Gauge Pressure

Gauge pressure measures the pressure of a fluid (liquid or gas) in a system relative to atmospheric pressure—the pressure of the surrounding air. It indicates whether the pressure inside a container or pipe is higher or lower than the air pressure outside. If the gauge pressure is positive, there’s more pressure inside than outside; if negative, there’s less. It’s commonly used in devices like tire pressure gauges, which show the pressure compared to atmospheric pressure, providing essential information for safety and performance without needing to account for atmospheric variations.