What does ‘a’ in psia mean?

What does ‘a’ in psia mean? Correct Answer Pressure is measured above absolute zero

All the units in NPSH are psi units. The psi units are kilopascal, bar, pounds per square inch etc. The ‘a’ in psia indicates that the pressure is measured above absolute zero which is a perfect vacuum.

Related Questions

Two statement are given as below I: 35 psia = 71.24 in Hg II: Barometer is used for the measurement of vacuum pressure
25 psia is equal to
40 psia equals