LETHAL R-134a concentrations from evaporator failure

E. William Lawrence III alisonaNOSPAM at umr.edu
Sat Nov 22 19:21:58 EST 1997


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



More information about the Toxicol mailing list