MAP gas cylinder drop and bending incidents

30-thousandths steel can't fail by overpressure (safety factor enormous, ~7×) — fails by abuse: torquing off with 80 ft-lb bar bends it; plumber-with-cigar incident; throw-it-on-the-ground crack initiation at 25–30° bend.

Another reason for bulking up safety factors: MAP gas cylinders. [Tom holds up a MAP gas cylinder.] These are one pound — they have about one pound of gas. It's okay to store them indoors. It's not okay to store a 20-pound cylinder, like on your gas grill, indoors. Does anybody know why you can store these indoors and you can't store the 20-pound propane indoors? If this leaks in a room 10 by 10, a thousand cubic feet, I could throw this across the room — burst it open — and you might burn up that corner of the room. Anyone standing there would be burned fairly badly, but I wouldn't be burned 10 feet away. You might blow the windows out from overpressure, but there's not enough gas in this to blow up the whole room. With a 20-pound cylinder you could have an explosion that would blow up the whole building.