On Fri, 20 May 2005, Steve W. wrote:

> The US for one. ANY flammable blend is illegal.
>
> The EPA has made it illegal to use flammable refrigerants in motor
> vehicle air conditioning systems.

If you mouse around on the websites selling this stuff, you'll find them
talking about "legal 2nd-generation drop-in" refrigerant. This is a bit of
doublespeak. Here's how it works: It's illegal to replace R12 with
hydrocarbon refrigerants, but it's not illegal to replace R134a with
hydrocarbon refrigerants. A law against the latter was never written,
'cause there's no reason why anybody would ever replace R134a with
hydrocarbons. Unfortunately, that legal omission is being treated as a
loophole by those selling hydrocarbon refrigerants. The idea, they say, is
to convert your system over to R134a (which is legal), then replace the
R134a with hydrocarbons. Nudge nudge, not illegal, wink wink, elbow in the
ribs, and if you happen, wink wink, to forget the "change to R134a" step,
wink wink, why, that would be awful. Wink wink. Just terrible. Wink wink.

> Each potential new refrigerant must be tested according to the American
> Society of Testing Materials (ASTM) E-681 testing method to determine
> flammability. In addition to testing the refrigerant itself, if a blend
> contains a flammable component, the EPA requires leak testing to ensure
> that the composition does not change during a leak and become flammable.

Yep. EPA also knows the difference between chicken salad and chicken ****.
The marketeers of hydrocarbon refrigerants tried playing leapfrog by
renaming their product -- EnviroSafe, HC-12a, OZ-12, MX-12a, ES-12a,
HC-12a, ("anything"-12a) -- every time EPA would ban the product. It did
not take EPA long to ban the isobutane/isopropane blend itself, regardless
of name.

> There has also not been any single refrigerant or blend that is a direct
> drop-in for R-12 in automotive air conditioning systems.

Legally there is no such thing as a drop-in. This is to support and
preserve the refrigerant recycling program. It's important for systems
with R12 fittings to contain ONLY R12, systems with R134a fittings to
contain ONLY R134a, etc.