|View single post by neurodoc|
|Posted: Wed Jul 22nd, 2009 07:36 am||
|Good questions, kdog!
But those are the EPA rules.
R12 and other Chlorine containing hyrdocarbon refrigerants (e.g."CFC's") are deemed to be ozone depleting and hence enviromental hazards. R12 is the prototype "bad boy." R22 is considered alsmost as bad, and is subject to a phase out plan.
Fluorine is considered less damaging to the ozone layer than chlorine, and flourinated hydrocarbons (HFCs) like R134a are considered "less" ozone depleting. You can syill buy them over the counter without an EPA license in most States, but there is a move to ban even these refrigerants.
The EPA actually prohibits venting HFCs as well as CFCs. They are silent about venting pure hydrocarbon (HC) refrigerents, like isopropane.
Though rarely enforced, the EP can levy huge Draconian penalties on folks who vent refrigerants into the air.
As regards the "safety" of R12 versus R134a, the later is more biologically harmful than the former. R12 has few significant adverse medical effects, aside from the fact that you can be asphyxiated if you are in an environment where it displaces so much oxygen that you can't get enough oxygen to breathe...
If you breathe R134a it gets absorbed through your lungs, gets into the bloodstream, and is very cardiotoxic. It can promote cardiac arrhythmias, which is why medical personnel are warned not to use epinephrine in cases of R134a exposure and cardiac arrest. But who cares about the life of some poor HVAC tech or other human being exposed to R134a? What is that compared to protecting the world from R12 induced ozone depletion?
I won't even mention the fact that R12, in terms of its thermodynamic and practical mechanical engineering properties is a much better refrigerant than R134a.