3. INTEGRATION OF SERVCES
• General learning objective
Understand the need for considering space
conditions and demands requested in
arrangement of services in buildings.
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4. Introduction
Every dwelling is required by the law to have at least one WC
unit (most local authorities require two, a domestic worker’s
WC being mandatory), one basin one kitchen sink and one
bath or shower.
The interrelation between drainage and plumbing now
becomes obvious, plumbing to supply the water, and
drainage to dispose the water after use.
Just as the municipal sewer was installed before the
foundations so has to be the drinking water connection.
On the boundary of the site there will be a small cast-
iron/plastic cover-plate bearing the municipality’s
initials/WASC in the case of Lesotho.
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5. Introduction
Some covers are oval, some square, some rectangular. Some
are even locked – certain municipalities don’t like consumers
looking at what the lid hides, which is the water meter for the
house.
Inside the lid, or near it, will be a brass tap, often with a large
red handle or any colour depending on the authorities.
It is important to locate and know the position of tap because it
is the mains connection, should there be the need arises to cut
off the water supply to the house and garden.
The supply of water to the dwellings comes from a 20 mm
diameter underground pipe.
The taps in the garden are directly connected to it and there
will be a charge for every drop of water that is used.
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6. Introduction
Below are some samples of the water meters
6
source: google.com
Water meter
Meter cover plastic
Cast iron cover
7. Introduction
The internal pipes
The only places in the house where pipes are likely to be seen is
under kitchen sink or bathroom basin. The remainder are chased into
the walls.
Chasing are accurate channels in brickwork, neatly machine or chisel-
cut to the correct size for the diameter of the pipe. Water supply
pipes in the house can be of different materials e.g. copper,
galvanised steel, PVC, etc this will be discussed later in the course.
Water pressure
Most new homes don’t need a water storage tank, but if the pressure
from the local authorities supply is low the tanks can be installed.
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8. Water Supply
Enough water to meet the need of the occupants must be available
for all buildings. Further water need for fire protection, heating, air
conditioning, and possibly process use must also be met.
Water use for process use must be computed separately because the
demand depend on the process served.
Water quality
Sources of water for buildings include:
Public water supplies
Groundwater and
Surface water.
Each source requires careful study to determine if a sufficient
quantity of safe water is available for the building being designed.
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9. Water Supply
Water for human consumption, commonly called potable water,
must be of suitable quality to meet local, state and national
requirements.
Public water supplies generally furnish suitably treated water to a
building, eliminating the need for treatment in the building.
However, ground and surface waters may require treatment prior
to distribution for human consumption.
If water from the public water supply does not suffice the
requirements/its not clean the local authorities should publish and
disseminate (on newspapers, radio, TV, etc.) the information that
will make people aware of such conditions.
The people can be told to purchase either clay and patented
water purifying systems or any other purifier. These systems
could either be connected directly to the tap in the kitchen or
would be freestanding units which requires topping up with tap
water.
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10. Water Supply
The units that are connected directly to the water supply
would pass through a concentrated carbon filter, which do
guarantee to remove 99.99% of all harmful water
contaminants.
The topped up units have a top section, which contained a
sealed carbonised filter, which allows the water to drip down to
a reservoir below for drinking purpose.
Classification of water from various sources:
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Wholesome 1. Spring water
2. Deep well water
3. Uplands surface
Very palatable
Moderately palatable
Suspicious 4. Stored rainwater
5. Surface water
from cultivated
lands.
Moderately palatable
Palatable
Dangerous 6. River water where
sewage gain access
7. Shallow well water
11. Water Supply
Hardness of water
• In order for water to be classified as palatable and potable, it
is necessary for it to be initially classified as either hard or
soft.
• In general instances, water that is obtainable from surface
supplies (rivers, dams, streams, etc.) is deemed soft, while
water obtainable from subterranean catchments is hard.
• The hardness of the water is entirely dependant, however, on
the type of earth strata with which the water comes into
contact with.
• The term “hard” or “soft” is the measure of difficulty it takes in
order to obtain lather with soap in the water.
• Water is an excellent solvent and the presence of dissolved
carbon dioxide increases this solvent power.
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12. Water Supply
Hardness of water
• There are two types of hardness in water, temporary and
permanent.
• Temporary hardness refers to water which passes through
strata containing carbonate of calcium or magnesium.
• A certain amount of these carbonates are dissolved in the
water depending on the amount of carbon dioxide present.
Upon being dissolved, these carbonates become bicarbonates.
• They can be removed by boiling the water, hence the term
temporary.
• The boiling of this water does however, causes scaling or
furring of hot water pipes and boilers and can ultimately block
the pipe on the long run.
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13. Water Supply
The diagrams below illustrates the above
occurrence:
• BEFORE AFTER
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Scaling and furring on pipes
Source: http://www.dualflo.co.uk/benefits/
14. Water Supply
The diagrams below illustrates the above
occurrence:
• BEFORE AFTER
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Scaling and furring on pipes
Source: http://www.dualflo.co.uk/benefits/
15. Water Supply
Permanent Hardness
Permanent hardness is when water passes through strata
containing calcium sulphate, calcium chloride or
magnesium chloride; the salts are readily dissolved in the
water without the presence of carbon dioxide.
This type of hardness cannot be removed by boiling and will
not cause scaling or furring, unless brought to extremely
high temperatures and pressures but it can cause corrosion.
In order to make the water fit for human use and
consumption, it is sometimes necessary to remove the
hardness depending on how much foreign matter is
detected.
As indicated above temporary hardness can be removed by
boiling or by adding small quantities of lime to the water.
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16. Water Supply
Permanent Hardness (to be cont…)
The lime takes up the carbon dioxide are results in the
precipitation of the insoluble carbonate which is allowed to
settle in a tank or is removed with fine mesh screens. This
method is called Clark Process.
Permanent hardness can be removed by adding washing soda
(sodium carbonate). The sodium carbonate becomes sodium
sulphate, which is harmless and can remain in the solution.
As most waters have both temporary and permanent hardness
particles to it, both soda and lime are added to it in the
required quantities and the precipitated salts settled out.
Although soft waters lathers easily, it is not palatable as hard
and can cause large amount of corrosion to metals such as
iron, steel, copper, zinc and lead.
As copper is labelled a safe metal, as a small amount induced
in not poisonous, it is the preferred metal for use in water
piping.
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17. Water Supply
Permanent Hardness (to be cont…)
If lead pipes are utilised and corrosion occurs, lead
poisoning would result
All the water for human consumption which is available
from taps, is filtered and chemically treated to rid it out
of any impurities and possible bacteria which may lead
to diseases such cholera, bilharzias, etc.
Chlorine is added to all our water, which oxides organic
compound within it.
The dosage is strictly regulated so as to kill the bacteria
but limits the smell and taste of the water.
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18. Water Supply
Water connection from water main
Service pipe
• Connections to the existing main are made by the water
undertaker/WASCO.
• The house or building service pipe connection is made to the
main and the service pipe is run to a stop valve near to the site
boundary of the building to served.
• The stop valve is situated either immediately outside or inside
the boundary.
• The purpose of the stop valve is to enable the water authorities
to disconnect the water supply where there is a waste of water
in the building served, or non-payment of water or charge.
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19. Water Supply
Water connection from water main
Supply pipe
• The pipe that is run from the stop valve to and into the building is termed supply
pipe.
• The supply pipe is run underground and into the building as illustrated in the figure
that follows.
• For convenience it is usual to run the supply pipe into the building through drain
pipes or pipe sleeves to facilitate renewal of the pipe if need be.
• It is the responsibility of the consumer to maintain so much of the incoming service
pipe as in on his/her land.
• At the point that the supply pipe enters the building there should be a stop valve to
disconnect the supply for repair and maintenance purposes.
• To reduce the risk of freezing, the supply pipe should be laid at least 750 mm
below the finished ground level however this can be different from either region to
region or country to country.
• If the supply pipe enters the building and rises closer than 750mm deep the pipe
should be insulated.
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20. Water Supply
Water connection from water main
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• Supply pipe
Below is sketch that shows the supply pipe
21. Water Supply
Water connection from water main
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• Supply pipe
Below is sketch that shows the supply pipe
22. Water Supply
Cold water supply
In many countries across the world, due to the nature of
purification of the supplied water, it is necessary to have local
domestic supplies done in one of two ways namely:
Directly or
Indirectly
The direct method is when all sanitary fittings are supplied
directly with a supply from the main feed line supplied to the
dwelling.
In some cases, a cold-water storage cistern is also required in
order to feed the water geyser.
Below is the illustration of the direct method:
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23. Water Supply
Supply of cold water
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Direct cold water system Source: R.Chudley.,Construction Handbook
24. Water Supply
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The indirect method.
• In this system, the supply to
the house is fed directly to cold
water storage cistern which in
turn supplies all the sanitary
fittings in the dwelling.
•This cistern has its own
filtration and chemical balance
system.
•In indirect system all the
sanitary fittings, except drinking
water draw-offs at sinks and
fountains, are supplied indirectly
with from a cold-water cistern.
Source: R.Chudley.,Construction Handbook
25. Water Supply
Supply of cold water
In other countries especially in Lesotho and South Africa
due to the exacting purity of the supply of water, the direct
system is utilised without the need of a cold water supply
cistern for the hot water geyser.
It is also indicated that the supply of cold-water storage
cistern allows for the possible contamination of water from
the supply line down to the person drinking the water
from the tap.
These countries are undergoing a major project to supply
potable water to many parts of its rural population as
directed at the World Summit for Sustainable
Development.
This information of supplying water to Southern Africa as a
whole is available for viewing at http://www.wsscc.org.
The campaign form this project is called WASH, meaning
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26. Water Supply
Supply of cold water
Where water is supplied to domestic units, it is a relative
simple procedure to connect the house up to the supply
without the fear of inadequate pressure to feed the various
items within the house, as the supply is generally more than
adequate.
However, when it comes to high rise buildings, or even
building higher than three storeys, it would be wise to have
the pressure of the supply line checked prior to design as it
may be necessary to provide a pumping room.
Additionally, should one be designing a large shopping centre
of the big mall, a pumping station would be required so as to
be certain that all aspects of the building have a suitable
supply of water at a decent temperature
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27. Water Supply
Supply of cold water
The size of the pumping room will depend entirely
on the distances to which the water is required to
be pumped along with its required elevation.
Generally, the pumping systems will consist of
water storage cisterns of a size to suit the
development, which will be fed directly by the
main water supply.
These cisterns will fitted with cut-off valves, which
will enable the water supply to be halted should
the cisterns be full of pressurised.
Once the water starts draining out of the cistern,
the valve will be activated and the cistern will be
filled.
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28. Water Supply
Supply of cold water
The pump required will be fitted after the
positioning of the cisterns and will be fitted with
pressure switches.
The pumps will be activated to supply water when a
tap is opened within the building and the pressure
within the water line drops.
The pumps will be fitted with safety cut-offs
switches and valves so as to limit damages should
the main water supply be temporarily disconnected.
These units will not allow the pump/s to activate
should there be no water within the cisterns so as
to cause the motors to burn out. 28
29. Water Supply
Supply of cold water
Additionally, the water line from the pumps to the
building will be fitted with non-return valves, so as
to prevent any backpressure or back-flow of water.
On all water supplies to sanitary fittings, it is wise
to allow for the installation of an in-line stopcock to
allow for the isolation of water to the fittings should
general maintenance be required .
This is for all taps to basins, sinks and prep-bowls,
as well as to geysers, bidets and water closets.
Stop cocks and gate valves are seldom shown on
Architects drawings and should be measured at the
following positions:
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30. Water Supply
Supply of cold water
◦ Boundary of the site at water meter (to isolate the building)
◦ At the start of any new branch off the main feed (to isolate
any individual branch) or where the branch meets the building
provided that no pipes branch off it before the building.
◦ At the start of all branches of the rising main
◦ One at the inlet and outlets of cold water storage tanks.
◦ At each flushing cisterns.
Stopcocks are available in 15 mm, 22 mm and 28mm
and gate valves are from 8 mm to more than 100 mm.
Where stopcocks are measured to pipes chased to pipe
chased into walls, they must be described as “underwall
type”.
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31. Water Supply
Cold water supply
Backsiphonage
• This is the backflow of water into the drinking water supply main. In order
for back siphonage to occur a partial vacuum must be created in the pipe
connected to a valve or tap, with its outlet submerged in water, which may
be contaminated. This is possible when the demand on the water main is
sufficient to draw back the water, thus leaving behind a partial vacuum.
• In order to prevent backsiphonage the following points must be observed:
Ball valves in cisterns should be fitted above the overflow pipe, and if a
silencer pipe is fitted its outlet must be above the valve.
The outlets of taps connected to sinks, baths and basins should be well
above the flooding level of the fitting.
Fittings having low-level water inlets, for example bidets, should be
supplied with cold water from the a storage cistern and never direct
from the water main.
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32. Water Supply
Supply of hot water
Hot water may be supplied to buildings in many
different ways, namely:
◦ Centralised system
◦ Direct system (supply of water is not combined with
central heating)
◦ Indirect system (supply of water is not combine with
central heating)
◦ Hot water geysers,
◦ Under-counter or above counter boilers and
◦ Solar heating.
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33. Water Supply
Supply of hot water
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• Centralised boiler system
• The boiler may be heated by gas, solid fuel or oil and should
be positioned as close to the hot water storage cylinder as
possible, so that heat losses from the primary flow and return
pipes are reduced to the minimum.
• The boiler and cylinder should be in a central position to
reduce the length of the secondary circuit to the various hot
water draw-off points.
• Direct system
• This is the simplest and least expensive system of hot water
installation. The water is heated in the boiler and the hot water rises by
convection to the hot water storage tank or cylinder to be replaced by
the cooler water from the bottom or the storage vessel
• Hot water drawn from storage is replaced with cold water from the cold
water storage cistern.
34. Water Supply
Supply of hot water
Direct systems
• Direct systems are suitable systems for soft
water areas and for installations which are
not supplying central heating circuit.
• The system is cheaper to install that the
indirect system and the water in the cylinder
will be heated quicker, due to the direct
circulation between the boiler and the
cylinder
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35. Water Supply
Supply of hot water
Direct systems
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Source: F. Hall, Building services and Equipment .vol. one
36. Water Supply
Supply of hot water
Direct systems (simplified)
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Source: www. Google.com
38. Water Supply
Supply of hot water
Indirect system
• This system is a more complex than the direct system but it does
overcome the problem of furring which occur in direct hot water
systems.
• This system is therefore suitable in temporary hard water districts,
or when heating is combined with the hot water supply system.
• An indirect cylinder is used which has an inner heat exchanger.
• The water from the boiler circulates through this heat exchanger
and heats the water in the cylinder indirectly.
• Since the water in this heat exchanger and boiler is not drawn off
through the hot water taps, lime is precipitated only after the
initial heating of the water and afterwards (unless the system is
drained) there is no further occurrence and therefore no scaling.
• This same water also circulates through the steel or cast iron
radiators and thereafter heating the water is freed from carbon
dioxide which then reduces corrosion of the radiators.
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39. Water Supply
Supply of hot water
Indirect system
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Source: F. Hall, Building services and Equipment .vol. one
41. Water Supply
Supply of hot water
In domestic houses in Lesotho and South Africa, hot
water is generally supplied by the installation of a
hot water geyser.
These geysers are insulated copper of galvanised
metal cylinders wrapped in an insulating foil or mat
and covered by either a plastic metal casing.
The units are fitted with pressure relief valves
allowing the boiling water within the unit to run off
without causing the unit to explode under extreme
pressure as well as controls the pressure of the cold
water supply entering the unit.
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42. Water Supply
Supply of hot water
The unit is connected to an electrical supply via a
thermostat, which able to control the temperature of the
water within the cylinder.
The water within the cylinder is constantly monitored by
the thermostat, which heats the water up to the required
temperature.
The geyser will be automatically filled when a hot water tap
is opened and will also start heating the incoming cold
water up immediately.
These geysers come in various sizes ranging from 50 litres
up 250 litres and are usually fitted as close to the sanitary
fitting requiring heated water as possible so as to prevent
a lengthy waiting time once the tap is opened to when hot
water is available at the draw-off point. 42
43. Water Supply
Supply of hot water
Below is an example of how this geyser is fitted:
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45. Water Supply
Supply Valves used in geyser installation
a) Pressure control valve –
Normally pressure reducing. Pressures ( 100,
200, 300, 400 kPa)
f hot water
45
46. Water Supply
Supply of hot water
46
• Valves used in geyser installation
b) Expansion relief valve
Serves the same function as the expansion pipe through roof. i.e. to
prevent excessive pressure build up when water expands on
heating.
47. Water Supply
Supply of hot water
47
• Valves used in geyser installation
b) Vacuum breakers
Function is to prevent water from being siphoned backward into the
public system. It prevents contamination should the public water
system’s water pressure drops
48. Water Supply
• Electric water heating
• The most common way of heating water in Lesotho is by
electricity. Heating water by electricity is more expensive than
using other fuels.
• However the setup in our country doesn’t allow people to
choose from various technologies except for solar which is
perceived to be relatively cheap but expensive at the beginning
of the installation.
• When heating water with electricity care is required in order to
conserve heat, below are some of the points to be observed:
1. The hot-water storage must be well insulated, with a
minimum thickness of 50- preferably 75 mm of good
insulation.
2. The heated water must not circulate, towel rails and
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49. Water Supply
• Electric water heating
3. The length of hot water draw-off points, particularly to
the sink, should be reduced to a minimum.
4. Single-pipe circulation in the hot-water pipes, vent
pipes, must be avoided.
5. Airing cupboards should not be heated by leaving part
of the hot water storage un-insulated.
6. An effective thermostat must control the temperature
of the water at a maximum of 60 ºC for temporary
hard water and at a maximum of 71 ºC for soft water.
The lower temperature for temporary hard water
greatly reduces the deposit of lime.
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50. Water Supply
50
• Supply of hot water
• Instantaneous electric water heaters
• These are designed for direct connection to the cold water
supply main, and are fitted with a pressure switch to prevent
the element switching on before water flows and vice versa.
• A thermal cut-out also prevents the water from over-heating.
• Shower water heaters with an electrical loading of 6 kW will
give a continuous supply of warm water at showering
temperatures at the rate of approximately 3 litres per minute.
• Instantaneous gas water heaters
• This gives instant hot water day or night, the water being
heated as it passes through a finned pipe of heat exchanger.
51. Water Supply
Supply of hot water
51
• Instantaneous water heaters
They are obtainable in the following classes:
1. Sink heaters, single or multipoint, to serve a sink, or basin,
or a sink and a basin where these are close together.
2. Bath heaters; they can serve a wash basin in addition to the
bath.
3. Boiling water heaters; will provide hot or boiling water for
making beverages, and humming device fitted to the heater
sounds when the water is boiling.
4. Multipoint heaters; will provide sufficient hot water to bath,
basin and sink or they may be used for several basins or
sinks in larger buildings.
52. Water Supply
• The supply of hot water
52
Centralised system Electric or gas water unit
heaters
1. Provides large bulk storage for
hospitals, hotels and factories.
1. May be fitted close to the fittings
being supplied, thus saving a great
deal of pipework.
2. One central boiler plant requires
less maintenance than several unit
heaters.
2. Saving in boiler house space
possible fuel store
3. Cheaper fuel may be used. 3. A number of heaters in large
buildings requires either separate
or electrical connections
4. Requires long lengths of
secondary pipework, which can lead
to large heat loss.
4. Greater risk of fire inside the
building, due to more gas or
electrical connections.
5. Reduction in flue construction
(unless electric heaters are used)
5. No need to pump the hot water
supply circuit.
6. Towel rails and airing coils may
be connected to secondary circuit
53. Water Supply
• The supply of hot water
53
• Defects in cold and hot water supply
• It is important that as manager you ensure that plumbers do take
great care when installing a hot or cold water system.
• If incorrect methods are employed or the work is done in a hurry,
defects like the following are bound to occur:
1. Water hammer
2. Air-locks
1. Water hammer –
• It is the given pounding, hammering noise, sometimes heard in
water pipes.
• This noise can be quite deafening and occurs in both hot and cold
water systems.
• The noise or series of jerks can be nerve – racking.
54. Water Supply
Defects in cold and hot water installations.
54
2. Airlock
Airlocks in pipe occur when air blocks the flow of water, very
little or no water will run from a tap when there is air in the
system.
Most airlocks are caused by unventilated arches formed by
badly fitted pipework.
Airlock is a small quantity of air trapped in a pipe which due
to the very long circulating pressure available prevents
water passing the pipe.
Air-locks are very often the result of pipes sagging there by
form a U-shape and thus trapping air.
Sometimes air usually gets into the pipes when the supply
