Flashcards in Chapter 13 Relay Pumping Operations Deck (24)
What is the maximum distance relay method?
A method that involves flowing a predetermined volume of water for the maximum distance that it can be pumped through a particular hose lay
All fire department pumpers are rated to flow their maximum volume at:
150 psi (1 000 kPa).
All fire department pumpers are rated to flow 70 percent of their maximum volume at:
200 psi (1 350 kPa).
All fire department pumpers are rated to flow 50 percent of their maximum volume at:
250 psi (1 700 kPa).
A relay pumping operation always begins with the:
As a rule, ___ should be used at the source.
the largest capacity pumper
If the relay is being supplied from draft, the ___ will have to develop a higher net pump discharge pressure than the other pumpers in the relay.
Failure to keep water moving through the pump could result in ___, thus delaying the operation.
loss of prime
The relay pumper should be waiting for water with the dump line or discharge ___ and the pump out of gear.
If the waiting period for receiving water from the source pumper or another relay pumper is only going to be a few minutes, the pump on the waiting pumper may be ___ before receiving the water.
Sometimes the relay can be started, or the hoselines filled, with water from the:
apparatus water tank.
It is most desirable to maintain an intake pressure of:
20 to 30 psi (150 kPa to 200 kPa).
If the relay pumper is receiving an intake pressure greater than ___, the valve to the dump line on the relay pumper must be adjusted to limit residual pressure to this maximum.
50 psi (350 kPa)
When water reaches the attack pumper, the operator should:
bleed air from the line.
Once the relay is in operation and the water is moving, all pump operators set their ___ to an appropriate level.
automatic pressure control devices
If equipped with the newest and most sensitive pressure governors, the attack pumper should be set in the ___ mode while all others in the relay should be set in the ___ mode.
If the intake relief valve is readily adjustable, it should be set to discharge at ___ above the static pressure of the water system it is attached to or above discharge pressure of the previous pumper in the relay.
10 psi (70 kPa)
At no time should the relief valve be set for a higher amount than the safe working pressure of the:
If the attack pumper is equipped with a readily adjustable intake relief valve, it should be set between ___ to establish a stable operating condition.
50 to 75 psi (350 kPa to 525 kPa)
Small variations in pressure are not significant and as long as the intake relay pumper does not drop below 10 psi (70 kPa) or increase above ___, no attempt should be made to maintain exact pressures.
100 psi (700 kPa)
Radios must be used ___ so as not to hamper fire fighting activities and efforts to establish water supply.
When pumpers are within sight of each other:
hand signals can be used.
Relay operations should be shut down first from the: