Method Statement -Water Reticulation Works

1.0               INTRODUCTION

This work method statement covers the water reticulation works at (your project name).

2.0               SCOPE OF WORKS

The works to be carried comprise of:

a)                  Clearing and preparing the ground for laying the 100mm dia. HDPE main pipe and constructing all ancillary works.

b)                  Excavating and preparing trenches and foundations to receive the main pipe, pipe piers or supports, chambers and other ancillary works including backfilling and disposing of excess spoils.

c)                   Construction pipe piers or supports, anchor blocks and chambers.

d)                  Supplying, laying and jointing pipes, specials, valves and other fittings.

e)                   Pressure test of installed pipes and necessary fitting.

All works shall comply with the requirement of Local Authorities and where required the plumber responsible for the execution of the work shall be a licensed plumber. The Contractor shall execute the works in strict conformity with the approved plans and shall arrange for the necessary formalities to be complied with.

3.0          WORK SEQUENCE FLOW

4.0          PREPARATORY WORKS

Obtain relevant approved construction drawings, shop drawings and materials from client / client’s representatives. Submit Request for Work Inspection to inform consultant before proceed the work. Since the approved material received to site, all materials are to be inspected and possible damages must be reported on the delivery note.

                                                                                                                                               

5.0          METHOD STATEMENT

5.1          SURVEY, SETTING OUT AND EXCAVATION OF TRENCH

The Contractor shall excavate to the line and levels as shown in the drawings, or as directed by E.R. The Contractor shall carry out all excavations in such manner and order as approved by the E.R and in whatever material as may be found. All excavations shall be carried out to the required lengths, widths, depths, inclinations or curvatures as may be necessary for the proper construction of the works or as shown on the drawings. All excavations shall be sufficient to provide for the necessary working space.

The bottom of all excavations shall be carefully trimmed and levelled, well rammed and consolidated to ensure good solid foundations. Before commencing the excavation of pipe trenches, the routes of the pipelines shall be pegged out accurately.

Where the pipes are to be laid on a concrete bed, the width of the excavation at the bottom of the trench shall be the width of the underside of the concrete bed.  The trench shall be excavated to the depths intended or shown in the drawings and shall be finished and trimmed accurately to level.

The Contractor shall lay sand since the trench is ready to receive the pipe. The bedding detail shall refer to the drawing.

5.2          LAYING PIPES AND FITTINGS

All pipes and fittings shall be laid to the lines and levels shown on the drawings or as otherwise directed by E.R. Before any pipe is lowered into the trench, it shall be cleaned and re-examined for cracks and flaws. If undamaged it shall be placed in position ready for jointing.  After laying, the interior of pipes shall be carefully cleaned again to remove any debris, dirt, stones or other matter that may have entered during laying.

Where the pipe lines encounter obstruction of laying such as drain, a galvanised iron pipe shall be used for crossing across the drain and exposed.

5.3          BACKFILLING OF PIPE TRENCH AND COMPACTION

After the pipe laying has been approved by the E.R and before the pipelines are tested, only sufficient backfilling of the trenches to prevent ‘snaking’ and to maintain the pipes in position will be permitted, but all joints shall be left exposed. In backfilling pipe trenches, only approved materials free from stones or rocks or other hard materials shall be carefully spread along the trench bottom between the pipes and trench walls to a depth of about 150mm thick of the same materials shall be hand rammed. Further layers each of about 150mm thick of the same materials shall then be spread and rammed in the same manner up to the top of the pipes. It shall be placed in layers each of 150mm thickness and hand or mechanically rammed until the backfill is 300mm above the top of the pipes.

5.4          TESTING OF PIPELINE

The Contractor shall provide all necessary equipment and material required for the purpose of testing work.

Test shall be carried out in the presence of a representative from Consultant or Pengurusan Air Pahang Berhad if required. No pavement will be made for pipe laying until the mains have been satisfactorily tested.

Wherever a section of any pipe has been laid, jointed and backfilled, it shall be prepared for testing by sealing the both ends temporarily with end cap. The end cap shall be of cast iron or steel. The end cap at the lower end or the section of the main shall be fitted with a valve inlet pipe for use to fill the section of the main with water and the stop end at the higher end of the section of the main shall be fitted with a valve air release vent pipe.

The test pressure to be applied shall be approximately 1.5 times the working pressure with details as shown in the drawings or as directed by E.R.

In testing, the main shall be filled with clean water and after a period of 24 hours, the pressure shall be raised by pumping to the specified test pressure. Pumping shall then cease and after a period of 3hours or a pressure fall of 9m whichever is sooner, pumping shall be resumed and the quantity required to be pumped, in order to restore the test pressure, divided by the time, shall be measure of the rate loss.

The length of main under test shall be deemed to have passed the test if the leakage does not exceed 0.05litres per mm of internal diameter per 24hours per kilometre of pipe length. If this specified rate of leakage is exceeded, a thorough inspection of the section of the main shall be made. All leaks discovered shall be repaired and the section shall be tested again.

The section of the main to be test shall be filled with water and the water shall be introduced into the section of the main through the valve inlet in the stop end at the lower end of the section. During filling provision shall be made for the air to escape from all high spots in the section by properly installing all air valves and from the air release vent pipe in the stop end at the higher end of the section.

 6.0          SAFETY AND ENVIRONMENT

6.1          Safety

1)            Safety induction to be conducted to all new workers that involved to this activity and safety tool box meeting shall be conducted every day to remind the workers about concerning the safety.

2)            All workers shall provide with proper PPE (Personal Protective Equipment) and shall be worn every time they are entering the site. Safety Officer / Safety Supervisor shall ensure all the workers wear all the safety equipment provided.

3)            Safety Officer / Safety Supervisor shall ensure that the activity shall carry out in a safe manner.

4)            All workers shall fully support and actively participate in all safety related activities and comply with all practicable safety measures.

5)            All workers shall be advised to report any accident or injury to supervisor and proper treatment to be obtained.

6)            The Safety Supervisor / Safety Officer shall ensure that the workers understand the safety regulations and explain in detail in particular hazards, where the workers are working and the precaution to be taken to ensure their safety.

7)            Proper and adequate provision of temporary signage’s and barricades at diversions and temporary haul road as necessary.

6.2          Environmental

1.            All workers shall educate on good environmental management practices and well-disciplined to environment.

2)            The garbage bin shall be provided at the working area and Supervisor shall ensure its must be collected regularly and disposed of at the approved dumpsite.

3)            Safety Officer/Supervisor shall ensure that no open burning of construction or domestic wastes is practiced.

4)                  All workers shall ensure that all tools and equipment machinery are in good condition to avoid any oil leakage that could harm to environment.

5)                  Open burning of construction and domestic wastes on the site premises are strictly prohibited.