Which is completely missing the point. To hotbox a room you need a bunch of the big cylinders. Look at the tare weights on page 3: https://www.airgas.com/med

Which is completely missing the point. To hotbox a room you need a bunch of the big cylinders. Look at the tare weights on page 3: https://www.airgas.com/medias/Airgas-Compressed-Gas-Cylinders-MCM-552.pdf https://www.airgas.com/medias/Airgas-Compressed-Gas-Cylinder... The have a volume in cubic feet specified, multiply by the 165 bar that's what's typically used to see how much space it will fill. Looking around our house there's a very odd-shaped closet under the stairs that would be difficult to measure. Of the more typical places the smallest room in the house is a closet. 6' x 5' (minus a 1' x 1' chunk that I believe contains an air duct) x 8' = 232 cubic feet. Suppose you dump 232 cubic feet of material into it--you'll displace half the air which gives a time of useful consciousness of 20-30 minutes. Not good enough. Let's try doubling that, now we end up with a time of useful consciousness of 30-60 seconds. That's probably enough. That's 2 cylinders at 137 pounds each. Or if you use aluminum, 3 cylinders of 90 pounds each.