Closed Relay Pumping

Personnel Required

  • 4 - 6 crew per appliance

Equipment required

  • 2 appliances closely matched in pump capacity
  • Tanker A + delivery hoses (65mm + 38mm)
  • Tanker B + suction lengths + strainer + 65mm delivery
  • Personal protection clothing

This technique is valuable because it allows provision of uninterrupted water delivery at the fire front. It can allow service on high ground when the water source is lower down the hill or distant from the tanker. The pump operators need to synchronise the relay carefully by the use of fireground radio.

Warning: Close operator co-ordination is vital.



If poor, it can result in excessive pressure and possible damage to relay hose and/or pumps parts. A typical scenario would be:

Non - Relay Operation

Tanker A arrives at the firefront and begins hose operations. His valve 2 is open together with output valves as necessary to support the hoses in use. To avoid leaving the firefront to refill, Relay Pumping is declared.

Start Relay Operation

AT TANKER B The operator locates at a water source and runs a 68mm hose to Tanker A. He drafts water via Valves 1, 4 to supply pressure to Tanker A. He needs to adjust Valve 4 position and pump speed to accommodate Tanker A's radio calls. If Tanker B supplies excess pressure due to Tanker A not being ready to accept it, then hose damage could result. The 68 mm hose provides a visual indication of the state of the relay (hard/soft/collapsed).

AT TANKER A The operator opens Valve 1 and closes Valve 2 to supply his hoses with Tanker B water. Since Tanker A tank is partially depleted, Tanker A Valve 3 is partially opened sufficient to accept water into his tank to refill it whilst still supplying pressure to Tanker A hoses.

Stop Relay Operation

AT TANKER A When the operator no longer needs supply from Tanker B, he radios for water off. When incoming water pressure reduces, the operator closes Valve 1 (and opens Valve 2 etc).

AT TANKER B The operator closes Valves 1 and 4 and idles the pump. He will also use Valve 3 to ensure his tank remains full.