Chapter 12 Flashcards
a factor in determining the need for relay pumping operations?
Distance between incident scene and the water source
Attack pumpers equipped with an adjustable intake relief valve should be set
between 50 and 75 psi (350 and 525 kPa) to establish a stable operating condition
When the source and relay pumpers are ready, the discharge supplying the hoseline on the source pumper is:
opened while the valve on the dump line is closed.
The driver/operator of the attack pumper should not attempt to correct minor fluctuations as long as the intake pressure:
does not drop below 20 psi
Pressure relief valves reduce the possibility of damage to the pump and other water supply components that may be caused by water hammer when valves are operated too quickly or:
intake pressures rise dramatically.
When would a discharge manifold be used to break down the large diameter hose (LDH) into two or more hoselines that may then be connected to different pumpers?
During LDH relay operations that must supply more than one attack pumper
When drafting from a static source, the source pumper
may need to develop a higher pump discharge pressure than other pumpers in the relay operation
Which of the following may be of smaller capacity due to its ability to use acquired energy of previous pumpers in the relay?
Relay pumper
When large diameter hose (LDH) is used in relay operations:
the LDH often requires only one supply line to meet fireground requirements.
Which of the following takes water from a hydrant or static source at the beginning of a relay operation?
Eliminates pressure surges and inconsistent supply
Putting a relay into operation begins with
the largest capacity pumper working from the water source.
is a characteristic of the open relay method?
Requires no adapters or other appliances to connect intake hoses in the system
allow later arriving pumpers to tie into the relay and boost pressure and volume after it has already started flowing, without interrupting the water supply?
Inline relay valves
Many screw-on intake pressure relief valves are also equipped with a gate valve that allows the:
water supply to the pump to be shut off.
describes the open relay method?
Consists of deploying portable folding drop tanks at each intake for pumpers in the relay operation
As a relay pumper, it is advisable for driver/operators to maintain an intake pressure of:
20 to 30 psi
Centrifugal pumps are rated to pump at their maximum volume capacity at
150 psi
The overall capacity of the relay system is determined by the:
smallest pump and the smallest diameter of hose used in the relay.
Which of the following should be the pumper with the largest pumping capacity?
Water supply pumper
When relay pumpers are equipped with an adjustable intake relief valve, one guideline is that it should be set to:
10 psi (70 kPa) above the discharge pressure of the previous pumper in the relay.
The distance of the relay is an important operational consideration because the longer the hose lay,:
the more friction loss will be encountered.
Loss of prime or overheating of the pump is MOST likely the result of:
failure to keep water moving through the pump when using a static water supply.
When pumpers in the relay operation increase their pump discharge pressure,:
a point will be reached where increased pressure will not increase volume.
Placing additional pumpers in the system will increase flow during a relay operation because it shortens the length of hose each pumper must supply and allows pumpers to:
operate at lower pressures and maximum flows within the relay operation.
receives water from the source pumper, raises the pressure, and supplies water to the next apparatus?
Relay pumper
describes the function of bleeder valves?
Allow air to bleed off as incoming supply hose is charged
hen pressure relief valves are preset to allow a predetermined amount of pressure into the fire pump and then the incoming pressure exceeds the preset level, the valve will:
open and dump excess pressure/water until water is entering the pump at the correct pressure.
When shutting down the relay, beginning with the attack pumper and coordinating with other pumpers in the relay, each driver/operator should:
slowly decrease the throttle and open the dump line valve.
Apparatus equipped with pressure governors should be set in:
pressure mode when acting as the attack pumper and rpm mode while working as a relay pumper.
When medium diameter hose (MDH) is used in relay operations, generally:
multiple hoselines are laid.
responsible for supplying attack lines and appliances required for fire suppression?
Fire attack pumper
can be done if the amount of flow through a relay operation needs to be increased?
Increase the diameter of the supply hose or the number of hoselines
When relaying long distances:
equalize spacing between pumpers as much as possible.
When need for relay pumping has ended, the operation should be discontinued:
from the fire scene first.
is a purpose of relay relief valves?
Enhance firefighter safety
statements about elevation pressure in relay operations is MOST accurate?
Elevation pressure is not affected by the amount of water being moved, only by the topography.
