Chapter 11, Operating Fire Pumps

Question 1

IFSTA recommends that the apparatus wheels be chocked when ?

Answer 1

Every time the apparatus is stopped with the engine running and driver operator exits the cab (in case truck jumps into gear).

Question 2

How can water be allowed to circulate in the pump, if no attack line is ready by the time pump pressure has built up?

Answer 2

Crack open the “tank fill”.

Question 3

If the master pressure gauge fails to register a reading (after you have put truck in pump), what would you check?

Answer 3

Pump may not be in proper gear. Immediately decrease rpm, go to cab and ensure transmission is in proper gear.

Question 4

What are the 2 basic pressurized water supply sources, that can be used to supply a fire pump?

Answer 4

• hydrant

- supply hose from another fire pump

Question 5

What happens if the discharge pressure from the pump is increased too much?

Answer 5

The intake pressure from the supply source may be reduced below zero (cavitation).

Question 6

To avoid possible damage to the fire pump, you should not allow the intake pressure fall below how much psi?

Answer 6

20psi (in rare instances, you may have to, but should never fall to zero).

Question 7

What is the first consideration when selecting a hydrant?

Answer 7

Determining which hydrant is most appropriate in terms of fire fighting and safety needs (The closest hydrant is not always the best choice).

Question 8

What are the 2 ways that a fire department pumper may use a hydrant?

Answer 8

• forward lay (stopping at hydrant, drop supply line at hydrant, proceed to fire)
• reverse lay (laying hose from fire scene back to hydrant)

Question 9

Departments that prefer forward lays use a 4 way hydrant valve. Why?

Answer 9

The valve (humat) has a 2nd discharge outlet, which allows a 2nd pumper to connect to the hydrant without interrupting flow (boosts pressure to initial pumper).

Question 10

When using the 2 1/2 or 3 inch lines to supply the pumper directly from the hydrant, its recommended that the lines not be any longer than 300 feet. Why?

Answer 10

Beyond 300 feet, the amount of friction loss is to great to provide an adequate supply of water.

Question 11

What hose lay is used as the most direct way to supplement hydrant pressure and perform drafting operations?

Answer 11

Reverse lay.

Question 12

What are 2 disadvantages of reverse lay?

Answer 12

• fire fighting equipment must be removed and placed at fire location before pumper proceeds to hydrant (time consuming)
• pumper may not carry enough hose to reach from fire to water source

Question 13

What are some methods of preventing overheating?

Answer 13

• pull off/secure booster line, open valve
• open discharge drain valve
• partially open the tank fill valve
• use circulator/bypass valve (if truck has one)

Question 14

What 3 methods are use to determine “additional lines” available?

Answer 14

• percentage method
• first-digit method
• squaring the lines method

Question 15

How do you check to see, after shutting down a dry hydrant, if the water is draining?

Answer 15

Cover a 2 1/2 outlet with your hand, if the hydrant is draining, a slight vacuum will be felt.

Question 16

The first consideration in establishing a drafting operation is selecting a site. What factors dictate the site selected?

Answer 16

• amount of water (most important)
• type of water
• accessibility of water

Question 17

How much water is recommended around the strainer during a drafting operation?

Answer 17

Minimum 2 feet of water over the strainer (desirable to have 2 feet all around the strainer). Helps to ensure max capacity and avoid drawing objects into pump (sand, gravel).

Question 18

What 2 methods are used to draft from a swiftly moving shallow stream?

Answer 18

• use a floating strainer (preferred)

- construct a dam

Question 19

During drafting operations, what is the most common, and most dangerous, type of contamination?

Answer 19

Dirty or sandy water.

Question 20

During drafting, as the amount of lift increases, what occurs?

Answer 20

• elevation pressure increases
• less friction loss can be overcome
• capacity of the pump decreases

Question 21

What are pump capacity ratings based on, for drafting?

Answer 21

A 10 foot lift.

Question 22

For effective drafting operations, what is the maximum lift considered reasonable for most fire department pumpers?

Answer 22

About 20 feet (at 20 ft, amount of water that can be supplied is only about 60% of the pumps rated capacity).

Question 23

Once the drafting operation is physically set up, what starts the draft operation?

Answer 23

Priming the pump.

Question 24

When do you stop the priming action?

Answer 24

When all the air is removed and the primer is discharging a steady stream of water.

Question 25

How long does the entire priming action typically take?

Answer 25

10 to 15 seconds from start to finish.

Question 26

What are the causes for inability to prime a pump?

Answer 26

• air leak (most common)
• insufficient fluid in priming reservoir
• rpm too slow
• lift is too high
• high point in the hard intake hose creating an air pocket

Question 27

The problems that can occur while drafting falls into what 3 categories?

Answer 27

• air leak on intake side of pump (most common)
• whirlpool allowing air to enter the pump (not enough water over the strainer
• air leak due to defective packing in the pump

Question 28

What’s the first line of defense against uncontrolled fire within an occupancy?

Answer 28

Fixed fire protection systems (sprinkler/standpipe).

Question 29

What does and FDC consist of?

Answer 29

A siamese with at least 2 2 1/2 inch female connectors, or one large diameter sexless connection.

Question 30

What are standpipes used for?

Answer 30

To speed fire attack in multistory or single story buildings with large floor plans.

Question 31

During standpipe operations, pump discharge pressure depends on what?

Answer 31

• pressure loss in the standpipe
• friction loss in the hose lay from pumper to FDC
• friction loss to hose on fire floor
• elevation pressure due to height of building
• nozzle pressure for type of nozzle used

Question 32

Pump discharge pressures for standpipes in the city of Glendale are standard 150 psi. What pump discharge pressure, in general, are we encouraged not to exceed?

Answer 32

Pump discharge pressures in excess of 200 psi are not encouraged, unless the standpipe system is designed to withstand higher pressures.

Question 33

When a standpipe system is known to be equipped with pressure reducing valves, the elevation pressure used must be based on what?

Answer 33

Based on the total height of the standpipe or the zone being used.