& Air Gauges

PSIG is an acronym stands for PSI (pounds per square inch) gauge.

We all wander around all day in a sea of air. This air has a pressure, or a force that it is exerting on everything, including our bodies, of one atmosphere, or about 14.7 PSI.

When you look at the pressure reading on the gauge, if it says 90 PSI, is that 90 PSI including or excluding the 14.7 PSI that exists all around us all the time?

air gauge

Gauge Usually Ignores Atmosphere

Recognizing that we all exist in a sea of air at around 14.7 PSI, the industrial air gauges have been adjusted to read zero at one atmosphere, ensuring that the reading you see is the actual pressure of the air in the line.

When compressed air usersare discussing air pressure, the assumption is that the pressure referred to is PSIG, and that the atmosphere is not a factor in the pressure level.

Therefore, you will hear folks talk about 90 PSI, or 120 PSI, and that is the actual compressed air pressure level in the system, and we all assume that the gauge has been factory adjusted to eliminate the force of the atmosphere.