LETHAL R-134a concentrations from evaporator failure

L. Smith larrNOSPAMys at online.no
Sun Nov 23 08:40:05 EST 1997


Adrian Brigham wrote:
> 
> E. William Lawrence III wrote:
> >
> > What a load of horse crap!
> > 4000 ppm of just about anything will kill something for sure, except
> > maybe oxygen or nitrogen!
> > Another scare tactic to sell a different product.
> > That's all I'm going to say as I personally don't make many comments
> > without proof as this fool did.
> > What about laws that prohibit human tests of this type, I guess that they
> > just ignored them huh?
> >
> > ghg at worldserver.com wrote:
> > >
> > > LETHAL R-134a CONCENTRATIONS IN PASSENGER COMPARTMENTS MAY OCCUR
> > > FROM EVAPORATOR FAILURE
> > >
> > > In August 1997, a study was done at the Armstrong laboratory, Wright
> > > Patterson Air Force Base, Dayton, OH. The report, "Human Inhalation of
> > > Halon 1301, HFC-134a and HFC-227ea for Collection of Pharmacokinetic
> > > Data" was authored by A. Vinegar, R. Cook, J McCafferty, M. Caracci, and
> > > G. Jepson.
> > >
> > > The concentration of R-134a being used was extremely low and (then
> > > thought) that nothing bad was going to happen. To quote from the bottom
> > > of page 10 (page 11 if abstract prepended), "Subject #3 was the first
> > > volunteer exposed to
> > >
> > > HFC-134a.  The exposure concentration was 4000 ppm (0.4% v/v) and was
> > > scheduled to last for 30 minutes with a 5 minute postexposure evaluation
> > > period as was accomplished in the Halon 1301 portion of the study.
> > > Approximately 4.5 minutes into the exposure, the subject lost
> > > consciousness and both pulse and blood pressure dropped to zero."
> > >
> > > The test was aborted and medical personnel intervened and revived the
> > > subject.
> > > Suppose it wasnt a test in a medical lab, that person would be "dead".
> > >
> > > The industry, has in general, tried to "coverup" this "problem", often
> > > reporting "Human Subject Faints During Botched Air Force R-134a
> > > Inhalation test".  They then go on to theorize that the nurse wiggled the
> > > blood drawing needle and that made the subject "faint".  See (on the web)
> > > www.autofrost.com/humanhal2.pdf to download your own copy or call Monroe
> > > Air Tech at 1-800-424-3836 for a copy. Be your own judge.  Using "0.4%"
> > > (4000 ppm) parts per million of R-134a vapor in air as the "lethal"
> > > amount, the following calculations were performed on several late model
> > > cars.  They assume a bad evaporator leak or rupture, allowing the factory
> > > listed charge amount
> > >
> > > to escape into the passenger compartment.  R-134a is heavier than air, so
> > > if the air is not "stirred" by a fan, heavier concentrations will be
> > > found in low spots and lower in high spots.  For these purposes, we will
> > > assume the air is stirred and the concentration is uniform.
> > >
> > > The specific Volume of R-134a vapor at "normal" pressure (from the NIST
> > > Standard Reference Database 23 "NIST THERMODYNAMIC PROPERTIES OF
> > > REFRIGERANTS AND REFRIGERANT MIXTURES") is 3.69 cubic feet per pound
> > > (cf/lb).  If you blow off a 1 lb can of R-134a into am empty garbage bag
> > > (sealed), it will occupy 3.69 cubic feet.
> > >
> > >              SPECVOL134a CF   R-134a CHG lb         1        1,000,000 parts
> > > conc. (ppm) = -----------   X -------------  X   --------  X
> > > ----------------
> > >                   lb                            Int.Vol CF   per million
> > >
> > > 1998 CAR                Interior(CF)    lb R134a  pass.conc ppm  Times
> > > lethal
> > > Ford Escort             87              1.75      74,224          18.6
> > > GEO Prism               84              1.7       74,679          18.7
> > > Chevy Cavalier          92              1.5       60,163          15.0
> > > Ford Taurus             101             2.13      77,819          19.5
> > > Ford F150*              80              2.38      109,778         27.4
> > > Toyota Camry            96.8            1.88      71,665          17.9
> > > Ford Mustang            83              2.13      94,695          23.7
> > > Chevy Malibu            98.6            1.75      65,492          16.4
> > > Honda Accord            90.4            1.43      58,371          14.6
> > > Chevy S-10*             80              2         92,250          23.1
> > > Chevy MonteCarlo        96.1            2         76,795          19.2
> > > Olds Cutlass Supreme    95              1.75      67,974          17.0
> > > Buick Skylark           87              2.25      95,431          23.9
> > > BMW 5 Series            93.5            3.27      129,051         32.3
> > > * Estimated, since interior volume was not available
> > >
> > > -------------------==== Posted via Deja News ====-----------------------
> > >       http://www.dejanews.com/     Search, Read, Post to Usenet
> Since he sited studies and apparent facts to promote his argument, it
> would help your side to do the same rather than just referring to his
> arguments as "a load of crap".
> 
> Adrian B.


Halon systems use the same general types of fluorocarbons, and have
been used without incident, to my knowledge.

These gases are not acutely toxic, but could asphyxiate you if they
filled your area.

Just like carbon dioxide and nitrogen can do.  Do you know of anyone
who has died from riding in a closed automobile with 2-3 other people
using up the oxygen and exhaling carbon dioxide and nitrogen?


Sure, I guess it is possible. But I think he's probably right...it most 
likely is a load of crap.


-- 
- Larry Smith Sr
Remove NOSPAM for email replies



More information about the Toxicol mailing list