Explain relay pumping.

• A. Linking two or more pumps in sequence to move water from a distant source to the incident.
• B. Using a single pump from a hydrant to a nearby attack line.
• C. Running a pump in parallel to increase flow to a single discharge.
• D. Drawing water from a hydrant and storing it in a portable tank.

Answer: (A)

Relay pumping is the practice of linking two or more pumps in series to move water from a distant source to the incident, adding pressure with each pump to overcome distance and friction losses. Water is drawn from the source into the first pump, its discharge feeds the next pump’s suction, and so on, until the water reaches the attack line at the needed pressure. This approach lets you use supplies that wouldn’t have enough pressure on their own or that are far away, by progressively boosting head along the way.

The other scenarios describe different methods. A single pump from a hydrant to a nearby attack line provides direct supply without relaying the water along a series. Running pumps in parallel increases the total flow to a single discharge, not the pressure along a supply line. Drawing water from a hydrant into a portable tank is drafting or a water shuttle operation, not relay pumping.