I don't want to start an off topic debate but the following might be relevant to some here. Our local pub has a large kitchen and the chefs often use disposble blow torch setups (creme brulee and such) the cans of butane are around a litre in volume. Yesterday the main chef came running out of the litchen shouting gas and them boom. He'd apparantly turned the torch off but managed to leave gas escaping, went off the other section to do somethign else without realising. I saw the aftermath first hand (my daughter works there) and I would NEVER have believed the destruction one little can of butane could acheive. The windows including the frames were blown clean out of two wall the lath and plaster ceilings blown up and out. One ancient oak structural beam lifted out and the tile roof on the floor above completely destroyed, tiles everywhere. The living room at the upstairs front of the pub has a huge crack in the brick wall top to bottom. All the equipment in the lvery large kitchen totalled. I 've always treated those compact torches as toys but my view on them has now changed dramatically!