Chapter 5
Any Pressure less than atmospheric pressure is referred to as a
Vacuum
What type of fog stream breaks water into fine, evenly divided particles by driving several jets of water together at an angle?
Impinging stream
The pump discharge pressure at the apparatus must be enough to overcome:
The sum of all pressure loss
What is the equation for determining friction loss in a 3-inch hose using the Condensed Q formula?
FL=Q^2
Switching from volume to pressure for a multistage centrifugal fire pump:
Can result in immediate doubling of previous discharge pressure.
If Velocity is increased beyond practical limits, the friction becomes so great that resistance agitates the entire stream, and creates:
Critical Velocity
Which of the following is customary formula for calculating nozzle reaction for solid stream nozzles?
1.57 x d^2 X NP
In order to avoid having two different nozzle pressure when using a wye, it is important that the two smaller attack lines wyed from the supply line are:
the same length and diameter
What is the equation for determining friction loss in a 4-inch hose using the condensed Q formula?
FL=Q^2 / 5
Which type of priming device uses an oil supply or other type of fluid to seal the gaps between the gears and the case and fill any irregularities in the housing caused by sediment or debris?
Positive displacement primers
Stored potential energy available to force water through pipes, fittings, hose and adapters is:
Static Pressure
When determining the flow from a solid stream nozzle, which of the following is the constant number in the customary formula?
29.7
The metric formula used to determine elevation pressure in a multistory building is:
35kPa x (number of stories - 1)
If the volume of water at the nozzle suddenly decreases, but there is no reduction in the flowmeter reading, what is the most likely assumption?
The hose line has burst
It is generally recommended that intake relief valves be set to open when intake pressure rises more than:
10 psi (70kPa) above necessary operating pressure.
What should the fire department do if there is any question about the reliability of a private water supply system or its ability to provide an adequate amount of water for a large-scale fire fighting operation?
Make arrangements to augment private water supply.
Solid stream nozzles on handlines should generally be operated at a maximum of:
50psi (350kPa) Nozzle pressure
Formula for determining friction loss
FL=CQ^2L
When calculating the required pump discharge pressures for each of the listed layouts on a pump chart, round pump discharge pressure to the nearest:
5psi (35kPa)
The total amount of water that can be pumped by a rotary gear pump depends on the speed of rotation and the size of the:
pockets in the gears
When a property is served by two sources of water supply for fire protection, municipal system and a private source consisting of nonportable water, why must these systems remain separate?
To prevent cross contamination
A rule of thumb for calculating nozzle reation for solid stream nozzle in the customary system is nozzle reaction (NR) equals the total flow of water in gpm flowing through the nozzle (Q) divided by:
3
What are two ways to determine friction loss?
Calculations and preforming tests
When using a flowmeter for relay pumping, ensure that the incoming pressure does not drop below:
20psi (140kPa)
Which pump panel instrument displays engine speed in revolutions per minute?
Tachometer