I-C-06 Relay Pumping 10/12/2023

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Questions and Answers

What should be done to prevent violent movement during relay operations?

Increase the pressure at the intake source.

Monitor the GPM targets throughout the operation.

Ensure all personnel are evacuated from the area.

Secure the bleed-off lines effectively. (correct)

What is the maximum rated capacity of a Source Apparatus operating at a residual intake pressure of 20 PSI?

The capacity cannot be determined from this information. (correct)

180 PSI EDP

150 PSI EDP

100 PSI EDP

Why is slowly opening and closing valves important in relay operations?

To adjust the water temperature during operation.

To prevent water hammer and unexpected pressure changes. (correct)

To maintain a constant pressure throughout the system.

To ensure quick adjustments to flow rates.

At what EDP pressure does the maximum capacity of Source Apparatus from draft start to decrease?

150 PSI Signup and view all the answers

What risk is associated with utilizing portable hydrants in place of hydrant assist valves?

It can interrupt water flow when adding/removing Relay Apparatus. Signup and view all the answers

What should the initial pressure be set at when the target GPM is unknown?

100 PSI Signup and view all the answers

What happens to the capacity of Source Apparatus at 200 PSI EDP while operating from draft?

It decreases to 70% of maximum. Signup and view all the answers

Which of the following is not a recommended practice when coordinating a relay pumping operation?

Keeping all personnel on a single radio frequency. Signup and view all the answers

What is the primary purpose of relay pumping in fire suppression?

To increase the water supply at the fire scene beyond what a single apparatus can provide. Signup and view all the answers

What does the constant pressure relay method rely on to function effectively?

A consistent water flow provided at the fire scene. Signup and view all the answers

Which riding position is responsible for operating the pump on a suppression apparatus?

Driver/Operator (D/O) Signup and view all the answers

In the context of relay pumping, what is a 'bleed-off line' primarily used for?

To discharge excess water and manage pump temperatures. Signup and view all the answers

Which method of relay pumping allows for the greatest distance of water flow?

Maximum distance relay method. Signup and view all the answers

What does the spacing and number of relay apparatus depend upon?

Waterflow requirements and hose lay length. Signup and view all the answers

Which of the following statements is true regarding personnel riding the apparatus?

All personnel must ride inside the apparatus for safety. Signup and view all the answers

What is the role of relay apparatus in relay pumping?

To overcome friction loss and increase pressure in the supply line. Signup and view all the answers

What is the maximum distance allowed between apparatus for a GPM of 1500?

900 feet Signup and view all the answers

Which valve must be used to connect a 5” supply line to the discharge during relay operations?

Hydrant Assist Valve Signup and view all the answers

During relay operations, which pressure governs the setting for the Source Apparatus?

Friction loss plus 20 PSI Signup and view all the answers

What should be done if the intake pressure falls below 20 PSI during relay operations?

Bleed air from the hydrant assist valve Signup and view all the answers

Which action is NOT recommended when shutting down relay operations?

Shut down discharges immediately Signup and view all the answers

What indicator should be watched to prevent cavitation during relay operations?

Intake gauge Signup and view all the answers

What must be connected to every apparatus from the Source Apparatus to the Attack Apparatus?

A 50-foot section of 3” hose Signup and view all the answers

What is the maximum operational pressure required for relay operations if it exceeds 200 PSI?

Each apparatus should throttle down before shutting down Signup and view all the answers

Which factor is essential for determining the need for a relay pumping operation?

The friction loss and maximum operating pressures Signup and view all the answers

Which of the following is a key component of the relay apparatus?

Intake gauge and air bleed mechanism Signup and view all the answers

What is indicated when a 20 PSI residual pressure is reached on the intake gauge?

The Source Apparatus can stop pumping Signup and view all the answers

What is the purpose of the crank handle on the hydrant assist valve during operations?

To direct water flow correctly Signup and view all the answers

Which GPM can sustain a maximum distance of 2000 feet between apparatus?

1000 GPM Signup and view all the answers

Study Notes

Relay Pumping Overview

Relay pumping is essential when waterflow requirements and hose lay lengths exceed a single apparatus's capacity.
It involves multiple apparatus positioned strategically to ensure water delivery to a fire scene.
Spacing and number of units depend on waterflow demands and hose length needed.

Apparatus Designation

Four designated positions on suppression apparatus:
- Unit Officer
- Driver/Operator (D/O)
- Hydrant Firefighter (behind D/O)
- Nozzle Firefighter (behind Unit Officer)
Riding on the tailboard of Miami-Dade Fire Rescue apparatus is prohibited.

Key Components

Attack Apparatus: The unit utilized directly at the fire scene for fighting the fire.
Bleed-Off Line: A 50' x 3" hose section to discharge excess water, aiding pressure management and pump temperature control.
Constant Pressure Relay Method: Maintains maximum flow using consistent pressure.
Maximum Distance Relay Method: Pumps a predetermined volume for the maximum possible distance through the hose.

Relay Pumping Procedures

Determination of relay necessity is based on friction loss and pressure capabilities of 5" hose.
A chart outlines maximum distances for various flow rates (GPM):
- 1000 GPM: 2000 ft
- 1250 GPM: 1300 ft
- 1500 GPM: 900 ft
- 2000 GPM: 500 ft

Conducting Hose Lay

Source Apparatus connects to hydrant or drafting source.
Relay Apparatus lays the maximum hose length permitted and connects through the hydrant assist valve.
Involves various connections including a 4½" NST male x 5" Storz adapter and additional 5" supply connections.

Starting Relay Operations

Begin at the Source Apparatus, gradually working toward the Attack Apparatus.
Set proper Engine Discharge Pressure (EDP) which equals friction loss + 20 PSI.
Notify key personnel when water volume is depleted.

Relay Apparatus Role

Receives and delivers water downstream while managing bleed air as necessary.
Must maintain adjusted pressure and be aware of end-point capacities.

Stopping Relay Operations

Reverse order of starting procedure, ensuring controlled throttling and safe shut down of discharges.
Essential to prevent over-pressurization and system damage.

Cautions and General Information

Coordination is crucial to avoid high pressures that could rupture hoses.
Continuous radio communication is vital between Driver/Operators (D/Os) for operational safety.
Adjustments to pressures must be minimal, as minor changes can affect the entire relay.
Ensure bleed-off lines are secured to prevent hazardous movement.

Alternate Connection Method

Use of portable hydrants instead of hydrant assist valves is possible but not advised due to operational interruptions.
Mechanical failure in Relay Apparatus can disrupt water flow entirely through this method.

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Description

This quiz covers the essentials of relay pumping in firefighting, focusing on the requirements for water supply and the arrangement of pumping apparatuses. Understand the strategies for maximizing efficiency in delivering water to the fire scene, including distance considerations and pressure methods. Test your knowledge on the techniques and best practices related to this vital firefighting evolution.