What is the correct sequence of pumpers in relay pumping from source to attack?

What is the correct sequence of pumpers in relay pumping from source to attack?

• A. Source Pumper -> Relay Pumper -> Attack Pumper
• B. Attack Pumper -> Relay Pumper -> Source Pumper
• C. Relay Pumper -> Source Pumper -> Attack Pumper
• D. Source Pumper -> Attack Pumper -> Relay Pumper

Answer: (A)

Water flows from the hydrant into the first pumper near the water source (the source pumper). To overcome distance and friction losses across the lay, a second pumper (the relay pumper) boosts the pressure as the water is carried farther. The final pumper, located near the fire, then takes that boosted water and delivers it through the attack line to the nozzle. This sequence—source, then relay, then attack—keeps the pressure and flow sufficient all the way to the nozzle. Choosing any other order would leave the attack pumper without adequate pressure or place the relay in a position where water can’t be boosted effectively, which is why those sequences aren’t correct.

Water flows from the hydrant into the first pumper near the water source (the source pumper). To overcome distance and friction losses across the lay, a second pumper (the relay pumper) boosts the pressure as the water is carried farther. The final pumper, located near the fire, then takes that boosted water and delivers it through the attack line to the nozzle. This sequence—source, then relay, then attack—keeps the pressure and flow sufficient all the way to the nozzle.

Choosing any other order would leave the attack pumper without adequate pressure or place the relay in a position where water can’t be boosted effectively, which is why those sequences aren’t correct.