2 Answers

psi is pound per square inch pressure

psia is pound per square inch absolute (in respect to absolute vacuum)

psig is pound per square inch gage (indicated differential pressure between ambient pressure and the measured pressure)

14 years ago. Rating: 0
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PSIA is pounds per square inch absolute it includes atmospheric pressure.

PSIG is the reading you get on a gauge and is atmospheric pressure (14.7 psi) less.

PSI is just pounds per square inch and it is appropriate to use this when one is talking about pressure difference.

14 years ago. Rating: 0
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