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Date Posted: 06:04:58 11/26/06 Sun
Author: ¦óÚZµØ±ø»«©P+Åwªï¬µÊ\: jameslam@hkpro.com.hk
Subject: ²bÎx¦óÚZµØ±ø¤²µó©O+Åwªï¬µÊ\: nancychow@hkpro.com.hk
In reply to: ¦óÚZµØ±ø»«©P+Åwªï¬µÊ\: jameslam@hkpro.com.hk 's message, "²bÎx¦óÚZµØ±ø¤²µó©O+Åwªï¬µÊ\: nancychow@hkpro.com.hk" on 05:50:50 11/26/06 Sun

Notes:-

No less than 2 supports must be used on all pipes having lengths less than the minimum intervals indicated.

b) For UPVC pipes in vertical installation, only the anchor shall rigidly clamp the pipe, the remaining "C" clamp or split pipe rings spaced at intervals in above table shall only constrain the pipe in lateral direction but shall allow free movement along the axis of the pipe. These metal clamps or rigs shall be lined with UPVC sleeve.


UPVC pipes used for tank overflows, drains etc. shall be adequately supported such that no deflection of pipe occurs.

c) All supports for steel pipes including unplasticized PVC shall be ferrous.

d) All supports for copper pipes shall be brass. Where copper pipes are installed with other pipes and a single ferrous support is used, a PVC sleeve shall be provided at the point of contact.

e) Unless Otherwise specified, all hangers, support and brackets for steel or
iron pipes and unplasticized PVC pipes shall be stainless steel and for UPVC pipes all brackets shall be sheathed with plastic collar. All bolts, nuts and washers shall be strainless steel.

e) All pipe supports are to be of such design and type as to allow
for the removal of any pipe section without the necessity of disconnecting other adjacent pipes.

f) Where pipe rings are used they are to be split pattern with top
and bottom bolts. For horizontal pipes the rings shall be held by mild steel rod screwed to pipe ring boss and in all cases where rocking movement of the pipe ring is expected spherical seating washers shall be provided to all adjusting nuts .

g) In pump room area all pipe supports shall incorporate resilient rubber-in-shear pipe mountings to prevent vibration being transmitted to structure.

h) The discharge pipework form pumps and all pipework where vibration could be transmitted to the Building structure shall be supported with brackets etc. which shall have tough rubber washers at contact of bracket to pipe.

i) All supports etc. fixing to concrete structures shall be by using
of Philips red-head bolt fixing or approved equivalent for concrete and cutting away and building in of brackets in brickwork etc. The Sub-Contractor is to particularly not that it will not be possible to fix bolt fixing directly above the pipes to be supported, in such event, cantilever brackets shall be used where required.

j) External pipe brackets shall be primed with one coat of anti-
corrosive paint prior to installation.

7.11 Pipe Sleeves

a) Where pipes pass through walls, floors, ceiling, etc. the
plumbing Sub-Contractor shall provide and fixed the pipe


sleeves at the actua1 positions. Sleeves for cast iron and galvanized iron pipes shall be black steel; for copper pipes shall be either copper or brass. All sleeves are fitted through floors, they shall extend to at least 6mm clear of finished floor.

b) Sleeves shall be of slightly oversized to allow free movement of pipes.

c) The Sub-Contractor's attention is drawn to the vertical pipe
ducts. At all floor levels in the building, the ducts are to have floors and where pipes pass through these, sleeves are to be provided.


d) The gap between pipe and the sleeve is to be packed with
figreglass blanket material. However, for pipes/sleeves through fire barrier the gaps must be firmly sealed with soft packings having a period of fire resistance equal to the fire barriers. The ends of sleeves are to be caulked with non-hardening mastic to Surveyor's approval.

e) Details of pipes through walls and floors to be approved by the
Fire Services Department and the Surveyor before installation.

7.12 Pipe Anchors

a) All pipes shall be anchored as required to control the movement
of pipes due to thermal charges.

b) The anchors shall securely hold the pipe in a rigid position to resist the attempted movement due to expansion and the weight of the pipe and contents.

7.13 Cocks and Valves

a) General

i) All cocks and valves shall be of the type approved by the Water
Authority for their various purposes, capable of withstanding a hydraulic working pressure of not less than 12 BAR and Installed in accessible positions for ease of operation and maintenance.

ii) All valves shall be arranged so that clockwise rotation of the
spindle will close the valves.

ill) All valves exposed to view in lavatories shall be chromium
plated unless 'Otherwise specified.

iv) All valves installed in the flushing systems shall be of sea water
corrosion resistance type.

b) Draw off Taps

i) Draw off taps for potable water supply system shall be brass
and that for flushing water supply system shall be zinc free bronze or gunmetal.

ii) Unless otherwise specified, screwed down or spring type action
bib and pillar cocks shall be either brass or zinc free bronze, chromium plated with capstan head marked "Hot" or "Cold" and conforming to B.S.1010.

c)Stop Cocks and Valves

i)All stop cocks and valves not exceeding „w 50mm shall be bronze

with crutch head conforming to B.S.1010 for potable water

system.

ii) UPVC stop cocks shall be with wheel head conforming to JIS-

B2212 and shall be suitable for a working pressure of 9 BAR.

The stop cocks shall be entirely suitable for use with sea water.

Samples shall be submitted for approval.

iii)All stop valves for fresh/potable and flushing water supply

system exceeding „w 50mm shall be flanged cast iron globe

valves with wheel head conforming to B.S.3961.

iv) Loose jumper type rough finish with easy clean cover brass stop

cock to B.S.1010, to be used where indicated bythe Water

Authority.

v) Drain cocks must be provided wherever required to ensure that

every section of pipework can be drainned.

vi) In particular cocks must be provided on the "dead" side of non-

return valves, and isolating valves on the mains.

d)Gate Valves

i) Gate valves up to and including 65mm bore shall be of

gunmetal construction fullway solid wedge pattern to B.S.5154.

All valves shall have inside screw gate, high tensile bronze

spindle and screwed bonnet. Valves shall have screwed female

ends.

ii)Gate valves of 80mm bore and over shall be flanged cast-iron,

fullway suice with inside screw solid wedge and high tensile

bronze spindle to B.S.5163. Valves shall have bolted bonnets.

iii) Valves fitted in valve pits shall have spindle with square head

and operating keys shall be provided, other valves to be cast

iron hand wheel to B.S.1218.


iv) All gate valves to be suitable for a test pressure of not less than 15 BAR.

v) Gate valves for flushing water system shall be fullway valves with external rising screw, flanged or screwed to suit the piping and shall be of cast iron construction with nickel alloy faces and Strainless steel spindle to B.S.3464. Valves shall be supplied by Glenfield and Kennedy or approved equal, full suitable and approved for use with sea water.

e) Ball Valves and Floats

i) Ball valves up to and including „w 65mm and using in potable
water supply system shall be brass conforming to B.S.1212 with copper float to B.S.1968.

ii) Ball valves up to and including „w 65mm and using in flushing water supply system shall be zinc free bronze conforming to B.S.1212 with plastic float to B.S.2456.

iii) Ball valves of „w 80mm and above shall be of the Glenfield and Kennedy type fig. no. 1005* with cast iron valve body with
nickel alloy and stainless steel working parts . The valves for flush water shall have construction entirely suitable for use with sea water and floats shall be copper with neoprene coating. ( or equal and approved to relevant British Standard.

iv) Ball valves shall be of the slow closing type as specified above.

f) Check Valves

i) Check valves shall be bronze with square nut head conforming to B.S.5154 for potable water system and zinc free bronze for flushing water system.

ii) For check valve on the discharge side of potable and flushing water pumps, with the discharge outlet over „w 50mm, the check valve shall be either one of the following:-

1. "Vag" cast iron resilient diaphragm type check valves.
(Working pressure 16 bar. and W. Germany origin).

2. "GLEMFIELD" RECOIL CHECK VALVE - shall be
cast iron recoil single dish type figure nos. M7 s (working pressure 14 BAR) and 5101 (working pressure 16.33 BAR) and of U.K. origin.



g) Pressure Reducing Valves (for Fresh and Flushing Water)

i) Pressure reducing valves shall be of adjustable spring type
¡§Bailey's" T pressure regulator or approval equal, cast iron body, zinc free bronze trim fully suitable for salt water, slow closure and damped to ensure smooth operation without slamming.

ii) Valve to be protected by 60 mesh monel metal screen "Y" or "T" type strainer installed upstream. Strainer to be fully suitable for use on sea water. Reducing valve assembly to be installed in a readily accessible location close to the down-feed mains.

iii) One(l) 65 mm dial pressure gauge (scale 0- 3 5bar) to be installed at the upstream immediately-down-stream of the valve, with valve cock to read controlled pressure.

vi) All pressure reducing valves to be approved by Water Authority.

7.14 Welding and Brazing

a) Welders must have a current certificate of competency and in addition will be required to perform site tests of competency, should a welder fail such tests he shall replaced.

b) The Surveyors reserve the right to carry out welding tests on up to 2% of the welds on the installations. The Contractor shall include for remaking the joints where Cutout. Should the results of these tests indicate that the welds are not to the requirements of this specification the Contractor shall, if instructed, remove all pipe-work and welds performed by the welder and replace the work and pay all Costs incurred by other Contractors (if affected) without any additional charge.

c) All pipework for welding shall be supplied with plain ends,
joints being made with butt welds on the site. All welded joints shall be made by an approved welding process, each joint being of sufficient strength to with-stand the stresses imposed by internal pressure, from the expansion, weight of tube, and contents and the thermal insulation.

d) All welded tees, branches, vent pipes, reducers, etc. shall have bevelled, mitred joints, fused by a penetration weld and finished off with a fillet weld of ample dimensions. Care shall be taken to ensure that the welding metal or flux does not project into the bore of the pipe.


e) All welds shall be of good clean metal , free from slag
inclusions and porosity, of even thickness and regular contour, well fused with the parent metal and annealed and hammered on completion and finished smooth. all cuts from standard lengths of pipes shall be made by means of hack-saw, and burrs removed with reamer and the ends trimmed to a fair faced joint for welding. Each weld on black steel pipe shall on completion be painted with a coat of red oxide.

f) Copper pipes shall be either brazed or bronze welded to an
approved technique to B.S.1723 and B.S.1724. the welding rods to be of a type that is suitable for pipe material, contents and atmospheric conditions. All oxy-acetylene welding shall be in accordance to B.S.4872.

g) Welded pipe joints shall be permitted on pipes up to 150mm nominal bore only in situations where flanged joints are deemed by the Surveyor to be impossible or impractical.

h) Steel pipes having welded joints on the run shall be prepared for jointing in a manner suitable for the technique employed. Welding may, alternatively be carried out by oxyacetylene flame, or by electric metal-arc methods.

i) Oxyacetylene welding shall be by the Rightward technique as
described in Technical Memorandum T.5 issued by the British Welding Research Association and B.S.2640. Pipes shall be prepared for welding with ends sawn or cut off by hand, flame cut by machine of flame cut by hand with subsequent truing up by filling or by grinding to a level as may be required. Welding rods shall in all cases, be of good quality copper coated low carbon steel, and the manufacturer shall provide test certificates representative of the rods used in accordance with B.S.1453.

j) Welders identification works required to be stamped at each weld.

k) Metal arc welding shall be carried out in accordance with the techniques described in Technical Memorandum T.3. issued by
the British Welding Research Association and B.S.2633 : 1973 :
Class I or B.S.2971 : 1961 : Class 2, butt ends to piping being built up on either a base run deposited by the oxyacetylene process or a permanent mild steel backing ring. Electronics shall be of good quality in accordance with B.S.639 : 1976, be coated and be of such diameter that performance may easily be controlled to produce a weld of the required quality. All slag shall be removed after each run, undercut edges, slag pockets unsound metal and blowholes being chipped out as the work proceeds.




1) All welded joints, whether produced by oxyacetylene flame or
metal-arc processes shall be of first quality , the butts being slightly convex with regular ripples and no undercutting , washing away or surface cavities being present. Notches at the root indicating incomplete penetration and excessive weld protruding into the pipe bore in excess of 1.6mm inch shall not occur and the external reinforcement shall run out smoothly to the pipe surface on either side.

m ) Welding shall in all cases be carried out by skilled craftsmen
who are in possession of a current certificate of competency issued by an approved authority. The provisions of specimen welds, representative of the thickness and diameter of the joints and the conditions of site welding shall be submitted as required by the Surveyor in respect of every craftsman employed in such work.


n) When the general hydraulic tests of the completed systems are
carried out, as detailed elsewhere each weld shall be lightly hammered during the time that pressure is maintained. If any leaks occur at welds the portion of the weld near the leak shall be cut out and re-welded. Such leaks shall not be repaired by caulking or attempted fusion of the surround metal. Should a considerable portion of the welded joints be made by a particular operator be found to be defective due to faulty workmanship, all such welds shall be cut out and re-welded by another operator whose work has proved satisfactory.

7.15 Jointing of Concrete Pipes

a) For spigot and socket pipes, the spigot shall be placed in the
socket of the pipe previously laid, and the pipe then adjusted and fixed in its :final position to correct lines and levels and accurately centered. A ring of tarred rope-yarn shall be next inserted in the socket of the pipe previously laid and driven home with a wooden caulking tool and mallet; when in position such yarn shall not occupy more than one quarter of the depth of the socket. The socket shall then be filled with a cement-mortar fillet worked all round. The fillet shall be bevelled off and shall extend for a length of not less than 50mm from the face of the socket.

b) For "Ogee" pipes, the joints shall be thoroughly cleaned and
wetted, and cement-mortar shall be applied evenly to the ends so as to completely fill the joint. The pipes shall then be properly drawn together and the outside of the joint shall be neatly pointed.

c) Special care shall be taken to remove any excess mortar and to
clean each pipe by drawing a tight-fitting was through as the work proceeds. The trenches and pipes shall be kept free from water until the joints are thoroughly set after which time the pipes shall be flushed from end to end with water, and left clean and free from obstruction.

d) For pipes with flexible joints , the pipe manufacturer's instructions shall be closely followed. The joint shall be carried through to the foundation so that the overall flexibility of the pipe line is maintained.

e) For pipes with precast concrete collar-joints , one half the length
of the collar shall be caulked onto the pipe using a suitable collar support to hold the collar concentric with the pipe. 1:3



cement mortar shall be used in caulking on the collar in layers not exceeding 40mm in thickness with suitable tools. After the caulking is completed the joints shall be covered and kept moist for three days. The tongue-end of the pipe shall be slipped into the collar during the laying process and the annular ring poured or caulked with 1:3 cement-mortar, taking care to make a smooth internal connection. This method of jointing shall be used on plain buttended pipes or on tongue-and-groove pipes.

f) For pipes butt ended with in-situ collars, cement-mortar shall be
applied evenly to the ends of the pipes to be jointed. The pipes shall then be properly drawn together. Excess mortar shall be removed to make a smooth external and internal connection.

g) Precast or in-situ collars shall be constructed as shown on the Drawings.

7.16 Jointing Pipes of Different Materials

a) Ductile Iron to UPVC Joints

Where UPVC branch pipes connect into ductile iron droppers on the flushing installation, special cast iron fittings shall be used. These fittings shall have flanged connections for coupling to the main and modified union connection on the branch with fibre-gasket for connection to UPVC branches

b) Copper to Ductile Iron or Steel Joints

Where copper flanges join to C.I. or steel fittings, valves etc. of ferrous metal, special sleeves shall be inserted in over-drilled bolt holes to isolate direct contact to bolts and flanges. Similarly , high strength flat fibre washers to be used on both ends of the bolt between the steel washers and flanges to prevent direct dissimilar metal contact.

c) Galvanized Steel to Cast Iron Drainage Pipe

Galvanized to cast iron joints are to be made with hemp and caulked lead , cold caulking compound "Philplug" PC3 or PC4, or an approved
jointing compound well rammed into the socket.

d) UPVC to Cast Iron Drainage Pipe



UPVC to cast iron sockets or bossed connections shall be made with screwed joints or caulked cement and yarn, cold caulking compound or approved jointing compound.

7.17 Expansion Joints

a) Wherever possible, advantage shall be taken of changes in direction of pipes to take up expansion and contraction due to temperature changes of the pipe contents .

b) Expansion joints and movement joints shall be provided on
pipes across the building expansion joints and elsewhere to absorb the effect of expansion on pipes as generally shown on the Drawings. Special attention shall be paid to provision of expansion joints on hot water pipework.

c) Where expansion joints are required, they shall be bellows type. Bellows shall be stainless steel with stele inner and outer telescopic sleeves. The joints shall have screwed ends and flanged joints for Joints of larger bore. The joints shall be suitable for a test pressure as specified for the pipes. Each joint shall be suitable for a traverse of not less than 25mm and if necessary a joint of larger diameter than the pipe shall be installed with reducing fittings to obtain the allowable required pipe movement.

d) Where movement points occur, couplings as Messrs. Viking Johnson or equivalent equal and approved shall be used so that building movement does not cause fracture of the pipework, etc.

e) Upon sizing and fixing expansion joints on pipes across the building expansion joints , the Sub-Contractor shall take into account, in addition to the expansion/contraction of pipes due to the temperature changes, the effect of the relative horizontal movement between the two parts of the building structure separated by the building expansion joint.

f) Expansion coupling with neoprene seal ring at one end to be used on UPVC piping.

g) On UPVC vertical/horizontal drainage pipe, axial expansion
coupling, as recommended by UPVC pipe/fitting manufacturer, to be supplied and installed as shown on the Drawings, of slip type with neoprene seal ring between the two coupling members. Class and standard of expansion joint to be the same those for pipes specified.



h) Where steel, cast iron, or UPVC drainage pipes cross building expansion Joints , expansion joints, mainly for lateral movement
(as well as for axial), of either stainless steel bellows of neoprene convolute design to be used.

i) Generally expansion bellows shall be installed mid way on each
water riser. Details and location of expansion joints shall be submitted to the Surveyor for approval.



7.18 Pipe Guides


Pipe guides, are for use in long lengths of pipe and tube and are to be fitted on each side of every joint to keep and to direct the movement of expansion and contraction from anchor points in true alignment in lateral direction towards the bellows or other flexible inserts shall take the form of enclosing hoops of mild steel flat to B.S.3974 : Part I, generally 40mm x 20mm in section. Such shall be secured to roller brackets and other fixings by means of bracket attachments. Metal guides for UPVC pipes shall be lined internally with UPVC material slightly oversized to allow axial movement of the pipe.


Generally, guides shall be fixed at points between the anchors and expansion joints to ensure that the thrust is linear to the axis of the pipe.


7.19 Flexible Connection


a) On suction of all flush and fresh water pumps.


All stainless steel construction, double flanged, flexible hose, one for each pump, full line size, rate 7 BAR, working pressure, fully suitable for sea water when used on flush water pumps. Minimum length between flanges to be 300mm.


b) On discharge of all pumps.


All stainless steel construction, externally braided, double flanged, flexible hoses, two for each pump, full line size, rate 17 BAR minimum working pressure, fully suitable for sea water when used on flush water pumps. Minimum length between flanges - 300mm.


7.20 Strainer


Strainer shall be Y pattern bronze body for potable water system and gunmetal body for flush water system with screwed connection up to „w 65mm and cast iron body flanged for „w 80mm and over, with removable mesh s.s. baskets and of such design as to permit blowing out of accumulated dirt without discontinuity of service. Strainer shall be provided as specified and shown on the Drawing.

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