Chapter 5 Charac Of Water Flashcards Preview

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Flashcards in Chapter 5 Charac Of Water Deck (67):
1

Whater is a compoundof hydrogen and oxygen formed when two hydrogen combine with:

1 oxygen atom

Pg 167

2

Water cannot be seen in its vapor form. It only becomes visible as it rises away from the surface of the liquid and:

Begins to condense
Pg 167

3

For fire protection purposes ordinary fresh water is considred to weigh:

8.3 lbs / gallon

Pg 167

4

Water has the ability to extinguish fire by:

Absorbing heat from the fire, smother fire by excluding oxygen
It can smother fires i combustible liquids whose specific gravity is greater than 1. It may also occur when water converts to steam within a closed space

Pg 168

5

What characteristics make water an excellent extinguishing agent:

Great heat absorbing capacity
The greater surface area exposed the more rapidly heat is absorbed
At 212 f it converts to steam and is increased 1,7000 times its original volume
Readily avail
Pg 169

6

Disadvantages of water:

High surface tension
Might react with certain fuels and combustible metals like sodium and triethyl aluminum
Freezes in cold weather

Pg 169

7

Pressure is defined as:

Force per unit area. Pressure may be expressed as pounds per square foot, pounds per square inch or kilopascals

Pg 170

8

Force is defined as

A simple measure o weight and is expressed in pounds of kilograms

Pg 170

9

Velocity

The speed at which a fluid travels through a hose or pipe is determined by the pressure upon that fluid as well as the size of the orifice through which it is flowing.
Pg 172

10

First principle of pressure

Fluid pressure is perpendicular to any surface

Pg 172

11

Second principal of pressure

Fluid pressure when fluid is at rest is the same in all directions

12

Third principal of pressure

Pressure applied to a confined fluid is transmitted equally in all directions

Pg 172

13

Fourth principal of pressure

The pressure of a liquid in an open container is proportional to its depth. The deeper the water the more pressure at the bottom of it.

Pg 173

14

Fifth principal of pressure

The pressure of a liquid in an open vessel is proportional to the density of the water. The denser the liquid the more pressure it will have

15

Sixth principal of pressure:

The pressure of liquid at the bottom of a vessel is independent of the shape of the vessel. No matter the shape the pressure is the same
Pg 174

16

Pressure is greater at...... Altitudes and lower at...... Altitudes
Atmospheric pressure is

Lower altitudes pressure is greater
Higher altitudes it is lower
Atmospheric pressure it is 14.7
Pg 174

17

The reading of psig is?

Pounds per square inch gauge when does not include atmospheric pressure into its reading.

Pg 174/175

18

In the fire service head refers to:

The height of a water supply above the discharge

Pg 175

19

To convert head in feet to head pressure you must divide the number of feet by

2.304
Pg 175

20

The water flow definition of static pressure is:

Stored potential energy available to force water through pipes, fittings, hose and adapters

Pg 175

21

Normal operating pressure:

The pressure found in a water distribution system during normal consumption demands

Pg 176

22

Residual pressure

The portion of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes fittings hoses or adapters

Pg 176

23

While water is flowing from a discharge opening the forward velocity pressure is considered

Flow pressure

Pg 176

24

The center line of the pump of the bottom of a static water supply source above or below ground level is:

Elevation

Pg 176

25

Altitude is the position of an object in relation to:

Sea level

Pg 176

26

The pressure losses or gains due to gravity are called:

Elevation pressure

Pg 176

27

Friction loss

Pressure loss due to friction

Pg 177

28

The friction loss in older hose may be as much as ..... Percent greater than that of new hose

50%

Pg 177

29

First principle of friction loss;

If all other conditions are the same, friction loss varies directly with the length of the hose or pipe

Pg 178

30

Second principle of friction loss:

When. Hoses are the same size, friction loss varies approximately with the square of the increase in the velocity of the flow
Pg 178

31

Third principle of friction loss:

For the same discharge, friction loss varies inversely as the fifth power of the diameter of the hose

Pg 179

32

When the flow remains constant, the friction loss in a hose will decrease when:

The diameter of the hose is increased

Pg 179

33

Fourth principle of friction loss:

For a given velocity friction loss is approx the same regardless of the pressure on the water

Pg179

34

Friction loss in a water system increases as the

Length of hose or piping increases

Pg180

35

Before water supply operations begin, the number of pumpers required to meet the requirements of the incident should be:

Determined and positioned for maximum efficiency

Pg181

36

There are practical limits to the velocity at which a stream can travel. critical velocity is an increase beyond this limit. It can be fixed by:

Using parallel hoselines or siamese lines to increase flow and reduce friction

Pg181

37

To reduce friction loss in hose length:

Reduce the length of the hose and increase the diameter

Pg 181

38

Sharp bends and kinks can usually be minimized by employing:

Proper hose handling techniques

Pg 181

39

To prevent water hammers when flowing master streams from hydrants you should partially close hydrants:

Stop the hydrant then close more as a prevention measure

Pg 181

40

Because the local water depts principle function is to provide potable water its officials are the experts in:

Water supply problems

Pg 182

41

When a large volume of water is needed the fire dept should request the water utility dept to:

Increase the water pressure in an area where there is a very large fire fighting operation

Pg 182

42

The primary water supply can be obtained from either:

Surface water or ground water

Pg 182

43

Two examples of surface water supply are:

Rivers and lakes

Pg182/183

44

Groundwater supply can be:

Water wells or water producing springs

Pg183

45

Direct pumping system uses:

One or more pumps that takes water from the primary source and discharges it through the filtration and treatment process. From there a series of pumps force the water into the distribution system

Pg 183

46

Gravity system:

Uses a primary water source located at a higher elevation than the distribution system. The gravity provides water pressure for the system. This is only sufficient pressure if the source is several hundered higher than the highest distribution point.

Pg183

47

Combination system is used by most communities and includes:

Direct and gravity systems

Pg 183

48

A dependable combination system involves:

Reliable duplicated equipment and proper sized strategically located storage containers

Pg184

49

Storage of water should be sufficient to provide:

Domestic and industrial demands plus the demands expected in fire fighting operations

Pg184

50

Water may be treated by:

Coagulation
Sedimentation
Filtration
Or the addition of chemicals, bacteria or other organisms

Pg184

51

The ability of a water system to deliver and adequate quantity of water relies upon the:

Carrying capacity of the systems network of pipes

Pg 184

52

When a fire hydrant receives water from two or more directions it is said to have a:

Circulating feed or a looped line

Pg184

53

A grid system should consist of the following components:

Primary feeders: large pipes widespread to convey large amts of water to smaller mains
Secondary feeders:
Network of intermediate sized pipes that reinforce the grid within the arious loops of the primary feeder system and aid the concentration of the required fire flow at any point
Distributors:
Grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers

Pg185

54

The function of a valve in a water distribution system is to provide a means for:

Controlling the flow of water through the distribution piping.
Valves should be located so that only small districts are cut off if it is necessary to stop the flow at a specific point.
Pg 185/186

55

One of he most important factors in a water supply system is the water depts ability to promply operate:

The valves during an emergency or breakdown of equipmet

Pg 186

56

The two most common indicating valves are the:

Post indicator valve and the outside screw an yoke valve

Pg186

57

The most common type of valve used on most public water distribution systems is the:

Nonindication valves

Pg 186

58

Control valves in public water distribution systems are generally:

Gate valves

Pg187

59

If a valve resists turning after fewer than the indicated number of turns it usually means:

Debrisor other obstructions are in the valve, or it may be corroded due to lack of maintenance

Pg187

60

Water pipe that is used underground is generally made of:

Cast iron, ductile iron, asbestos cement, steel plastic, or concrete

Pg187

61

Whenever pipe is installed, it should be the:

Proper type for the soil conditions and pressures to which it will be subjected

Pg187

62

The adverse effects of encrustation and sedimentation (friction loss) can be reduced by:

Flushing hydrants periodically

Pg188

63

The water supply system average daily consumption is the:

Average amount of water used per day based on the total amount of water used in the water distribution system over the period of one year

Pg188

64

The water system maximum daily consumption is the:

Maximum total amount of water that was used during any 24 hr interval within a 3 year period

Pg188

65

The water system peak hourly consumption is the:

Maximum amount of water used in any 1 hour interval over the course of a day

Pg188

66

Private water supply systems are most commonly found on:

Large commercial industrial, or institutioinal properties, and may also be found in some residential developments

Pt 188

67

Private water supply systems exists for one of 3 purposes:

Fire protection
Sanitary
Manufacturing processes

Pg 188