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Relay Pumping Operations

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Relay Pumping Operations Sugar Land Fire Department Driver/Operator-Pumper Academy Spring 2003 Relay Pumping Operations Hoses & Appliances Medium diameter Hose (MDH ... – PowerPoint PPT presentation

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Title: Relay Pumping Operations


1
Relay Pumping Operations
  • Sugar Land Fire Department
  • Driver/Operator-Pumper Academy
  • Spring 2003

2
Relay Pumping Operations
3
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6
Hoses Appliances
  • Medium diameter Hose (MDH)
  • Large diameter Hose (LDH)
  • Pressure Relief Valves
  • Intake pressure relief valves

7
Hoses Appliances
  • Bleeder valves on the intake pressure relief
    valve
  • In-line relay valves
  • Discharge manifold

8
Relay Considerations
  • Amount of water required at the emergency scene
  • Distance from emergency scene to water source

9
Mo Water
  • Increase the size of the hose
  • Increase the number of hoselines
  • Increase the pump discharge pressure of relay
    pumpers.
  • Increase the number of pumpers in the relay.

10
Restrictions
  • Increasing the size of the hose or number of
    hoselines
  • Increasing the pump discharge pressure
  • Increasing the number of pumpers in the relay

11
Relay Considerations
  • Increasing the size of the hose or number of
    hoselines
  • Increasing the pump discharge pressure
  • Increasing the number of pumpers in the relay

12
Relay Considerations
  • Increasing the size of the hose or number of
    hoselines
  • Increasing the pump discharge pressure
  • Increasing the number of pumpers in the relay

13
Relay Pumping Operations
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15
Constant Pressure Relay
  • Establishes 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
  • Attack pumper maintains constant flow rate by
    using an open discharge or securing a waste line
    to handle the excess beyond the flow being used
    in the attack lines.

16
Advantages
  • Speeds relay activation. Each driver/operator
    knows exactly how much hose to lay out and how to
    pump it without awaiting orders.
  • Requires no complicated calculations on the
    emergency scene.
  • Reduces radio traffic and confusion between pump
    operators.
  • Allows attack pumper driver/operator to govern
    fire lines with greater ease.
  • Simplifies pressure regulation as driver/operator
    in the relay only have to guide and adjust
    pressure to one constant figure.

17
Modifications
  • Variations in relay pumper spacing
  • Severe elevation differences between source and
    fire
  • Increases in needed fire flow
  • Large diameter hose

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20
Putting a Relay in Operation
  • A relay pumping operation always begins with the
    source pumper
  • Generally, the largest capacity pumper is used at
    the water source
  • The maximum capacity of the relay is determined
    by the capacity of the smallest pump and the
    smallest hoseline used within the relay.
  • Failure to keep water moving through the pump
    could result in a loss of prime, thus delaying
    the operation

21
Putting a Relay in Operation
  • The relay pumper should be waiting for water with
    the dump line or discharge open and the pump out
    of gear.
  • If the waiting period for receiving water from
    the source pumper or another relay pumper is only
    a few minutes, the pump on the in-line relay
    pumper may be engaged before receiving the water.
  • Sometimes the relay can be started, or the
    hoselines filled with water from the apparatus
    water tank.
  • It is most desirable to maintain an intake
    pressure of 20 to 30 psi

22
Putting a Relay in Operation
  • If the relay pumper is receiving an intake
    pressure greater than 50 psi, the valve to the
    dump line on the relay pumper must be adjusted to
    limit residual pressure to the 50 psi maximum.
  • Because pump discharge pressure increases as the
    throttle setting on the relay pumper is
    increased, the valve to the dump line must be
    gated down to maintain the 50 psi residual
    pressure and prevent cavitation.

23
Putting a Relay in Operation
  • Once the pump discharge pressure on the relay
    pumper has reached the desired pressure with the
    water being discharged, this portion of the relay
    has been established and no further adjustments
    should be necessary.
  • When water reaches the attack pumper, the
    operator should bleed air from the line by
    opening the bleeder valve on the intake being
    used.
  • When one of the attack lines is shut down, an
    alert attack pumper operator can open the dump
    line to allow water to flow, thus preventing a
    dangerous pressure buildup in the relay.

24
Few Facts
  • Once the relay is in operation and water is
    moving, all pump operators set their automatic
    pressure control devices to an appropriate level.
  • If the intake relief valve is readily adjustable,
    it should be set to discharge at 10 psi above the
    static pressure of the water system it is
    attached to or above discharge pressure of the
    previous pumper in the relay.
  • Small variations in pressure are not significant
    and as long as the intake relay pumper pressure
    does not drop below 10 psi or increase above 100
    psi, no attempt should be made to maintain exact
    pressures.

25
Few Facts
  • If the attack pumper is equipped with a readily
    adjustable intake relief valve, it should be set
    between 50 and 75 psi to establish a stable
    operating condition.
  • At no time should the relief valve be set for a
    higher amount than the safe working pressure of
    the hose.
  • The auxiliary cooler can be adjusted as necessary
    to maintain the proper engine operating
    temperature over the extended periods of time
    that are often necessary during a relay.

26
Few Facts
  • Radios must be used cautiously too much radio
    usage in establishing a relay can hamper fire
    fighting activities and efforts to establish
    water supply
  • If additional radio frequencies are available,
    one channel should be dedicated to coordination
    of the water supply operation.
  • When pumpers are within sight of each other, hand
    signals can be used or messengers can be sent on
    foot.

27
Few Facts
  • Once the water is moving, a minimum of
    communication should be required.
  • Portable radios may be used if relay units are
    equipped with incompatible radios.
  • Radio-equipped ambulances or utility units that
    are not otherwise occupied can be used to
    establish communications throughout the relay.
  • Relay operations should be shut down from the
    fire scene first.
  • If the source pumper is shut down while the rest
    of the relay is still operating, cavitation can
    result.
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