20# propane tank

I believe propane tanks have a " pop out" that releases pressure . Many years ago I went around the State of Florida visiting fire depts , I taught courses in " Propane ". We traveled with a very large propane tank on a trailer . We would assemble a crowd of firefighters from several fire depts . We would place a large propane burner under the tank and light her off . The crowd would gasp and back up , waiting for the explosion ! After several minutes the pop off would blow and was usually ignited by the lower flame . The pop off flame lasted a second or two and then all was well again . As far as a twenty pound tank blowing and being thrown many feet away , well the propane may not have any thing to do with it . As said above any sealed container will blow in a fire . As any firefighter who works where there are a lot of boat fires will tell you , one of the scariest things with a yacht fire is all of the **** fire extinguishers blow up and flying thru the air !