What pressure is indicated when measuring 0 PSIG?

When a measurement indicates 0 PSIG (pounds per square inch gauge), it means that the pressure being measured is equal to the atmospheric pressure. Therefore, the pressure indicated is actually 14.7 PSI, which is the standard atmospheric pressure at sea level. PSIG does not account for atmospheric pressure; instead, it measures pressure relative to the surrounding atmosphere.

Thus, when a gauge reads 0 PSIG, it is indicating that the pressure is neither above nor below atmospheric pressure. Since standard atmospheric pressure is approximately 14.7 PSI, this represents the baseline for understanding gauge pressure measurements. This is why the answer reflects 14.7 PSI, highlighting the relationship between gauge pressure and atmospheric pressure.