Chapter # 13 Relay Pumping Operations Flashcards Preview

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Flashcards in Chapter # 13 Relay Pumping Operations Deck (41):

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?



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.


What is the PDP for the source and relay pumpers when using the constant pressure method?



Driver/operator in a constant pressure relay should continue to adjust their PDP to 175 psi until what?

Intake pressure drops to 20 psi. Operating the hand throttle doesn't result in increased rpm's.


When can the constant pressure of 175 psi be modified?

Variations in relay pumper spacing. Extreme elevation differences. Increase need in fire flow. LDH.


What pumper increases PDP first? Which decrease PDP first?

Increase PDP = source pumper
Decrease PDP = attack pumper


What is the maximum capacity of the relay determined by?

The smallest capacity pump and the smallest hoseline used in the relay.


T or F The relay pumper should be waiting for water with the dump line or discharge open and the pump out of gear.



When should a relay pumper engage its pump?

After water is exiting the dump line.


When can a relay pump be engaged prior to receiving water?

When it will only be a few minutes to get water. When the tank to pump and pump to tank line is pulled.


It is most desirable to maintain a intake pressure of what?

20-30 psi


If a relay pumper has a intake of greater then 50 psi, what should be done?

Open a dump line to maintain below 50 psi.


What should be done on the attack pumper to prevent a pressure buildup when a attack line is closed?

Open a dump line.


Once the relay is in operation and water is moving what should operators do next?

Set their pressure control devices.


If apparatus are equipped with a pressure governor what pumpers should be set at pressure, and which should be set at RPM's?

Attack pumper = Pressure
All other pumpers = RPM's


What should a attack pumper set its intake pressure relief valve at?

50-75 psi


T or F When operating in relay, small variations in pressure are not significant and no attempts should be made to maintain exact pressures. As long as the intake pressure does not drop below 10 psi or increase above 100 psi no action should be required?



What should each operator do when it is their turn to shut down from the relay?

Slowly decrease the throttle. Open the dump line. Take the pump out of gear.


Can hand signals or foot messengers be used to communicate between pumpers that are close together?