w1-water services 1
TRANSCRIPT
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IMPERIA INSTITUTE OF TECHNOLOGYSCHOOL OF BUILT ENVIRONMENT
AND ENGINEERINGDIPLOMA OF CONSTRUCTION MANAGEMENT/QUANTITY
SURVEYING
BUILDING SERVICES 1
SER 402
SEMESTER SEPTEMBER 2010
WATER SERVICES 1
LECTURER: MS. NADZIRAH ZAINORDIN
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CONTENT OF MODULE
INTRODUCTION
SOURCES OF WATER
MAIN WATER TO BUILDING
COMPONENTS OF WATER SUPPLY
BASIC OPERATION SYSTEM
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To exposed students with the knowledge
regarding design and installation of the
services commonly in habitable buildings.
OBJECTIVE
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At the end of the lessons, students are
anticipated to:
- Understand what is the main sources of water.- Understand how the water are being supply into
the buildings.
- Understand the basic operation system of cold
water- Understand the components of cold water supply.
LEARNING OUTCOMES
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INTRODUCTION
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Hot and cold water systems in buildings areused for washing, cooking, cleaning and
other specialized functions
Cold water for buildings is also known aspotable water.
Non-potable water is supplied in some
countries, this is not for drinking or
cooking.
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Water services should be designed and
installed accordance with the
recommendations of
BS 6700
The water regulations, relevantstatutory regulations,
By laws.
Other relevant British standards
Manufacturer recommendations.
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SOURCES OF WATER
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WATER SUPPLY SOURCES
Most buildings can receive theirwater supply from the waterAuthoritys main. But in rural
areas, it is sometimes necessary toobtain water from private sourcessuch as:
Wells
Springs Rivers
Lakes
http://definations.ppt/http://definations.ppt/ -
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For human consumption, the best
quality of water usually comes
straight from the ground, rather than
froma stream or pond which isexposed to probable air pollution.
WATER SUPPLY SOURCES
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A dug well is normally of big enough
diameter to admit a man and his spade
and 3 to 6 metres deep.
In some countries a well is much
deeper to access strata of water
bearing bearing rock
WATER SUPPLY SOURCES
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It may be more economical to sink a
borehole in such circumstances. A borehole is of small diameter and is madeby a drilling rig- just big enough to admitthe mechanical pump and delivery pipe.
WATER SUPPLY SOURCES
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A typical borehole uses a multistagecentrifugal pump delivering sufficient
water from a depth of 30metres to 60metres.
Most modern wells are lined with pre-castconcrete liners and boreholes with steel
tubing.
WATER SUPPLY SOURCES
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In drier regions of the world the engineer
has to study the most economic method ofobtaining a suitable source of water fordomestic and industrial use.
WATER SUPPLY SOURCES
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MAIN WATER TO
BUILDING
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MAIN WATER TO BUILDINGS
Water mains can be divided into 3
categories:
1. Trunk mains
2. Secondary mains
3. Service pipes
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MAIN WATER TO BUILDINGS
Trunk mains- These carry waterfrom a source of supply(reservoir, pumpling station, etc)to adistrictwithout supplying consumersroute
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MAIN WATER TO BUILDINGS
Secondary mains- The distribution mains, fed from a trunkmainand supplying the consumesconnections in the district.
- Connections to a trunk or secondary mainare normally only carried out by thewater supply company
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MAIN WATER TO BUILDINGS
Service pipes- The branch supplies from the secondary
mains that serve individual premises.- Service pipes are fitted by the watersupply company from the main up to theboundary of the premises to be supplied.
- At this point, a stop valve is providedto enabled the premises water system tobe isolated from the mains.
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MAIN WATER TO BUILDINGS
The drinking water supply should be free from
any chemical contamination.
There must be no inter-connection or cross-
connection of the supply with any other water
supply.
Reflux valves or stop valves are not considered
adequate to prevent cross-contamination.
The design of water services must be arranged to
prevent the possibility of backflow or back
siphonage into the water system from any outlet.
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MAIN CONNECTIONS
It is often normal to have a meter installed so
that water suppliers will be able to charge all
customers on how much water is used.
The service pipe to the building should be kept
at about 760mm minimum depth to avoid frost
damage and damage from heavy vehicles.
The valve pit can be a purpose made plastic
chamber with key operated lid.
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TYPICAL MAINS WATER CONNECTION
TO A BUILDING
Owned & maintainedby Water Authority :
Supply pipe
Installed & maintainedby building owner :
Communication pipe
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TYPICAL MAINS WATER CONNECTION
TO A BUILDING
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COMPONENTS OF COLD
WATER SUPPLY
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COMPONENTS
Water meter
Cistern
Valve
Tap
Pipes
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A)WATER METERS
Water meters are installed at the discretion of
the local water authority.
Required on all new build and conversion
properties, plus existing buildings which have
been substantially altered.
Meters are either installed in the communication
pipe, or by direct annular connection to the stop
valve
If underground location is impractical, the water
authority may agree internal attachment to the
rising main.
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Most required meter on:
WATER METERS
All new buildings
Conversion Buildings
Existing buildings which have beensubstantially altered
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WATER METERS
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B) CISTERN
STORAGE CISTERN / WATER TANK
Cistern can be manufactured from galvanized mildsteel (old version), polypropylene or glassreinforced plastics.
They must be well insulated and supported onadequate bearers to spread the concentrated load.
Plastics cistern will require uniform support onboarding over bearers.
A dustproof cover is essential to preventcontamination.
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STORAGE CISTERN / WATER TANK
For large buildings, cistern are accommodated in a
purpose made plant room at roof level or within
the roof structure.
Where storage demands exceeds 4500 liters, cisternmust be duplicated and interconnected.
In the interest of load distribution, this should
be provided at much lower capacities.
For maintenance and repairs each cistern must be
capable of isolation and independent operation.
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Domestic Cistern
Rising Main
Vent Pipe
Screened air
inlet
Full way
gate - valve
Warning pipe
to outside
Screen to prevent ingress
of insects( filters)
Insulation slab
50mm thk.
Bolted cover
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STORAGE CISTERN / WATER TANK
A balanced flow of water to and from tanks isrecommended
- Achieved by installing inlets and outlets at thesame level and with the same lengths of pipe work.
- This ensures that the same amount of water enterseach tank from the ball valve.
- Tanks should be periodically cleaned out to removedust and grime build-up and a valve drain is used
for this purpose.
- The use of delayed action float valve may also beconsidered to ensure a greater turn over of water.
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C) VALVE
1) GLOBE VALVES The globe valvetocontrol flow of waterat high pressure.
To close the flow ofwater, the crutch headhandle is rotatedslowly in a clockwisedirection( to preventsudden impact andpossibility ofvibration )
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C) VALVE
2) GATE / SLUICE VALVE
Gate/ sluice valves isused to control theflow of water on low
pressure installation. The wheel head isrotated clockwise tocontrol the flow ofwater.
Less resistance toflow than a globevalve.
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C) VALVE
3) DRAIN VALVES
The drain valves has several applications
and is found at the lowest point in pipesystems, boilers and storage vessels.
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C) VALVE
4) FLOAT VALVES
Float valve are automatic control devices fitted to cistern tomaintain an appropriate volume of water.
Few types of float valve:- The diaphragm typesthe least noisy- The Portsmouthpiston moving horizontally
- The Croydon Typepiston moving vertically.
Water outlet must be well above the highest water level to preventback siphonage of cistern water into the main supply.
Nozzle diameters reduce as the pressure increases.
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D) FITTINGS
1) PILLAR TAP
Pillar Tapsupply water to basins, baths, bidets
and sinks
Combined hot and cold pillar taps are availablewith fixed or swivel outlets.
The outlet of these taps must be bi-flow, toseparate waterways for hot and cold water toprevent cross flow of water within the pipe work.
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1) PILLAR TAP
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D) FITTINGS
2) BIB TAP
The bib tap for wallfixing, normally about
150mm above a sanitary
appliances.
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BASIC OPERATION SYSTEM
COLD WATER STORAGE SYSTEM &ARRANGEMENT
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COLD WATER SUPPLY
Water storage in dwelling is usuallyrequired to meet a 24hours demand, thatis, if the supply is cut off, there willbe a supply of cold water for 24 hours.
The consumption of cold water in anybuilding depends upon:
the use to which the water is put the number of consumers served
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TYPICAL WATER STORAGE TANK
Main watersupply
Screened vent& overflow
Cold wateroutlet
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TYPICAL WATER STORAGE TANK
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WATER SUPPLY OPERATIONSYSTEM
DIRECT AND INDIRECT SYSTEMS
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COLD WATER SYSTEM PRINCIPLES
There are two principle of coldwater supply systems:
1) Direct System 2)Indirect System
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SUMMARY OF DIRECT SYSTEMS
In this system, all sanitaryfittings are supplied with coldwater direct from the main.
For efficient operation, a highpressure water supply is essentialparticularly at peak demand.
Pipe work is minimal and the storagecistern supplying the hot watercylinder.
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SUMMARY OF DIRECT SYSTEMS
Drinking water is available at everydraw-off point and maintenance valveshould be fitter to isolate each
section of pipe work. Every outlet supplied from the main,the possibility if back siphonagemust be considered. Back siphonage
can occur when there is a highdemand on the main.
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DIRECT COLD WATER SYSTEM
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DIRECT COLD WATER SYSTEM
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DIRECT COLD WATER SUPPLY
The cistern may be located within the
airing cupboard or be combined with the
hot water cylinder.
Negative pressure can then draw waterback into the main form a submerged
inlet, e.g : a rubber tube attached to a
tap or a shower fitting without a check
valve facility left lying in dirty bathwater.
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SUMMARY OF INDIRECT SYSTEMS
In this system, all the sanitary fittings
except drinking water draw-offs at sinks,
are supplied indirectly from a cold water
cistern. In addition to its normal supply
function, it provides an adequate
emergency storage in the event of water
main failure.
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SUMMARY OF INDIRECT SYSTEMS
The system requires more pipework than
direct system and is therefore more
expensive to install but uniform pressure
occurs at all cistern-supplied outlets. Gives uniform pressure at all cistern-
supplied outlets
The water authorities prefer this system
as it imposes less demand on the main.
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SUMMARY OF INDIRECT SYSTEMS
Fewer fittings attached to the main-lesschance of back siphonage.
Lower pressure & less noise
The cold water storage cistern has aminimum capacity of 230 liters, forlocation in the roof space.