Chapter 6 What is Water and Where Does It Come From

Question 1

Water is a compound of hydrogen and oxygen formed when:

Answer 1

two hydrogen atoms combine with one oxygen atom.

Question 2

Water exists in a liquid state between:

Answer 2

32ºF and 212ºF (0ºC and 100ºC)

Question 3

Water converts to a solid state (ice) below:

Answer 3

32ºF (0ºC)

Question 4

Water converts to steam above:

Answer 4

212ºF (100ºC)

Question 5

Water is lightest close to its boiling point – weighing approximately:

Answer 5

60 lb/ft3 (0.96 kg/L).

Question 6

For fire protection purposes, ordinary fresh water is generally considered to weigh:

Answer 6

8.33 lb/gal (1kg/L)

Question 7

What is specific heat?

Answer 7

A measure of the heat-absorbing capacity of a substance

Question 8

What unit is used to measure amounts of heat transfer?

Answer 8

British thermal unit (Btu) or joule (J)

Question 9

What is a Btu?

Answer 9

The heat required to raise the temperature of 1 pound of water 1ºF

Question 10

What unit of measurement has the joule taken the place of in the SI (International System of Units)?

Answer 10

Calorie

Question 11

The latent heat of vaporization is:

Answer 11

The quantity of heat absorbed by a substance when it changes from a liquid to a vapor

Question 12

What is the name for the temperature at which a liquid absorbs enough heat to change to a vapor?

Answer 12

Boiling point

Question 13

Vaporization does not completely occur at boiling point. Each pound of water requires approximately ___ Btu (kJ) of additional heat to completely convert into steam.

Answer 13

970 Btu (1 023 kJ)

Question 14

Approximately how much does water expand beyond its original volume when converted to steam at 212ºF (100ºC)?

Answer 14

1,700 times

Question 15

The speed with which water absorbs heat increases in proportion to:

Answer 15

the water surface exposed to the heat.

Question 16

Steam expansion is ___ inside a burning building.

Answer 16

rapid

Question 17

What is specific gravity?

Answer 17

The density of liquids in relation to water

Question 18

What kinds of liquids are lighter than water and therefore float on water?

Answer 18

Those with a specific gravity less than 1

Question 19

What kinds of liquids are heavier than water and sink to the bottom?

Answer 19

Those with a specific gravity greater than 1

Question 20

Most flammable liquids have a specific gravity of:

Answer 20

less than 1

Question 21

How much pressure is required to reduce the volume of water one percent?

Answer 21

30,000 psi (210 000 kPa)

Question 22

Friction loss in a system ___ as the length of hose or piping ___.

Answer 22

increases/increases

Question 23

Flow pressure will always be ___ near the supply source and ___ at the farthest point in the system.

Answer 23

greatest/lowest

Question 24

If an opening is made directly at the hydrant, as opposed to the nozzle, the flow will be much ___ at a ___ pressure.

Answer 24

greater/higher

Question 25

If velocity is increased beyond practical limits, the friction becomes so great that resistance agitates the entire stream, creating:

Answer 25

critical velocity.

Question 26

What is water hammer?

Answer 26

The sudden stopping of water moving through a hose or pipe resulting in an energy surge being transmitted in the opposite direction, often at many times the original pressure

Question 27

Close nozzles, hydrants, valves, and hose clamps ___ to prevent water hammer.

Answer 27

slowly

Question 28

Equip apparatus inlets and remote outlets with ___ to prevent damage to equipment.

Answer 28

pressure relief devices

Question 29

High-volume systems should be protected with:

Answer 29

dump valves.

Question 30

Where can the primary water supply be obtained?

Answer 30

Surface water or groundwater

Question 31

Which of the following is NOT a means of moving water?

Answer 31

A. Gravity system B. Treatment system* C. Combination system D. Direct pumping system

Question 32

Which means of moving water uses one or more pumps that take water from the primary source and discharge it through the filtration and treatment processes?

Answer 32

Direct pumping system

Question 33

Which means of moving water uses a primary water source located at a higher elevation than the distribution system?

Answer 33

Gravity system

Question 34

What is the fire department's main concern regarding treatment facilities?

Answer 34

hat a maintenance error, natural disaster, loss of power supply, or fire could disable the pumping stations

Question 35

From where does the water supply distribution system receive water?

Answer 35

From the pumping station

Question 36

When water flows through pipes, its movement causes friction that results in a reduction of pressure. There is much less pressure loss in a water distribution system when fire hydrants are supplied:

Answer 36

from two or more directions.

Question 37

A fire hydrant that receives water from only one direction is known as a:

Answer 37

dead-end hydrant.

Question 38

A fire hydrant that receives water from two or more directions is known as a:

Answer 38

looped line.

Question 39

A distribution system that provides circulating feed from several mains constitutes a:

Answer 39

grid system.

Question 40

___ are large pipes (mains) with relatively widespread spacing, that convey large quantities of water to various points of the system for local distribution to the smaller mains.

Answer 40

Primary feeders

Question 41

___ make up a network of intermediate-sized pipes that reinforce the grid within the various loops of the primary feeder system and aid the concentration of the required fire flow at any point.

Answer 41

Secondary feeders

Question 42

___ make up a grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers.

Answer 42

Distributors

Question 43

To ensure sufficient water, two or more primary feeders should run from the source of supply to the ___ districts of the community by separate routes.

Answer 43

high-risk and industrial

Question 44

In residential areas, the recommended size for fire hydrant supply mains is at least 6 inches (150 mm) in diameter. These should be closely gridded by 8-inch (200 mm) cross-connecting mains at intervals of not more than:

Answer 44

600 feet (180 m).

Question 45

In the business and industrial districts, the minimum recommended size is a(n) ___ main with cross-connecting mains every 600 feet (180 m).

Answer 45

8-inch (200 mm)

Question 46

___ mains may be used on principal streets and in long mains not cross-connected at frequent intervals.

Answer 46

12-inch (300 mm)

Question 47

Water mains as large as ___ may be found in major cities.

Answer 47

48 inches (1.2 m)

Question 48

What is the function of a valve in a water distribution system?

Answer 48

To provide a means for controlling the flow of water through the distribution piping

Question 49

Valves should be operated at least ___ to keep them in good condition.

Answer 49

once a year

Question 50

Valve spacing should be such that:

Answer 50

only a minimum length of pipe is out of service at one time.

Question 51

Which type of valve shows whether the gate or valve seat is open, closed, or partially closed?

Answer 51

Indicating valve

Question 52

Which type of valve is a hollow metal post that is attached to the valve housing?

Answer 52

Post indicator valve

Question 53

Which type of valve has a yoke on the outside with a threaded stem that controls the gate's opening or closing?

Answer 53

Outside screw and yoke

Question 54

Which types of valves are the most common types of valves used on most public water distribution systems?

Answer 54

Nonindicating valves

Question 55

Valves that are only partially open cause:

Answer 55

high friction loss.

Question 56

Which of the following is NOT a material commonly used to make water pipes?

Answer 56

A. Steel* B. Plastic C. Concrete D. Cast iron

Question 57

Friction loss of pipes is most frequently increased by:

Answer 57

encrustation of minerals on the interior surfaces of the pipe.

Question 58

Friction loss can be reduced by:

Answer 58

flushing hydrants periodically.

Question 59

Private water supply systems are NOT normally found on:

Answer 59

fire protection properties.

Question 60

Which of the following statements about private water supply systems is FALSE?

Answer 60

A. Private water supply systems are most often found in residential developments.* B. The design of private water supply systems is typically similar to that of municipal systems. C. Private water supply systems may service one large building or a series of buildings on the complex. D. Most private water supply systems separate piping for fire protection and domestic/industrial services.