Chapter # 13 Relay Pumping Operations Flashcards
(41 cards)
Connected to the water supply. Should have the largest pump capacity. Also called the supply pumper.
Source Pumper
Receives water from another pumper, boost the pressure, sends it to the next pumper. Also called the in-line pumper.
Relay pumper
Located at the fire scene. Receives the water and supplies the attack lines and appliances.
Attack pumper
How much hose do hose tenders typically carry.
A mile or more of LDH
When smaller size hose ( 2” or 3”) is used on a relay, typically how many lines are laid?
2 or 3
Intended to enhance fire fighter safety and prevent pump and hoseline damage due to water hammer. Also called relay relief valves.
Intake pressure relief valves
If a intake pressure relief valve is adjustable, what should it be set at?
Within 10 psi of the static pressure of the water system supplying the pumper or 10 psi above the discharge pressure of the previous pumper in relay.
Be sure to have the bleeder valve on the intake closed when doing what?
Operating from a draft.
Allow late arriving pumpers to hook up to the relay with out interrupting the flow of water.
In-line relay valves
If a relay operation is going to support more then one attack pumper what can be used to supply the multiple pumpers from the one relay operation?
A discharge manifold.
What are the two basic things a relay operation is based on?
The amount of water required at the scene. The distance from the scene to the water source.
List the three options for increasing flow in a relay operation.
Increase hose size or the number of hoses being used. Increase the PDP of the pumpers in the relay. Increase the number of pumpers in the relay.
What size hose should initially be laid in a relay operation?
The largest hose available.
When operating from draft, increasing the NPDP above 150 psi will reduce what?
The volume capability of the pumper.
Relay pumping pressure should never exceed what?
The pressure used to test the hose being used.
How many pumpers may be included in a relay task force or strike team?
3-5
What are the two basic designs of relay pumping operations?
The maximum distance relay method.
The constant pressure relay method.
Involves flowing a predetermined volume of water for the maximum distance that it can be pumped through a particular hose lay.
The maximum distance relay method.
All fire pumpers are rated to flow their max volume at ….psi, 70% of their max at ……psi, and 50% of their max at …….psi, at draft.
Max = 150 psi 70% = 200 psi. 60% = 250 psi.
What is the equation for the number of pumpers needed in a relay when using the maximum distance relay method?
Relay distance (from table 13.1 or 13.2) + 1 = Total # of pumpers needed.
Provides the maximum flow available from a particular relay setup by using a constant pressure in the system. This depends on a consistent flow being provided on the fire ground.
The constant pressure relay method.
What can a attack pumper do to maintain a constant flow when operating from a constant flow relay?
Open discharges or secured waste lines.
What are some advantages of a constant flow relay operation?
Speeds relay activation. No complicated calculations. Radio traffic and confusion is reduced. Attack pumper operator can govern fire lines easier. Operators in relay only have to adjust pressure to one constant figure.
What can be opened on a relay pumper is there is no relay relief valve present?
A unused discharge valve.
