During a fire pump test, which instrument is commonly used to determine the flow reading?

• A. Tachometer
• B. Pitot gauge
• C. Hydrometer
• D. Multimeter

Answer: (B)

In a fire pump test, you need to know how much water the pump is moving, which comes from how fast the water is flowing in the discharge line and the pipe’s cross-sectional area. A Pitot gauge (Pitot tube) measures the velocity pressure of the flowing water, from which you can calculate the water velocity. Once you have the velocity and the pipe area, you can determine the volumetric flow rate. This method is practical for field testing and directly relates to flow, which is why it’s the best choice for determining the flow reading.

Tachometers measure rotational speed, not how much water is moving. Hydrometers check liquid density, not flow. Multimeters measure electrical properties, not hydraulic flow.