Absolute pressure is typically stated in what unit?

Absolute pressure is typically expressed in PSIA (Pounds per Square Inch Absolute) because this unit accounts for the total pressure exerted by a fluid, including atmospheric pressure. It provides a measure of pressure relative to a vacuum, meaning that it starts at zero pressure in a vacuum environment. This makes it particularly useful in fields such as engineering and meteorology, where understanding the full impact of pressure is crucial.

In contrast, the other units are often used to measure pressure in specific contexts but do not account for atmospheric pressure. PSIG (Pounds per Square Inch Gauge) is a measure that indicates pressure relative to atmospheric pressure, whereas Bar and Torr are metric units that also define pressure but do not specifically signify absolute pressure unless noted as such (for example, in terms of BarA or TorrA). Hence, PSIA is the most appropriate unit for expressing absolute pressure.