QCS-2010 Section 19 Part 2 Water Distribution
QCS-2010 Section 19 Part 2 Water Distribution
QCS-2010 Section 19 Part 2 Water Distribution
Section 19
Part 2
Water Distribution
Page 1
2.
2.1
GENERAL ...................................................................................................... 2
2.1.1
2.1.2
2.1.3
Scope
References
Quality Assurance
2.2
2.2.1
2.2.2
2.2.3
2.2.4
General Requirements
Cold Water Systems
Hot Water Systems
Pressurised Systems
2.3
PUMPS .......................................................................................................... 4
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
General Requirements
Lift Pumps
Circulation Pumps
Pipework Connections
Control
2.4
2.4.1
2.4.2
2.4.3
General Requirements
Pipe Materials
Pipework Jointing
2.5
2.5.1
2.5.2
General Requirements
Spacing of Pipe Fixings
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
Draw-off Taps
Drain Taps
Ball Float Valves
Servicing Valves
Stopvalves
Backflow Protection Devices
2.7
2.7.1
2.7.2
2.7.3
2.7.4
General Requirements
Pipework Expansion
Pipe Sleeves
Concealed Pipework
2.8
2.8.1
2.8.2
General
Application
2.9
MISCELLANEOUS ...................................................................................... 12
2.9.1
2.9.2
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QCS 2010
Section 19
Part 2
Water Distribution
Page 2
2.
WATER DISTRIBUTION
2.1
GENERAL
2.1.1
Scope
This Part specifies the requirements for the installation, testing and commissioning of
services supplying water for use within buildings. It covers the system of pipes, fittings and
connected appliances installed to supply any building with water for ablutionary, cleaning,
sanitary and laundry purposes.
General
Cold Water Storage
Hot Water Storage
Commissioning of Systems
General
Mechanical and Electrical
2.1.2
References
QCS 2010
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Section 19
Part 2
Water Distribution
Page 3
BS 6281----- Devices without moving parts for the prevention of contamination of water by
backflow.
BS 6282----- Devices with moving parts for the prevention of contamination of water by
backflow.
BS 6283----- Safety devices for use in hot water systems.
BS 6437----- Specification for polyethylene pipes (type 50) in metric diameters for general
purposes.
BS 6572----- Specification for blue polyethylene pipes up to nominal size 63 for bellow
ground use for potable water.
BS 6700----- Specification for design, installation, testing and maintenance of services
supplying water for domestic use within buildings and their curtilages.
BS 7671----- Requirements for electrical installations.
DIN 8079 --- Pipes made of chlorinated PVC
DIN 8080 --- Pipes made of chlorinated PVC
2.1.3
Quality Assurance
Items and equipment specified in this Part shall be provided by experienced and approved
manufacturers and fabricators as designated in the Project Documentation or to the written
approval of the Engineer.
2.2
WATER SYSTEMS
2.2.1
General Requirements
Internal hot and cold water supply installations shall be constructed so that water delivered is
not liable to become contaminated to the extent that it is hazardous to health or is unfit for its
intended use.
2.2.2
Cold water systems shall be capable of providing cold water at the locations and in the
quantities required and specified in the Project Documentation.
All cold water draw-off points shall be served via a cold water storage tank. The cold water
storage tank will be served directly from the Qatar General Electricity & Water Corporation
(QGEWC) supply mains.
2.2.3
Hot water systems shall be capable of providing hot water at the locations, in the quantities
and at the temperatures required and as specified in the Project Documentation.
To promote maximum economy of fuel and water the hot water distribution system should be
designed so that hot water appears quickly at the taps when opened. To this end, dead legs
should be as short as possible. The hot water pipe feeding a spray tap for hand washing
should not exceed 1 metre in length. When draw-off points are situated at a distance from
the hot water storage vessel, consideration should be given to the use of a separate water
heater installed close to those draw-off points. When this is impracticable a secondary circuit
with flow and return pipes to the storage vessel should be considered. Secondary circuits
inevitable dissipate heat and should be avoided where possible
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Section 19
Part 2
Water Distribution
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2.2.4
Pressurised Systems
Whether hot or cold water is involved, it shall be ensured that no part of the system bursts
due to the hydraulic pressures to which it is subjected. The pressures in the system shall
never exceed the safe working pressures of the component parts. The maximum working
pressure in a sealed primary circuit shall not exceed 3 bar but it shall be capable of passing a
test at 1.5 times the working pressure at the working temperature. The maximum working
pressure in an unvented hot water storage vessel or secondary circuit shall not exceed 6 bar.
Where necessary the supply pressure shall be controlled by using an atmospheric break tank
or pressure reducing valves. If the supply to a storage type water heater is through a
pressure reducing valve of the type that permits backflow, the working pressure in the system
shall be assumed to be the maximum pressure upstream of the valve. Where reliance is
placed on pressure reducing valves to limit the maximum working pressure, these shall
comply with BS 6283: Part 4.
(b)
(c)
allow the expansion water to travel back along the cold feed pipe, provided that
heated water cannot reach any communication pipe or branch feeding a cold water
outlet
where reverse flow along the cold feed is prevented by a stopvalve a with loose
jumper, replace this valve by one with a fixed jumper
where reverse flow along the cold feed is prevented, provide an expansion vessel in
accordance with BS 6144 to accommodate expansion water. This vessel shall be
sized in accordance with the volume of water heated and the water temperature rise
so as to limit the pressure to the maximum working pressure for the system. The
expansion vessel shall accommodate an expansion equal to 4% of the total volume of
water heated. Any discharge from relief valves shall be readily visible and disposed
of safely.
2.3
PUMPS
2.3.1
General Requirements
All pumps and associated equipment shall be capable of continuous operation in ambient
0
temperatures of up to 50 C.
Pumps shall be firmly mounted. Measures to prevent vibration shall be taken where
necessary.
No pump, required to increase pressure in or rate of flow from a supply pipe or any fitting or
appliance connected to a supply pipe, shall be connected unless prior written approval from
QGEWC is obtained.
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Section 19
Part 2
Water Distribution
Page 5
2.3.2
Lift Pumps
The pumps may be either the vertical type or horizontal type and shall be directly coupled to
their electric motors.
Where the pumping system has duty and standby pumps, the pumps shall be used
alternately.
2.3.3
Circulation Pumps
Circulating pumps shall comply with the relevant provisions of BS 1394: Parts 1 and 2.
Circulating pumps shall be suitably suppressed to prevent radio and television interference.
2.3.4
Pipework Connections
Flexible connections shall be used so as to prevent the transmission of pump and motor
noise via pipework.
All pipework connections to and from the pump shall be adequately supported and anchored
against thrust.
Inlet and outlet pipework connections to lift pumps shall be fitted with gate valves complying
with the relevant provisions Clause 2.10 of this Part.
Inlet and outlet pipework connections to circulating pumps shall be fitted with servicing valves
complying with the relevant provisions Clause 2.9 of this Part.
2.3.5
Control
2.4
2.4.1
General Requirements
Every pipe, pipe joint and connected fitting shall be capable of withstanding, without damage
or deterioration, sustained temperatures of up to 40C for cold water installations and up to
70C, with occasional short-term peaks of up to 100C for heated water applications.
Pipes, pipe joints, pipe linings and connected fittings shall be made of materials that do not
impart taste, colour, odour or toxicity to the water nor promote or foster microbial growth
under the conditions where they are going to be installed.
If pipes, pipe joints or fittings are of dissimilar metals, measures shall be taken to prevent
corrosion. Dissimilar metals shall be avoided in below ground installations.
2.4.2
Pipe Materials
Copper pipework shall comply with the relevant provisions of BS 2871: Part 1; underground
pipes shall be to Table Y with a coating of seamless continuous PVC sheeting and above
ground pipes shall be to Table X. Copper and copper alloy tube fittings should comply with
the relevant provisions of BS 864: Part 1, Type B or BS 864: Part 2, Type A.
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Section 19
Part 2
Water Distribution
Page 6
The use and installation of polyethylene pipework shall comply with the relevant provisions of
BS 1972 (above ground use), BS 6437 (general purposes) and BS 6572 (below ground use).
Copper alloy tube fittings for polyethylene pipes shall comply with the relevant provisions of
BS 864: Part 3. Joints for polyethylene pipes shall comply with the relevant provisions of BS
5114 and BS 3505.
The use and installation of polypropylene pipework shall comply with the relevant provisions
of BS 4991 and shall be Series 1.
The use and installation of unplasticized PVC (PVC-U) pipework shall comply with the
relevant provisions of BS 3505. Solvent welded joints and fittings for PVC-U pipes shall
comply with the relevant provisions of BS 4346: Part 1. Mechanical joints and fittings for
PVC-U pipes shall comply with the relevant provisions of BS 4346: Part 2. PVC-U pipework
shall only be used for cold water applications.
The use and installation of chlorinated PVC (CPVC) pipework shall comply with the relevant
provisions of DIN 8079 and DIN 8080.
Stainless steel pipework shall comply with the relevant provisions of BS 4127.
2.4.3
Pipework Jointing
All proprietary joints shall be made in accordance with the manufacturers instructions.
Care shall be taken to establish satisfactory jointing techniques for all water service pipework.
All burrs shall be removed from the ends of the pipes and any jointing materials used shall be
prevented from entering the water system
All piping and fittings shall be cleaned internally and be free from particles of sand, soil metal
filings and chips etc.
Jointing systems using elastomeric sealing rings shall be Type W, complying with the
relevant provisions of BS 2494, and shall be obtained from the pipe manufacturer.
2.5
PIPE FIXINGS
2.5.1
General Requirements
Copper and stainless steel piping shall be secured by clips or brackets made from copper or
copper-alloy.
Steel piping shall be secured by clips or brackets made from steel, copper alloy or suitable
plastic. Copper clips or brackets shall not be used for fixing steel piping.
PVC-U, polyethylene, polypropylene and CPVC piping shall be secured by clips or brackets
made from suitable metal or plastic. Allowance shall be made for free lateral movement
within the clips and brackets.
Piping that is insulated shall be secured on clips or brackets that allow sufficient space
behind the back of the pipe and the batten or wall to which the pipe is fixed for the insulation
to be properly installed.
2.5.2
The spacings for fixings for internally located piping shall be in accordance with Table 2.1,
2.2, 2.3 and 2.4 as applicable. The figures given are based on an ambient temperature of
20C. For other temperature ranges the pipe manufacturer should be consulted.
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Section 19
Part 2
Water Distribution
Page 7
Table 2.1
Maximum Spacing of Fixings for Internal Piping
Type of Piping
Nominal size of
pipe
Spacing on
horizontal run
Spacing on
vertical run
(mm)
(metres)
(metres)
15
1.200
1.800
22
1.800
2.400
28
1.800
2.400
Part 2
35
2.400
3.000
42
2.400
3.000
54
2.700
3.000
76
3.000
3.600
108
3.000
3.600
133
3.000
3.600
159
3.600
4.200
Table 2.2
Maximum Spacing of Fixings for Internal Piping
Type of Piping
Nominal size of
pipe
Spacing on
horizontal run
Spacing on
vertical run
(mm)
(metres)
(metres)
15
1.800
2.400
22
2.400
3.000
28
2.400
3.000
35
2.700
3.000
42
3.000
3.600
54
3.000
3.600
76
3.600
4.500
108
3.900
4.500
133
3.900
4.500
159
4.500
5.400
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Section 19
Part 2
Water Distribution
Page 8
Table 2.3
Maximum Spacing of Fixings for Internal Piping
Type of Piping
Nominal size of
pipe
Spacing on
horizontal run
Spacing on
vertical run
(inches)
(metres)
(metres)
0.530
1.060
0.610
1.220
/4
0.685
1.370
0.760
1.520
1 /4
0.840
1.680
1 /2
0.915
1.830
1.065
2.130
1.370
2.740
1.525
3.050
1.830
3.660
/8
/2
Tables 2.4
Maximum Spacing of Fixings for Internal Piping
Type of Piping
Nominal size of
pipe
Spacing on
horizontal run
Spacing on
vertical run
(inches)
(metres)
(metres)
/8
0.300
0.500
0.400
0.800
/8
0.400
0.800
0.400
0.800
1 /4
0.450
0.900
1 /2
0.550
0.900
0.550
1.100
2 /2
0.600
1.100
0.700
1.200
0.700
1.400
2.6
2.6.1
Draw-off Taps
Metal bodied draw-off taps shall conform to the relevant provisions of BS 5412: Parts 1-5.
Plastic bodied draw-off taps shall confirm to the relevant provisions of BS 5413: Parts 1-5.
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Section 19
Part 2
Water Distribution
Page 9
Taps not fixed directly to an appliance shall be screwed into a suitable pipe fitting.
The fitting, or the pipe immediately adjacent to the tap, shall be firmly secured to a suitable
support so as to prevent strain on the pipe and its joints when the tap is operated.
2.6.2
Drain Taps
Draining tap shall be of the screwdown type with a removable key and shall be fixed over a
drain or have provision for discharging the water to the nearest convenient point for disposal.
2.6.3
Except for interconnected tanks arranged to store water at the same level, every pipe
supplying water to a storage tank shall be fitted with a float operated valve or some other
equally effective device to control the inflow of water and maintain it at the required level.
The inlet control device shall be suitable for the particular application, taking into account the
supply pressure and the temperature of the water in the cistern.
(b)
comply with BS 1212: Part 2 or 3 and be used with a float complying with BS 1968 or
BS 2456 of the correct size corresponding to the length of the lever arm and the
water supply pressure; or
where any other float operated valve or other level control device is used, it shall
comply with the performance requirements of BS 1212 where applicable to the
circumstances of its use and shall be clearly marked with the water pressure,
temperature and other characteristics for which it is intended to be used.
Every float operated valve shall be securely fixed to the cistern it supplies and where
necessary braced to prevent the thrust of the float causing the valve to move and so alter the
water level at which it shuts off. This water level shall be at least 25 mm below the lowest
point of the warning pipe connection or, if no warning pipe is fitted at least 50 mm below the
lowest point of the lowest over flow pipe connection
Every pipe taking water from a cistern of capacity exceeding 18 litres shall be fitted with a
servicing valve close to the storage cistern, tank or cylinder.
Every ball float valve shall be so placed that it is readily accessibly for examination,
maintenance and operation.
2.6.4
Servicing Valves
Servicing valves shall be located in accessible positions so as to enable the flow of water to
individual or groups of appliances to be controlled and to limit the inconvenience caused by
interruption of supply during repairs.
A servicing valve shall either comply with the requirements for stopvalves as specified in
Clause 2.13 of this Part or shall be capable of withstanding a static pressure 1.5 times the
maximum pressure it will be subjected to in use, be leaktight when closed against the latter
pressure and, when installed on any pipe pressurised from the mains or on any pipe under a
static pressure exceeding 1 bar, shall be operable only by means of a key, screwdriver or
coin inserted into a slot on the valve. Screwdown servicing valves shall not be of loose
jumper design. Copper alloy gate valves complying with the relevant provisions of BS 5154
may be used as servicing valves.
A servicing valve shall be fitted upstream of, and as close as practicable to, every float
operated valve connected to a supply pipe.
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Section 19
Part 2
Water Distribution
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Pipes taking water from a storage tank of capacity exceeding 18 litres shall be fitted with a
servicing valve. The valve shall be fitted as close to the storage tank as practicable. Pipes
taking water from storage tanks with a capacity that does not exceed 18 litres shall not be
fitted with servicing valves.
2.6.5
Stopvalves
The use and installation of stopvalves shall comply with the relevant provisions of BS 6700.
Stopvalves fitted to service pipes shall comply with the relevant provisions of the British
Standards referenced in Table 2.5.
Table 2.5
Stopvalves Fitted to Service Pipes
Nominal Size of Pipe
50 mm or smaller
Standard
Above Ground
Below Ground
BS 1010: Part 2
BS 2580
BS 2580
BS 5433
BS 5433
50 mm or larger
BS 5163
BS 5163
Stopvalve components of fittings incorporating stopvalves shall comply with the requirements
for stopvalves.
Stop valves shall be so placed that they may be readily inspected, operated and maintained.
2.6.6
Every pipe through which water is supplied to a point of use or draw-off where backflow or
backsiphonage is likely to occur shall be fitted with a backflow protection device.
Pipe interrupters for backflow protection shall comply with the relevant provisions of BS 6281:
Part 3.
Vacuum breakers for backflow protection shall comply with the relevant provisions of BS
6282: Part 2 and 3.
Check valves for backflow protection shall comply with the relevant provisions of BS 6282:
Part 1. Any additional installation instruction issued by the manufacturer or supplier of the
check valve shall also be complied with.
Combined check valve and vacuum breaker for backflow protection shall comply with the
relevant provisions of BS 6282: Part 4.
Double check valve assembly for backflow protection shall comply with the relevant
provisions of BS 6282: Part 1, with a draining tap complying with the relevant provisions of BS
2879 connected between them.
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Section 19
Part 2
Water Distribution
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2.7
PIPE INSTALLATIONS
2.7.1
General Requirements
Pipe runs within buildings should not be laid exactly horizontal but to a slight fall to reduce the
risk of air locks forming.
2.7.2
Pipework Expansion
In installations with limited straight runs and many bends and offsets, thermal movement is
accommodated automatically. In installations that do not have limited straight runs and many
bends and offsets, allowance for expansion and contraction of the pipes shall be made by
forming expansion loops, by introducing changes of direction to avoid long straight runs or by
fitting proprietary expansion joints. This is particularly important where temperature changes
are considerable and where the pipe material has a relatively large coefficient of expansion.
The maximum length of a straight run for each different pipe material to be used shall be
detailed in the Project Specification or shown on the Project Drawings.
2.7.3
Pipe Sleeves
Where a pipe enters a building it shall be accommodated in a sleeve that has previously been
solidly built-in and the space between the pipe and the sleeve shall be filled with nonhardening, non-cracking, water-resistant material for a minimum length, of 150 mm at both
ends to prevent the passage of water, gas or insects.
2.7.4
Concealed Pipework
Concealed pipework shall be housed in properly constructed builders work ducts or wall
chases and have access for maintenance and inspection.
Ducts and chases should be constructed as the building structure is erected and should be
finished smooth to receive pipe fixings.
No pipe or joint in or under a building shall be embedded in any wall or solid floor or in any
material below a solid floor at ground level except for the following:
(a)
(b)
(c)
(d)
the enclosing of any pipe and associated pipe joints in a purpose made duct or chase
in a solid floor in such a way that the pipe and pipe joints can be exposed for
purposes of examination, repair or replacement without endangering the structural
integrity of the building
the enclosing of any pipe and associated pipe joints in a purpose made chase in a
solid wall (but not within the cavity of a hollow wall) in such a way that the pipe and
pipe joints can either be capped off and isolated or be exposed for purposes of
examination, repair or replacement without endangering the structural integrity of the
building
the enclosing of any pipe and associated pipe joints in any internal wall that is not a
solid wall
the enclosing of any pipe within a purpose made pipe sleeve or duct in or under any
solid floor in such a way that the pipe may be removed and replaced; for pipes laid in
such a way, there shall be an inspection access point at each joint.
No pipe or pipe joint shall be located under floorboards or a suspended floor, at ground floor
level unless every pipe and pipe joint is accessible for examination.
Where access panels are formed in floor panels of structural chipboard or plywood, the
structural stability of the building shall not be affected.
All pipe laid in ducts shall be adequately supported by clipping as specified in Table 2.1.
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Section 19
Part 2
Water Distribution
Page 12
2.8
2.8.1
General
Thermal insulating materials shall comply with BS 5422 and BS 3958 where applicable.
Where necessary, the insulating material shall be resistant to, or protected by a suitable
covering against, mechanical damage, rain, moist atmosphere, groundwater and vermin.
polyurethane foam
(b)
(c)
corkboard
(d)
amoliated vermiculite.
2.8.2
Application
While insulating material shall be continuous over pipes and fittings, it shall be finished in
such a manner as to allow access to valves for operation.
Where cold water pipes pass through areas of relatively high dew point, e.g. habitable areas,
they shall be insulated to prevent condensation forming on them.
Pipes in hot water supply systems that exceed the maximum lengths given in Table 2.6 shall
be thermally insulated in accordance with BS 5422.
Table 2.6
Maximum Permissible Lengths of Uninsulated Hot Water Pipes
Outside diameter of pipes
Maximum length
(mm)
(m)
12
20
12
Over 28
2.9
MISCELLANEOUS
2.9.1
Electrical works related to plumbing works shall be done in accordance with the relevant
provisions of BS 7671 and the requirements of QGEWC.
2.9.2
Water meter cabinets shall comply with the Rules and Regulations Guide for Plumbing
Works prepared by QGEWC.
Water meter cabinets shall be located in an easily accessible place as approved by QGEWC.
END OF PART
QCS 2010