The Difference Between Gauge and Absolute Pressure
There are different ways to measure pressure, which is the applied force to an object or area. Two of the most common pressure measurements are gauge and absolute, but there’s often some confusion about the difference between the two.
Gauge Pressure (PSIG)
Gauge pressure is the difference between absolute pressure and atmospheric pressure. If the gauge pressure is above the atmospheric pressure, it’s positive. If the gauge pressure is below the atmospheric pressure, it’s negative. Since gauge pressure readings include atmospheric pressure, gauge pressure can differ depending on weather and sea level. If you’re measuring pressure in an environment that won’t be heavily affected by the atmosphere, you can measure in pounds per square inch gauge (PSIG).
Absolute Pressure (PSIA)
Absolute pressure is gauge pressure plus atmospheric pressure. An absolute pressure reading of zero can only be achieved in a perfect vacuum and only naturally occurs in outer space. If you want to measure pressure in an environment where the atmospheric pressure is constantly changing, you’ll want to measure in pounds per square inch absolute (PSIA). One of the most common uses of absolute pressure measurements is to understand and predict weather patterns. Absolute pressure measurements are also used in food packaging, aeronautical equipment, and gas analysis systems.
Tools for Measuring Pressure
Measuring the wrong pressure can lead to substantial data errors, so it’s essential to purchase the right equipment to measure pressure effectively. Whether you’re working in an industry that measures gauge pressure or absolute pressure, MadgeTech has various data loggers to measure PSIA and PSIG, such as the PR1000 data logger with an NPT fitting. The PR1000 is compact, submersible, and available in 10 measurements ranging from 30 to 5000 PSI.
The PR1000 is compatible with the latest MadgeTech 4 software, allowing for simple data downloads and easy analysis.