chapter 7 Flashcards
What is the primary function of the driver/operator on the fireground?
to provide water to attack crews in sufficient volume and pressure to achieve control and extinguishment of fires.
How does a driver operator precisely determine the friction loss of various flows through specific hose
layouts?
hydraulic calculations
What is the only truly accurate method for determining pressure loss in a particular hose lay?
measuring the pressure of the line on both ends
All of the following are measuring devices that can be used to record an accurate pressure in a hose
lay except for:
A) in-line gauges
B) pitot tubes
C) flowmeters
D) clapper valve correct answer
While preforming testing procedures to determine friction loss in a hoseline, all in line gauges should
be calibrated in increments of:
5 psi
For this manual, a friction loss of _______ for all master stream appliances, regardless of flow, will be used.
25 psi
Elevation pressure is the difference between:
the nozzle and the pump
Elevation pressure loss Formula
EP = 0.5H
Where:
EP = Elevation Pressure in pounds per square inch (psi)
0.5 = A constant
H = Height in feet (ft)
When charging multiple handlines of equal lengths and equal diameter, friction loss should be calculated for?
One line
While supplying multiple hoselines, the driver should set the pump discharge pressure based on the
hoseline with:
the greatest pressure requirement
What best describes net discharge pressure?
the difference between the PDP and incoming supply source
Wyed Hoselines (Equal Length) formula for friction loss
1.) Compute the number of gpm (L/min) flowing in each wyed hoseline by using the equation:
Q = flow rate (gpm or L/min) 100
2.)Determine the friction loss in one of the wyed attack lines using For-mula 7.1 - Friction Loss.
FL = CQ2L
3.)Compute the total number of gpm (L/min) flowing through the supply hoseline to the wye:
QTotal= (flow in Attack Line 1) + (flow in Attack Line 2) /100
4.) Determine the friction loss in the supply hoseline using Formula 7.1: Friction Loss adjusted for the total for Q.
FL = (C)(QTotal)2(L)
5.)Add the friction loss from the supply hoseline, one of the attack lines, 10 psi (70 kPa) for the wye (if total flow is above 350 gpm [1 400 L/min]), and elevation pressure (if applicable) to determine the total pressure loss.
what is this definition of?
Actual pressure of the water as it leaves the pump and enters the hoseline; total amount of pressure being discharged by a pump. In mathematical terms, it is the pump intake pressure plus the net pump discharge pressure. Measured in pounds per square inch or kilopascals.
Pump Discharge Pressure (PDP)
PDP formula
PDP = NP + TPL
Where:
PDP = Pump Discharge Pressure in pounds per square inch (psi)
NP = Nozzle Pressure in pounds per square inch (psi)
TPL = Total Pressure Loss in pounds per square inch (psi)
(TPL accounts for pressure loss due to friction, elevation, and appliances)
Net Pump Discharge Pressure (NPDP) formula
NPDPPPS= PDP – Intake Reading
