Chapter # 13 Relay Pumping Operations

Question 1

Connected to the water supply. Should have the largest pump capacity. Also called the supply pumper.

Answer 1

Source Pumper

Question 2

Receives water from another pumper, boost the pressure, sends it to the next pumper. Also called the in-line pumper.

Answer 2

Relay pumper

Question 3

Located at the fire scene. Receives the water and supplies the attack lines and appliances.

Answer 3

Attack pumper

Question 4

How much hose do hose tenders typically carry.

Answer 4

A mile or more of LDH

Question 5

When smaller size hose ( 2” or 3”) is used on a relay, typically how many lines are laid?

Answer 5

2 or 3

Question 6

Intended to enhance fire fighter safety and prevent pump and hoseline damage due to water hammer. Also called relay relief valves.

Answer 6

Intake pressure relief valves

Question 7

If a intake pressure relief valve is adjustable, what should it be set at?

Answer 7

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.

Question 8

Be sure to have the bleeder valve on the intake closed when doing what?

Answer 8

Operating from a draft.

Question 9

Allow late arriving pumpers to hook up to the relay with out interrupting the flow of water.

Answer 9

In-line relay valves

Question 10

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?

Answer 10

A discharge manifold.

Question 11

What are the two basic things a relay operation is based on?

Answer 11

The amount of water required at the scene. The distance from the scene to the water source.

Question 12

List the three options for increasing flow in a relay operation.

Answer 12

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.

Question 13

What size hose should initially be laid in a relay operation?

Answer 13

The largest hose available.

Question 14

When operating from draft, increasing the NPDP above 150 psi will reduce what?

Answer 14

The volume capability of the pumper.

Question 15

Relay pumping pressure should never exceed what?

Answer 15

The pressure used to test the hose being used.

Question 16

How many pumpers may be included in a relay task force or strike team?

Answer 16

3-5

Question 17

What are the two basic designs of relay pumping operations?

Answer 17

The maximum distance relay method.

The constant pressure relay method.

Question 18

Involves flowing a predetermined volume of water for the maximum distance that it can be pumped through a particular hose lay.

Answer 18

The maximum distance relay method.

Question 19

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.

Answer 19

Max = 150 psi 70% = 200 psi. 60% = 250 psi.

Question 20

What is the equation for the number of pumpers needed in a relay when using the maximum distance relay method?

Answer 20

Relay distance (from table 13.1 or 13.2) + 1 = Total # of pumpers needed.

Question 21

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.

Answer 21

The constant pressure relay method.

Question 22

What can a attack pumper do to maintain a constant flow when operating from a constant flow relay?

Answer 22

Open discharges or secured waste lines.

Question 23

What are some advantages of a constant flow relay operation?

Answer 23

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.

Question 24

What can be opened on a relay pumper is there is no relay relief valve present?

Answer 24

A unused discharge valve.

Question 25

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

Answer 25

175psi

Question 26

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

Answer 26

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

Question 27

When can the constant pressure of 175 psi be modified?

Answer 27

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

Question 28

What pumper increases PDP first? Which decrease PDP first?

Answer 28

Increase PDP = source pumper

Decrease PDP = attack pumper

Question 29

What is the maximum capacity of the relay determined by?

Answer 29

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

Question 30

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

Answer 30

True

Question 31

When should a relay pumper engage its pump?

Answer 31

After water is exiting the dump line.

Question 32

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

Answer 32

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

Question 33

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

Answer 33

20-30 psi

Question 34

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

Answer 34

Open a dump line to maintain below 50 psi.

Question 35

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

Answer 35

Open a dump line.

Question 36

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

Answer 36

Set their pressure control devices.

Question 37

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

Answer 37

Attack pumper = Pressure

All other pumpers = RPM’s

Question 38

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

Answer 38

50-75 psi

Question 39

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?

Answer 39

True

Question 40

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

Answer 40

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

Question 41

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

Answer 41

Yes