Don Foreman wrote:

On Wed, 23 Jun 2010 09:48:02 -0700, Winston
wrote:

15 PSIG distributed under a 22" diameter drum lid is
~5700 lbs of force.

http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

Any of these is likely to be far less dramatic
than pressurizing the drum.

--Winston

But you don't need nearly that much pressure. A 55 gal drum is about
35" high. 35" of water is a head of 1.26 PSIG. Oils have lower
specific gravity than water so will have less head for given height.

I plan to use a scheme like this for fuel transfer. No motors, no
sparks. The air reservoir will be an old fire extinguisher
pressurized to 120 PSIG, with a propane regulator set to about 1.5
PSIG.

What happens with a 5 gallon jerrycan with 1.5 PSIG inside? Well, the
vapor pressure of "summer" gasoline varies about 3.5 PSI from 50F to
90F, so a jerrycan certainly can handle 3.5 PSIG without problem.

http://www.harborfreight.com/12-gpm-...ump-93755.html

Has 10psi relief valve, so presumably a standard 55 gal drum can handle
10psi.