Flashcards in Chapter 12 - Relay Pumping Operations Deck (49):
- Using two or more pumpers to move water over a long distance by operating them in series; water discharged from one pumper flows through hoses to the inlet of the next pumper and so on.
Relay Operation ( also known as Relay Pumping )
- Pumper that takes water from a hydrant or static source and pumps under pressure to the next apparatus in the relay pumping operation.
Water supply pumper
Water supply pumpers should be the apparatus with the largest ?
Some jurisdictions refer to water supply pumpers as ?
- Pumper or pumpers connected within the relay that receive water from the source pumper or another relay pumper, raises the pressure, and then supplies water to the next apparatus.
- Pumping apparatus located at the fire scene that receives water from the relay and is responsible for supplying the attack lines and appliances required for fire suppression.
Fire attack pumper
Some fire departments, especially those that have occasion to make many long hose lays, employ hose _________ to assist in relay pumping operations.
- Term used within the Incident Command System for a mobile piece of apparatus that has the primary function of supporting another operation.
ex. Water tender or fuel tender
It is possible for a hose tender to carry a mile or more of ?
large diameter hose (LDH)
- Relay supply hose of 3 1/2 to 6 inches in diameter; used to move large volumes of water quickly with a minimum number of pumpers and personnel.
Large Diameter Hose (LDH)
Basically the need for relay pumping is determined by the amount of ________ required at an incident and the __________ between the incident scene and the water source.
water / distance
If the amount of flow through a relay operation needs to be increased, depending on the size of the supply hose and fire flow requirements, at least one of three conditions must be met:
* The ___________ of the supply hose or the _________ of hoselines must be increased.
* The pump __________ __________ of the pumpers involved in the relay must be increased.
* More __________ must be added to the relay to overcome friction loss or elevation.
* diameter / number
* discharge pressure
True or False:
If pumpers in the relay operation increase their pump discharge pressure, the volume of water through the system will always increase ?
this action will not necessarily increase the volume of water
Centrifugal pumps are rated to pump at their maximum volume capacity at ______ psi at draft. When pumping at pressures higher than _____ psi, the volume capability of the pump is reduced proportionately.
150 / 150
At no time should discharge pressures exceed the pressure at which hose or appliances have been ?
Elevation pressure is not affected by the amount of water being moved only by the ____________.
Increasing flow during a relay operation may be accomplished by placing ?
additional pumpers in the system
Relay operations may use ______ to supply a low flow rate where the distance between each pumper exceeds the length of supply hose carried on each pumper.
Fire department pumpers are rated to flow their maximum volume at 150 psi, ____ percent of their maximum at 200 psi, and ____ percent of their maximum at 250 psi at draft.
70 / 50
When relaying long distances, the hose lays between each pumper should be as ?
equalized as possible
A relay pumping operation begins with the ________ ________ pumper working from the water source.
The source pumper does not have the __________ pressure at the intake that the relay pumpers receive that aids in preventing cavitation.
For their own safety and the efficient operation of the system, all personnel involved in the relay operation must understand that the overall capacity of the system is determined by the ________ pump and the _________ diameter of hose used in the relay.
smallest / smallest
Once water supply has been established, the source pumper should open a __________ or allow water to discharge through a ______ ______ until the first relay pumper is ready for water.
discharge / dump line
The relay pumper should be waiting for water with a _____ ______ or __________ open and the pump out of ______.
dump line / discharge / gear
When the source and relay pumpers are ready, the __________ supplying the hose line on the source pumper is opened while the valve on the ______ ______ is closed in a coordinated action.
discharge / dump line
- Secured hoseline that is used to handle excess water during a relay operation.
It is advisable for the D/O to maintain an intake pressure of ____ to ____ psi as a relay pumper.
20 to 30 psi
As water begins to reach each pumper, the D/O should _____ any air from the line before opening the intake valve.
- Process of releasing a liquid or gas under pressure, such as releasing air from the regulator or cylinder of a SCBA; or allowing air to escape from a hoseline before or during operations.
Once the relay operation is flowing water at the desired pressure, the D/O of the attack pumper should set the __________ ___________ at an appropriate level.
Apparatus equipped with pressure governors should be set in the _________ mode when acting as the attack pumper and in the _____ mode while working as a relay pumper.
pressure / rpm
For relay pumpers equipped with an adjustable intake relief valve, they should be set to ____ psi above the static pressure of the water supply system to which it is attached or ____ psi above the discharge pressure of the previous pumper in the relay.
10 / 10
Attack pumpers equipped with an adjustable intake relief valve should be set between ____ and ____ psi to establish a stable operating condition.
50 and 75 psi
The D/O of the attack pumper should expect small variations in __________ during relay pumping operations. You should not attempt to correct minor fluctuations as long as the intake pressure does not drop below ____ psi.
pressure / 20 psi
During long relay operations smaller capacity pumps may require higher _________ pressure as the relay operation stabilizes.
Like all fireground operations, relay pumping requires the use of effective, clear _____________ for success.
When the need for relay pumping has ended, the operation should be discontinued from the ______ _______ first.
During relay pumping operations, the ______ _______ method may be employed to provide an alternate water supply system.
Open relay method
This method consist of deploying __________ ________ ______ tanks at each intake for pumpers in the relay operation.
portable folding drop tanks
Operating from portable folding drop tanks eliminates the __________ ______ and inconsistent ________ sometimes found in closed relays.
pressure surges / supply
Open relay method:
Additionally, this method requires no _________ or other ___________ to connect intake hoses in the system.
adapters / appliances
Closed relay method:
When using medium diameter hose, 2 1/2 or 3 inches in diameter, generally _________ hoselines are laid. Large diameter hose, 4 or 5 inches in diameter, often requires only _____ supply line to meet fireground requirements.
multiple / one
Closed relay method
D/O should refer to NFPA ______ for information regarding the placement of relief devices.
There are two basic types of intake pressure relief valves. One type, supplied by the pump manufacturer, is an integral part of the pump ________ ___________. The second type is an add-on device that is screwed onto the pump ________ connection.
intake manifold / intake
Many of the screw-on intake pressure relief valves are also equipped with a gate valve that allows the water supply to the pump to be ?
Relay pumping operations that require the use of later arriving companies to achieve the required flow can set up an initial operation of lesser volume and greater spacing with _______ _______ valves placed in the relay line awaiting the arrival of incoming pumpers.
inline relay valves
An _______ _______ valve is placed along the length of a supply hose that permits a pumper to connect to the valve to boost pressure in the hose.