21 October 2021

Difference between PSI and PSIG

What is PSI?

PSI is a per square inch, it is a common pressure measurement unit used in a variety of applications. It is commonly used for non-SI industrial and technical purposes such as there pressure, fuel storage, and distribution. wastewater management, and test and measurement, among many others.

What is PSIG?

PSIG is the gauge pressure, which is expressed in pounds per square inch gauge. It is a pressure unit that is measured relation to the ambient or atmospheric pressure. It is the measurement of pressure without taking into account local atmospheric pressure. When the pressure inside the system exceeds the atmospheric pressure, the gauge pressure is applied. And atmospheric pressure is the pressure exerted by the weight of the atmosphere, or more simply the pressure within the earth's atmosphere.

Difference between PSI and PSIG:

  • PSI stands for pounds per square inch, while PSIG stands for pound per square inch gauge.
  • PSI is the force applied on a surface with one square inch of the area, while the PSI gauge is a measure of pressure, but a gauge measure only.
  • PSI is mostly used in wastewater management, fuel storage and distribution, tire pressure and so on, while the PSIG is mostly used in the refrigeration and air conditioning industry.
  • PSI can be changed to a various unit that is used to measure pressure, while the PSIG specifies that pressure is a measure relative to the atmospheric pressure only.
  • PSI is a measure relative to a vacuum, while the PSIG is a measure relative to the atmospheric pressure.