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Pump Course > Module One - Characteristics of Water > Flashcards

Module One - Characteristics of Water Flashcards

1
Q

States of Water

A

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

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2
Q

Specific gravity

A

Water = 1

Less than one – float
Greater than one – sink

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3
Q

Water Density

A

Weight per unit of volume

Measured in kg/m3

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

Lightest when close to boiling point

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4
Q

Specific Heat

A

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

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5
Q

Force

A

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

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6
Q

Pressure

A

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

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7
Q

Pressure affect on flow rate

A

Pressure on the fluid

Size of opening its flowing through

Speed the fluid travels

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8
Q

Velocity

A

Determined by the pressure of fluid and size of the orifice

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9
Q

Six Principles of Pressure

A
  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
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10
Q

Principles of Pressure - First

A
  1. Fluid pressure is perpendicular to any surface on which it acts
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11
Q

Principles of Pressure - Second

A
  1. Fluid pressure at a point in a point in fluid at rest is the same intensity in all directions (hydrostatic testing)
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12
Q

Principles of Pressure - Third

A
  1. Pressure applied to a confined fluid from without is transmitted equally in all directions
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13
Q

Principles of Pressure - Four

A
  1. The pressure of a liquid in a open vessel is proportional to its depth
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14
Q

Principles of Pressure - Five

A
  1. The pressure of a liquid in an open vessel is proportional to the density of the liquid
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15
Q

Principles of Pressure - sixth

A
  1. The pressure of a liquid on the bottom of a vessel is independent of the shape of the vessel
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16
Q

Atmospheric Pressure

A

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

17
Q

vacuum

A

Any pressure less than atmospheric pressure

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

Perfect vacuum = absolute zero pressure

18
Q

Head Pressure

A

Refers to the height of water supply above the discharge orifice

Convert head in m to pressure by times by 10

19
Q

Static Pressure

A

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

20
Q

Normal Operating Pressure

A

Pressure found in a water distribution system during normal consumption demands

21
Q

difference between static pressure and normal operating pressure

A

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

22
Q

Residual Pressure

A

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

23
Q

Flow or Velocity Pressure

A

The forward velocity pressure while water flows from a discharge opening

24
Q

Elevation

A

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

25
Q

Elevation pressure

A

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

26
Q

Altitude

A

Position of an object above or below sea level

27
Q

Friction Loss

A

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

28
Q

FL Caused by:

A

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.

29
Q

Friction Loss Principles

A
  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
30
Q

Friction Loss Principles - First

A
  1. If all other conditions are the same, friction loss varies directly with the length of the hose or pipe (length)
31
Q

Friction Loss Principles - second

A
  1. When hoses are the same size, FL varies approximately with the square of the increases in the velocity of flow (velocity)
32
Q

Friction Loss Principles - third

A
  1. For the same discharge, FL varies inversely as the fifth power of the diameter of the hose (diameter)
33
Q

Friction Loss Principles - fourth

A
  1. For a given flow velocity, FL is approx. The same regardless of the pressure of water
34
Q

Other factors that affect FL:

A

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

35
Q

Reducing friction Loss:

A

Hose length

Hose diameter

Sharp bends (kinks) in the hose

36
Q

Critical Velocity

A

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

37
Q

What are the purposes of a private water supply system?

A

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

38
Q

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

A
  • 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.

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