What type of measurement does a pressure gauge provide?

A pressure gauge primarily measures relative pressure, which is the pressure of a fluid compared to the surrounding atmospheric pressure. This type of measurement is widely used in various applications, such as in HVAC systems or industrial settings, where it is essential to know how the pressure of the fluid being measured compares to the ambient air pressure.

Relative pressure gauges are designed to zero out the atmospheric pressure at sea level, thus providing readings that reflect only the pressure above or below this reference point. This is extremely useful for determining if a system is operating within safe or effective pressure ranges.

While absolute pressure gauges provide measurements relative to a perfect vacuum, vacuum pressure gauges measure pressures below atmospheric pressure, and hydraulic pressure pertains to systems operating under hydraulic fluids, the concept of relative pressure is most commonly associated with general pressure measurements in everyday applications.