Ch 8. Fireground Hydraulic Calculations Flashcards
What is the definition of Pump Discharge Pressure
The actual pressure of the water as it leaves the pump and enters the hose line.
*In mathematical terms, the pump intake pressure plus the net discharge pressure.
What is a flow meter?
A mechanical device installed in a discharge that senses the amount of water flow and provides a readout in GPM.
Why is a flow meter advantageous when using an automatic nozzle?
An automatic nozzle will maintain a pre determined nozzle pressure and a stream that appears adequate even though the actual flow may be insufficient, leading the operator to provide an insufficient discharge pressure.
Per NFPA 1901, for every discharge equipped with a flow meter, a _______ shall be also be present.
A guage
Each discharge with a flow meter must have a digital readout display within _____ inches of the control valve for that discharge.
6 inches
If a pressure gauge is mounted at the 6 inch location, then a flow meter must be mounted within ______ inches adjacent to the pressure gauge.
2 inches
With proper calibration, a flow meter in good order should be accurate to within +/- __________ percent.
3%
What is a paddle wheel flow meter?
Small paddle wheel is mounted in a straight section of pipe. Water passes and spins paddle which translates into GPM flow.
What is a spring probe flow meter?
Steel spring mounted in pipe, as water passes, it bends the spring which translates into GPM flow.
Few moving parts, requires very little maintenance.
If a flow meter registers good flow, but the nozzle reports no water, this may indicate that what might have occurred?
A burst hose line.
In relay pumping, the supply engine might have no idea what the attack flow is. How can the operator use the flow meter to supply the attack engine?
As throttle increases, the flow meter will rise. Keep increasing throttle until the flow meter no longer increases. This will ensure enough water supply for the attack engine.
When supplying a relay, the intake pressure cannot be allowed to drop below ________ psi?
20 psi
When supplying in a relay operation, apparatus equipped with electronic pressure governors should always operate in ______ mode to avoid over pressurizing the next engine to prevent damage.
RPM mode
When supplying a standpipe, average out the flow rate of each nozzle and provide a volume to match. Set the electronic governor to _______mode so that it will adjust for changes in flow as lines are opened or shut down.
PSI mode
How many psi increments must be displayed on flow meters?
10 psi increments.
