Explain relay pumping and name two hazards associated with it.

• A. Relay pumping uses multiple pumps in series to maintain pressure; hazards include pressure surges (water hammer) and miscommunication or misalignment among pumps and valves.
• B. Relay pumping uses a single pump with automatic throttle.
• C. Relay pumping reduces water temperature.
• D. Relay pumping is only used in hydrant operations.

Answer: (A)

Relay pumping is a method where more than one pump works in sequence to push water to the fire scene at the needed pressure. The first pump draws from a water source and delivers into the intake of the downstream pump (or into a booster line), which then raises the pressure further to reach the attack engine or nozzle. This setup lets you overcome distance or elevation limits that a single pump cannot handle, by progressively boosting pressure along the supply path.

Two hazards to watch for are pressure surges, or water hammer, which can occur when pumps are started, throttled, or valves are closed too quickly and the resulting sudden pressure change stresses hoses, fittings, and equipment. The second hazard is miscommunication or misalignment among the pumps and valves, where improper timing or valve settings can cause incorrect flow, backflow, or loss of prime, potentially compromising flow or damaging components.