Relay Pumping

A relay keeps water moving across distance by handing pressure pump to pump — each engine only has to beat the hose to the next one, not the whole lay. The mental switch: you're pumping to an intake gauge, not a nozzle.

Supply hose diameter (in)

Supply hose length (ft)

Flow (GPM)

Intake target at next pump (psi)

Blank uses the training floor (20 psi). Some departments specify 50 psi for high-demand relays.

Elevation change to next pump (ft)

Positive uphill, negative downhill. Blank means level.

Total relay distance (ft) — optional

Fill in to plan how many pumpers the relay needs.

Current intake reading (psi) — optional

Reading on the receiving engine's intake gauge right now — checked against the bands below.

Enter values above to see the result.

Intake pressure bands (receiving engine)

Intake reading	Status
≥ 30 psi	Above the floor
20 to < 30 psi	Approaching the floor
< 20 psi	Below the floor

Below the floor, the source side of the receiving pump can cavitate — call for more pressure before the gauge gets there.