Personally, I have to respectfully disagree. And the why.
For quite a few of us those hoses aren't anywhere near the manifolds and the manifolds don't run hot enough to ignite squat unless something is misfiring or seriously awry. I have never measured hotter than 900F manifold temps when running excessively hard even when racing late model dirt track engines, and exhaust gas itself burns at around 300-1200F depending on hard use. Turbo manifolds are a different story, I don't think I would take the chance with a hard run turbo engine.
R134a has a rated ignition temp of about 1400F, but for whatever reason it's not labeled as flammable. I suspect it's not rated flammable as at atmospheric pressure it is indeed not flammable. The problem is when R134a is being used at the pressure it's designed to be used, it is indeed flammable. The only difference with ES12 is it is both flammable at atmospheric pressures and compressed pressures, but for both instances it's flammability is temp is still higher than R134a so I still don't see the big deal. And considering it runs at much lower pressures than R134 there is a much lower probability of anything being blown anyway. So unless someone is planning on taking a propane torch or blow torch to a line, I don't think there's going to be any issue.
The EPA was overly paranoid in not approving the stuff because they were being lobbied against approving it by GM, Ford, who obviously didn't want any liable cases on their hands. On one hand I can understand it, but my profession as a catastrophic auto accident litigation guy I see the most horrible auto wrecks imaginable. In those wrecks with semi trucks plowing through a small SUVs and the like, R134 explodes at times albeit rarely, and the fire is out before anyone knew it ever started, the stuff literally vanishes extremely quick when lit. Still, that's all it takes at times.
Both have their cruxes, and it's arguable which is worse. Still, it takes a freak occurance or outright stupidity for either to be overly dangerous. Personally, I'm more fearful of having 20 gallons of gasoline strapped while driving to my back than this haha.
Just my 2c
It should be noted that the various EPA type of organizations in several other countries have approved the stuff, Australia, Korea, Japan being the largest.
Last edited by ferraripilot; 07-09-2013 at 02:59 PM.