1. Key Plumbing Principles
Science Definitions

2. Measurement
In UK what are the two principle units of measurement?
Imperial
Metric
Most older plumbers still use the imperial system
Since the 1970’s metric has been used for many plumbing materials/fittings.
These are:
Kilogramme for weight
Litre for liquids
Metre for length
The standard international measurement system, commonly known as SI units
SI stands for ‘Système Internationale d’Unités’

3. Science, Definitions Attribute SI Unit Abbreviation Mass Kilogram Kg
Length
metre m
Time
Second s
Angle
Radian
Rad
Area
Metres Sq M2
Volume
Metres Cu M3
Capacity
Litre L
Speed
Metres per second
m/s
Acceleration
Metres per sec/per sec
m/s2
Force
newton's n

4. Mass (m)
What is Mass?
In its simplest terms, mass is the amount of matter in an object and is measured in:
grams (or for larger weights, kilograms).
Mass does not change with a body's position, movement or alteration of its shape unless material is added or removed.
The unit of mass in the SI system is the kilogram

5. Weight (w) In Science, what is weight?
The weight of a body is the gravitational force acting on it and hence it should be measured in Newton's (abbreviation N)
This force depends on the local acceleration due to gravity.
So without Gravity what would you weigh ?
But do you still have the same Mass?

6. Gravity (called Force)
Force exerted by each and every object
Expressed as Newton's
What is the difference between Mass and weight ?
On Moon little gravity ?
Gravitational pull on moon is 1.633m/s
What is the gravitational pull on earth?
9.81m/s

7. Density What is density
Practical terms Density is measurement of Mass (g/Kg) compared to its volume (cm3/M3)
Density of Solids
Same size and shape object can have different Mass. Known as Density
Density=Mass divided by Volume
All Density of objects are worked out
Water is classed as 1.0

8. Density of Liquids What is the density of water Water 1.0
Molecules within a volume (more molecules more Dense)
Water has less Mass when heated as Molecules move further apart
What temperature is water at it’s Max density ?
4oC

9. Density of Gases What is the density of gases compared to?
Comparisons are usually made to the density of air.
What is the density of air?
Air 1.0
Above or below will rise or sink, e.g. Butane density 2.0, does it rise or sink ?
What is the density of Propane?
1.5

10. Relative Density or ( Specific Gravity)
Measure Density of a Substance by comparing it to an equal amount of water
Eg. 1m3 of water has a Mass of 1,000kg
1m3 of copper has a Mass of 8,900kg
It is 8.9 times heavier , so its Relative Density = 8.9
Relative Density of Air is 1.0, so comparisons can be made for Gases

11. Relative Density Cont’d
Any solid/liquid substance with a relative density less than 1 compared to water will do what?
Will float on water.
Any gaseous substance with a relative density less than 1 compared to air will do what?
They will Rise

12. Questions Density is a measurement of what?
At what temperature does water achieve its maximum density?
If 1m3 of lead has a mass of 11,300kg what is it’s relative density?
What would be the weight of a 2kg block of lead if gravity is measured at 9.81m/s?
If a cistern holds 115trs of water (115kg) what is the gravitational force acting downwards on the base of the cistern?

13. Answers
Mass / Volume
40 C
11.3
19.62 Newtons
Newtons

14. Lesson Complete

15. Plumbing Science
Pressure
Properties of water

16. Pressure Defined as force per unit area and is measured in? N/M2
a unit is also known as?
Pascals (Pa)
Plumbers also use other terms such as?
Bar or Ibs per square inch. These are expressed as
1 bar = 100,000N/m2 Approx
1 Ibf/in2 = 6894 N/m2
1metre head of water = 0.1 Bar
10 metre head of water = 1.0 Bar

17. Pressure Pressure in solids is in a downward direction only
Pressure in liquids is in a downward and sideward direction
It is important for a plumber to Know these facts when
Choosing materials for system components such as cisterns
Or cylinders and even type of pipework.

18. Pressure Two basic means of obtaining pressure Fit pump
Use weight of water
Higher the column of water the greater the intensity of pressure
Formula for calculating intensity of pressure is?
Head X 9.81
Result is Newtons
After the last result do the example on page 33
6 x 9.81
= 58.86kpa 2
(50-3)x9.81
=461.07kpa or kn/m2

19. Pressure
What would you have to do to obtain a greater pressure in the water supply that is fed from a cistern?
So higher cold water cistern = greater pressure
Gravitational force (Atmosheric pressure)=Force applied per unit area, Newton's per meter squared (N/M2)
The Force produced by 1kg mass =9.81N
See next example
After 3 give the formula for force
Page 31 bpec module
Force (acting on base of cistern) = mass x acceleration
= 1000kg x 9.81m/s2
= 9810n 0r 9.81kn

20. Pressure Task Eg, a container. 1m x 1m x 1m =1m3 It will weigh 1,000kg
It would exert a pressure of
1,000kg x 9.81N = 9,810 N
Divide by 1,000 to get Kilo Newton's =
9.81 KN/M2
If lifted by 3 meters then the pressure is increased 3 times to 3 x 9.81 =
29.43KN/M2
Bpec book page 31 do the first example

21. Total Pressure = Intensity of Pressure x Area acted upon
Is the actual pressure acting on a given point.
Formula
Total Pressure = Intensity of Pressure x Area acted upon
(kN) (kN/m2) (M2)

22. Total Pressure TOTAL PRESSURE The intensity of pressure at Tap ‘A’C
TOTAL PRESSURE
The intensity of pressure at Tap ‘A’
The intensity of pressure at Tap ‘B’
The total pressure tending to push the manhole lid ‘C’ off the hot store cylinder

23. Total Pressure CALCULATE THE FOLLOWING
Intensity of Pressure at Tap A 2. Intensity of Pressure at Tap B
3. Area of Circular Manhole lid
= Head x 9.81 kN/m2
= 2.4 x 9.81
= kN/m2
= Head x 9.81 kN/m2
= 4.8 x 9.81
= 47 kN/m2
= r2
Where  =
0.15 X 0.15 =
X =
X =
Or dec places
300mm dia = 150mm Radius = 0.15m Radius
Therefore: Intensity of Pressure
Total Pressure
= Head x 9.81 kN/m2
= 3 x 9.81
= kN/m2
= Intensity of Pressure (kN/m2) x Area (m2)
= x (3.142 x (0.15 x 0.15))
= 2.08 kN

24. Atmospheric Pressure Weight of the air creates pressure on earth
Top of the mountain has less pressure than down in a valley below sea level (Mountain climbers use breathing apparatus)
Pressure at sea level is Pascal
Or 100 kPa
1bar = 100kPa
1 m = 0.1bar

25. Pressure Cont’d Pressure is a measure of a concentration of force.
Where can we see a concentration of pressure of water flowing through a pipe?
Hose pipe, seating of a float valve
You can lower pressure by spreading the applied force over a wider area.
Example?
Rescue teams, Fragile roofs, thin ice

26. Properties of water

27. Properties of water
Water is a chemical compound of 2 gases, what are they?
Hydrogen 2parts , oxygen 1 part
Formed when hydrogen gas is burned
Water has solvent powers
It can dissolve numerous gasses and solids
Purest form is what?
Rainwater collected in the countryside
Does not affect its potability (suitability for drinking)
Rainwater collected in the countryside contains dissolved gasses such
As nitrogen ,oxygen, and carbon dioxide these do not affect its
Potability
Ask what would be added to the rainwater if collected in towns
Soot and other pollutants

28. Soft & Hard Water
Soft Water ; absorbs carbon dioxide (how do you know its soft)
ph value lower than 7.0, better lather, brass fittings corrode
Hard Water; absorbs calcium carbonates or sulphates (how do you know its hard)
Ph value higher than 7.0, difficult to lather, lime scale deposits

29. Water Hardness
water hardness can be described in two ways, what are they called?
PERMANENT HARD
Absorbs calcium sulphates
Difficult to lather
TEMPORY HARD
Absorbs calcium Bi-carbonates
Lime scale deposits
Permanenet hardnes occcurs as a result of natural solvency of pure water which enables it to dissolve the sulphates of limestone
Temporary hardness is responsible for the hard scale which accumulates on the inside of boilers and circulating pipes.

30. PH value and Corrosion Ph values ?
Logarithmic scale / measures acidity or alkalinity of substances
Pure water, ph value = 7.0
Acidic, ph value falls
Alkaline, ph value rises
Water changes , dependant on what ground it falls on
Ph refers to the level of acidity or alkalinity of a substance
As a plumber you need to be aware of the affects of acidity and alkalinity that they can have on materials
Appliances and components
Acid and alkaline can be damaging to materials?
why by causing corrosion
See the table in the book for

31. Corrosion What are the main causes of corrosion? Air and water Acids
Electrolytic action
Atmospheric corrosion
(Oxygen and water vapour) combined to form moist air, attack ferrous metals (metals which contain iron) to form the common oxide known as rust.
Various other chemiclas (c02 sulpher dioxide, sulpher trioxide present in our atmosphere also increase the corrosive effect air can have on particular metals especially iron steel and zinc. They are more abumndent in industrial areas
Coastal areas suffer increased atmospheric corrosion due to sodium chloride(salt) in the atmopsphere
Copper and lead have a significant protection against atmosp corrosion in the form of protecticve barriers
(usually sulpahtes) which form on these materials. They are more commonly known as patinas

32. CHEMICAL PROPERTIES OF WATER
Rain
H2O
(Water)
absorbs
CO2
(Carbon dioxide Gas)
and becomes
H2CO3
(Carbonic Acid)
which falls upon
Peaty Moorland
Sandstone
Limestone (CaCo3)
(Soft)
Calcium Bicarbonate
(Temporary Hard)
CO2 added to by decaying vegetation
Retained
CO2 used up to dissolve limestone
ACID
ALKALINE

33. Corrosion Corrosion by Water
Ferrous metals such as iron and steel are vulnerable to the effects of corrosion by water.
Where would you see this?
Central heating systems
What could happen in a soft water area with lead pipes?
In central heating systems it is seen as black ferrous oxide and red rust build up in radiators
This in turn produces hydrogen gas in the radiators and needs to be ‘bled’
Answer water could become contaminated because the soft water can dissolve the lead ‘PLUMBOSOLVENT’

34. Corrosion Underground conditions
Some types of soils can affect pipework underground what are they?
Heavy clay
Ash, cinders
What should you do to prevent corrosion?
Protect them

35. Electrolytic Action and Corrosion
Electrolytic action is the flow of electrically charged ions from an anode to a cathode through an electrolyte (usually water) as shown

36. Electrolytic Action and Corrosion
Electrolytic corrosion takes place when?
The process of electrolysis leads to the destruction of the anode.
What affects the length of time for the anode to be destroyed?
Heat of water
Acidity of water
Position of the metals that make up the anode and cathode in the electromotive series
See table on next page
Other examples lead sheet fixed with zinc nails or screws

37. Electromotive Series Cathodic Copper Tin Lead Nickel Cadmium Iron
Anodic
Copper
Tin
Lead
Nickel
Cadmium
Iron
Chromium
Zinc
Aluminium
Magnesium
What will the Elements higher in the list do to those lower down?
Will destroy those lower down through the process of electrolytic action

38. Lesson Complete

39. Temperature and Specific heat capacity
Plumbing Science
Temperature and
Specific heat capacity

40. TEMPERATURE

41. Temperature is the degrees of “HOTNESS” or “COLDNESS” of a body.
DEFINITION
Temperature is the degrees of “HOTNESS” or “COLDNESS” of a body.
If a temperature measuring instrument reads 100°C, this gives no indication of the quantity of heat present only its level of HOTNESS.
It is obvious that 10 litres of water at 100°C would contain more heat than 1 litre of water at 100°C.
SCALES
Fahrenheit
Not widely used now
Celsius
Sometimes called centigrade, usually written as “C”
Kelvin
0 Kelvin being Absolute Zero
A temperature not yet recorded. At 0K a gas would
be reduced to nothing.

42. TEMPERATURE 32 100 212 TEMPERATURE SCALES
The scales are identified as follows at Atmospheric Pressure (1013mb) 32
100
212
0K = -273°C known as absolute zero
273K = 0°C the ice point of water (change of state)
373K = 100°C the steam (gas) point (change of state)

43. TEMPERATURE Conversion Formula
Both scales are still widely used and conversion from one to the other is sometimes necessary. To convert:
Centigrade to Fahrenheit =
°C x 9/
Fahrenheit to Centigrade =
(°F - 32) x 5/9
An “approximate” method of conversion:
Centigrade to Fahrenheit =
°C x
Fahrenheit to Centigrade =
°F - 30 2

44. TEMPERATURE °F °C Freezing point of water 32 Boiling point of water
There is sometimes a need to convert from one temperature scale to another.
By using your conversion formulas, complete the following table. °F °C
Freezing point of water 32
Boiling point of water
100
Hot water storage temperature 60
Typical room temperature 70
Typical showering temperature 40
Melting point of lead
327
212
140 21
104
620

45. Temperature can be measured using a number of devices. Name TWO. 1) 2)
THERMOMETER
THERMOSTAT
Name TWO devices which might be used to control the
temperature of water in a central heating system. 1) 2)
CYLINDER THERMOSTAT
BOILER THERMOSTAT

46. SPECIFIC HEAT CAPACITY (SHC)

47. SPECIFIC HEAT CAPACITY
Definition
Is a form of energy and so may be converted into
other forms of energy. Heat is measured in
units of energy. SI unit = JOULES.

48. SPECIFIC HEAT CAPACITY
If we take equal quantities of water and oil and warm them in separate containers but by the same flame, we may find that the oil temperature may rise by 15°C in 5 minutes, but the water may only rise by 8°C in the same period of time. Since the supply of heat is the same in both cases, it is clear that oil has a lower heat capacity than water.
When comparing the heat capacities of different substances, we talk of the Specific Heat Capacities.
Definition
The specific heat capacity of a substance is the amount of heat energy required to change the temperature of a 1 kg mass of a substance by 1°C and the unit of specific heat capacity is the Joule per kilogramme degree C. = J/kg°C

49. SPECIFIC HEAT CAPACITIES IN KJ/KG °C
SPECIFIC HEAT CAPACITY
SPECIFIC HEAT CAPACITIES IN KJ/KG °C
SUBSTANCE
KJ/KG °C
Water
0.125
0.234
0.380
0.385
0.397
0.460
0.502
0.544
0.887
1.046
2.100
2.400
4.186
Methylated Spirit
Ice
Air
Aluminium
Cast Iron
Mild Steel
Iron
Zinc
Copper
Brass
Tin
Lead
Mercury

50. SPECIFIC HEAT CAPACITY
The formula generally used for calculating Specific Heat Capacity is as follows:
Quantity of heat (kJ) = Mass (kg) x Specific Heat (kJ/kg) x Temperature Change ºC

51. SPECIFIC HEAT CAPACITY
Examples:
Calculate the quantity of heat required to raise 80 litres of water from 10°C to 55°C.
Answer
Quantity of heat = =
18kg of cast iron is heated through 75°C. How many joules of heat energy are absorbed by the cast iron.
Mass x Specific Heat x Temperature Change
80 x x 45
15069 kJ
Mass x Specific Heat x Temperature Change
18 x x 75
747.9 kJ

52. SPECIFIC HEAT CAPACITY
Examples continued:
25 litres of water cool from 62°C to 15°C. What quantity of heat is given off.
Answer
Quantity of heat = =
Mass x Specific Heat x Temperature Change
25 x x 47
4918 kJ
A 117 litre hot water storage cylinder is heated from 10°C to 60°C and uses KJ of heat energy to heat it. Calculate the specific heat capacity of the water.
Answer
Specific Heat capacity =
Total / Mass / Temperature Change =
24570 / 117 / ( 60 – 10 ) =
4.2

53. SPICIFIC HEAT CAPACITY
Water exists in nature as a liquid, a solid (ice) and as a gas (steam).
Each of these states can be changed from one to the other, simply by raising or lowering the temperature.
Pure fresh water boils at –
100ºC at atmospheric pressure
AP = =
101.3 kN/m2
Approx 1 bar
Water freezes at and becomes ice with an immediate expansion of
0ºC
1/10th its volume

54. SPICIFIC HEAT CAPACITY
Temperature
Steam (gas) expansion about 1600 times
Density kg/m3
100 BP
956.32 82
968.96
Water (liquid) expansion from 4ºC to 100ºC
Expansion
about 1/24th 60
982.16 15
997.92
4 Maximum
density FP
998.4
Ice (solid) expansion about 1/10th
THE THREE PHYSICAL STATES OF WATER

55. SPECIFIC HEAT CAPACITY
SPECIFIC LATENT HEAT
If a block of ice is placed in a vessel with a thermometer and heat is applied, the temperature remains steady at 0°C (273°K) until the whole of the ice has been melted and then the temperature begins to rise. The heat given to the ice has not caused any rise in temperature, but a change of state from solid to liquid and is called the “Specific Latent Heat of Fusion”.

56. SPECIFIC HEAT CAPACITY
SPECIFIC LATENT HEAT
There is no rise in
temperature as the
water turns into
steam. All the heat
energy is required
to cause the change
of state. This is the
LATENT HEAT of
VAPORISATION.
( Boiling )
100°C
The heat source
is raising the
temperature of
the water formed
by the molten ice.
This is
SENSIBLE HEAT
There is no rise in
temperature as the
ice melts. All heat
energy is required
to cause the change
of state. This is the
LATENT HEAT of
FUSION.
( Melting )
0°C
The heat source
is raising the
temperature of
the ice. This is
SENSIBLE HEAT
TIME

57. Thermal Expansion Conduction, Convection, Radiation
Plumbing Science
Thermal Expansion
Conduction, Convection, Radiation

58. Thermal Expansion Most materials expand when heated
Why do they expand?
Because they are made up of molecules which move about more vigorously when heated.
What do the molecules do when they do this?
They move further apart and consequently take up more room or as we say ‘expand’

59. Thermal Expansion
What do you think happens when a material cools down?
Yes they do the reverse of when they expand. The material gets smaller and contracts
How do we measure this
By using the formula
length x temperature rise x coefficient

60. Coefficient Table Material Coefficient 0C Plastic 0.00018 Zinc
lead
Aluminium
Tin
Copper
Cast Iron
Mild Steel

61. Example
Find the amount a 6m long plastic discharge stack will expand due to a temperature rise of 190C.
Length x temp rise x coefficient
=6 x 19 x
= m or 20.52mm

62. Thermal Expansion What does this prove to us?
That we need to take into account the amount that materials expand and contract.
When do we need to take this into account?
When designing or installing systems
What could be the result of not allowing for this?
A breakdown of the systems or materials.

63. Heat Transfer

64. Heat Transfer How many methods of heat transfer are used in plumbing?
Three
What are they called?
Conduction
Convection
Radiation

65. Conduction What is Conduction?
It is the transfer of energy through a material
What causes conduction to occur?
It is the result of increased vibration of molecules as the material is heated.
Which materials are good conductors of heat?
Metals. Wood is a poor conductor of heat

66. Conduction Do gas and liquids conduct heat? Yes but poorly
Which material that plumbers use has a high conductivity compared to steel?
Copper
Other materials that are poor conductors :
Wood
Ceramic
Plastics
What are these materials better known as?
Thermal insulators

67. Convection What is convection?
Is the transfer of heat by means of the movement of a locally heated fluid substance (usually air or water).
What causes convection?
When heat is applied it causes expansion and which in turn causes lowering of the density.
What happens to the fluid now?
It will rise as in the following example

68. Convection
An example of gravity circulation using the effects of convection
Where else would convection be used?
Radiators
Gas fires
Convector Heaters
As water is heated it rises
As water cools it then drops to low level

69. Radiation What is Radiation?
It is the transfer of heat from a hot body to a cooler one without the presence of a material (other than air)
From what would we feel heat radiation?
The sun
Gas fire radiant’s
Radiators
Dull matt surfaces absorb heat more efficiently than shiny polished surfaces

70. Radiation What would have a dull matt surface? Solar panel
Where could these be used?
As in the photo on a house.
NOTE!!!!!!!
Heat can be transferred through a Vacuum by……
Radiation

71. LESSON COMPLETE

72. Capillary Action, Siphonage and Water Flow

73. Capillary Action What is capillary action?
It is the process by which a liquid is drawn or hauled through a small gap between the surfaces of two materials.
It is important for plumbers to know about this phenomenon as capillary action can affect the way that water enters buildings.

74. Forces of Attraction
What is the force that is making the water cling to the glass below?
Cohesion (water molecules sticking together) as result of surface tension.
What force is acting on the image below
Adhesion what is the meaning of it?
is the force of attraction between water molecules and the side of the vessel the water is contained in.
This leads to slightly curved skin called what:
The meniscus
Which measuring tool that you use would have a meniscus

75. Capillary Attraction
Of the five tubes in the drawing which one would draw up water the furthest?
Number 5
Why?
Because it has the smallest gap between the surfaces.

76. Practical examples What could happen at drip on a roof
How do you prevent it happening

77. Practical examples
What could happen if a cloth gets in a trap

78. Siphonage Principles of siphonage What is the key to siphonage?
Atmospheric pressure
Why do we need to know about siphonage?
Because as plumbers we can use it on a daily basis

79. How does Siphonage work
Atmospheric Pressure
When atmospheric pressure is able to force water through a channel (such as a hose), often seemingly against the pull of gravity
In the illustration the air pressure in the channel must be reduced to below that of atmospheric pressure
Positive
Negative

80. Practical uses
On which type of appliances would siphonic action be used in plumbing?
Siphonic W.C’s., such as single trap and double trap pans.
Cistern siphons
Auto cisterns

81. Water flow What would affect the flow of water in pipes?
Length of pipe and internal diameter
Pressure by head of water
Reduction in bore of pipe
Restrictions due to fittings
Flow of water in pipework systems associated with industrial and commercial buildings may be delivered by head of water

82. Water flow
but in reality most, if not all, are accelerated by the installation of pumps.
WHY?
due mainly to building design and quantities of water required.
Pumps for CW, HW and Heating etc have what is called a ‘Duty’.
What is the ‘Duty’
The amount of water delivered in litres per second to overcome the resistance (metres head) kPA of the system.

83. Water flow
Frictional resistance is the loss of energy by pipe and fittings and must be allowed for.
How is frictional resistance allowed for in pipework
By calculating the loss of pressure head due to fittings etc
Is normally calculated in terms of “equivalent length of pipe”
See next slide

84. Water Flow Copper Elbow Tee 15 0.5 0.6 22 0.8 1.0 28 1.5 LCS 1.2 20
1.4 25
0.7
1.8

85. Calorific Values of fuels
Calorific values are calculated in MJ/M3
Natural gas = 39
Propane = 94
Butane = 118
Kerosine = 47
Manufactured gas = 34

86. Lesson Complete