What is the PSIG equivalent of 54 PSIA?

To determine the PSIG equivalent of a pressure measurement given in PSIA, it is essential to understand the relationship between these two units. PSIA (pounds per square inch absolute) measures pressure relative to a perfect vacuum, while PSIG (pounds per square inch gauge) measures pressure relative to the atmospheric pressure.

The atmospheric pressure at sea level is typically around 14.7 PSI. To convert from PSIA to PSIG, you subtract the atmospheric pressure from the absolute pressure. Therefore, in this case, to convert 54 PSIA to PSIG, you would perform the following calculation:

54 PSIA - 14.7 PSI = 39.3 PSIG

This shows that the PSIG equivalent of 54 PSIA is indeed 39.3 PSIG, confirming that this option is the correct answer. Knowing how to make this conversion is important in industrial settings where both absolute and gauge pressures are commonly used.