Relay Operations

1
Relay Operations

• Chapter 13
• State Fire Academy

2
Objectives

• Pump a supply line of 2½ in. Or larger,
  given a relay pumping evolution the length and
  size of the line and the desired flow and intake
  pressure, so that the proper pressure and flow
  are provided to the next pumper in the relay.

3
Objectives

• Pump a supply line, given a relay pumping
  evolution the length and size of the line and
  the desired flow and intake pressure, so that the
  proper pressure and flow are provided to the next
  pumper in the relay.

4

OutlineI. Relay Apparatus and
EquipmentII. Relay Pumping Operational
ConsiderationsIII. Types of Relay Pumping
Operations A. Maximum Distance Relay Method B.
Constant Pressure Relay MethodIV. General
Guidelines for Relay Operations A. Putting a
Relay into Operation B. Operating the Relay C.
Shutting the Relay
5
Relay Apparatus and Equipment

• Source pumper- connected to the water source
• Relay pumper (in-line-pumper)- connected within
  the relay and receives water
• Attack pumper- located at the fire and receives
  water
• Hose tenders

6
Appliances For Relay

• Intake pressure relief valve
• Supplied by manufacturer
• Add-on
• Bleeder valves

7
Relay Pumping Operational Considerations

• Relay operations are based on
• Amount of water
• Distance from the emergency scene

8
Types of Relay Pumping Operations

• Maximum Distance Relay Method
• Constant Pressure Relay Method

9
Maximum Distance Relay Method

• Flowing a predetermined volume of water for the
  maximum distance it can be pumper
• Note Table 13.1 to determine number of pumpers
  needed

10
Constant Pressure Relay Method

• Speeds relay activation
• Requires no complicated calculations
• Radio traffic and confusion is reduced
• Attack operator governs with greater ease
• Operators only have to adjust to one constant
  pressure

11
Forming the Constant Pressure Relay

• 1. Position the attack pumper at the
  fire
• 2. Place largest pumper at the source
• 3. Lay out hose
• 4. Connect all hose to all pumpers

12
Forming the Constant Pressure Relay

• 5. All D/O open discharges except source
  pumper
• 6. Source pumper develops 175 psi
• 7. D/O close discharges slowly throttle to
  175 psi
• 8. Set relief valve

13
General Guidelines for Relay Operations

• Putting a Relay into Operation
• Always begins with the source pumper
• Use a dump line until relay is ready
• Maintain 20-30 psi residual.

14
Operating the Relay

• Once in operation
• Set pressure relief valve
• Operate auxiliary cooler
• Monitor all gauges