Module One - Characteristics of Water

Question 1

States of Water

Answer 1

Below 32 F (0 C) – freezing point of water – solid

Above 212 F (100 C) – boiling point of water – gas

Between 32 F and 212 F (0-100 C) – liquid

Question 2

Specific gravity

Answer 2

Water = 1

Less than one – float
Greater than one – sink

Question 3

Water Density

Answer 3

Weight per unit of volume

Measured in kg/m3

Weight of fresh water = 1000kg/m3
1kg/L

Lightest when close to boiling point

Question 4

Specific Heat

Answer 4

A measure of the heat absorbing capacity of a substance

A calorie is the amount of heat required to raise the temperature of 1g of water 1 C

Question 5

Force

Answer 5

Simple measure of weight

Push or pull on an object resulting in the objects interaction with another

Only exists as a result of an interaction

If several objects of the same size and weight are placed on a flat surface, they all exert the same force on that surface

Question 6

Pressure

Answer 6

Force per unit area exerted by a liquid or gas measured in pounds per square inch (PSI) or kilopascals (KPA)

Question 7

Pressure affect on flow rate

Answer 7

Pressure on the fluid

Size of opening its flowing through

Speed the fluid travels

Question 8

Velocity

Answer 8

Determined by the pressure of fluid and size of the orifice

Question 9

Six Principles of Pressure

Answer 9

1. Fluid pressure is perpendicular to any surface on which it acts
2. Fluid pressure at a point in a point in fluid at rest is the same intensity in all directions (hydrostatic testing)
3. Pressure applied to a confined fluid from without is transmitted equally in all directions
4. The pressure of a liquid in a open vessel is proportional to its depth
5. The pressure of a liquid in an open vessel is proportional to the density of the liquid
6. The pressure of a liquid on the bottom of a vessel is independent of the shape of the vessel

Question 10

Principles of Pressure - First

Answer 10

1. Fluid pressure is perpendicular to any surface on which it acts

Question 11

Principles of Pressure - Second

Answer 11

2. Fluid pressure at a point in a point in fluid at rest is the same intensity in all directions (hydrostatic testing)

Question 12

Principles of Pressure - Third

Answer 12

3. Pressure applied to a confined fluid from without is transmitted equally in all directions

Question 13

Principles of Pressure - Four

Answer 13

4. The pressure of a liquid in a open vessel is proportional to its depth

Question 14

Principles of Pressure - Five

Answer 14

5. The pressure of a liquid in an open vessel is proportional to the density of the liquid

Question 15

Principles of Pressure - sixth

Answer 15

6. The pressure of a liquid on the bottom of a vessel is independent of the shape of the vessel

Question 16

Atmospheric Pressure

Answer 16

Surrounds earth, has depth and density

Greatest at lower altitudes

Sea level of 101kpa (14.7psi) is used as a standard

Calgary is 89KPA, gauges are set to 0

Question 17

vacuum

Answer 17

Any pressure less than atmospheric pressure

A vacuum is need to facilitate drafting of water from a static source

Perfect vacuum = absolute zero pressure

Question 18

Head Pressure

Answer 18

Refers to the height of water supply above the discharge orifice

Convert head in m to pressure by times by 10

Question 19

Static Pressure

Answer 19

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

Pressure in a system before it flows from a hydrant is considered static for fire service purposes

Question 20

Normal Operating Pressure

Answer 20

Pressure found in a water distribution system during normal consumption demands

Question 21

difference between static pressure and normal operating pressure

Answer 21

is the friction caused by water flowing through the various pipes, valves, and fittings to the system

Question 22

Residual Pressure

Answer 22

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

Question 23

Flow or Velocity Pressure

Answer 23

The forward velocity pressure while water flows from a discharge opening

Question 24

Elevation

Answer 24

A pumps centerline or an objects position above or below ground level

Question 25

Elevation pressure

Answer 25

Pressure loss or gain due to elevation above or below ground level

Question 26

Altitude

Answer 26

Position of an object above or below sea level

Question 27

Friction Loss

Answer 27

The pressure loss due to friction that is in part or total loss while forcing water through pipes, fittings, hose or adapters

Question 28

FL Caused by:

Answer 28

Movement of water molecules against each other Lining of fire hose Couplings Sharp bends Change in hose size (by adapters) Improper gasket size Bends, kinks, etc.

Question 29

Friction Loss Principles

Answer 29

1. If all other conditions are the same, friction loss varies directly with the length of the hose or pipe (length) 2. When hoses are the same size, FL varies approximately with the square of the increases in the velocity of flow (velocity) 3. For the same discharge, FL varies inversely as the fifth power of the diameter of the hose (diameter) 4. For a given flow velocity, FL is approx. The same regardless of the pressure of water

Question 30

Friction Loss Principles - First

Answer 30

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

Question 31

Friction Loss Principles - second

Answer 31

2. When hoses are the same size, FL varies approximately with the square of the increases in the velocity of flow (velocity)

Question 32

Friction Loss Principles - third

Answer 32

3. For the same discharge, FL varies inversely as the fifth power of the diameter of the hose (diameter)

Question 33

Friction Loss Principles - fourth

Answer 33

4. For a given flow velocity, FL is approx. The same regardless of the pressure of water

Question 34

Other factors that affect FL:

Answer 34

A pressure of 210,000 kpa is required to reduce its volume 1% Size of the hose determines the velocity for a given volume of water The smaller the hose, the greater the velocity needed to deliver the same volume

Question 35

Reducing friction Loss:

Answer 35

Hose length Hose diameter Sharp bends (kinks) in the hose

Question 36

Critical Velocity

Answer 36

There are limits to the speed at which a stream can travel If velocity increases beyond these limits, the friction becomes so great the entire system is agitated by resistance Beyond this point: Twin or triple the lay or use a larger diameter hose to increase flow and decrease friction

Question 37

What are the purposes of a private water supply system?

Answer 37

To provide water strictly for fire protection To provide water for sanitary and fire protection To provide water for fire protection and manufacturing

Question 38

What are some advantages of using water as an extinguishing agent?

Answer 38

- Great at absorbing heat - A large amount of heat is required to change water to steam, allowing more heat to be absorbed from the fire. - The greater the surface area of water exposed, the more rapidly heat is absorbed. - Inexpensive and readily available.