08-16-2009, 06:36 PM
|
|
Registered User
|
|
Join Date: Aug 2009
Posts: 6
|
|
Quote:
Originally Posted by Matt L
That's an old but good myth. But is it true? I've only see it referenced where people are trying to sell me HC's that cost three times as much.
|
here some interesting health facts regarding R134a, see also attached document. I had to upload the document as a text file.
the .pdf version is to big.
Quote:
> 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.
|
|