Chapter 9 - Fire Pump Theory

Question 1

________ operate using a piston that moves back and forth in a cylinder. These multicylinder, PTO-driven pumps can provide pressures up to _____ psi for high-pressure fog lines, or to inject foam concentrate into a water line or manifold at a higher pressure than the water pump is creating.

Answer 1

Piston Pumps

1,000 psi

Question 2

The total amount of water than can be pumped by a rotary gear pump depends on the ______________ and _________.

Answer 2

Size of the pockets in the gears and the speed of rotation.

Question 3

Three main factors influence a centrifugal fire pump’s discharge pressure:

Answer 3

> Amount of water being discharged
Speed at which the impeller is turning
Pressure of water when it enters the pump from a pressurized source.

Question 4

The increase is ______ is roughly equal to the square of the change in impeller ____. For all other factors remaining constant, doubling the ______ of the impeller will result in four times as much _______.

Answer 4

pressure
speed

2x speed = 4x pressure

Question 5

In parallel mode, the pump will be capable of supplying 100% of its rated capacity at ____ psi at ___ feet of lift with ___ feet of suction hose while drafting.

Answer 5

150 psi
10 ft
20 ft

Question 6

A very close tolerance must be maintained between the pump casing and the hub of the impeller. This opening is usually limited to ____ inch or less

Answer 6

0.01 inch

Question 7

The most common type of seal packing material is composed of ____________________________.

Answer 7

Rope fibers impregnated with graphite or lead.

Question 8

The most common applications for auxiliary engine driven pumps are:

Answer 8

> Airport rescue fire fighting (ARFF) vehicles
> Wildland fire apparatus
> Mobile water supply apparatus
> Trailer mounted fire pumps
> Portable fire pumps

Question 9

In some cases, Auxiliary Engine Driven Pumps may be part of a skid-mounted assembly that includes small water tank, booster reel, and small diameter attack lines. With a pumping capacity of generally ____ gpm or less.

Answer 9

500 gpm

Question 10

In the past, conventional PTO units were limited to powering pumps up to approximately ____ gpm. However, some manufacturers now provide full torque power take-offs that allow for the installation of pumps as large as _____ gpm.

Answer 10

500 gpm

1,250 gpm

Question 11

The maximum capacity of a front mounted pump depends on the limitations of the engine driving it, typically up to _____ gpm.

Answer 11

1,250 gpm

Question 12

On mid-ship mounted pumps the gear ratio is arranged so that the impeller turns faster than the engine, usually ____ to ____ times as fast

Answer 12

1-1/2 to 2-1/2 times

Question 13

Some mid-ship mounted pumps can be rated anywhere from ____ to _____ gpm with no major changes to the pump itself.

Answer 13

500 to 2,250 gpm

Question 14

With the engine idling and the pump engaged, most speedometers will indicate between ___ to ___ mph.

Answer 14

10 to 15 mph

Question 15

The rear-mount design offers a number of advantages, including _________ and ____________.

Answer 15

More even weight distribution on the chassis and more usable compartment space.

Question 16

The primary parts of the piping system are ______ and _________ piping as well as _________ and ______.

Answer 16

Intake and discharge piping

pump drains and valves

Question 17

Most pipes are constructed of __________, _______, ________, or ____________ and may include __________ in certain applicaitons

Answer 17

Cast Iron, Brass, Stainless Steel, or Galvanized Steel

Rubber Hoses

Question 18

The piping system and the fire pump itself must be capable of withstanding a hydrostatic test of ____ psi before being placed into service.

Answer 18

500 psi

Question 19

According to NFPA 1901, pumpers with a capacity of _____ gpm or less should have the piping capable of flowing ____ gpm. Pumpers with a capacity greater than ____ gpm should be able to flow at least ____ gpm.

Answer 19

<= to 500 gpm - 250 gpm

> than 500 gpm - 500 gpm

Question 20

Many pumpers are equipped with tank-to-pump piping as large as __-inch in diameter

Answer 20

4-inch

Question 21

Pumps rated greater than _____ gpm capacity may require more than one large intake connection at each location.

Answer 21

1,500 gpm

Question 22

Based on NFPA 1901, a sufficient number of 2-1/2-inch discharge openings must be provided to flow the rated capacity of the pump. As a minimum, all fire apparatus with a rated pump capacity of ____ gpm or greater must be equipped with at least ___ 2-1/2-inch discharges. Pumps rated less than ____ gpm are required to have only ___ 2-1/2-inch discharge. Discharges greater than 2-1/2-inches in diameter may not be located on the pump operator’s panel.

Answer 22

> =750 gpm - 2 x 2-1/2 inch discharges

< 750 gpm - 1 x 2-1/2 inch discharge

Question 23

A minimum of _____-inch pimping, valves, and elbows must be used to supply discharges where 1-1/2, 1-3/4, or 2-inch handlines are attached.

Answer 23

2-inch

Question 24

All valves should be designed and maintained so that they are easily operable at pressures of up to ____ psi.

Answer 24

250 psi

Question 25

According to NFPA 1901, apparatus equipped with tanks of less than _____ gallons must have a tank fill line of at least __-inch in diameter. Tanks greater than _____ gallons must be provided with at least a __-inch tank fill line.

Answer 25

< 1000 gallons - 1-inch tank fill line

> 1000 gallons - 2-inch tank fill line

Question 26

The most common type of valve is the ____-____ valve that permits the full flow of water through a line with the minimum friction loss. The most common actuators for ____-____ valves are either ____-____ handles (T-handles) or _______-____ handles. The ____-____ valve handles on some pumpers use a sliding gear tooth rack that engages a sector gear connected to the valve stem.

Answer 26

ball-type
ball-type
push-pull handles (T-handles) or quarter-turn handles
Push-pull

Question 27

____ valves are most commonly operated by a _________. _________ valves are most commonly operated by _______-____ handles.

Answer 27

Gate valves
handwheel
Butterfly valves
quarter-turn handles

Question 28

NFPA 1901 requires that all intake or discharges that are __ inches or greater be equipped with slow acting valve controls. This feature prevents the valve movement from open to close (or vice versa) in less than __ seconds

Answer 28

3-inches

3 seconds

Question 29

NFPA 1901 requires some type of pressure control device to be part of any fire apparatus pumping system. This device must operate within ___ to ____ seconds after the discharge pressure rises and restricts the pressure from exceeding ___ psi about the set level.

Answer 29

3 to 10 seconds

30 psi

Question 30

There are two basic concepts for pressure relief valves:

Answer 30

> Those that relieve excess pressure on the “discharge side” of the pump.
Those that relieve the excess pressure on the “intake side” of the pump.

Question 31

The two basic types of intake pressure relieve valves include:

Answer 31

> One that is supplied by the pump manufacturer and an integral part of the pump intake manifold
The second type is an add-on device that is screwed onto the pimp intake connection.

Question 32

The ___________ is designed to regulate the engine speed to match the pump discharge requirements.

Answer 32

Pressure Governor

Question 33

The electronic governor also features ________ protection by returning the engine to idle when intake pressure drops below ___ psi.

Answer 33

Cavitation

30 psi

Question 34

A ____________ is needed to create a vacuum that makes drafting posssible.

Answer 34

Priming Device

Question 35

Primers fall into several categories including _________, _____, ______, and ________.

Answer 35

Positive Displacement
Exhaust
Vacuum
Air Primer

Question 36

NFPA 1901 requires that all controls and instrucments necessary to operatet the pump are located on the pump operator’s panel. These include:

Answer 36

> Master pump intake pressure indicating gauge
Master pump discharge indicating gauge
Pump engine tachometer
Pumping engine coolant temperature indicator
Voltmeter
Pimp pressure controls (discharge valves)
Pumping engine throttle
Primer control
Water tank to pump valve
Tank-fill valve
Water tank level indicator

Question 37

The master intake gauge is usually calibrated from __ to ____ psi of positive pressure and from __ to ___ inches of mercury on the negative side.

Answer 37

0 to 600 psi

0 to 30 in Hg

Question 38

When the vacuum reading approaches ___ psi, the pump is nearing its capacity and is not able to supply additional lines.

Answer 38

20 psi

Question 39

There are severl types of throttles available, inclduing a throttle knob (also called a _______), that can be turned clockwise or wounterclockwaide to achieve the required pressure. Automatic throttle controls operated by a ________ or ________ are commonly found on newer apparatus.

Answer 39

Vernier

Throttle switch or Push Button

Question 40

The primary function of an _________________ is to control the temperature of coolant in the apparatus engine during pumping operations. Older apparatus usually contain one of two ___________: either the _______ or ________ type

Answer 40

Auxiliary cooling system
Auxiliary coolers
Marine or Immersion