Pump Ops Chpt 12 Flashcards
Pumper that takes water from a hydrant or static source and pumps it under pressure to the next apparatus in the relay pumping operation water supply should be the apparatus with the largest pumping capacity.
Water supply pumper
Source pumpers
Pumpers or pumper connected within the relay that Receive water from the source pumper or another relay pumper, raises the pressure, and then supplies water to the next apparatus.
Relay pumper
Pumping apparatus located at the fire scene that receives water form the relay and is responsible for supplying the attack lines and appliances required for fire suppression.
Fire attack pumper
Some for departments, especially that that have on occasion to make many hose lays, employ hose ________ to assist in relay pumping operations.
Hose tenders
Hose tenders may be equipped with a fire pump that allows the apparatus to participate in the pumping operation once the supply line is laid. It is possible for a hose tender to carry a mile or more of _______.
Large diameter hose LDH
Pumpers in the relay operation could increase their pump discharge pressure . However this action will not necessarily increase the volume of water through the system. Centrifugal pumps are rated to pump at their at maximum capacity at _______ at draft. When the pumping at pressures higher than _____ psi, the volume capability of the pump is reduced proportionately.
150 psi
As previously mentioned, fire department pumpers are rated to flow their maximum volume at 150 psi, _______ of their maximum at 200 psi and ____ of their maximum at 250 psi at draft.
70 percent
50 percent
Relay distance formula
P= R/D + 1
P total number of pumpers needed
R relay distance
D distance
When relaying long distances, the hose lays between each pumper should be as equalized as possible. In cases where multiple diameters of hose are used, the distances between pumpers may be adjusted accordingly. For example, of several pumpers are setting up a relay of 1000 gpm using 5 inch hose, each pumper can be placed _______ apart. If a pumper carrying 3 inch supply hose lays dual supply lines as part of the operation, itβs portion of the lay must be ____.
2050 feet apart
900 feet apart
A _______ begins with the largest capacity pumper working from the water source
Relay operation
The relay pumper should be waiting for water with a dump line or discharge open and the pump out of gear. When the source and relay pumpers are ready, the discharge supplying the hoseline on the source pumper is opened while the valve on the ______ is closed in a coordination action.
Dump line
As water begins to reach each pumper, the driver/operator should _____ any air from the line before opening the intake valve.
Bleed
For relay pumpers equipped with an adjustable intake relief valve, they should be set to ____ above the static pressure of the water system to which it is attached or _____ above the discharge pressure of the previous pumper in the relay.
10 psi
When the need for relay pumping has ended, the operation should be discontinued from the _______.
Fire scene first
Driver/operators should refer to NFPA 1962 for further information regarding the placement of relief devices. Sometimes referred to as _______, these appliances are intended to enhance firefighter safety and reduce the possibility of damage to the pump and other water supply components that may be caused by water hammer when valves are operated too quickly or intake pressure rises dramatically.
Relay relief valves