Duracool Misstatements

[Tom Mathews <bimrone@xxxxxxxxxxxxx>]

There has been a number of mistatements regarding duracool vs. HFC-134a.

HFC-134a is not flammable in air at temperatures up to 212 deg F. That happens to
be one of the features of HFC-134a.  On the otherhand, Duracool which is a blend
of LPG is highly flammable. With Duracool, flammable air-vapor mixtures may form
if allowed the mixture leaks to atmosphere. Accumulation of Duracool gas is an
ignition hazard. Vapours are heavier than air and may travel to an ignition
source. A static discharge will ignite this mixture.

HFC-134a is not an ozone depleting chemical. It is a greenhouse gas like the CO2
coming out of the tailpipe. Assuming the vehicle is not leaking, there should be
no emissions of HFC-134a from a vehicle. On the other hand, vehicles always have
continuous emissions of CO2. This is a bogus arguement to recommend Duracool over
HFC-134a.

HFC-134a is not carcinogenic at levels of less than 10,000 ppm (1 per cent)
and an exposure duration of 2 years. For you greenhouse advocates, 10,000
ppm is about 30 times the concentration of CO2 in the atmosphere. And the normal
oxygen concentration in the atmosphere is 15 percent. None of the
components present in this HFC-134a material at concentrations equal to or
greater than 0.1% are listed by IARC, NTP, OSHA or ACGIH as a
carcinogen.

ACGIH has no established exposure limits for HC-134a, but has an exposure
limit of 800 ppm for Duracool. ACGIH is an industrial hygienist organization
which obviously considers Duracool to be more toxic than HC-134a.

Duracool's MSDS has this warning: "Use only in well ventilated situations or
employ extraction ventilation to maintain atmospheric concentrations well
below exposure standards. All mechanical equipment used in ventilation
systems should be spark proof."

Why use Duracool? It is more hazardous than HFC-134a, it is more expensive than
HFC-134a, it is not a recommended refrigerant by BMW, and it is illegal (federal
law) to use as a replacement for R-12 in the US.

MSDS sheets: http://www.duracool.com/msds.html
http://www.dupont.com/msds/40_37_2188fr.html

The flammablity issues are discussed in this position paper:
http://www3.gov.ab.ca/hre/whs/publications/pdf/ch058.pdf

Tom Mathews
Not employed by Duracool or Dupont

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