CONTENTS
- Scope of Work
- Definitions
- References
- Subcontractors
- Materials
- Plant & Equipment
- Safety
- Prior Activities
- Procedure
- Responsibilities
- Attachments
1. Scope:
| 1.1 | This Method Statement covers the installation of D.I pipes. |
2. Definitions:
| 2.1 | MS: D.I Method Statement: ductile iron method statement. |
| 2.2 | ITR Inspection And test Request |
| 2.3 | PPS Particular Project Specification |
| 2.4 | GPS General Project Specification |
| 2.5 | UG Underground |
| 2.6 | TPS Technical Project Specification |
3. References:
| 3.1 | Contract drawings No. PGAD 745/1008/C/927 & PGAD /745/1008/C/401,402,403 and PAGD /745/1008/C/421,422 |
| 3.2 | TPS Section 901: Clause 901.5, 901.2.7, 901.2.8, 901.2.9 Pipe work and testing. |
| 3.3 | TPS Section 901: Clause 901.3.6 & 901.3.7 Construction of pipes and manholes. |
| 3.4 | MS-1004 Dewatering |
| 3.5 | MS-1005 Surveying |
| 3.6 | MS-1008 Earthwork |
4. Subcontractors:
| 4.1 | None |
5. Products:
| 5.1 | D.I Pipes, dia. 200mm to 300mm and fittings. |
| 5.2 | Rubber gasket rings of approved source. |
| 5.3 | Wrapping tape from approved source. |
| 5.4 | Warning tapes. |
| 5.5 | Lubrication soap for rubber rings. |
| 5.6 | Granular Material. |
| 5.6 | Primer from approved source. |
6. Tools & Equipments:
| 6.1 | Dewatering Equipment |
| 6.2 | Excavators |
| 6.3 | Front End Loader (Shovel) |
| 6.4 | Tipper Trucks |
| 6.5 | Crane (if required) |
| 6.6 | Flat-bed truck and trailer |
| 6.7 | Concrete Mix Trucks |
| 6.8 | Small Vehicles |
| 6.9 | Compactor (Plate or Roller) |
| 6.10 | Concrete vibrator |
| 6.11 | Surveying Instruments |
| 6.12 | Nylon lifting slings |
| 6.13 | Cable pullers (come-along) |
| 6.14 | Ladders |
| 6.15 | Concrete Barricades |
| 6.16 | Flagging Tape/Warning Tape |
| 6.17 | Concrete Formwork |
| 6.18 | Concrete Temp. Gauge |
| 6.19 | Slump cone, cube moulds |
7. Safety
| 7.1 | PPS Section100: Clause 100.2 Airport emergency and safety. |
| 7.2 | GPS. Section102: Clause 102.11,12,14 General and preliminary. |
| 7.3 | CSM Construction Safety Manual |
| 7.4 | OAJ JV Safety Manual. |
| Safety Hazards and Precautions. | |
| a)- Strike UG Services: Use Locator and/or hand excavation (trial holes) | |
| b)-Excavation Collapse: Batter sides to safe slope or provide shoring (as directed by Geotechnical Consultant) and subject to Engineer’s approval. Keep vehicles/equipment safely away from excavation edge Keep spoil at least 2.0 meters away from edge c)- Fall into excavation: Provide fencing, night–time lighting, guardrails and flagging tape around edges. Provide safety fixed ladders (every 50m) Provide banks man when operating equipment near excavation. d)-Crane Accidents: All cranes should be checked and certified Operators professional and well experienced Provide banks man when operating near excavation Check load indicator, slings and wire ropes daily e)- Falling Objects: Stand clear during lifting operations Wear hard hats f)- Equipment & Vehicles: Use Safety belts Slow down and obey speed limits Provide “back-ups” alarms Provide banks man when operating equipment near excavation. g)- Confined Space: Check air with gas monitor before entering assembled pipeline or manholes Check air in deep narrow trenches and excavation before entry. | |
| Check excavations and pipes for snakes and scorpions before entry. | |
| Develop rescue procedures |
8. Prior Activities:
| 8.1 | Calibrate Surveying Instruments. |
| 8.2 | Check for existing utilities before excavation (Trial Holes). |
| 8.3 | Check all pipes free of cracks and chips or damage to linear |
| 8.4 | Prepare and get approval of Shop Drawings. |
9. Procedure:
All activities carried out will comply with the OAJ-JV Inspection Test Plan which reflects the testing requirements of the Contract.
| 9.1 | Prepare the Shop Drawings and submit to the Consultant to get his approval prior to starting any excavation works. | |
| Note: | Only the drawings marked as approved “Issued for Construction” are allowed to be used by the Site Staff. | |
| 9.2 | Survey will be conducted according to MS-1005 | |
| 9.3 | Dewatering if required, will be conducted according to MS-1004 | |
| 9.4 | Excavation and filling will be conducted according to MS-1008 | |
| Note: | The Engineer’s Inspector will be notified if any areas are over excavated or unsuitable materials are encountered, in which case replacement material will be used. | |
| 9.5 | The formation level will be to the required lines and grades as detailed in the approved Shop Drawings. | |
| 9.6 | The trench formation shall be compacted to 98% MDD or to the soil bearing value. | |
| Note: | Formation compaction is a Hold Point and will be confirmed by the Engineer’s Inspector before proceeding with the bedding. | |
| Note: | The pipe installation is a hold point and lines and levels must be checked and approved by the Consultant’s Inspector before other work proceeds. Any adjustment in the line and grade shall be made by scrapping away or filling and tampering in under the barrel of the pipe. | |
| 9.7 | Trailer with hoist crane shall be used for shifting pipes from yard to the site. | |
| 9.8 | End lifting hooks for lifting the pipes shall be insulated with rubber sleeve to prevent damage to cement lining and other coating. | |
| 9.9 | Stacking of pipes along the trench side opposite to the excavated material heap with the sockets pointing the direction of laying. Transportation, storage and handling of pipes will be according to the manufacturer’s instructions. | |
| 9.10 | A single wide flat sling shall be used to lift the pipe at its center of gravity and in order to lower the pipe into the trench. | |
| 9.11 | Each pipe shall be laid accurately to line and gradient. | |
| 9.12 | All open ends to be plugged when pipe laying is not in progress | |
| 9.13 | The socket of the pipes shall be carefully cleaned to eliminate all soil and sand. | |
| 9.14 | Check the gasket condition and place it in its seat, looping it into the shape of a heart for insertion. | |
| 9.15 | Apply the lubricant paste to the exposed surface of the gasket and the pipe spigot. | |
| 9.16 | Insert the spigot, checking the alignment of the assembled components, until the jointing mark on the spigot is in line with the socket face. | |
| 9.17 | Clamps and chains shall be used for jointing pipe and straight fittings. | |
| 9.18 | In order to avoid damage to the coating of the pipes, it is essential to use rubber paid at the points of contact between chains and pipe. | |
| 9.19 | Any joint deflection required shall be made only after the completion of the joint. | |
| 9.20 | Flanged joint is to be made using flat gasket and bolt shall be inserted and must be turned to fingers tightness. Thereafter the final tightening of the nuts to be completed by the toggle spanners in such sequence that diametrically opposite must be tightened together. | |
| Notes. | Restrained joints are to be made of the approved locking system. | |
| All valves and fittings to be installed as per the approved shop drawing. | ||
| All pipes, fittings, valves etc. will be carefully lowered in the trench with suitable equipment in a manner that will prevent damage and all foreign materials shall be removed from inside the pipes and fittings before being lowered into position. | ||
| Valves, fittings, adapter, meters, fire hydrant, etc which are housed in concrete chambers shall be protected to avoid damage to the factory applied coating. Pipe ports and fittings inside the chambers with bituminous coating to be protected with approved paint. | ||
Backfilling:
| Backfilling will proceed in layers in accordance with MS-1008. | |
| By hands to a level 500mm above the crown of pipe. With rollers or plate compactors up to the final ground level. | |
| Pressure test. | |
| 01. | The hydrostatic pressure testing of pipeline shall be carried out on section of completed pipelines as approved by the engineer/client. |
| 02. | Complete construction of D.I pipeline with all thrust blocks and valve chambers for a particular section to be tested in accordance with the approved shop drawing. |
| 03. | Before commencement of pressure testing of a particular section, all the line valves will be opened to prevent pressure being applied against closed valves. |
| 04. | Install test heads with provision of bleeding air vent at the highest point. |
| 05. | Install test heads with provision of filling water at the lowest point of the pipeline. |
| 06. | Calibrated pressure gauges will be installed at both ends of the pipeline. |
| 07. | With approval from Engineer, the water from pressure testing shall be taken from existing fire hydrant , washout or air release valve, whichever is nearer to the filling point. |
| 08. | Subsequent to obtaining approval from the client, the filling of water and testing shall commence. |
| 09. | During the water filling all air in the pipeline shall be expelled through the air bleeding nozzles installed at the highest. |
| 10. | The pressure in the pipeline shall be raised steadily by a small capacity high-pressure positive displacement pump until normal operating pressure of 6 bars is reached. |
| 11. | The pipeline shall be maintained at 6 bars pressure for a minimum of 24 hours soaking period during which a record of the water added to maintain the 6.00 bar pressure shall be kept . |
| 12. | In case of any visible leaks during inspection, the particular section shall be repaired to the satisfaction of the Engineer after which the 24 hours soaking period shall be repeated at 6 bars pressure. |
| 13. | Upon satisfactory completion of 24-hour soaking period the pipeline shall be brought to the test pressure of 9 bars and maintained at this pressure, by pumping if necessary. |
| 14. | Subsequently, the pump shall be disconnected and further water allowed to enter the pipeline for a period of 1 hour and at the end of this period the pressure will be recorded. |
| 15. | The pump will be reconnected, if a pressure drop is noted and the original pressure (9 bar) will be restored in the pipeline. The water pumped into the pipeline to rebuild the pressure will be collected in a calibrated tank. The volume of the water used to rebuild the pressure to 9 bars shall not exceed ( 0.1litre/mm of diameter/KM of length/24hours/30metres of head) |
| Note. | IN case leakage exceeds permissible allowance, the leakage spot shall be detected and remedial work shall be carried out and the pressure test shall be repeated until satisfactory pressure test is achieved. |
10. Responsibilities:
| 10.1 | It is the Construction Manager’s duty to ensure that all necessary safety and protective equipment are provided along with properly trained and qualified personnel. |
| 10.2 | It is the Site Supervisor’s duty to organize the work in a safe manner to ensure that safety and protective equipment are being properly utilized. He must also assure the method statement procedure is followed and must observe the Hold-points and notify the Engineer for inspection. |
| 10.3 | It is the worker’s duty to properly wear the protective equipment provided and obey all safety rules. He must also perform the work as described in the method statement procedure. |
| 10.4 | The Site Engineer will ensure that the site preparation activities are conducted according to the approved method statement. |
| 10.5 | The Material Engineer will ensure that the materials being used are in accordance to the project specifications and the approved method statement. |
