*CBHVAC* writes:

Also, you mentioned that you could vent 134a..that you cant..I missed
that before. Not a big deal, but that much I remember..

The EPA sayeth:

http://www.epa.gov/ozone/title6/608/subrecsm.html

My interp:

Section 608 originially prohibited CFC venting, not 134a. The EPA added
a 134a non-venting rule in 1998 based on junk science of alleged "global
warming potential". For some reason, the EPA did not choose to apply
the same thought process to ammonia, CO2, methane, or nitrogen, against
which 134a is ridiculously inconsequential, even if you believe the junk
science. The EPA still mercifully permits flatulence, for now. No
doubt they are working on licensing, to be followed by phase-out.

Observation: 134a is widely sold to be vented, such as toy propellants
("airsoft") and dusters.

How is this?

The rule sez, "Releases of HFCs and PFCs that are not used as
refrigerants" are exempt!?

So spew all the billions of pounds you like. Just don't let it change
phase more than once.

It is obvious the chief purpose of this regulation is to benefit the
HVAC trade, by creating still more barriers to entry (costly tooling and
certification) that increase prices and profits for those in the biz.

I happily note that they promise that with my ancient 608 license I will
be grandfathered to buy 134a when they get around to further "helping"
the HVAC biz by banning consumer sales, at least in my free state of
Florida; I think you mentioned North Carolina as jackbooting do-it-
yourselfers from buying anything related to HVAC, including cleaning
chemicals (although you never did cite an actual chemical substance that
was untouchable except for you high priests of HVAC).