What gauge is primarily used for hydrant flow testing?

The Pitot gauge is specifically designed for measuring the flow of water in hydrants. It is used to assess the velocity of the water as it exits the hydrant, which in turn helps to determine the flow rate. When conducting hydrant flow tests, the Pitot gauge is inserted into the water stream flowing from the nozzle of the hydrant. By measuring the velocity pressure, the operator can calculate the flow rate using specific formulas or charts. This measurement is critical for understanding fire protection capabilities in an area and for ensuring that hydrants are functioning properly.

Other instruments, while useful for various measurements, do not specialize in this specific application. Pressure gauges are used to measure static pressure, which does not provide flow rate information, and flow meters are typically more complex devices used in various systems rather than for single-point hydrant testing. Piezometers measure the height of water in a column, which is also not applicable for flow measurement in hydrant tests. Thus, the Pitot gauge is the correct choice for this specific purpose.