In what unit is the capacity of a safety valve measured?

The capacity of a safety valve is measured in pounds of steam per hour. This is because safety valves are primarily used in systems that deal with steam, such as boilers and pressure vessels, to ensure that excess pressure is released safely. The measurement is focused on the amount of steam that can safely pass through the valve in an hour, which is crucial for maintaining the integrity and safety of pressurized systems. Safety valves are designed to operate based on steam pressure, and understanding their capacity in terms of steam flow helps in the proper sizing and selection of the valve for specific applications.

Other measurements, such as pounds of water, gas, or oil per hour, are not suitable for safety valves as they may be designed for different applications or types of fluid, thereby not reflecting the essential function of the valve in steam-producing and high-pressure environments.