LETHAL R-134a concentrations from evaporator failure

Adrian Brigham 73531.1307 at compuserve.com
Mon Nov 24 04:02:40 EST 1997


L. Smith wrote:
> 
> 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
This is what I meant.  Your answer certainly makes more sense.  As a
reader of postings I will give a lot more attention and credence to
logical, documented, and well stated arguments rather than, shall we say
"crap".

Adrian



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