I'm no physics major, but I think warming up a 0 degree or so pressurized container too fast may cause the expansion to happen too quickly, also. I know a co-worker of mine had to warm up a cylinder of refrigerant in order to get it to charge a small outdoor condensing unit on a late-night call out. He took the can to one of the deep sinks in the bakery dept., filled a deep sink up with HOT water, (grocery stores keep their water hotter than we do at home) and placed the 50# sized cylinder in the sink and it blew the pressure-relief, in his words, almost instantly! Gosh almighty I wish I had been there to see Mr. Almighty's gift to the Steamfitters' refrigeration servicemen's look on his face! (This dude had one arm longer than the other so he could pat himself on the back.) But, I believe the sudden temp. rise had a lot to do with this "accident".