Chapter 10 - Operating Fire Pumps

Question 1

Driver/operators should maintain a residual pressure of at least ___ psi on their master intake gauge at all times during pumping operations.

Answer 1

20 psi.

Question 2

A ________ ___ consists of stopping at the hydrants, dropping the end of one or more supply hoselines at the hydrant, and then proceeding to the fire location.

Answer 2

Forward Lay

Question 3

With the ________ ___, hose is laid from the fire to the water source.

Answer 3

Reverse Lay

Question 4

Several methods for preventing overheating are as follows:

Answer 4

> Establish a continuous minimum flow during intermittent use of water in firegound operations to keep the pump from overheating.

> Pull a length of the booster line or other small diameter line off the reel and fasten it to a sturdy object.

> Open the valve that supplies the booster reel and discharge water in a direction that will not interfere with the operation or damage other property. The booster line may also be directed back into the tank to circulate water continuously.

> Open a discharge drain valve.

> Partially open the tank-fill valve or tank-to-pump line.

Question 5

When the pumper is discharging water, the intake gauge displays the residual pressure. The difference between the two pressures is used to determine how much more water the hydrant can supply. Several methods are available for making this determination:

Answer 5

> Percentage Method
First-Digit Method
Squaring-the-Lines Method

Question 6

Percentage Drop Equation

Answer 6

Percentage Drop = (Static-Residual)(100) divided by Static

0-10 - 3 Times
11-15 - 2 Times
16-25 - Same Amount
25+ - 0

Question 7

First Digit Method

Answer 7

> (Static - Residual) = X
First-digit of Static times 1, 2, or 3 = Y1, Y2, Y3

> If X is <= Y1 —–> 3 additional lines
If X is <= Y2 —–> 2 additional lines
If X is <= Y3 —–> 1 additional line

Question 8

Atmospheric pressure decreases approximately ____ psi or __ in Hg for every _____ feet of altitude gain.

Answer 8

0.5 psi or 1 in Hg

1,000 feet

Question 9

Most pumps are able to develop a vacuum capacity of approximately ___ in Hg

Answer 9

22 in Hg

Question 10

The _________ of the water, the ______ of the lift, and the _______ __ ______ being dischared affect the point at which cavitation begins

Answer 10

Temperature
Height
Amount of Water

Question 11

A drafting site may be selected by:

Answer 11

> Amount of water
Type or quality of water
Accessibility of water

Question 12

The most important factor in choosing a draft site is the ______ __ ______ ______.

Answer 12

Amount of water available

Question 13

In order for a pumper to approach its rated capacity using a traditional strainer, there must be at least ___ inches of water over the strainer.

Answer 13

24 inches.

Question 14

As the amount of lift required to reach the pump increases, the following effects occur:

Answer 14

> Elevation pressure increases
Less friction loss can be overcome
Capacity of the pump is decreased

Question 15

A pumper in good working order can lift water a maximum of ___ feet.

Answer 15

25 feet

Question 16

To create an effective fire stream, a lift no greater than ___ feet is recommended.

Answer 16

20 feet

Question 17

Other important variables to consider during draft site selection include:

Answer 17

> The stability of the ground surface
The convenience of connecting hoselines
The safety of the driver/operator

Question 18

Most priming pumps are intended to work effectively when the engine is set at a rate between _____ and _____ rpm.

Answer 18

1,000 and 1,200 rpm

Question 19

As the air is evacuated from the pump the master intake gauge will register a vacuum reading. this reading should equal __ in Hg for __ foot of lift.

Answer 19

1 in Hg for 1 foot

Question 20

The entire priming action typically requires ___ to ___ seconds from start to finish. However, when up to ___ feet of intake hose lifting a maximum of ___ vertical feet, it may take as long as ___ seconds (___ seconds for pumps larger than 1,250 gpm) to accomplish this.

Answer 20

10 to 15 seconds
20 feet
10 feet
30 seconds
45 seconds

Question 21

Several types of problems occur during drafting operations:

Answer 21

> Air leak on the intake side of the pump. (Most common source of problems)
Whirlpool allowing air to enter the pump.
Air leakage due to defective pump packing.

Question 22

The actual capacity of the pump is determined in a given scenario by the ______ and ______ of the intake hose, the _______ design, and the _______.

Answer 22

Diameter and length
Strainer
Vertical Lift

Question 23

If no specific information is available, the general guideline is to discharge ____ psi into the FDC.

Answer 23

150 psi.

Question 24

Standpipe Ops
Pump discharge pressure will depend on the following variables:
(5)

Answer 24

> Pressure loss (25 psi in the standpipe)
Friction loss in the hose lay from the pumper to FDC.
Friction loss in the hose on the fire floor.
Nozzle pressure for the type of nozzle used.
Elevation pressure due to the height of the building.

Question 25

Do not use pump discharge pressure in excess of ____ psi unless the standpipe system, hose, and appliances have been designed to function under high pressure.

Answer 25

185 psi