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BUILDING SERVICESBUILDING SERVICES

CHAPTER 1

WATER SUPPLY

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1.1 Functions of water supply1.1 Functions of water supply

A ready supply of cold water

Warmed to provide hot water supplies

Heated to provide space heating

Incorporated into industrial processes

Removing various types of waste

Liquid feed for plants

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1.2 Water supply to urban areas1.2 Water supply to urban areas

The size of the water main

The pressure of water in the mains

The demand upon the main

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1.2 Water supply to urban areas (Contd)1.2 Water supply to urban areas (Contd)

Head the height to which water in the mainwould rise in a vertical pipe

A head of30-70m is sufficient

Reservoirorwater toweris built to give watersupply to buildings

A building rising above the mains head whichwill require its own system ofpumps to raisewater to the top of the building

The actual head will be reduced by the frictionloses due to the water flow

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1.3 Pressure loss1.3 Pressure loss

The size of the supply pipe

The actual distance of the water flow The number of fittings through the supply pipe

The demand upon the main

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1.4 Connection of water supply1.4 Connection of water supply

to a propertyto a property

Regional water authority (Kuching Water

Board) connect aproperty to the water main Communication pipe service pipe

Service pipe should be laidbelow ground

Stop valve & drain valve

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1.5 Distribution and operation of cold water1.5 Distribution and operation of cold water

systems systems Direct SystemDirect System

1) All fittings and appliances are served directly fromthe main

2) No provision is made for cold water storage. Mains-supplied storage cistern only for the hot part of the

system3) Less pipework, smaller storage load and neater

plumbing than in the indirect system

4) The plumbing under higher mains pressure is likelyto cause water hammer (noise), pipe burst, taps andvalves are more stressed

5) Risk of contamination of the mains supply by backsiphonage

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From

watermains

Risingmain

s

Sink

Basin

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1.5 Distribution and operation of cold water1.5 Distribution and operation of cold water

systems systems

Indirect SystemIndirect System

1) Supplies to fitting and appliances with the

exception of the kitchen sink, are fed from the

storage cistern

2) Space and support must be strong and stable

enough to bear the load of larger storage cistern

3) More extensive pipework is required especially

distribution pipes4) Less vulnerable to water hammer (noise)

5) Risk of mains contamination reduced

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1.5 Distribution and operation of cold water1.5 Distribution and operation of cold water

systems systems

Indirect SystemIndirect System

(contd)(contd)

6) Most of the fittings operate at a pressure less thanthe main

7) Water drawn off from indirect cold taps is not safe

for drinking purpose8) Water resources are optimised whenever supplies

are restricted or mains failure

9) Water storage cistern rechargeable for 24 hours

relieves peak demands on the mains10) The flow rate of the indirect cold taps has no

significant influence by the fluctuations in mainspressure

Cold water storage

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Sink

Basi

n

Cold water storagecistern

Basin