nothing to do with heat rising, chimney effect (which has nothing to do with heat by the way – just dP) or air infiltration. It’s simple physics.
I find it amusing that even when we agree it comes off as disagreement. Have no idea why. Dumping into the garage is not going to work. Opening the garage door is not going to help. Dust will fall out and settle in the garage. I doubt cross ventilation does as much as people think and for exactly the reasons you give.
At long long last!
It looks a little shabby on the surface but that will change once it has been painted.
I was hoping someone might be able to recommend a good way of heating the place because it gets cold during winter to the point I can’t go in there. I was considering a wood burner vented out a side wall (instead of through the roof) but until then I’ll need something else. The only two options I can think of are:
> Calor gas heater
> Electric convection heaterNot sure which would be cheaper. Is there a third option?
16 April 2019 at 1:54 am #555984Another option, and the most civilized, IMO, is a mini split air conditioner/ heat pump.
Something like these, although I have used other brands. ( Mitsubishi)
https://www.homedepot.com/b/Heating-Venting-Cooling-Ductless-Mini-Splits/N-5yc1vZc4m1
They usually require 15-40 amp 230v feeds, depending on size.
About twice as efficient as electric resistance heaters. -
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