What does PSIG refer to?

PSIG stands for Pounds per Square Inch Gauge, which refers to the measurement of pressure relative to atmospheric pressure. When pressure is stated in PSIG, it indicates how much pressure exists in a system above atmospheric pressure, which is crucial in many applications including refrigeration and HVAC systems.

Using gauge pressure is important because it allows technicians to understand how much pressure is being applied in comparison to the surrounding environment. This measurement plays a significant role in system performance and safety checks, as you need to ensure that the pressures within a system are within recommended limits to avoid failures or hazards.

The other options mention different forms of pressure but do not accurately reflect the specific meaning of PSIG. Pounds per square inch absolute refers to total pressure, including atmospheric pressure, which is not what PSIG measures. Pounds per square inch gas is not a standard term in pressure measurement, and Pounds per square inch average does not convey a recognized concept in this context. Thus, the term PSIG is distinctly defined by its focus on gauge pressure above atmospheric conditions.