pressure

Pressure measurements quantify the amount of force per unit of area, usually to describe constant forces on a surface or within a volume. The standard unit of pressure is a pascal (Pa), and the standard atmosphere is defined as 101325 Pa.

Data fields in this category can describe either absolute pressure relative to a vacuum, or differential pressure measured as the deviation from a benchmark (the benchmark usually being the amount of pressure in the surrounding area).

An absolute pressure uses a vacuum as its zero reference. A differential pressure can be zero even when both spaces contain pressurized air, because their pressures are equal.