Quote:
Originally Posted by jimmy o
You go not have to worry about storing propane tank in garage or lanai or anywhere else. I don’t know what people are talking about this 120 degree stuff, but for propane to ignite without ignition source the temp would need to be about one thousand degrees. Gasoline is way more dangerous and that ignition point is about 500. Are you worried about leaving you far in the garage? Of course not, stop worrying about nothing.
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This post is wrong on many points. I will try to state what the issues and concerns are for storing combustible material.
1. Never store material that can create explosive mixtures in enclosed spaces. Propane tanks can leak and have pressure relief valves that relieve when the internal pressure reaches the pressure relief valve setting. Without researching tank designs for transport companies, 120F propane will have a vapor pressure of about 250 psig which I believe is a typical setpoint for the Propane tank. So this makes sense from a tank design standpoint.
2. The temperatures you quoted of autoignition temperatures without a source of ignition of 1000F for propane and 500F for gasoline are directionally correct for autoignition. However it is totally misleading in that all garages have potential sources of ignition besides open flame. Light switches, and garage door openers are examples of sources of ignition in past explosions. Autoignition is not the issue since the place is already on fire.
3. The key property to worry about is flashpoint temperature. Flashpoint T for gasoline is ~45F while propane is -150F. So both propane and gasoline fumes can form explosive mixtures in enclosed spaces and should be avoided. Ideally, store both portable gasoline containers and propane tanks outside in a shaded well ventilated situation. Your car is a different story. You want to store it in your garage. Pay attention to any spills or leaks and ventilate if necessary. It is a much smaller risk in my estimation. The potential for gasoline leaks is smaller and the amount leaked should be less. It is an accepted practice by Fire Officials and Insurance Companies.