Federal Electricity & Water Authority Water Directorate ...fewa.gov.ae/en/OpenData/Documents/18.CS17-Water Pipe line works.pdf · BS 5834 Surface Boxes Guards & Underground Chambers

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Client: FEDERAL ELECTRICITY AND WATER AUTHORITY (FEWA) Project: STANDARD SPECIFICATIONS FOR WATER WORKS

Engineer WATER DIRECTORATE - ASSET MANAGEMENT DEPARTMENT

Title: Technical Terms / Chapter-4 / Engineering Specifications / Civil Engineering Works Specification

CS17-WATER PIPELINE WORKS

Office:

DUBAI Order: Document: MWA_PRO_07/WAM-04-CS17 Rev: OCT/2014 sheet: 1 of: 18

Federal Electricity & Water Authority

Water Directorate

Asset Management Department

STANDARD SPECIFICATIONS

FOR WATER WORKS

TECHNICAL TERMS

Chapter – 4

Engineering Specifications

[C-Civil Engineering Works Specifications]

CS17-Water Pipeline Works

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CS17- WATER PIPELINE WORKS

Office: DUBAI Order: Document: MWA_PRO_07/WAM-04-CS17 Rev:

OCT/2014 sheet: 2 of: 18


TABLE OF CONTENT

1. GENERAL

2. STANDARDS AND GENERAL REQUIREMENTS

3 CONSTRUCTION REQUIREMENTS

3.1 Route of Pipelines

3.2 Surveying Alignments

3.3 Setting Out

3.4 Preparation

3.5 Diversion of Traffic

3.6 Shoring up of Building

4. EXECUTION

4.1 Excavation

4.2 Water to be removed

4.3 Timbering of Pipe Trenches

4.4 Pipe Bedding

4.5 Backfilling of Trenches

4.6 Pipelines in Filling

4.7 Pipe Installation

4.8 Pipe Transport and Storage

4.9 Transport and Delivery to Site

4.10 Joints and Laminations

5. THRUST BLOCKS AND ANCHORAGES

6. VALVE PITS AND MANHOLE PITS

7. ROAD CROSSINGS

7.1 Road Crossings by Open Cut Trench Method

7.2 Concrete Encasing

7.3 Road Crossings by (NDRC) Method

7.4 Casing Pipe

7.5 Duty Pipe Installation

8. WADI CROSSINGS

9. CONTROL AND COMMUNICATION CABLES LAYING

10. POTABLE WATER SYSTEM

10.1 Pipes and Fittings

11. SANITARY WATER SUPPLY


12. HOT WATER SUPPLY


12.2 Thermal Insulation & Weather Protection

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13. MATERIALS

13.1 Stop Valves And Stopcocks And Fittings

13.1.1 Ferrules (with Combined Stopcock)

13.1.2 Compression Fittings

13.2 Flexible Hose Assemblies

13.3 Water Filter Units

13.4 Cold Water Cisterns & Break Tanks

13.5 Water Heater Cylinders

14. INSPECTION AND TESTING

14.1 Civil Works

14.2 Pipe Works

14.3 Testing

15. MISCELLANEOUS WORKS

15.1 Field Pressure Test

15.2 Marker Post

15.3 Restoration of Surfaces

16. COMMISSIONING

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1. GENERAL

This section covers the construction aspects of pipelines for water system. This specification defines the requirements for the design, manufacture, inspection, testing,supply, installation and commissioning of the Water Supply Systems, to be used for the project water works.

The water supply system consists of three sub-systems as follows : - Potable Water Supply System - Sanitary Water Supply System - Hot Water Supply System

The Contractor shall prepare all necessary calculations and construction drawings and details for FEWA/Engineer approval, based upon this specification together with project water supply layouts and general arrangement drawings prepared for the proposed water works.

2. STANDARDS AND GENERAL REQUIREMENTS (To include all latest amendments)

Unless otherwise stated in these specifications, the design, rating and capabilities, performance characteristics, limits, tolerances, protections, etc, and selection of materials manufacture, installation, testing and commissioning shall conform to all applicable internationally recognized standards, such as BS, DIN, ISO, VDI, ASME, ASTM, VDMA, AFNOR, JIS, etc. including the latest amendments thereof at the time of issuing tender specifications.

GENERAL: British Standard No BS 6700 shall be generally followed. Reference shall also be made to the following British Standards :

British Standards BS 853 Hot Water Cylinders BS 864 Capillary and Compressive Fittings of Copper and Copper Alloy BS 1010 Stop Valves and Draw - off Taps BS EN 1057 Copper Tubes for Water, Gas and Sanitation BS EN 12165 Copper & Copper Alloy Forged Fittings BS EN ISO 1452-1 Plastics piping systems for water supply BS 4213 Polyolefin Cisterns BS 5433 Underground Stop Valves BS EN 1796 Glass-reinforced thermosetting plastics (GRP) piping systems for

water supply with or without pressure. BS EN 14154-3 Water meters. Test methods and equipment BS 5834 Surface Boxes Guards & Underground Chambers Gas& Water Works BS 6700 Water Supply BS 6501 Flexible Metal Hose Assemblies BS 6572 Blue Polyethylene Pipes for Below Ground Cold Potable Water BS EN 12201-1 Plastics piping systems for water supply, and for drainage and

sewerage under pressure. Polyethylene (PE). General. BS 6920 Potable Water - Non Metallic Products & their effect on Water Quality BS 7181 Storage Cisterns for Water Supply BS 7291 Thermoplastics Pipes & Fittings for Hot & Cold Water Purposes BS EN 1452 uPVC Joints and Fittings for Cold Potable Water BS EN 1982 Copper Alloy Ingots and Castings (Supercedes BS 1400). BS EN 12620 Aggregates for concrete BS 21 Specification for pipe threads for tubes and fittings

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BS ISO 3601-2 Fluid power systems. O-rings. BS EN 682 Elastomeric seals. Materials requirements for seals used in pipes and

fittings BS EN 124 Gully tops and manhole tops for vehicular and pedestrian areas. BS EN 13101: Steps for underground man entry chambers BS 7668 Weldable structural steels. Hot finished structural hollow sections in

weather resistant steels. Other reference documents: C 651 American Water Works Association Standard

3 CONSTRUCTION REQUIREMENTS

3.1 Route of Pipelines General route of lines are shown in the drawings supplied along with the Tender Documents. The Contractor shall obtain approval of the final route and alignment of the pipelines from the concerned Local Municipality. The information given in the Tender Specifications and drawings is not intended to be a complete and detailed description of Work to be done. The information given is only a guideline for execution of the Works.

3.2 Surveying Alignments The Contractor shall be responsible for all the necessary surveying and pegging out of the pipeline route. Deviations from the proposed route shown on the Tender drawings due to the local site condition shall require the approval of FEWA/Engineer in writing.

The final route and alignment shall however be approved by the concerned Local Municipality. The Contractor shall prepare and submit to FEWA/Engineer, all necessary survey drawings, including longitudinal profiles for approval and record.

3.3 Setting Out The Contractor shall be responsible for true and proper setting out of the alignment, and for correctness of the position, levels, dimensions of all parts of the Works and for the provisions of all necessary instruments, appliances and labour in connection therewith.

Sight rails shall be set in position, using a surveyor's level and properly established bench marks alongside the work. The practice of "transferring" levels by means of a straight edge and spirit level will not be permitted. Where long lengths of Water Supply Pipe are to be constructed in trenches, sight rails shall be fixed across the trench at intervals of at least 20 metres and at a height equal to the length of the looping rod to be used, above the required level of the pipe at the point where the sight rail is fixed. As built drawings shall be prepared to accurately record the final location of all concealed and buried Water Supply Pipes.

If at any time during the progress of the Works any error shall appear or arise in the position, level, dimension or alignment of any part of the Works, the Contractor shall rectify such errors. The Contractor shall carefully protect and preserve all benchmarks, sight rails, pegs and other things used in setting out the Works. 3.4 Preparation Before commencing the excavation of any pipe trench surface layers such as road surfacing, interlocking blocks, bricks, tiles, kerbstones, turf, etc. shall be carefully removed from the working

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area. Reusable materials shall be placed on one side and retained for later reinstatement. Materials, which are not suitable for re-use, shall be immediately removed from the area and disposed in a location designated by the Local Authority. The removal of walls, fences, trees etc. shall only be carried out with the approval of FEWA/Engineer and the Local Authority. The reinstatement of the same shall also meet with the approval of FEWA/Engineer and the Local Authority. Where carriageways, footpaths, verges, plantations or other surfaces outside the limits are damaged during operations associated with the Works, the Contractor shall be responsible for restoring the surfaces to their original condition.

The cover between the crown of the pipe and the finished surface level shall not be less than 1.2 m in areas accessible to traffic. This minimum cover shall be increased to 1.5 m or a reinforced concrete protection slab shall be constructed.

When crossing existing buried utilities the level of the pipe must be adjusted accordingly and the utility protected in accordance with the requirements of the relevant Authority.

Changes in line and level between sections of the trench shall be achieved by gradually sloping the bottom or sides of the trench where the changes in line and level occurs.

3.5 Diversion of Traffic The Contractor shall make full arrangements for the diversion of traffic including arranging permission from Road Authorities, Traffic Police and Local Municipality, fixing and maintenance of signs, caution boards, providing of night signals. The contactors shall ensure to comply with the requirements of local Authorities.

3.6 Shoring up of Building The tendered cost of the Project shall be inclusive of all Works required for shoring up of the buildings along or near the trench, which are likely to be endangered by the execution of the Work.

4 EXECUTION 4.1 Excavation The trenches shall be dug to a depth so that 25 cm minimum sand bedding can be provided under the pipeline and the normal cover shall be 100 cm or more above the top of the pipe. In sandy areas 25 cm depth for sand bedding shall not be required.

The bottom of the trench shall be properly compacted to make perfectly plane surface and irregularities shall be leveled.

The Contractor shall lay pipe in straight lines in horizontal and vertical planes. The cost on account of extra depth (if any) involved for keeping the pipes straight in horizontal and vertical plane or for making connection with existing works or for avoiding interference with the existing services, structures etc. shall be considered to have been included.

While excavating the trenches, the road metal, bricks, soling material, tiles, kerbstones, turf etc. shall be placed on the side and shall be preserved for reinstatement when the trench is filled up. Extra care shall be taken when trench is to be excavated through private property. Cutting of any

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fence or trees, etc. in line of trench shall be done only with the approval of the Engineer and concerned Authorities. All works necessary for the breaking and removal of rocks, boulders, etc or protecting the trenches from the shore/ground water are deemed to be included and Contractor shall execute them very diligently and carefully.

4.2 Water to be Removed The Contractor is to keep the Site and excavations, whether above or below ground water level, at all time well drained and free from storm and percolating water which may accumulate on the Site and which may interfere with progress or construction or has or is likely to have deleterious effect on the Work in progress or the use thereof, by the provision of temporary open drains diversion of ditches and other surface water channels, etc. or by pumping or other means as required.

The Contractor shall provide and carry out all pumping, bailing out or removing of water accumulated in the trench during the execution of Work in such a manner as will neither cause hindrance or nuisance to the public nor to private property.

If the pipeline or other works have to be executed below underground water level, the trenches and excavation shall be kept dry during laying and jointing the pipeline and during testing of the pipeline employing well point dewatering system. Pipe laying, testing, etc. shall not be allowed unless the trench is dry.

4.3 Timbering of Pipe Trenches Where necessary, the Contractor shall support the sides of the pipeline trench and other excavation by suitable timbering. The trench sides shall be close timbered, wherever the Engineer may so desire. Normally timber shall be removed as the work proceeds and the trenches filled up after due test, but it may be necessary in certain cases to leave a certain portion of the timbering in the ground.

4.4 Pipe Bedding Pipe bedding and surrounding material shall be well rounded not angular.When the as dug material is suitable, the bottom of the trench shall be trimmed and loosened to form the bed otherwise the trench shall be excavated to a depth below the invert level to allow for the thickness of bedding material. No sharp material shall be in contact with the supply pipe.When as dug material is not suitable, imported granular material as per the table given below shall be used to provide a 100 mm bedding and surrounding material. Table -Requirements for imported material for bedding and surrounding

Nominal pipe size Material (complying with BS EN 12620)

Up to 2½" Coarse sands up to 5 mm nominal size.

3" to 6" 10 or 14 mm nominal single sized or 5 to 14 mm graded aggregate.

8" and over 10, 14 or 20 mm single sized or 5 to 14 or 5 to 20 mm graded aggregate.

All surround and backfill materials up to 500 mm above the pipe shall be loose laid and hand compacted only.If the as dug material contains stones larger than 40 mm the bedding material must be extended 150 mm above the circumference of the pipe. Alternatively the backfill can be graded to eliminate stones exceeding 40 mm and this selected backfill used for the first 300 mm

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above the circumference of the pipe. The remainder of the trench may be backfilled with suitable excavated material.

4.5 Backfilling of Trenches After the pipes have been laid, jointed and tested and proved to be water tight, the trenches shall be refilled in the manner described below, after taking written permission of fewa/Engineer.

The first 25 cm of filling material immediately above the pipeline and on the sides of pipe shall consist of fine sand. No lumps of material shall be put around the pipe or thrown into the trench until the same has been protected in the manner described above. If the excavated material is found suitable for this 25 cm filling, the Engineer may allow the same to be used.

The remainder of the depth shall be backfilled and rammed in layers not exceeding 15cm at a time. Sufficient water shall be used to aid the consolidation of the trenches so as to achieve a maximum dry density of 90%. The top 30 cm under the sub grade level of the road shall be compacted to achieve a maximum dry density of 95%.

Where fewa/ Engineer does not consider the excavated material is suitable for forming the bed and filling the sides and top, the pipe shall be laid on a compacted layer of fine sand not less than 250 mm in thickness and surrounded and covered with the same material. The sand must be such that 100% passes through BS sieve no.16 (1.00 mm) and not more than 50% pass through BS sieve no. 100 (0.152 mm). The Contractor shall allow for the additional 250 mm excavation, the disposal of the unsuitable material and the imported material.

Pipes laid at road crossings or beneath hard standing areas shall be surrounded with sulphate resisting concrete.

4.6 Pipelines in Filling In some areas, where the pipeline route is much lower than the nearby road level or in areas of local depression, fewa/ Engineer may order to lay the pipeline in full embankment or partial embankment. The level of embankment (filling), depth of pipeline, width embankment, slope and depth of filling etc. shall be approved by fewa/ Engineer.

4.7 Pipe Installation Prior to lowering the pipes, the respective pipe trenches shall be subjected to thorough inspection by FEWA/Engineer with respect to alignment, slope, dimensions and suitability of bottom to meet the requirements of proper pipe laying.All socketted pipes shall be laid with the sockets facing upstream.

Before the pipe is lowered in the trench, FEWA/Engineer shall approve the suitability of the material in the trench bottom. Additional excavations shall be carried out to provide extra space around couplings/joints. The trench bottom shall be free from stones and other sharp objects, which might damage the pipes.

Manual and mechanical tools and hoist for lifting and lowering of pipes shall allow for smooth and continuous moving.

All pipes shall be laid and maintained to the agreed alignments and grades ensuring that the pipe is properly bedded along its whole length. After placing, each pipe section shall be thoroughly checked as to alignment, level and slope.

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All pipes shall be fully supported at the intervals and using mounting in strict accordance with the recommendations of the pipe material manufacturer. Pipe supports shall be constructed to guarantee the uniform transmission of loads.Neither line nor point bearing of loads will be allowed.

The bearing section for supported circular profiles shall cover at least an arc of 90° if not otherwise specified. The trench bottom shall not be loosened by any means. If, however, loosening occurs, the loosened soil shall be excavated and replaced by non-cohesive soil, which shall then be compacted, all at the expense of the Contractor.

Supports in sand or coarse sand shall be executed by forming the bed according to the shape of the pipe to be laid to allow each pipe section support along its full length.

Soil not usable for direct pipe laying shall be excavated from the trench bottom to place a supporting layer of sand or coarse sand, thoroughly compacted. The minimum thickness of such layer shall be 10 cm plus 1/10th of the pipe outer diameter but not less than 20 cm thick.

Fittings and valves shall be provided at the required locations. No deviation shall be made from the agreed alignment or grade except with the written consent of FEWA/Engineer. The permission to lay pipe will not be given in case the trench is not dewatered as described earlier.

The trench shall be kept dry till the pipe is tested and backfilled. Before stopping the dewatering pumps the completed pipe should be plugged watertight so that the sub soil water does not seep into it.

When pipes pass through walls, floors or ceilings they shall be sleeved and sealed. All concealed pipes within walls, ceilings or floors shall be run within protective conduit.

Pipes which are laid, or built into walls and manholes, but not immediately connected up, shall be fitted with suitable temporary stoppers or seals, and the position of such pipes shall be clearly defined by means of stakes or training wires properly marked or labelled.

Before the commencement and for the smooth progress of the pipework installation, the Contractor shall coordinate and finalize the routes, ground/invert levels, positions of the manholes etc. with FEWA/Engineer.All the changes in the design shall be subject to the approval of FEWA/Engineer.

4.8 Pipe Transport and Storage All pipes shall be transported, stored and installed strictly in compliance with the requirements of the manufacturer.

4.9 Transport and Delivery to Site Special care shall be taken to avoid any damage during transport, loading and off-loading, storage, etc. Storing of pipes along side trenches shall be done only for the shortest time possible before placing into the trench. All pipes shall be checked for defects and damages prior to placing.Material which does not conform to the Specifications or which is found to be defective or damaged shall be rejected and removed from the work. If more than 10% of the pipes are rejected because they do not conform to the Specification the Engineer has the right to reject the whole consignment.

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4.10 Joints and Laminations Lamination joints are to be provided for GRP pipes only. The lamination joints shall be made only under the exclusive supervision of the GRP pipe manufacturer. All material for the joints shall be brought to the site before execution. The place where joints are to be made shall be well compacted and shall be dry.

During connection of pipe sections, the contact surfaces carrying sealing compounds shall be kept clean; all open ends for later connections shall be closed to avoid soil or other contamination entering into the bores.

5. THRUST BLOCKS AND ANCHORAGES

Concrete thrust blocks and anchorages shall be provided at all bends, tees, tapers, end caps, blank flanges and other equipment where pressure exerted by the pipeline would result in movement of the pipe.

Thrust blocks and anchorages shall be designed to resist the anticipated forces exerted by the pipes, taking into consideration the existing ground conditions and the passive resistance provided by the soil. The blocks shall be cast against undisturbed soil. If the ground has been disturbed it shall be removed and the resulting extra volume filled with concrete as specified for the thrust blocks.

Concrete for the thrust blocks shall contain nominal reinforcement, be sulphate resistant and shall have strength of minimum 30 N/mm2. The cover to the reinforcement shall be 75 mm minimum. Where restrained or similar joints are proposed, only nominal thrust blocks are required.

6 VALVE PITS AND MANHOLE PITS

Where sectionalizing valves are installed in the pipeline these valves shall be housed in valve pits, which may be of precast or in-situ reinforced concrete construction to the internal dimensions laid out in BS 5834.

Manholes and Pits shall be designed for the vehicular or other loading to which they will be subjected.The pits shall be provided with CI heavy-duty manhole covers.

Minimum material characteristics for pits shall be sulphate resistant 30/mm² reinforced concrete. Valve pits shall be coated externally with a bituminous membrane. The materials entering into the work, and their combination, construction, and/or fabrication, shall conform to the requirements of prevailing standards and these Specifications.

Cast-iron frames and covers shall be free of pouring faults, blowholes, cracks, and other imperfections. The castings shall be sound, true to form and thickness, clean, and neatly finished and shall be coated with coat a tar compound. Covers, which are to be placed on frames, shall lie on them evenly. Cast-iron or steel frames shall be set on full mortar beds composed of one part of Portland cement and two parts of fine aggregates.

Sections of connection pipe shall be incorporated into the construction of wall and placed at the elevation, direction, and grade required with puddle flange and the gaps shall be sealed off for water tightness.

Where the depth of invert of manholes exceeds one metre below the finished ground level,

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aluminum steps as specified in BS EN 13101 shall be built in at vertical intervals of 300mm, with alternate steps in line vertically and at 225mm centre to centre horizontally.Entry to deep manhole chambers (> 2500 mm) shall be by means of one or more caged vertical aluminium ladders.Manhole covers and frames shall be coated cast-iron complying with BS EN 124 approved or equal and shall be designed for the loading category to which they will be subjected.

7. ROAD CROSSINGS

Where the pipeline crosses the roads and wadis, the pipe shall be laid with proper protection and cover. The Contractor shall encase the pipes at these crossings. Road crossing shall be affected either by open cut trench method or by NDRC method. FEWA always prefers the pipeline to cross the roads by open cut trench method followed by reinstatment of asphalt.One of the following two methods shall be employed.

The tentative locations for such crossings could be noted from the drawings. However, the actual locations, alignment, depth etc. shall be finalized in consultation with the local Municipality/Road Authorities/Ministries, etc. The factors influencing the actual location could be alignment and route of pipeline, density of traffic, existing services, congestion and other such Site conditions. The Engineer may instruct the Contractor to lay the pipeline by open cut trench method instead of NDRC or vice versa, depending on Site conditions and Local Authority requirements.

For all road crossings it is preferred the pipe shall be of single length equal to the crossing length. No joints or couplings are allowed in the middle of the crossings except for busy roads where single lap joint could be considered. The Contractor shall ensure this requirement. If required special length pipes shall be fabricated and delivered.

7.1 Road Crossings by Open Cut Trench Method For all roads (single or dual carriage ways), the length of the encasing shall be at least 2meters on either side of the edge of the road including complete footpath and services area. In the case of busy roads crossing the operation may be divided in 2 portions to facilitate the immediate resumption of traffic. In the first instance the ground trenches shall be dug open to the required level, top asphalt material/debris shall be immediately disposed, the lower clean level material shall be removed and stored separately, the trenches shall be shored properly, if required dewatered and the bottom of the excavation shall be compacted as required.

7.2 Concrete Encasing This could be done either in-situ or pre-concreted externally. The in-situ construction shall be followed for single and low traffic roads and pre-concreted pipes construction for duel carriage and busy roads.

For in-situ construction the pipe with steel cage shall be prepared externally. The pipe shall be fixed central to the encasing such that the required concrete cover is obtained uniformly all around the space. To achieve this, suitable spacer blocks or pads shall be fixed around the pipe. The pipe with the cage shall be lowered in the open trench and concreted in a single pour. For pre-concreted pipe construction the pipe shall be prepared with concrete encasement externally, cured and then brought for placement in the open ground trench.

After completion of the work the road and the surrounding area shall be reinstated to its original finish as specified elsewhere.

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7.3 Road Crossings by NDRC Method A part from laying the pipeline across the road, by conventional open cut trench method, there must be provision for laying the pipeline across the roads by horizontal directional drilling or such other NDRC method. For dual carriage way roads, the starting point shall be on one side of the road and target point on the other side with boring continuing through central reservation/island. However, if the central reservation/island is very wide or because of Site conditions, the Engineer may decide to have two separate borings for both carriageways instead of one continuous boring through reservation/island. On getting such instructions, the Contractor shall execute two separate borings, maintaining proper alignment. While laying the pipeline by boring method, first the casing pipe shall be installed along with the boring. If the ground surrounding the casing pipe is disturbed during the pipe installation, grouting shall be carried out around the casing pipe over its entire length. The duty pipe shall be laid through the casing pipe. Casing pipelines shall be of welded steel construction.

The horizontal boring shall be done to its approved alignment and levels and the casing shall be free from kink(s), bend(s), etc. The duty pipe must pass though the casing pipe, freely without applying any undue pressure. If any boring is found to have kink(s), bend(s) etc. or is out of alignment/level beyond reasonable allowance, such boring shall be rejected. Such boring shall have to be filled with lean concrete and abandoned. It will not be allowed to retract the casing pipe from such borings. No compensation is allowed for any of the material, labour or works carried out for such abandoned boring.

A new alignment shall be finalized in consultation with the Municipality and Engineer in lieu of the abandoned boring and the Contractor shall drill a new boring as per Specifications.

7.4 Casing Pipe Casing pipes shall be mild steel conforming to ASTM – A 53, Grade A or API – 5L, Grade A or BS 7668, Grade 43 A. The casing shall be of welded construction and welding shall be carried out in accordance with API – 1104 – 1983 or equal.

Each length of the encasing pipe shall be legibly marked by rolling, stamping or stencilling to show, the name or brand of manufacturer, the kind of pipe and the Specifications number to which it conforms.

The Contractor shall submit the bill of lading and mill certificate and other quality documents showing chemical composition and strength test results of the pipes brought for encasing to the Engineer/Authority for their review and approval.

The casing pipe’s internal diameter shall be at least 100 mm more than the outside diameter of duty pipe at socket end, which is passing through the casing. The boring diameter shall be determined considering the outside diameter of casing pipe. The casing pipe shall be designed to withstand the external pressure under the heavy road traffic conditions.

The inside and outside of casing pipe shall be sandblasted to Sa 2-1/2 and coated with anti-corrosive bituminous paint. The coating shall be applied in two or three coats and total thickness shall be about 250 microns. The coating shall be applied as recommended by the manufacturer. If primer coat as recommended by the piping Manufacturer or by the Engineer is required, then the blast-cleaned surface shall be first applied with the recommended primer and then the coating as specified above shall be applied.

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7.5 Duty Pipe Installation The duty pipe shall be laid central to the casing pipe i.e. the space all around duty pipe shall be uniform. To achieve this, suitable spacer blocks or pads shall be fixed to either of the pipes. The duty pipe shall be suitably wrapped in accordance with the manufacturer’s recommendations before placing in the casing pipe. After laying the duty pipeline, the annular space between casing and duty pipe shall be grouted all through it’s length with mortar mix (1:6) having water cement ratio about 0.90. Care shall be taken to ensure that grout fills the gap all through the length. At both ends the mortar shall be neatly finished.

8. WADI CROSSINGS

The pipes shall be encased in concrete at these crossings or supported on concrete structure. The concrete cover shall be similar to that described for road crossing above.

Additionally at wadi crossings the encased pipe shall be anchored to the ground with suitable method. Where required suitable culverts or other provisions shall be made for water in the wadi to flow across the encased pipeline. Across the wadi the pipeline can be routed through viaduct on pillars and beams depending upon the site conditions.

9. CONTROL AND COMMUNICATION CABLES LAYING

Where control cables or communication cables are to be laid along the pipeline route they shall be installed alongside the pipe in the trench at the time of backfilling the trench. The cables shall normally be laid at the top of the compacted, selected fill and shall be protected by marker tiles and warning tape, Where the pipe is encased in concrete or installed by a ‘No-Dig’ method at a road crossing, the cable shall pass through a PVC duct set in the concrete.

10. POTABLE WATER SYSTEM

The Potable Water Supply System is required to supply Cold Potable Quality Water to all consumers on site. Potable Quality is to be assured by installing in line filter units immediately upstream of each consumer.The Potable Water Supply is also to be used to supply break tanks and cisterns which serve sanitary and hot water systems. The Potable Water Supply System also delivers water for service within buildings.Potable Water Supply System runs from the branch on the local main to the Potable Water Storage Tanks via pressuring pumps and through a distribution network of underground pipes. The Potable Water Supply system is to be a nominally 12 bar rated system and shall be designed to a test pressure of 18 bar. Piping between the termination point and the individual consumers shall be detailed and installed by the Contractor.

10.1 Pipes and Fittings Cold water pipes less than 3" diameter shall be of one of the following options throughout:

i) u-PVC pipes and fittings to BS EN 1452. ii) Polyethylene pipes to BS EN 12201- Fittings to be of either compatible thermoplastics

to BS 7291 or Brassware to BS EN 12167/BS 864. iii) Copper pipes to BS EN 1057 with fittings to BS EN 12165/BS 864.

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Cold Water pipes of 3" diameter or greater shall be of one of the following options throughout.

i) GRE/GRP Pipes and Fittings to BS EN 1796. ii) U-PVC pipes and fittings to BS EN 1425. iii) DI pipes and fittings to ISO 2531.

The Contractor shall perform the detail design for each supply system using one of the above material options. The Contractor's complete detail design including calculations,detail drawings and samples shall be submitted for FEWA/Engineer approval.

11.SANITARY WATER SUPPLY

The Sanitary Water Supply System is required to supply cold water to non potable consumers within the plant building and other buildings.Local connection between the Sanitary Water Supply System and individual consumers shall be made using flexible metal hose assemblies and angle valves.To ensure that no back contamination of the potable supply occurs, all sanitary water is to be supplied from high level break tanks and cisterns fed from the potable water system.

The sanitary water system is in consequence a low pressure system although for design,installation and test purposes it shall conform to the same requirements as those for thepotable water supply system.All Breaktanks and Cisterns shall be protected by isolation valves at inlet and outlets.

11.1 Pipes and Fittings Pipes and Fittings for Sanitary Water Supply System shall be provided in accordance with the materials options as specified in respect of Cold Potable Water Supply System above.

12. Hot Water Supply The Hot Water Supply System is required to provide Hot Water to non potable consumers within buildings.Local connection between the Hot Water Supply System and individual consumers shall be made using flexible metal hose assemblies and angle valves.Hot water is to be supplied from local water heater tanks located at convenient proximity to the consumers. Fed from the high level break tanks and cisterns each system shall be in consequence a low pressure system although for design, installation and test purposes shall conform to the same requirements as those for the potable water supply system.

12.1 Pipes and Fittings Pipes and Fittings shall be provided in accordance with the following :-

i) Above ground copper pipes shall conform to BS EN 1057 related table and shall have joints and fittings of copper alloy to BS EN 12165 or BS 864 Part 2. ii) Below ground copper pipes shall conform to BS EN 1057 and shall have joints and fittings of gun metal to BS EN 1982.

12.2 Thermal Insulation & Weather Protection All exposed Hot Water Supply System pipes and fittings shall have thermal insulation. Hot Water Supply Pipes and Fittings buried within walls ceilings or floors shall be surrounded with fine grade vermiculite mixture.

Minimum thickness of thermal insulation shall be as follows : i) Pipes upto 1½" diameter 15 mm ii) Pipes 1½" to 2½" diameter 32 mm iii) Pipes 3" diameter and above 50 mm.

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All pipes and fittings exposed to the effects of weather shall be thermally insulated as above and provided with an approved white abrasion resistant weather proof coating system.

13. MATERIALS

All materials to be supplied and installed in accordance with this specification shall be subject to FEWA/Engineer approval. The materials of all pipes fittings valves and equipment supplied for the project shall be new and of first class quality, free from scale, lamination, inherent corrosion and any other defects. Pipes, fittings, valves and equipment shall be manufactured, inspected and tested in accordance with the relevant British Standards and Codes of Practice, and shall be suitable for service under the stated pressures and temperatures. All component materials for incorporating into the water supply system shall be procured with BSI certification.Prior to the complete ordering of the required service materials the following shall be provided: Sample lengths of pipe, saddle straps, ferrules (combined with stop cocks), stop valves, angle valves, water meters and fittings such as elbows, tees, reducers, couplings, adaptor,connectors and metal flexible hose assemblies, etc ... (for each intended material service and pipe size).These materials shall be trial assembled at site and subjected to pressure testing, all in the presence and to the satisfaction of FEWA/Engineer.All materials to be incorporated in the work shall be handled and stored strictly in accordance with the recommendations of the manufacturer.

13.1 STOP VALVES AND STOPCOCKS AND FITTINGS Stop valves less than 3" diameter shall be of the medium pattern type with female ends and manufactured and tested in accordance with the requirements of BS 1010. The spindle shall be fitted with a brass crutch head. The valve shall be manufactured to thefollowing specifications :

- The body, valve head and spindle head shall be manufactured from cast gunmetal to BS EN 1982. - The headworks, consisting of the spindle, gland nut and washer plate shall be manufactured from brass to BS EN 12165 or BS EN 12167 and the washer plate nut in gunmetal. - The washer shall be manufactured from EPDM rubber to the requirements of of BS 3457. - Threads shall be B.S.P in accordance with BS 21. Inserts shall be of copper. - The sealing between the valve body and head shall be achieved by the provision of a EPDM rubber head seal which complies with British Standards BS ISO 3601-1, BS EN

682, BS 4518. - The packing between the spindle and the valve head shall consist of one piece PTFE impregnated graphite aramid fibre valve packer. - The stopvalve shall withstand a test pressure of 16 bar without leakage. - The valve shall close in a clockwise direction.

Stop valves of 3" diameter or greater shall be approved standard stainless steel ball valves complete with 150lb class flanges as per project specifications change pieces and adaptors shall be provided.The name of the manufacturer, patent number and flow direction shall be engraved on the body of each valve.

13.1.1 Ferrules (with Combined Stopcock)

The ferrule combined with stopcocks shall be of hot pressed brass to BS EN 12165 with

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heavy gauge, swivel balancing, screw down type. ½" square head for closing and opening with female ends. The spindle shall be of high tensile manganese bronze to BS EN 12167.Threads shall be B.S.P in accordance with BS 21.

13.1.2 Compression Fittings

Where pipe joints and equipments couplings are made using compression fittings, these shall be threaded B.S.P in accordance with BS 21. Inserts shall be of copper and male and female fittings shall be chamfered to suit assemblage and to avoid crossing of threads.Suitable change pieces and adaptors shall be used where required for coupling of individual items of equipment not available with B.S.P threads.

13.2 Flexible Hose Assemblies All flexible hose assemblies shall comply with BS 6501 and shall be of a type suitable of withstanding the same pressure as the piping to which they are attached. Assemblies shall be proprietary items and shall have compatible couplings with both the pipe system and the individual consumer to which they are attached.

13.3 Water Filter Units In-line water filter units shall be provided immediately upstream of each potable water supply system consumer. Each filter unit shall be proprietary item capable of withstanding the same pressure as the piping to which it is connected, shall be wall mounted of canister type with removable porous unglazed ceramic filter element and shall be protected by a stopcock at its inlet side. Filter units shall be supplied complete with all fittings and fixings. Complete units shall be capable of delivering water to meet the quality provisions of BS 6920.

13.4 Cold Water Cisterns & Break Tanks Cold Water Cisterns shall be provided in accordance with BS 7181 for up to 500 litre size.Cisterns provided for holding of potable water shall be of a suitable grade and materials to meet the provisions of water quality required under BS 6920. Cisterns provided for holding of sanitary water only shall be of either GRP construction in compliance with BS EN 1796 or of polyolefin construction in compliance with BS 4213. Where storage requirements as per design exceed 500 litres, storage shall be in approvedcovered segmented galvanised steel Break Tanks. Tanks shall be suitably jointed, coated,lined and insulated using materials to meet the provisions of water quality required under BS 6920.

13.5 Water Heater Cylinders Water Heater Cylinders shall be in strict compliance with the requirements BS 853.Cylinders shall be of double walled pre insulated type and of 50 litres minimum capacity for each consumer location.

14. INSPECTION AND TESTING 14.1 Civil Works

The following items shall be subject to field inspection in respect of setting out, excavation,concrete works including reinforcement, protective membranes and linings, inserts fixings and supports, backfilling and finishes, covers and frames and access provisions :

i) All manholes, inspection and valve chambers and pits ii) All pipe trenches, road crossings, sleeves and ducts.

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14.2 Pipe Works

As a minimum the following acceptance tests shall be performed at site : i) Visual inspection of all materials and fabrications installed ii) Dimensional check iii) Hydrostatic pressure test and leak test iv) Impact resistance check

14.3 Testing

The Contractor shall test all water supply systems pipelines, joints and fittings prior to surrounding, backfilling, building in to walls & floors or other concealment.All tests shall be performed in convenient sections for each system in the presence and to the satisfaction of the FEWA/Engineer by experienced personnel. All costs in providing personnel, apparatus, equipment and temporary works for testing shall be borne by the Contractor.Prior to the commencement of testing the system shall be thoroughly cleaned by flushing with potable quality water to ensure no foreign matter remains within the pipe. The pipes shall then be filled and allowed to stand for a period of 24 hours before testing.During the filling operation care must be taken to ensure that there is no entrapped air in the system.The test pressure shall be applied gradually by means of a suitable pump connected to the pipe in a manner satisfactory to FEWA/Engineer. All gauges used shall be new and shall be accompanied by the valid respective calibration and test certificates. During the test all exposed pipes, joints, fittings, valves etc. shall be carefully examined, and any joint or item showing signs of leakage shall be rejected. All sections or items rejected shall be removed and replaced by the Contractor at his ownexpense, and the test shall be repeated to the satisfaction of FEWA/Engineer.

15. MISCELLANEOUS WORKS 15.1 Field Pressure Test

After laying the pipeline in the trench as specified above, it must be tested with the fittings, valves, etc. in sections of about 500 meters or as directed by FEWA/ Engineer or as dictated by Site conditions, at the time, with a pressure testing pump. The pipes shall be tested in accordance with requirements as in Mechanical works specifications or as recommended by the Standards.The Contractor under the supervision of FEWA/ Engineer shall carry out the tests. No backfilling shall be done until and unless a clear certificate in writing is given by FEWA/ Engineer that the pipeline section has been successfully tested.The testing shall be done as soon as stretch of pipeline is completed.

The Contractor shall not be allowed to continue laying the pipeline, without carrying out testing simultaneously. The maximum length of pipeline awaiting testing at any time shall be decided by FEWA/ Engineer to suit the Site conditions.

15.2 Marker Post

Marker posts of approved design and specifications should be provided and fixed at valves, change in direction, end caps, etc. Along longer routes of pipelines marker posts shall also be provided at intervals as directed by FEWA/ Engineer.

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15.3 Restoration of Surfaces

All tiled, interlock block, paved or asphalted surfaces through which the pipe is laid shall be restored in as good a condition as before disturbance or the execution of the Work. Any deficiency in the filling materials, tiles, blocks, etc. resulting from theft, wastage or any other cause whatsoever shall be made good by the Contractor.

In the case of roads the operation may be divided in 2 portions to facilitate the immediate resumption of traffic. In the first instance the trenches shall be compacted and the soling laid so that it shall conform to the finished formation level of the road.

After further compaction has occurred with movement of traffic, the requisite thickness of road metal shall be provided, compacted and finished with such surface dressing as prescribed. The thickness and type of asphalting / tiling / paving / base / sub-base material etc. shall be restored to the original specification of the surface before it was disturbed.

16. COMMISSIONING

Prior to final handover each supply system shall be drained of test water, flushed, refilled and disinfected in accordance with the requirements of AWWA C 651 or as directed by and to the satisfaction of FEWA/Engineer. Pipes shall be flushed with sufficiently high velocities to remove any sediment or debris. The flushing velocity shall be not less than 1 m/s. The time required for flushing shall be at least the time necessary to discharge three times the contents of the section being flushed.Flushing water shall be discharged via temporary discharge hoses to either the surface water drainage system, if commissioned, or to mobile tanker for disposal.All costs associated with providing experienced personnel, apparatus, equipment,consumables and temporary works for flushing and disinfecting shall be borne by the Contractor.