Whoa! Thanks for bringing this to our attention! Yikes, I didn't think Redtek R12a was a propane/butane mix, but after researching a bit more on these alkane refrigerants, I'm worried there's going to be a cabin kaboom.
I wouldn't think that they could sell something like this which could be potentially hazardous. I'm very shocked to find this out. I guess in the end, it's buyer/installer beware. From what I read, R134a can also be flammable as well. If other people want to try this R12a drop-in charge, maybe it's best not to smoke in the car and to open the windows a little. I don't know if a leak could let enough R12a into a closed cabin to explode.
After reading up on R12a, I don't know if I can recommend it to anyone now.
On one hand, I'm happy as heck to have cold AC after 10 years of sweating it in the summertime, but on the other hand, I'd hate to see someone else try this out and have an accident.
Here's an excerpt from a page I found on R12a safety. It's quite long so be warned.
Automotive Air Conditioning
Some time ago I mentioned a new refrigerant that we heard about from a Manitoba visitor to our web site. The following is in answer to the query for further information. John Stephenson is the secretary of the Durham Electric Vehicle Association.
Re your question in the SVAO Newsletter, and our recent conversation.
R12a is what is called a 'natural refrigerant' because it is a mixture of stable organic compounds, which have been around forever (?). It is a mixture of stable hydrocarbons to which the name 'paraffin's' was given in the early days of the study of Organic Chemistry. The mixture consists of approx. 40% butane, 59% propane and 1% ethane. Note that these materials are said to be 'highly purified' in order to use them as a refrigerant. You should not try to mix these materials out of a standard cylinder and expect that the air conditioning system will work perfectly.
It is well known that ethane, propane and butane are flammable in air and, when mixed in certain proportions with air, will burn with explosive speed. Nevertheless, propane and butane were used as refrigerants, along with ammonia, carbon dioxide, and sulphur dioxide, before the development and commercial use of freons in the early 1930's. It was an explosion involving propane in a school air conditioning system, which resulted in the death of a number of students, which lead to the banning of the 'natural' (flammable) refrigerants, in favour of the 'freons' in North America. At that time, the damaging environmental properties of the freons were not even imagined. As a family of products they were considered to be unreactive, non-toxic, non-flammable, i.e. the perfect refrigerants.
In the late 1970's the environmental effects of the freons began to be known and understood. They are, as a group, very damaging to the stratospheric ozone layer, and very strong global warming agents. As a result of the damage done to the stratospheric ozone layer, the freons, known as the cfc's or chloro-fluoro-carbons, have been banned by international treaty (although still available if you know where to buy them!). The fact that they are very strong global warming agents is less well known, and to some extent the chemical manufacturers have tried to keep this a dark secret.
The chemical manufacturers have introduced new compounds of the freon type to replace the banned
cfc's. The new compounds are hydro-chloro-fluoro-carbons (hcfc's) and hydro-fluoro-carbons (hfc's).
The hcfc's are in the process of being banned because they still affect the ozone layer (at about 5% or less, than the cfc's) and because they are strong global warming agents. The hfc's have no adverse effects on the ozone layer, but are still very strong global warming agents. There is one other group that must be mentioned - the per-fluoro-carbons, which are extremely stable compounds (have long lifetimes in the atmoshpere) and are strong global warming agents.
The following table summarizes the ozone depleting and global warming characteristics of the common refrigerants, with the 'natural' hydrocarbon refrigerants included for comparison:
Note: Global warming potential is calculated by using carbon dioxide =1 (i.e you can compare the effect of releasing 1 tonne of the various agents). Also, the lifetime of the various agents in the atmosphere has to be taken into account. For this reason the global warming potential (GWP) is calculated for time horizons of 20 years, 100 years and 500 years. Thus the GWP for an agent which has a short lifetime in the atmosphere will be at its highest when averaged over the 20 year Horizon and an agent with a long lifetime will be highest when averaged over the 500 year Horizon. In general, we are most immediately concerned with the 20 year time horizon, because it affects the most immediate future of the planet.
Refrigerant Ozone depletion Global Warming Potential
20 yr 100 yr 500 yr
Carbon Dioxide No
R12 Very strong 7,800 8,100 4,200
R11 Very strong 4,900 3,800 1,400
R134a 0.05 3,400 1,300 420
R12a No 8 0 0
Per fluoro-methane No 4,400 6,500 10,000
(Source International Panel on Climate Change 1994)
R134a is the currently used substitute for R12 in automobile air conditioning systems. R134a is a very good cleaning agent - it will remove deposited gums in the interior of the system. It is also very acidic if moisture is allowed into a system, and it needs special lubricants, because it is not compatible with the lubricant used in R12 systems. On the other hand,
R12a is a direct drop-in replacement for both R12 and R134a systems.
Because R134a is a strong global warming agent the government has decreed that all refrigeration systems must be built to 'contain' the refrigerant, for the lifetime of the system, i.e. the system must not leak. However it is by no means certain that this requirement is being met in current automotive systems. Conversely, it must be true that if a system will contain a freon, then it will also contain a 'natural' refrigerant.
The table (above ) illustrates the environmental benefits of using R12a. However it must never be forgotten that it is a very flammable refrigerant - although I personally know of no cases where R12a has been associated with a fire in an automobile - even as the result of a crash. There are three or more possible reasons for this:
1) the weight of refrigerant charged into the average automobile system is only about 12 to 16 ozs.
2) In the event of a sudden release of refrigerant only about half of the charge is released - the rest is retained for a short time in the oil in the system.
3) In the event of a slow release, the gas is heavy and will sink towards the ground where usually it will dissipate without problems.
However, it is extremely important that the air conditioning system be clearly labeled that it contains a flammable refrigerant. Many refrigerant technicians are not conversant with the properties of R12a - the name is too close to R12 to be comfortable (for me) - I think that this may lead to an accident.
Finally, although propane is used in Europe in many refrigeration type appliances, its use on this continent is being resisted by the freon manufacturers, and the current Canadian Standard (B52-95 Mechanical Refrigeration Code) is deficient in its treatment of flammable refrigerants. That is to say that its use may not be properly covered by insurance companies on the grounds that it is a flammable refrigerant.