|
Hi Butch, Ah, a subject almost guaranteed to generate a long thread (at least for this board) :o). The reason I do not recommend using a shop air supply for breathing air is because I have tried it myself in the past and found it to be objectionable. When I decided to get some type of fresh air breathing system back in the '70's, there were no units available for the part time user such as the Hobby-Air. The hazards of isocyanates were not well known outside of possibly medical circles and the guidance was slim. Even big paint manufacturer's such as DuPont and PPG (Ditzler back then) didn't emphasize the use of fresh air systems. At that time the cheapest system I could find ran about $900. That's '70's dollars. That was outside the reach of myself and most other part-timers. But I was forced into doing something because of two bad experiences with isos. I had to either get some type of breathing system or give up using hardeners in paint. It was that simple. I decided I would get a full face mask designed for continuous flow and plumb the thing into my shop compressor. Easy fix I thought and I could get by for less than $200. I only gave a passing thought to the fact that my compressor was marginal for my spray gun even without the extra load. Well, it didn't work out as well as I had hoped. When I tried it out, I noticed a very distasteful "aftertaste" in my mouth that I will characterize as an "oily taste" for lack of a better term. My shop compressor was a standard, oil lubricated, recip that was not known to use any great amount of oil. I doubt I had to add even a cupful to the crankcase over twenty years of operation, most of which was running air tools and not painting. I also had plenty of conventional filters and separators in line but they don't do anything for stuff in vapor form. In any event, I decided that I did not want to breath anything that resulted in such a taste in my mouth. It was an unacceptable risk that I was not willing to take. A personal judgment, to be sure. This is what lead me to look into a separate air supply. I found what was a reasonable solution, at least for me, in a non-lubricated, tankless compressor. It is referred to as a compressor but is not really used as such to any real extent. As there is no storage tank, the pressure never gets over a few psi in operation. Less than about 10 or so - whatever is needed to push the cfm delivery (3-4) down 50 ft of standard 3/8" airline. It runs continuously when being used. I have never noticed it to supply hot air, even after extended operation. You are entirely correct. The system I use is not "approved". I think the actual face piece is but everything else is not. Not the pvc hose and certainly not the "compressor". Approval of a piece of the system means nothing. Only entire system approval is important if one needs such approval, as in a commercial setting. As far as I know, there are NO compressors (or turbines for that matter) of any kind that are approved, at least by NIOSH. There are approvals on masks, hose, fittings and a requirement that the air supply meet federal spec grade "D" breathing air - any which way you can. That is generally obtained commercially by using special non-lubricated "breathing air" compressors (tankless) and a rather sophisticated filtration system, including CO monitoring and alarm. This is expensive to buy and to maintain. Outside the reach of most of us that monitor this forum. Some time back I recall seeing a commercially available filter package that one could place on their belt and use shop air for breathing. I don't remember the manufacturer - could be SAS. I don't think it was "approved" by any agency as it did not guarantee grade "D" air but it could be something for additional consideration. I do have a certain distrust for having to filter out any bad stuff. I have full personal control over where I place my air intake such that I don't have to be concerned with the effectiveness or the maintainence of such things. Better to avoid putting in bad stuff in the first place than trying to filter it out after the fact. I agree that personal safety (outside of an employee situation) is a matter of the individual evaluating the potential hazards and risks associated with any endeavor and coming to a very personal decision of how much "safety" is enough and how much risk is acceptable. That's as it should be. I have made such a judgment call myself regarding the use of standard pvc air hose for breathing air. Some would say I should be concerned that it is not "food grade" and I could be subject to breathing bad leachates from the hose itself. While that may be true, I have decided that it is an acceptable risk that I am willing to take. However, I can't recommend something (shop air for breathing) to others that I have previously rejected for myself. To put together a system similar to mine would cost up in the $400-$500 range today which, by coincidence, is about the same as the commercially available Hobby-Air. While still expensive for the part-timer, this is not an unreasonable price to pay for respiratory safety, even if not "approved" for such use. At least in my opinion. I would be the first to agree though, that most any improvement effort is better than nothing when you are dealing with isocyanates. The wide area between nothing and full agency approvals is certainly a ripe one for differing opinions on what is acceptable and what isn't. I pass along my own thoughts on this in the forum only for the consideration of others who may be evaluating options. As you do also. No guarantees. Your mileage may vary. And whatever works for you :o).  Rod
|
