redneckalbertan wrote:There has been lots of talk about brake cleaners, I thought I would mention the fact that chlorinated hydrocarbons, found in some brake cleaners, and intense UV light source, ie. arc welding, create phosgene gas. Not fun to get a good whiff of it.
Remember those A/C leak detectors that used a little propane torch & drew freon through a tube into the flame? If the flame turned green, you had a leak...yep, created phosgene...
Luckily, they were banned just about the time I had decided I needed one...
Occupational exposures hold true no matter who you're working for, even if its yourself. Solvent exposure goes a lot farther than skin irritation, especially with the chlorinated solvents. Trouble is, these solvents do a really good job and many times evaporate quickly (think carbon tet and methylene chloride), so they're going to be available and convenient.
Since your liver, skin and lungs all have to last a lifetime, it pays to get serious about protecting them.
Dave makes a good point about air quality in the wood shop. Aside from toxicity, fine particles have issues of their own from a mechanical standpoint. Sometimes I think the home shop dust collection systems are more of a janitorial accessory than a health appliance.
What to do then? Use a fine filter and it becomes a maintenance issue, it is always clogging up. Use a coarse filter and the fine stuff gets through. How about a dual system, with coarse collection with a cyclone for the shavings, and then with a mechanical filtration element for the fugitive dust. Since there are a number of the former systems available, I will concentrate on the latter.
The box fan and furnace filter, while admirably pragmatic, has shortcomings, namely noise and a failure to channel air effectively.
Where I am going with this stems from the fact that almost every climate control device has built-in air handling capability. When the heat exchanger fails, out goes the unit with a perfectly good, quiet and reasonably high capacity air handler. These should be able to be adapted for air cleaning purposes. The idea would be to capture the air coming through the filtration bag(s) of the dust collection blower in it's entirety and subject it to another two or three stages. Essentially a "polishing" filter.
First would be a nylon gauze filter, set at a 45deg angle and kept slightly loose in it's frame. The air is pulled upward through the gauze, causing it to billow up slightly. Upon shutdown, the gauze falls down into a reverse curve and tends to "shed" the trapped material, and thus is, to a certain extent, self-cleaning. The material thus dislodged falls onto a tray for removal. A prime example of this type of technology is found in commercial dryers, where the lint falls into a bin at the bottom. Ask the attendant to show you how they remove the accumulated lint, and take a good look.
The second stage would be nested furnace filters. Filters "mature" in operation and actually filter better as they become loaded. They actually do their best work right before they stop working altogether. Servicing the nested filters would consist of removing the upwind, and consequently dirtiest, filter, moving the stack forward, and installing the new filter on the downwind side, thus keeping filters with some degree of "maturity" in the system.
If utilizing a third stage, I would envision a HEPA type filter or electrostatic filter. I remember the old "Smokeeter" filters used in restaurants until they came to the conclusion that having smoking and no smoking sections in a restaurant was akin to having peeing and no peeing sections in a swimming pool.
I'm kind of thinking out loud here, but the dead furnace ought to be a good place to start with such an endeavor.
