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Gas pressure

In round numbers atmospheric pressure is 30 inches (of mercury in a
barometer) and is also 15 psi (pounds per square inch). Hence gas
pressure that is 10 inches is about 5 psi. In round numbers, we can
think 2 inches per psi. So gas pressure that has been reduced by
regulator to 2 psi is about 4 inches (of mercury).

To put this into perspective, for my Smith Little Torch, I run my
acetylene at 2 psi and my oxygen at 5 psi.


Wrong! as it applies to gas pressure. The inches mentioned are water
column not mercury. 1 atmosphere is roughly 34 feet of water.
Therefore 11 inches of water column is about 1/2 Psig . All
roughly but good enough for everday.


Natural Gas and LP (propane) is measured in inches of _water
column, not mercury! Vacums are measured in inches or mm of mercury.
There is approx 14- 15 inches of water column in1/2 psi . A household
regulator at the gas meter should not deliver more than 1/2psi under
load, for safety reasons. And even commericial services run 2 to 5
psi in high usage industrial plants.

Dan Wellman