Vapor pressure at 86 deg F:

Propane - 166 psi
Butane - 41 psi

Construction of typical camping gas cylinders suggest contents is
primarily Butane, with a skoche of Propane to keep some positive
pressure in the cylinder at or near freezing temps.

Propane tank safety valves are designed to vent at circa 300 psi, IIRC.

800 psi seems unlikely. Hope this helps.

Jack
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist