Underground Drainage Pipe Installation Method Statement

The purpose of this plumbing method statement is to describe the methodology for underground laying of UPVC pipes as per the contract specifications and approved drawings, including the backfilling for the site facilities and to detail the steps to be taken to meet the quality and HSE requirements of the project.

Method statement is applicable to all activities related to UPVC Push Fit pipe laying, the document will ensure that the work is carried out and complies with the project plumbing specifications.

Below is list of necessary tools for the pipe installation activities.

• Cutting/Grinding Tools
• Measuring Tape
• Spirit Level
• Pipe Cutter
• Hack saw
• JCB
• Hand Tools

Roles and Responsibilities

Project Manager is responsible for overall project execution and implementation of quality and safety requirements. He will adopt a leading role with respect to compliance with quality and safety procedures. The Project Manager shall ensure that the key personnel are well aware of the project specifications including HSE and quality procedures/standards.

Construction manager shall arrange all materials, equipment, safety related items & manpower & direct the Site Engineers & foremen to resort appropriate action for the smooth execution of the drainage pipe installation works.

Safety Engineer shall be responsible for ensuring the safe working environment & conditions, coordinate with site engineers to control and minimize potential hazards before starting the pipe installation works.

QA/QC Engineer shall be responsible for ensuring that execution of works are complying with approved method statement, ITP, checklists, specifications and approved shop drawings. He shall ensure WIR are submitted based on the inspection and testing plan ITP requirements.

MEP Coordinator / Engineer shall be responsible for proper execution of MEP works involved before, during and after concreting works.

Project Engineer (Mechanical)

Ensure that the activities are carried out according to the specifications, drawing and approved method statement.

To make sure that all required submittal are made in timely manner.

Arrange all materials and tools required for installation as per agreed project schedule.

Provide all necessary information and distribute the responsibilities to the pipe installation team.

Monitoring that all in process test are carried out and obtained approval from clients representative.

Monitoring and ensuring that the work is performed in accordance within the time and cost constraints.

Foreman ( Mechanical)

Carrying out the work and the proper distribution of all the available resources in coordination with the Site Engineer on daily basis.

Continuous coordination and following Site Engineer’s instructions to meet quality requirement during the job execution.

Incorporate all the QC and Safety requirements as requested by the client’s representative.

Report to Site Engineer the accomplishments and problem encountered on daily basis.

HSE Requirements

• All safety precautions shall be followed as per the established project health and safety plan.
• Dust masks, goggles and gloves shall be worn while doing the excavation and drainage pipe laying activities.
• All necessary personnel protection equipment PPE shall be worn as appropriate according to the nature of the job.
• Work area shall be maintained neat and clean on daily basis.

Storage and Handling of Materials

Material received at site shall be inspected and stored according to manufacturer recommendations.

Store all the material in a covered and dry space.

When off loading, pipes shall be lowered not dropped to the ground.

Pipes shall be given adequate support at all the times and shall be stacked on flat surface.

Timber supports shall be placed at an interval of one meter.

Pipes shall be protected from direct sunlight and moisture to avoid deterioration.

Pipes shall be stacked size wise separately.

Material approval to be taken immediately after receiving on the site.

Installation Sequence of Works

Sufficient manpower shall be deployed to shift the material from store to site. All necessary safety precautions as per established procedure shall be implemented during shifting and installation.

Before main installation works prepare a mockup/sample installation and get its approval.

The routes for the pipes will be marked based on the approved shop drawings and coordinated with other services at site.

All gully and manholes are marked on the appropriate location as per approved mechanical shop drawing.

The trench should be excavated up to the required length, width and depth.

Bottom of the trenches shall be leveled and prepared to provide uniform bedding throughout the entire length of the pipe.

Provide sufficient pipe supports at interval spacing as per specification to avoid any bulging.

Lubricant should be applied to the pipe end which is then inserted into the coupling.

Should the pipe cutting, the cut end should be chamfered to approximately 15 degree for half the pipe wall thickness with a sharp edge tool.

All horizontal drainage piping shall be installed with 1% slope unless otherwise indicated.

The UPVC coupling incorporates an elastomeric sealing ring which is compressed by the pipe spigot to form an effective seal.

Each joint permits 5 degree of angular deflection to facilitate installation and allows adjustment for ground movement.

Before making the joint ensure that that both the pipe ends and the sealing ring are clean.

Hand tamp the backfill fully at the sides of the pipes while tamping lightly over the crown.

Hand tamping should continue until a minimum thickness of 300mm has been placed over the pipe.

As dug material may then be placed in 300mm layers and mechanically compacted.

Dumpers or other vehicle must not be driven along the trench as a means of compaction.

Road cutting/road boring shall be done in case of pipe road crossing.

Inspection shall be offered for QA/QC verification and approval from consultant/client.

Leakage Testing of Underground Drainage Piping

Suitable strutted plugs are inserted at the lower end of of the drain or sewer and at the head of any connections.

A suitable bend together with a vertical length pipe is fitted at the head of the sewer or drain to provide the necessary test head.

The system is then filled with clean water.

A test pressure of 1.5 meter head above the crown of the pipe is applied at the higher end of the drain or sewer ensuring that the resultant head at the lower end does not exceed 4m. It may be necessary to test in sections to avoid exceeding this figure.

The sewer or drain under test should be left filled with water for 1-2 hours.

The loss of water over a period of 30 minutes should be measured by adding known quantities of water every 10 minutes to maintain the original level in the stand pipe.

The source of leakage should be visible and the defective part of work should be removed and made good.

During the water test, precautions should be taken to prevent any movement of the drain or sewer.

Attachments

Quality Control Procedure

Inspection Test Plan ITP

Installation Check List

Risk Assessment