Pumping Apparatus Driver/Operator — Lesson 13

Pumping Apparatus Driver/Operator — Lesson 13

Pumping Apparatus Driver/Operator Handbook, 2nd Edition

Chapter 13 — Relay Pumping Operations

Pumping Apparatus Driver/Operator

13–2

Learning Objectives

1.Distinguish among characteristics of units in a relay pumping operation.

2.Distinguish among characteristics of hose and pump appliances that may be used to assist with relay pumping operations.

3.List operational considerations for relay pumping.

(Continued)


13–3

Learning Objectives

4.List ways to increase the amount of flow through a relay.

5.List the four steps of a basic relay pumping operation.

6.Answer questions about the maximum distance relay method.

(Continued)


13–4

Learning Objectives

7.State the equation for calculating the number of pumpers needed to relay a given amount of water.

8.Calculate the number of pumpers needed to relay a given amount of water.

9.Describe the constant pressure relay method.

(Continued)


13–5

Learning Objectives

10. Select from a list advantages of using the constant pressure relay method.

11. List instances in which pressure may be modified in a constant pressure relay.

12. Explain how relay pressure is increased or decreased.

(Continued)


13–6

Learning Objectives

13. Operate in a constant pressure relay.

14. Select facts about putting a relay into operation.

15. Answer questions about operating and shutting down the relay.

16. Use a flowchart to troubleshoot relay pumping operations.


13–7

Units in a Relay Pumping Operation

• Source pumper

• Relay pumper

• Attack pumper

• Hose tenders


13–8

Source Pumper

• Also called the supply pumper

• The pumper connected to the water supply at the beginning of the relay operation

• Should be the engine with the largest pumping capacity

• Pumps water to the next apparatus in line


13–9

Relay Pumper

• Also referred to as the in-line pumper

• A pumper connected within the relay that – Receives water from the source pumper or

other relay pumper,– Boosts the pressure, and then– Supplies water to the next apparatus in the

relay


13–10

Attack Pumper

• An engine or other pumping apparatus located at the fire scene that will be receiving water from the relay and supplying attack lines and appliances as needed for fire suppression


13–11

Hose Tenders

• May assist in the long hose lays associated with relay pumping operations

• May or may not be equipped with a fire pump that allows them to participate in the pumping operation once the hose is laid

• Usually carry a mile (1.6 m) or more of large diameter (4-inch [100 mm] or larger) hose


13–12

Units in a Relay Pumping Operation


13–13

Appliances that May Assist with Relay Pumping Operations

• Large diameter hose (LDH) — Ranges in size from 3½ to 12 inches (90 mm to 300 mm)

• Intake pressure relief valves– Intended to enhance firefighter safety – Reduce possibility of damage to pump and

discharge hoselines caused by water hammer

(Continued)


13–14


• Intake pressure relief valves (cont.)– Are of two types

–Supplied by the pump manufacturer and an integral part of the pump intake manifold

–Add-on device screwed onto the pump intake connection

(Continued)


13–15


• Intake pressure relief valves (cont.)– Are sometimes preset to allow a

predetermined amount of pressure into the fire pump; if the incoming pressure exceeds preset level, the valve dumps excess pressure/water until the water entering the pump is at the preset level

(Continued)


13–16


• Intake pressure relief valves (cont.)– May be equipped

with a manual shut-off valve

(Continued)


13–17


• Bleeder valves on intake pressure relief valve– Allow air to be bled off as the incoming

supply hose is charged– May be located directly on the intake piping

to the pump itself

(Continued)


13–18


• In-line relay valves– Are placed in the relay line for incoming

pumpers– Allow late-arriving pumpers to hook up

after the relay is operating and boost the pressure (and corresponding volume) without interrupting the relay operation

(Continued)


13–19


• In-line relay valves (cont.)

(Continued)


13–20


• Discharge manifold– Is used if an LDH

relay pumping operation is intended to support more than one attack pumper at the fire scene

(Continued)


13–21


• Discharge manifold (cont.)– Is used to break down LDH into two or more

hoselines that may then be connected to attack pumpers


13–22

Operational Considerations for Relay Pumping

• Amount of water required at the emergency scene– In some cases, the relay must supply the

total water necessary to complete the fire fighting operation.

– In other cases, the relay is used to supplement an inadequate municipal water supply system.

(Continued)


13–23

Operational Considerations for Relay Pumping

• Distance from emergency scene to water source– A longer relay distance needs more hose.

More hose means more friction loss.– To increase amount of flow through relay,

–Increase size or number of hoselines, or–Increase pump discharge pressure, or–Increase number of pumpers in relay


13–24

Steps of a Basic Relay Pumping Operation

• 1 — The incident commander determines that it is necessary to use a relay to provide an adequate amount of water to the scene.

• 2 — The dispatch center is ordered to send a relay task force or strike team.

(Continued)


13–25

Steps of a Basic Relay Pumping Operation

• 3 — Three to five pumpers, each with large capacity fire pumps and usually LDH, are dispatched to the scene.

• 4 — Pumpers set up the water supply independent of the companies already operating on the scene.


13–26

Maximum Distance Relay Method

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

• By using Table 13.1 or 13.2 on page 402 of the manual, the driver/operator can determine the distance that a certain flow may be pumped through the type of hose carried on the apparatus. (Continued)


13–27


• All fire department pumpers are rated to flow: – 100% of their maximum volume at 150 psi

(1 000 kPa)– 70% of their maximum volume at 200 psi (1

350 kPa)– 50% of their maximum volume at 250 psi (1

700 kPa)

(Continued)


13–28


• Using the figures in Tables 13.1 and 13.2, the number of pumpers needed to relay a given amount of water can be determined by using the following formula:

Relay distanceGiven distance

Note: Always round up to the nearest whole number. For example, if the answer is 3.2, you actually need 4 pumpers.

+ 1 = total number of pumpers needed


13–29

Constant Pressure Relay Method

• Provides the maximum flow available from a particular relay setup by using a constant pressure in the system

• Depends on a consistent flow being provided on the fireground


13–30

Advantages of a Constant Pressure Relay Method

• Speeds relay activation

• Requires no complicated calculations at the emergency scene

• Reduces radio traffic and confusion between pump operators

(Continued)


13–31

Advantages of a Constant Pressure Relay Method

• The attack pumper driver/operator is able to govern fire lines easier.

• Operators in the relay only have to guide and adjust pressure to one constant figure.


13–32

When Pressure May be Modified in a Constant Pressure Relay

• Variations in relay pumper spacing

• Extreme elevation differences between source and fire

• Increases in needed fire flow

• Large diameter hose


13–33

Increasing the Relay Pressure in a Constant Pressure Relay

• The source pumper is adjusted until the desired pressure is reached.

• Each successive pumper is similarly adjusted.


13–34

Decreasing the Relay Pressure in a Constant Pressure Relay

• The attack pumper throttles down.

• The source pumper discharges its dump line back into the water supply source.

• The relay pumpers throttle down to the desired pressure, successively from the water source.


13–35

Putting a Relay into Operation

• A relay pumping operation always begins with the source pumper, which should be the largest capacity pumper.

• If the relay is being supplied from draft, the source pumper will have to develop a higher net pump discharge pressure than the other pumpers in the relay.

(Continued)


13–36


• Once the water supply has been established, the source pumper opens an uncapped discharge or allows water to waste through a dump line until the first relay pumper is ready for water.

• Failure to keep water moving through the pump could result in a loss of prime, thus delaying the operation.

(Continued)


13–37


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

• When both the source pumper and the relay pumper are ready, the discharge supplying the hoseline on the source pumper is opened while the valve on the dump line is closed in a coordinated action. (Continued)


13–38


• The discharge to the supply line must be opened slowly to prevent a sudden discharge into the empty hoseline that could cause the pump to lose prime if pumping from draft.

• The water then begins to move from the source pumper to the relay pumper.

(Continued)


13–39


• As the water fills the line, the air will be forced through the pump and out the open dump line of the relay pumper.

• When water comes out of the dump line, the pump on the relay pumper can be engaged.

(Continued)


13–40


• If the waiting period for receiving water from the source pumper or other relay pumper is only going to be a few minutes, the pump on the waiting pumper may be engaged before receiving the water.

• Another option is to start the relay, or fill the hoselines, with water from the apparatus water tank.

(Continued)


13–41


• It is most desirable to maintain an intake pressure of 20 to 30 psi (150 kPa to 200 kPa).

• If the relay pumper is receiving an intake pressure greater than 50 psi (350 kPa), the valve to the dump line on the relay pumper must be adjusted to limit the residual to the 50 psi (350 kPa) maximum.

(Continued)


13–42


• The pump discharge pressure increases as the throttle setting on the relay pumper is increased; therefore, the valve to the dump line will have to be gated down to maintain the 50 psi (350 kPa) residual pressure.

(Continued)


13–43


• Once the pump discharge pressure on the relay pumper has reached the desired pressure with water being discharged, this portion of the relay has been established and no further adjustments should be necessary.

• When the next relay pumper is ready for water, the same procedure will be followed.

(Continued)


13–44


• When water reaches the attack pumper, the operator should bleed out the air from the supply line by opening the bleeder valve on the intake being used.

• The intake valve on the attack pumper can then be opened and a water supply established through the relay.

(Continued)


13–45


• There is a need for dump line on the attack pumper as well. When one of the attack lines is shut down, an alert operator can open the dump line to allow water to flow, thus preventing a dangerous pressure buildup in the relay.


13–46

Operating the Relay

• Once the relay is in operation and the water is moving, all pump operators set their automatic pressure control devices to an appropriate level.

• If equipped with newest and most sensitive governors, the attack pumper should be set in the “pressure” mode while all others in the relay should be set in the “RPM” mode.

(Continued)


13–47

Operating the Relay

• If the pumper is equipped with an intake relief valve, it should be put in service by taking off any caps on the outlet or by opening any valve associated with it.

(Continued)


13–48

Operating the Relay

• If the valve is readily adjustable, it should be set to discharge at 10 psi (70 kPa) above the static pressure of the water system it is attached to or 10 psi (70 kPa) above the discharge pressure of the previous pumper in the relay.

(Continued)


13–49

Operating the Relay

• At no time should the relief valve be set for a higher amount than the safe working pressure of the hose.

• If the attack pumper is equipped with a readily adjustable intake relief valve, set it between 50 to 75 psi (350 kPa to 525 kPa) to establish a stable operating condition for the attack pumper.

(Continued)


13–50

Operating the Relay

• Small variations in pressure are not significant and no attempt should be made to maintain exact pressures.

• As long as the intake pressure does not drop below 10 psi (70 kPa) or increase above 100 psi (700 kPa), no action should be required.

(Continued)


13–51

Operating the Relay

• Radios must be used cautiously at a relay operation.

• Too much radio traffic when setting up a relay can interfere with fireground communications and impede efforts to establish the water supply.

(Continued)


13–52

Operating the Relay

• When pumpers are within site of each other, hand signals can be used.

• Where additional radio frequencies are available, one channel should be dedicated to coordination of the water supply operation.


13–53

Shutting Down the Relay

• Shut down from the fire scene first.

• Starting with the attack pumper and coordinating with the other pumpers in the relay, slowly decrease the throttle, open the dump line, and take the pump out of gear.

• Drain hose and ready for reloading.


13–54

Summary

• In areas not served by municipal or other pressurized water supply systems, fire departments must provide water for fire fighting in some other way.

(Continued)


13–55

Summary

• In some cases, water can be supplied by water tenders. In other cases, especially where large structures are at risk, fire departments may choose to supply water through relay pumping operations from the nearest adequate water source.

(Continued)


13–56

Summary

• As with any other critical operation, fire departments that expect to use relay pumping should periodically reinforce these tactics with realistic training exercises that include all other nearby entities that may be needed in relay pumping operations during actual emergencies.


13–57

Discussion Questions

1.What is a source pumper?

2.What is a relay pumper?

3.What is an attack pumper?

4.What are hose tenders?

(Continued)


13–58

Discussion Questions

5.How can you increase the amount of flow through a relay?

6.List the four steps of a basic relay pumping operation.

7.What is the equation for calculating the number of pumpers needed to relay a given amount of water?

8.What are some of the advantages of the constant pressure relay method?

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Pumping Apparatus Driver/Operator — Lesson 13