How do you convert 181 PSIG to PSIA?

To convert from pounds per square inch gauge (PSIG) to pounds per square inch absolute (PSIA), it is necessary to understand the difference between these two measurements. PSIG measures pressure relative to atmospheric pressure, whereas PSIA measures pressure relative to a perfect vacuum, which effectively means it includes the atmospheric pressure in its calculation.

Since atmospheric pressure is approximately 14.7 psi at sea level, to convert PSIG to PSIA, you need to add this value to the gauge pressure. In this case, when converting 181 PSIG to PSIA, you add the atmospheric pressure:

181 PSIG + 14.7 psi = 195.7 PSIA.

This increase in value reflects that PSIA is always higher than PSIG by the amount of atmospheric pressure. Thus, choosing to add 14.7 to the PSIG value accurately provides the absolute pressure in PSIA.