METHOD STATEMENT
FOR
TESTING AND COMMISSIONING
DICL PIPE
1 INTRODUCTION
1.1 Purpose
The work method statement shall describe the construction procedures, materials, plant and equipment’s required, resources needed and precautions to perform the testing and commissioning ALL size ductile iron pipes for water supply system.
The core forming vectors of the works encompasses the following:
- Material Resources
- Machinery & Equipment Resources
- Testing and Commissioning Procedure
1.2 Scope of work
This procedure will define the method to be used to ensure that the testing and commissioning of the pipes correctly and acceptable and shall conform to the contract document and specification. The scope of work included:
a) Site preparation.
b) Sectional and Leakage Test
c) System Test
d) Flushing and Sterilizing
2 ABBREVIATION & DEFINITIONS
Abbreviation | Definition |
Reps. | Representative |
SPW | Standard of pipe work |
No. | Number |
Ref. | Reference |
ROW | Right of Way |
Qty. | Quantity |
3 REFERENCES
3.1 Project Documents & Construction Drawings
No. | Document | Remark |
1. | Contract Specification | Technical Requirement |
2. | Construction Drawing | Overall |
3.2 Standards
No. | Document | Remark |
1. | General Specification Water Main Construction | - |
4 RESOURCES
4.1 Materials
Detail of materials to be used in the work:
No. | Type of Material | Qty. | CD Ref. No. |
1. | 500mm End Cab & Adaptor | 4 nos. | - |
2. | 400mm End Cab & Adaptor | 4 nos. | - |
3. | 300mm End Cab & Adaptor | 4 nos. | - |
4. | 250mm End Cab & Adaptor | 4 nos. | - |
5. | 200mm End Cab & Adaptor | 4 nos. | - |
6. | 150mm End Cab & Adaptor | 4 nos. | - |
7 | Meter Stand | 4 nos. | - |
3. | Pressure Gauge | 2 nos. | - |
4. | Bolt and Nut | 128 nos. | - |
4.2 Plant Machinery & Equipment
Detail of plant and machinery proposed to be used to perform work:
No. | Plant & Machinery | Qty. | Purpose |
1. | Excavator (EX-60) | 1 no. | Excavation work |
2. | Backhoe | 1 no. | Excavation work |
3. | Lorry (3 tons) | 1 no. | For transporting the pipe materials and fitting to site |
4. | Water Pump | 3 nos. | For pumping water into pipe for testing and commissioning propose. |
5. | Power Driven Abrasive Disc | 2 nos. | To cut the Ductile Iron pipe |
Detail of equipment proposed to be used to perform work:
No. | Equipments | Qty. | Purpose |
1. | Scope | 2 nos. | For remove the soil on the road and digging. |
2. | Hand Tools | 4 sets | For tighten the bolt and nut |
4.3 Manpower
List of supervision and workforce to be involved in the work:
No. | Description | No of person | Role and Resposibilities |
1. | Site Engineer | 1 | To ensure overall works implementation in order and monitor correct way of installation and pumping works |
2. | Site Supervisor | 1 | Coordination and Supervising site activities. |
3. | Machine Operator | 2 | Operating the machinery. |
4. | General Works | 5 | To set up, jointing and tighten the bolt and nut. |
5 TESTING AND COMMISSIONING
5.1 Preparation Work
1. Once the pipe completely laid underground including pipe crossing, fittings and thrust block, the location and length of the pipes to be tested shall be identify immediately. The sectional test for the pipes is not more than 1.5 km and/or from sluice valve to another sluice valve.
2. The once of sluice valve shall be remove and tighten the end cab with adaptor. Once end cab installed, the meter stand to be place at the end of end cab with meter stand. Pump machine shall place and connect to the meter stand.
5.2 Pressure Test – Sectional and Leakage Test
a) Testing of pipe shall be carried out in strict accordance with the specifications.
b) The pressure gauge shall be placed at the end of the pipe (at end cab). Stop ends shall be cast iron or steel.
c) Pressure gauge shall have a dial not less than 150mm diameter and graduated to read up to 15 bars with 0.25 bar graduation.
d) Pressure test should be carried first to the pressure test head of water is 90m head or 9 bars.
e) After the pressure reach 9 bars, the pipes shall be left a night or not more than 24 hours to ensure water into the pipe absorbed in cement lining. If pressure of pipes decreased, more water shall be pumped to raise the pressure slowly to the 9 bars.
f) The pressure shall be maintained for one (1) hours and witnesses by JBALB and consultant.
g) If the pressure remains within or not exceed 5% of the test pressure for 1 hours, this indicate that there is no leakage in the system and the test section of the pipeline shall be deemed to have passed the pressure test.
h) The recommended maximum section of pipeline to be tested should not exceed 1500 meters maximum or from sluice valve to another sluice valve.
i) If leaks are discovered, depressurize the test section before repairing the leaks for 8 hours.
j) All defects shall be repaired and the test shall be repeated.
5.3 System Test
a) Testing of pipe shall be carried out in strict accordance with the specifications.
b) Prior any test to be conducted, consultant and JBALB representatives shall be invited to inspect the pipeline, pump, pressure gauge, etc.
c) The required working pressure and test pressure shall also be ascertained prior to commencement of the pressure test. The water pressure test will carry out with pressure pump until 7.5 bars for duration of not less than 20 minutes.
d) More water should be pump for into the entire pipe to raise the pressure slowly in increment of 1bar bar until 7.5 bars with a pause of one minute in each increment.
e) Should any appreciable drop in pressure be noted during any of this pauses the test should be stopped until the cause of the pressure drop has been investigated and rectified.
f) The pressure test should consider passed when the pressure gauge show no more reduction once reach 7.5 bars and holding time not less than 20 minutes. The allowable of the pressure drop is 5% within time period of testing.
5.4 Flushing and Sterilisation of pipelines
a) After the pressure and leakage test passes, the new pipeline will carry out the flushing and sterilisation. The section is to be thoroughly flushed to remove any debris trapped during pipe laying until the water flow shows only clean water.
b) The sterilizing agent to be used for the sterilization will be calcium hypochlorite (CaHCI) of 65% concentration. CaHCI solution of 20mg/l concentration (pre-mixed) will be injected into the pipe via the air valve tees at predetermined location to achieve maximum utilization.
c) The new pipeline shall be filled with water and CaHCI solution will then be injected. Only the clean water or treated water is allowed for this testing.
d) Left within 24 hours after the pipe is injected with CaHCI solution.
e) The water samples will be taken after 24 hours from various points, should the sample shown residual chlorine show a positive value of at least 0.2ppm (0.2mg/L) then the pipeline is considered sterilized. The process will be repeated until 0.2ppm is achieved.
f) Every pipeline shall be tested and witnessed by consultant and JBALB representatives for the main pipeline testing.
6 QUALITY ASSURANCE & QUALITY CONTROL
6.1 Inspection and Testing
1. Implementation of QAQC works shall be in accordance to Approved Project Quality Plan and relevant quality system procedures.
2. The quality of works shall comply with the requirements of Testing & Commissioning Manual and other relevant standard documents.
6.2 Work Inspection Request & Checklists
1. The work shall be carried out using the inspection form/checklist attached in Appendix 4 to ensure the finishing quality of work shall be acceptable by the contractor, consultant and/or JBALB representative.
2. Should there is any Non-conformity of work issued, we will respond within 7 days. Root cause shall be determined, correction of work shall be taken immediately if possible and corrective action shall be taken accordingly within agreed date. All NCR shall be closed within the agreed completion date.
7 APPENDICES
Appendix 1: Testing and Commissioning Sequences
Appendix 2: Inspection Forms and Checklist
Appendix 3: Site Locality and Layout Plan
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