Flashcards in Engineer Resource Manual Deck (59)
Intake gauge is also known as
Registers intake pressure (psi) from pressurized source or vacuum (inHg) when drafting.
Registers discharge pressure on charged lines. 2 types are master (overall PDP) and individual/port (pressure for individual line).
Pressure of the water at rest in a system
Pressure left in the system while water is flowing
Forward velocity pressure at a discharge opening while water is flowing
Loss of pressure created by the turbulence of moving water against the wall of the hose or pipe
Short relay operation (usually side by side) where one pumper discharges water to the intake of a second pumper. The second pumper then boosts the pressure even higher. Essentially two pumpers placed together to work as a two-stage pump in series mode.
Operation where a strong hydrant is used to supply two or more engines by connecting them intake to intake.
Size of tank to pump piping
3" to 3.5"
GPM limit when pumping from tank
Safe minimum of your intake gauge
What is the size of the main supplying the hydrant and what does it mean?
At least 6", meaning if you have a 4" or 5" hose from a steamer port of the hydrant, there is still water left from that 6" pipe.
The amount water can be raised by atmospheric pressure in a controlled environment.
The height a pumper in good condition can be expected to lift water at draft. Generally 2/3 of theoretical lift.
The height a column of water can be lifted while still providing a reliable fire flow. 14.7 feet at sea level.
The engine connected to the water supply at the beginning of the relay operation.
The engine located at the fire scene that receives incoming water and discharges the water for fire attack.
3.5" to 12" hose
2.5" or 3" hose
What is attack hose service tested at?
When should a relay operation be considered?
When more than 300 GPM is the needed fire flow.
Standard maximum pressure for relay pumping.
180 psi (Pump tested at 250 psi, 50 psi safety margin, 20 psi safety residual)
Apparatus designed to carry 1000-3000 gallons of water and must be able to fill and dump at a rate of 1000 GPM.
Large capacity tender/tanker that sits next to the attack engine and receives all the shuttle water to provide an uninterrupted water source for the attack pumper.
Fill site layout in tender supply evolution
Both 2.5" ports have a hydrant gate valve, lay out and connect 2 50-foot sections of 2.5" supply hose to the gate valves and then open the hydrant.
Modern fire apparatus use what type of priming pumps?
Rotary vane or rotary gear pumps
How is the priming pump powered?
On older apparatus, by a small starter motor. In newer apparatus, by a multistage venturi powered by compressed air.