What is a relay pump operation?

• A. A hydraulics technique where multiple pumpers relay water to maintain required discharge pressure when the source cannot supply enough water.
• B. A method to test pump performance using only one engine.
• C. A plan to drain the system to reduce pressure.
• D. A technique to increase pressure by using a booster pump on a single unit.

Answer: (D)

Relay pump operation means coordinating several pumpers along a water supply line to move water from a source to the fire while maintaining the required discharge pressure. Each engine picks up the boost from the previous one and re-pressurizes the water so the line remains full and the nozzle receives a steady flow. This approach makes it possible to reach a fire when the initial source can’t provide enough volume or pressure on its own, by splitting the workload and compensating for friction losses along the hose lay. The emphasis is on teamwork between engines and keeping the line pressurized to the needed nozzle pressure as water travels toward the fire.

The concept described as using a booster on a single unit to increase pressure does not accomplish relay pumping. That method enhances pressure for one engine rather than relaying water from multiple engines to extend reach and maintain pressure over distance.