METHOD STATEMENT FOR HDPE PIPE
LAYING WORK
PROJECT
: LAYING OF 500 DIA HDPE TWO PIPE LINE IN A COMMON TRENCH FOR SEA
WATER INTAKE AND DISCHARGE LINE FROM PROPOSED POWER PLANT TO
INTAKE OF 350 MW LNG FIRED COMBINED CYCLE POWER PLANT PROJECT
EMPLOYER
: LAKDHANAVI LTD.
PREPARED BY
: CEYLEX ENGINEERING (PVT) LTD
Method Statement for HDPE Pipe Laying
1
GENERAL APPROACH
Ceylex Engineering (Pvt) Ltd, (Contractor) will carry out the project with optimum approach and
methodology for client.
This document has been prepared by Ceylex Engineering, to explain how the Contractor approaches
to execute the project to meet the client’s needs. The successful completion of the project will
depend on the ability of implementing optimum methodology that leads to integrating the required
solutions through timely & technically optimum outcome of the project.
1.1
PROGRAM OF SUBMISSIONS
The civil work contractor will submit the detail program to the client after receiving the client’s input
on equipment installation and finalizing the method of construction with finalized conceptual design.
However, should the client and contractor accept to have a kick-off meeting to expedite the progress
of subsequent major dependent activities of the contract upon “the date of site possession” to be
given by the client & consultant prior to the commencement date. Project manager of the contractor
will make presentation of “program of submissions” in the said meeting.
In this case, Ceylex
Engineering will submit the aforementioned documents with enough periods for review by the
consultant prior to the date of “the site possession”. Otherwise, Ceylex Engineering will submit the
“programme of submissions” on the earliest date after the contract of this project.
1.2
PROCUREMENT SERVICES
Procurement services will be supervised for review the procurement engineer under the control of
the Project Manager.
1.3
QUALITY ASSURANCE AND QUALITY CONTROL
Ceylex Engineering will carry out the construction strictly according to the quality procedures
prepared by the company in accordance with international standards and practices.
The detail QA and QC procedure will be submitted after the contract is finalized.
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Method Statement for HDPE Pipe Laying
2
SETTING OUT WORK
Setting out on the ground will be done by a competent person with total station/theodolite as per
approved construction drawings. Correct coordinates and levels shall be taken referring to TBMs
established along the road.
Pipe line trace shall be marked on the ground as per the construction drawings and agreed by the
Engineer. After finalizing the trace, trial pit investigation and other studies shall be carried out.
Final setting out work shall be done as per the Engineer instructions after the trial pit excavation.
2.1
PROCEDURE OF SETTING OUT

The line and the level of the trenches shall be as per the drawing.

The route of the trenching shall be pegged out accurately.

Strong sight rails shall be fixed and maintained at every change in gradient and also at as
many intermediate points as may be required.

Centreline and level to which the excavation shall be carried out shall be marked on these
rails.

Sight rails shall not be more than 15m apart unless otherwise it is agreed by the engineer.

Setting out shall be checked and approved by the engineer before commencing the work.

If any objection arises from the vicinity on a marked pipe trace, the excavation shall be hold
until the matter is settled by the engineer/employer.
3

Any deviation of the line and/or grade shall be permitted by the engineer.

Nominal trench width shall be as indicated in the drawings.
AUTHORITIES TO BE CONTACTED BEFORE COMMENCING WORK

Sri Lanka Telecom

Ceylon Electricity Board

Lanka Electricity Company

National Water Supply & Drainage Board

Department of Wild Life Conservation (if required)

Sri Lanka Police

Road Development Authority (for major roads)

Provincial Road Development Authority (for secondary roads)
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Method Statement for HDPE Pipe Laying

Residents in the vicinity

Sri Lanka Forces

Local Government (relevant) (for minor roads)

Irrigation Department
Contractor coordinates the above listed authorities and relevant other parties through the employer
and obtains permission for the excavation and pipe laying.
SLTB and private bus companies shall be informed at least one week earlier if any traffic re-routing
happens due to the excavation and pipe laying work. In such case alternative routes shall be provided
and at the both ends of the closed roads signs shall be placed. Traffic Police shall be informed and
arrow symbols shall be shown the alternative route for the road users.
4
4.1
HANDLING OF MATERIALS AND EQUIPMENTS
MATERIAL
The attention shall be paid at the stage of transportation of the material to the site and the method of
transportation shall be provided in advance to the engineer for the approval. Protection shall be
provided, to the approval of the engineer, for the ends of all pipes and fittings prior to the pipes and
fittings leaving the place of manufacture and shall maintain the protection until the items reach their
destination in order to guard effectively against damage during transit and storage and the ingress of
foreign matter inside the pipes and fittings.
Ceylex Engineering shall procure DI pipes and fittings from approved suppliers which ever locally
available, since the quantity of material is comparably a smaller amount. Therefore, inspection is not
considered for such smaller amount. For transporting bulk loads, vehicles shall be provided with a
clean flat bed, free from nails/other projections.
All material shall be carefully inspected at the time of delivery and any defective material identified
shall be set aside before accepting the delivery into stores/storage yard. Any such defects shall be
notified to the supply source immediately and shall be stored separately and returned to the supplier.
Material from the different suppliers shall be stored separately for clear identifying.
Caps/plugs are to be provided to protect the joining surfaces during the transportation and storage.
Pipes and fittings shall be stored well away from exhaust system/other heat sources and possible
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Method Statement for HDPE Pipe Laying
from material such as diesel oil shall be avoided. Care shall also be taken to avoid contact with
lubricating/hydraulic oil, gasoline, solvent and other aggressive chemical.
As far as practicable protective packaging (pallets, strapping, bags, etc) shall be kept intact until the
material is required for use. Temporary capping/plugging of pipe ends shall be done for hygiene
purposes. Pipes and fittings likely to be stored outside for a long period longer than 12 months shall
be covered by a tarpaulin/black polyethylene sheeting to prevent ultra violet degradation form
sunlight.
Other than backfilling soil all the materials shall be transported and stored as per the manufacturer’s
recommendation in a proper storage yard referring to the approved storing system. For this purpose
one/several rented/hired lands shall be used and the location of those lands shall be informed to the
engineer in advance. Exact location such lands shall be approved first to the engineer. As the project
is spread out through a large area temporary site office shall be located in rented/hired land and the
space shall be received for the engineer at the contractor’s site office.
All the material other than soil shall be handled as per the manufacturer’s recommendation by using
sling wires, cranes and excavators depending on the type of the material, weight, space available,
location of the site and other factors to be considered. Metal chains/slings shall not be brought into
direct contact with the material if required. Webbed slings of Polypropylene/Nylon shall be used for
such cases. Straight pipes shall be fully supported and bound together. For the pipe bundles lengthen
than 6m, load spreading beams of a length at least equivalent to one quarter of the length of the
pipe/bundle pack shall be employed. Lifting points shall be well spread and evenly spaced which
allows some bending in the middle of the lift.
All pipe stacks shall be made on sufficient firm, flat ground to support the weight of the pipes and any
necessary lifting equipment. Stacking height shall be kept to a minimum and adequate space shall be
allocated for lifting machinery. For safety and the convenience of handling, the stacking height shall
be maintained to 3m as far as possible. Bundles shall be stored timber to timber to prevent possible
deformation of the pipes.
The set of recommendations from the manufacturer shall be followed for handling, loading,
unloading, transporting and storing of all the sensitive materials.
Hooks shall not be used for the lifting of fittings which are generally supplied in cardboard
boxes/polythene bags.
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Method Statement for HDPE Pipe Laying
Where the coating of pipes/specials damaged, the surface shall be cleaned and dried and the
damaged area shall be painted with a minimum of three coats of approved paint to the full thickness
and specification as the original coating.
The maximum allowable depth of scoring of the external surface of the pipe is 10% of the wall
thickness. Pipes and fittings showing obvious defects/excessive scoring shall be withdrawn, clearly
identified as unsuitable and stored separately and returned to the source of supply.
Material that can be blown away by the wind during the transportation (soil, sand, etc.) shall be
transported by covered trucks. Pipes and fittings shall be inspected before they are transported to the
site and records shall be maintained. Engineer shall be notified for the inspection of such material
before dispatching to the pipe laying site. Excavated materials that can be used for the backfilling shall
be stored in suitable location protecting from weather in a practical manner.
4.2
PACKING OF BOLTS, JOINT RINGS AND GASKETS
Bolts of the same length and size shall be packed together in boxes not exceeding 100kg gross weight.
Joint Rings and Gaskets shall be packed in boxes and separate packages shall be provided for each size
and description of ring/gasket. Each box and package therein shall be clearly labelled stating the
number, size and description of the contents.
4.3
MACHINERY AND EQUIPMENTS
Utilizing machinery and equipment and their capacities will be varying site wise depending on the
ground condition, excavation depths, pipe type, size of the pipe, etc. However as a minimum
requirement the sub contractor expect to provide a set of survey instruments, crane (if necessary)
and a trailer on sharing basis. Excavator/backhoe loader, dump truck, pile driving equipment (if
necessary, water pump, plate compactor, generator shall be generally provided to the sites as the
requirement. These equipment shall be maintained periodically by a separate crew. Crew Cab shall be
utilized for the transportation needs. Other transportation shall be provided depending on the type of
the machinery/equipment to be transported.
Parking of the vehicle, storing material/equipment shall be done at the site premises. But in a case of
this premises shall not be practicable, a land shall be arranged by the officer-in-charge after discussing
with the construction manager. However in a case of cease work for a considerable period all the
equipment/machinery shall be stored at the site.
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Method Statement for HDPE Pipe Laying
The engineer shall be informed to inspect shoring material, etc before using them. Such materials
shall be listed and the list shall be submitted to the engineer in advance.
5
SAFETY & SECURITY
All field personnel will work in accordance with recognized safety standard and codes by government
and/or local regulation which may exist or be made. All field personnel will be responsible for
adhering to safety and site maintenance rules, and any reasonable recommendation from employer
will be closely followed. The identification of the potential treats to safety is necessary.
Safety & security plan comprises the following elements:

A statement for safety organization of the project.

A statement of our corporate and project safety and security policy

Identification of the applicable safety regulations, rules and guideline standards

Assignment of general and specific responsibilities for safety and security activities to staff,
supervisory, foreman and craft personnel and to subcontractors.

Requirements for initial safety & security orientation for all employees, subcontractors, if any
and their personnel.

Identification of work classified as hazardous, and the specification of requirements for
hazardous assignment indoctrination and training.

Requirements for the issuance, use and care of personnel protective equipment.

Requirements for regularly scheduled periodic supervisory and craft safety

Requirements for safety & security inspections of work sites and construction tools and
equipment.

Specifications for required keeping systems.

Accident report and record keeping system requirements.

Requirements for investigation of accidents.

Specifications for standard safety equipments and the usage.

Specifications for zero-accident campaign
It shall be pay attention to work in the vicinity of followings especially:

Fire hazard(naked lights)

Work in the vicinity of electrical equipment

Portable electrical equipment
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Method Statement for HDPE Pipe Laying
6

Electrical/ICA test equipment

Chlorine
TRAFFIC CONTROL PLAN
Individual traffic arrangement shall be provided with coordination of relevant police station, traffic
division. Night work shall be introduced to the highly congested roads. For the other roads one lane
shall be closed and single lane traffic shall be allowed for the pipe laying work.
Maximum speed for the vehicle shall be 20kmph where the pipe laying work going on.
Barricade Boards
Road narrow
ahead sign board
25m
Approx. 100 m
Traffic Cones at
5 - 7m intervals
Men at Work
ahead sign board
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Method Statement for HDPE Pipe Laying
Figure 1: Traffic control plan for pipe laying along the road
6.1
SIGN BOARDS
Sign boards shall be used for the road users to inform about the pipe laying.
Following sign boards shall be used mainly.
Men at work
Road narrow ahead
or
Figure 2: Traffic signs
6.2
METHOD OF TRAFFIC CONTROL
Vehicles shall be controlled at the both ends of the construction part of the road. Two men (traffic
controllers) shall be allocated at the both ends to signal the vehicles to move/not to. They will carry
“GO” and “STOP” boards and shall have communicative equipments (walky-talky) according to the
site location and the distance. The traffic will move when the traffic controller shows the board “GO”,
and the traffic will stop and allow the opposite traffic to flow while traffic controller shows the board
“STOP”.
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Method Statement for HDPE Pipe Laying
Figure 3: Traffic controller carrying the boards
The boards shall be used both the day and the night time due to its property of reflecting the light,
but where the engineer requests for another arrangement for the night shifts, reflecting lighting guns
shall be used for the traffic control.
6.3
CONSIDERATIONS

No more than half of the carriageway shall be obstructed due to the pipe laying by the time of
single lane traffic is allowed.

The contractor shall be responsible for allocating reasonable material/man power to maintain
a smooth traffic flow.
7
7.1
CONSTRUCTION EXECUTION PLAN
GENERAL
Ceylex Engineering execution plan includes the activities to be developed for site erection and
measures to be taken to enhance effectiveness and constructability are discussed together with site
coordination and interface requirements. The key element to the successful project is depending on
the ability how to approach the project with optimum methodology that leads to integrating the
required solutions through timely & technically optimum outcome since each solution is interactive
and needs decision making which will lead to the outcome of projects.
7.2
CONSTRUCTION EXECUTION
In order to ensure that construction is executed in a planned, efficient and safe manner, principal
approach would be to use "constructability concept" during planning, design and procurement phases
of the project. The constructability concept is the optimum use of construction knowledge and
experience in engineering, procurement and field operations to achieve overall objectives.
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Method Statement for HDPE Pipe Laying
Constructability input is realized by involving experience and competent construction personnel from
early stage of the project so that construction related issues are properly reflected in up-front
activities.
The successful completion of the construction phase will depend upon two fundamentals:

A comprehensive and realistic construction strategy;

An experienced site organization and the requisite labor resources, all motivated to execute
the strategy.
In order to achieve this goal, it is essential that the correct project balance of trades is maintained
throughout the project and the drawings, materials and equipment lead construction requirements.
Ceylex Engineering policy to attain this objective is summarized below:
Prior to site mobilization, a comprehensive construction execution plan will be prepared. This will
allow the construction team to define in detail the requirements of the project. All fabrication and
erection work will be carried out under the direct and continuous management of supervisory staff,
backed by detailed planning and coordination of site activities.
The construction work will proceed under detailed weekly and monthly work plans developed by the
project control section. Loss prevention, site security and sanitation during construction activities are
given the highest attention. At the outset of construction, the construction chief engineer will
implement the employer's project requirements that will be enforced and maintained by all levels of
the assigned loss prevention and site security.
7.3
7.3.1. Ceylex HSEQ officer is
required to be part of the team
MANPOWER

The supervisory and craft personnel will be mobilized in local.

For the purpose of efficient mobilization, an advance party, consisting of the construction site
manager and selected members of his team, will arrive at site prior to actual start of
construction activities.

Ceylex Engineering will mobilize key construction personnel in accordance with the
construction schedule.
The first stage in the supervisory staff mobilization program will be the assignment of key personnel
during design/procurement phase to input constructability into the design and for a period of
familiarization with the project prior to being assigned to the field. Concurrent with their
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Method Statement for HDPE Pipe Laying
familiarization program, all necessary visas, inoculations, etc. required for entry in Local will be
completed.
7.4
CONSTRUCTION EQUIPMENT
Ceylex Engineering will use existing construction equipment and tools required for the construction of
the facilities. However, some of construction equipment and tools required for the project will be
transferred from other job sites and/or purchased abroad based upon our plentiful experiences of
overseas construction.
Size and type of equipment are subject to change depending on market availability at the actual
construction stage.
8
EXCAVATION
Trial pits shall be excavated to such depths as necessary to determine and confirm the alignment of
the trench. Trial pits shall also be useful for determination of existence of other underground
services/utilities.
The excavation shall be carried out using backhoe machines/mini excavator/by manually but
depending on the type of the pipe, ground condition and depth of the excavation. The excavation in
vehicle movable road shall be done using backhoe and mini-excavator. The excavation in footpath
shall be done manually.
Usually open excavation shall be done with braced cut. Excavated soil shall be directly loaded dump
trucks/tractors and transported to separate yard approved by the engineer. The excavated soil
suitable for backfilling shall be stock piled in the site/separate locations as required. Any unsuitable
excavated shall be legally disposed. Waste disposal lands shall be informed to the engineer later.
Excavation for structures such as thrust blocks, valve chambers shall be allowed 300mm working
spaces in minimum.
Excavation length shall depend on,

duration of ground water lowering

effect of settlements to adjoining properties

width of the road and traffic density

Existing services.
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Method Statement for HDPE Pipe Laying
8.1
PRIOR TO THE EXCAVATION
Before starting excavation in any road, the approval shall be obtained from the engineer and the
relevant authorities (Listed in section 04) shall be informed with the detailed work program and the
relevant details (chainage of the roads, date of commencement, completion date of backfilling,
planned dates of completion of temporary reinstatement and the date of handing over).
Excavation work shall be started only after,

Granting the approval for the program by engineer/relevant authorities.

Granting the approval for the pipe and fittings.

All the required plants are available for speedy work.
The available details of underground services shall be obtained by the relevant authorities and
respective residence. The contractor shall protect the underground services and utilities as far as
possible. A list of authorities/personnel to be contacted before commencing the excavation work is
shown under Section 3 (Authorities to be contacted before commencement of work).
8.2
CONTROL OF WATER
The contractor shall keep the excavation free from water during the time of the construction and pipe
installation by installing and operating all necessary machinery, appliances and equipments. Disposal
of water shall not damage any private property, or should not create any nuisance to the public.
A suitable dewatering system shall be used for the excavation depths passes the water table level and
for the excavation in the rainy season. The dewatering system shall be supervised and monitored by
appropriate qualified personnel. Dewatering system shall be inspected by the engineer if he/she
needs.
Sump pumping from the edge of the trench shall not be done under any circumstance due to
instability of the formation arises.
Surface run off shall be controlled so as to prevent entry/collection of water on excavation.
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Method Statement for HDPE Pipe Laying
8.3
TRENCH WIDTH AND DEPTH
The width of trench shall be decided in accordance with the efficient working requirement, ground
stability and number and size of pipe to be laid in the trench. The trench dimensions will be
maintained as per detail given in table below.
Detail of trench for PE pipes
8.4
Dia (mm)
Width (m)
Depth (m)
90
0.30
1.00
110
0.40
1.12
160
0.45
1.17
225
0.50
1.24
8.3.1 Trench
details for OD
500 is missing.
Include alongwith
OD 250 as well.
PIPE BEDDING
Before placing the bedding material the excavated surface shall be properly levelled and trimmed.
Boulders, loose particles and other impurities shall be removed before compaction and shall be
wetted if required for achieving the required CBR value.
8.5
EXCAVATION IN NARROW ROADS
Police permission shall be obtained in a rerouting of traffic. Special consideration shall be paid to
reroute traffic and make provisions to access adjoining building. Before start of the excavation the
existing situation shall be photographed with the consent of property owner. Possible damages to the
boundary walls and other properties, the possibilities of repairing such damages with the least
inconvenience to the owners and cost effective manner shall be discussed with the owners. The
vicinities shall be informed at least one week earlier about the excavation. Excavation length along
such roads shall be limited to the minimum. Excavation shall be carried out with an optimum care.
Parking spaces and security for the parking premises shall be provided for the residents in case if they
cannot use their usual parking place due to construction.
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Method Statement for HDPE Pipe Laying
8.6
EXCAVATION NEAR UTILITIES
Edges of the trench shall be marked on the ground, cut with asphalt cutter and removed by backhoe
loader/excavator. Details of house connections for shops, etc shall be inquired and marked on the
ground prior to the excavation work.
All services lines crossing or along the trench shall be exposed. Such services shall be temporary
rerouted/modified wherever possible, to perform trenching operation. Every precaution shall be
taken to avoid any damage to the existing services. Under the worst scenario they will be left as they
are by providing the supports without disturbing to such services.
In case of interrupting water supply due to Contractor’s work, such situation shall be coordinated with
the NWS&DB to rectify the situation immediately. Overhead electric wires shall be protected from
the construction vehicle operations. Temporary disconnecting the electric services/temporary shifting
of electrical wires shall be arranged by coordinating with the relevant authority.
8.7
EXCAVATION NEAR EXISTING STRUCTURES
Any existing structures that cannot be temporarily relocated shall be preserved prior to the
excavation proceed in the opinion of the engineer. Above mentioned structures shall be carefully
protected from damages by the contractor.
In order to protect existing structure, the contractor shall do shoring where required. The shoring
method shall be submitted for the approval of the engineer. For deep excavation very near to the
existing structure, sheet pile shoring shall be used to protect the structures.
The arrangement made shall be approved by the contractor and work should be hold until the
engineer’s decisions are issued.
8.8
ROCK EXCAVATION
Weathered rocks shall be removed by mechanical means as far as possible.
8.9
HANDLING OF EXCAVATED MATERIAL
Excavated materials shall be dumped only in locations approved by the engineer and relevant local
authorities. Materials that can be reused for backfilling shall be approved by the engineer. Such
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Method Statement for HDPE Pipe Laying
material shall be protected from weather as far as possible. Temporary stock piles at site shall be used
along the side of the trenches if there would not be any objection from the relevant authorities. But
the disturbance to the public shall be minimized and the rented/hired lands shall be used as
temporary stock piles if needed. All the other material shall be dumped legally.
8.10 PRECAUTIONS
 Breaking of the carriageway shall be done only with the prior approval of the relevant road
authorities.
 Only controlled blasting shall be permitted during the excavation (Refer to the Health, Safety
and Environment Programs for more details).
 Ensure the minimum damage/disturbance to the above/below ground utilities/services.
 Base and sub base of the road shall be excavated with necessary shoring and ground
protecting measures to minimize the collapse/damage to the balance portion of the
carriageway.
9
SHORING METHOD AND TRENCH SUPPORT
Trenches shall be excavated without shoring/with light shoring/with heavy shoring depending on the
stability of the ground. Light shoring/no shoring shall be used for shallow trenches in stable ground
with lower ground water table. Arrangements for heavy shoring shall be submitted for the approval to
the Engineer before using them.
Excavated surfaces too steep shall be protected and supported as necessary to safeguard the work
and workmen, to prevent sliding or settling of the adjacent ground.

Sheeting

Bracing

Shoring

Other support installation
The method of shoring shall be pre-planned in accordance with the trial hole soil logs and shall be
submitted to the Engineer for prior approval.
Excavation above ground water level shall be done without any side supports where possible.
Excavation exceed ground water level shall be provided with timbering/sheeting depending on the
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Method Statement for HDPE Pipe Laying
site condition. Sheet piles shall be driven by a drop hammer when it is excavated to the greater
depths.
GI Pipe Support
GI Sheet
Jack
"H" Iron
Figure 4: Trench supporting system
Trenches shall be effectively supported including sheet piles where necessary to prevent any fall/run
from any portion of the ground outside the excavation into the trench and to prevent
settlement/damage to structures adjacent to the excavation.
Where battered sides shall be elected there shall be provided with stable slope (height at a slope of
not steeper than one to one from point of 300mm above the pipe).
The Contractor shall remove all the supporting installation once the work is finished.
10 PIPE LAYING PROCEDURE
Pipe laying between two adjacent manholes/chainages shall be started from the lower elevation to
higher elevation for easy draining of ground water in the trench. However there can be case where
need to lay pipes in opposite direction also.

All pipes shall be laid to lines and grades shown on the drawings.

Pipes shall be lowered by using a proper lifting mechanism which is approved by the
engineer.

Pipes shall be bonded to even gradient.

Open ends of the installed pipes shall be plugged with a watertight plug/other approved way
when there is no pipe laying in progress.

When the pipes are to be ready for joining the plug shall be taken off.
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Method Statement for HDPE Pipe Laying

Pipe ends shall be well cleaned.

Material used for plugging shall be approved type that shall adequately protect the pipe from
damage, prevent dirt, debris and water from entering the pipe.

All pipes shall be checked for defects and cleaned before joining. 10.1.1 Pipe Laying for
above ground piping is
not mentioned.
10.1 PIPE LAYING
Specially, the ground
needs to be prepared
 All pipes shall be carefully inspected for defects before installation.
and level before laying
 Proper installation of pipe shall be carried following steps.
the pipes. And
subsequently the pipes
o Excavation
has to be covered with
o Preparation of the bed for pipe
provided soil. (after
o Placing the pipe without damage
flushing & Hydro test)

The section of the pipe shall be fitted together correctly.

Pipe shall be laid true to line and grade.

As far as possible pipe shall be lowered by a crane.

Whenever the work cease for any reason the unfinished end of the pipeline shall be securely
closed.

Where the water table is encountered, shall be kept below the sockets when joining by
pumping or any other mean.

Pipe cutting to the required length shall be done by using pipe cutter and cutting edge of the
pipe shall be tapered by using a grinder.

The spigot socket shall be cleaned and shaped to ensure that there are no any sharpen edges.

The rubber ring shall be cleaned, wiped and placed in the groove of the socket.

After placing of the pipe inside of the trench, a thin film of lubricant shall be applied to the
inside surface of the rubber ring which shall be contacted with the entering spigot.

The outside of the pipe spigot shall be cleaned and the portion shall be piled until rough
edges removed and a thin film of lubricant shall be applied at the edge of the pipe.

To assemble the joint one of the methods which are mentioned, shall be used to suit the site
conditions.
o
Using ratchet
o
Using the excavator bucket
o
Manual
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10.2 CUTTING OF PIPES
Cutting shall be basically depending on the instructions given by the manufacturer.
10.3 JOINTING PIPES
Manufacturer’s joining instructions shall be followed.
HDPE Pipes
10.3.1 Need to
stick to Wiik
Welding Manual
and welding
parameters.
Butt fusion welding of pipes
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Method Statement for HDPE Pipe Laying
Fig.1. Aligning and clamping the pipes
Butt fusion welding is the name given to hot plate welding of thermoplastic pipes. It is one of two
main techniques for the fusion joining of PE (HDPE) water pipe.
The Process
The heating phase, sometimes referred to as 'bead up', is where the pipe ends are pressed against a
heated plate for a period of time. This is followed by the 'heat soak' phase where the pressure is
reduced to just hold the pipe ends on the hot plate. This allows time for the heat to soak into the
material at the pipe ends.
After the heat soak phase, the hot plate is removed and the pipe ends brought together. The time
taken to do this is called 'dwell time' and needs to be as short as possible. The final phase is the
welding/cooling time, predetermined subject to pipe diameter and wall thickness.
Machine set up
Before making any pipe welds, the butt fusion welding machine needs to be checked for smooth
running and set up for the pipe materials to be welded.

Selection of the correct clamps or inserts, ensuring all fixings are tight, to reduce the
possibility of misalignment due to axial movement.

Correct temperature of the hot plate, for the material being welded; this should be checked
with a surface temperature probe and digital thermometer in several positions after a
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Method Statement for HDPE Pipe Laying
stabilization period of at least 20 minutes. Between welds the hot plate should be covered by
a heatproof bag to protect it from surface contamination and to prevent heat loss.

Check the planer blades used to trim and square the pipe ends; they need to be sharp,
undamaged and firmly fixed to the planer surface to avoid slippage of the planer during
rotation.

Check all moving parts for smooth operation and, if using a hydraulic machine, check the
hoses and fittings for signs of leakage.
Preparing the pipe
Fig.2. Planing the pipe ends so they are ready for welding
Prior to welding, correct preparation of the pipes is necessary. When measuring pipe lengths,
allowance should be made for the trimming and melting sequences to guarantee correct lengths after
welding.
Before clamping the pipes into the machine, the ends should be checked for irregular shape, damage,
or embedded grit. The maximum allowable depth of this must be less than 10% of the wall thickness.
Damaged or deeply scored pipe should be discarded. Any loose contamination can be removed by
wiping the pipe ends with a lint-free cloth on both inner and outer surfaces.
Once cleaned, the pipes are clamped into the machine. To help alignment, it is good practice to clamp
the pipes in such a way that their stamped markings are in line. This also helps with identification at a
later date if required.
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Method Statement for HDPE Pipe Laying
Once securely fitted in the clamps, the pipe ends should be brought into contact with the rotating
planer tool until continuous shavings are cut from each end. The planning process ensures the pipe
ends are smooth and square ready for the welding phase. Loose shavings should be removed from
the machine and inside the pipes taking care not to touch the planed ends. This ensures that no
grease or dirt is transferred from hands to pipe ends. The pipes should then be checked for alignment
and adjustments made to the clamps where necessary to ensure there is minimal mismatch in
diameter.
Welding
Fig.3. The hotplate is positioned between the pipes
Fig.4. Bead formation needs to be monitored carefully
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Method Statement for HDPE Pipe Laying
Before the welding sequence, heating and cooling times and fusion pressures should be noted for the
specific pipe diameter and written down for quick reference during the welding cycle. Some machines
have all the relevant tables on them for convenience. A timer or stopwatch should be available for
accurate timing.
The heatproof bag should be removed from the hotplate, and the temperature should be checked
using a digital thermometer and surface probe.
It is good practice to complete a dummy weld before undertaking actual welding. This is to ensure the
surface area of the hotplate in contact with the pipe ends is totally clean of any dust particles or other
contaminants.
Place the hotplate between the pipe ends, ensuring that it is properly located and square to the pipe
faces. Move the pipes into contact with the surface applying an axial force. The force should be
applied smoothly making sure that the required pressure is not exceeded. The force needs to be held
securely, allowing the formation of a bead of molten material around the pipe.
The bead needs to be even around the pipe circumference, on both sides of the hotplate. This is the
'bead up' phase of the process.
The means of applying the force will vary with the type of equipment. On certain types of machine,
the force will be applied by mechanical means using a spring loaded mechanism with the force being
maintained by a locking screw. On other types of equipment, hydraulic rams are used with the
pressure maintained by switching valves in the hydraulic power pack.
When the required bead has been achieved, the pressure is reduced for the heat soak phase. The
pipes rest on the hot plate which allows the heat to permeate the material, reducing the possibility of
cold welds.
This time will vary subject to pipe diameter and wall thickness, therefore manufacturers
recommended times should be used.
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Method Statement for HDPE Pipe Laying
Fig.5. The pipes should be kept clamped during the welding/cooling phase
When this phase is completed, the pipe faces are moved away from the hotplate as smoothly as
possible to ensure that none of the molten bead sticks to the surface and the hotplate is removed.
The pipes are then brought together as smoothly and quickly as possible to minimize the possibility of
temperature drop, taking care not to exceed the required force.
The welding/cooling phase begins when the required force has been achieved. The weld force should
be maintained throughout this phase, to ensure maximum weld strength.
On completion of the cooling time, the pressure can be reduced to zero, and the pipe removed from
the clamps. The finished weld can now be visually inspected for uniformity and alignment.
PIPE LINE INSTALLATION
In handling pipes & fittings every care will be taken to avoid distortion or other damage. Pipes &
fittings will not be allowed to drop or strike objects & will be lifted by means of the mobile crane &
belts will be used at the correct lifting points along the length of the pipe.
Pipes will be stockpiled on timber pieces on level ground, in such a manner as will prevent damage to
any part of the pipe. During stacking and removal operations, safe access to the top of the stack will
be provided. Stacking type & the maximum stacking height will be maintained in accordance with the
manufacturer’s recommendations.
All pipes, fittings & accessories will be examined, and no piece which is found to be defective will be
installed. All pipes will be laid to lines and to true alignment and gradient as shown on the drawings.
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Method Statement for HDPE Pipe Laying
As far as possible, pipes will be lowered into trench by using either boom truck or excavator. No pipe
will be rolled from place to place or into trench except over suitable timber planking free from
roughness likely to damage any coating. If the prepared bed is disturbed for any reason, the pipe will
be raised and the bed is made good before pipe laying is continued.
Pipe & Fitting jointing will be carried out using Butt Fusion Welding Techniques & Electro Fusion
Welding Techniques using the Specific Welding Machines following the Heating & Cooling times &
procedures defined for respective Pipes & Fitting Sizes.
Well experienced Skilled Pipe Fitters will be used to operate these Machines & carry out these works
to the Approval of the Engineer.
Any pipe which is not in true alignment or shows any undue settlement after laying will be taken up &
re-laid correctly.
In case of flanged joints, gaskets will be fitted so that no part is projected and obstructs flow of water.
The complete joint will be perfectly aligned. Flanged joints will be completed with all nuts, bolts,
gaskets and two washers per bolt.
Whenever the work ceases for any reason, the unfinished end of the pipeline will be securely closed
with a tight fitting wooden plug & will be covered with polythene.
10.4 PIPE LAYING IN CULVERT CROSSINGS
Pipe laying in culvert crossings shall be done according to the details of the standard drawings/other
drawings specifically prepared for this work.
Without Pipe Supports (Short Spans)

Excavation shall be done to the minimum depth of 150mm below the deck level by using the
backhoe/excavator. If it is not possible for machine excavation, manual excavation shall be
done.

Length of the pipe between couplings shall be considered as “Width of the Culvert
Opening+1800 mm” according to the given drawings.

Required pipe lengths shall be placed and couplings shall be fixed by using the boom truck.

Lifting belts shall be used for lifting and placing the pipes.
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Method Statement for HDPE Pipe Laying
With Pipe Supports (Long Spans)

After completing the pipe support (if it is pipe, the head shall be casted at required height),
the bracket shall be fitted on it to hold the pipe.

Inclined length shall be determined and cut at the site to suit the incoming and outgoing
invert levels as given in the longitudinal sections.

Boom truck shall be used to place the pipe and to hold the pipe on the support until it fix to
the support.

The annular space between pipes shall be filled with stand.
10.5 PIPE LAYING IN BRIDGE CROSSINGS

Under crossing/over crossing/offset crossing of the pipe laying shall be carried out in
accordance to the approved drawings by the relevant authority.

Bore holes shall be done in either sides of the riverbank to identify bed rock level.

Type of the foundation for abutments shall be decided on both sides and the pier at the
centre by considering bore-hole data.

Sheet piling shall be carried out for work for abutments.

Sheet piling shall be carried out cofferdam for pier.

Foundation construction shall be done at abutments and piers. (Bored insitu piling, pre-cast
piling/casing shall be done considering depth to the bed rock).

Reinforced concrete abutment and pier construction shall be carried out. Design and
construction shall be in accordance to BS 8110.

Design and fabrication of pre-fabricated pipe shall be in accordance with BS 5440.

Installation of pre-fabricated pipe bridge shall be done by the help of crawler crane of
required capacity after providing necessary on abutment and pier.
10.6 PIPE LAYING IN ROAD CROSSING
Traffic arrangement shall be introduce for road crossings. Refer to the Chapter 5 (Traffic Control Plan).
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Method Statement for HDPE Pipe Laying
10.7 INSTALLATION OF VALVES AND ACCESSORIES
All sluice valves shall first be tested for smoothness and accuracy of operation and then shall be fixed
with their spindles truly vertical except where otherwise directed by the Engineer. Air valve tees shall
be carefully laid using a level across the flange to ensure vertically.
11 CONCRETE WORKS VALVE CHAMBERS AND THRUST BLOCKS
11.1 VALVE CHAMBERS
There are air, gate, scour and district meter chamber. It is intended to precast value
chambers where possible with the approval of the engineer at site the idea, behind this is to
expedite work and while laying of pipe this work could be done parallel.
11.2 THRUST BLOCKS
Thrust blocks will be carried out at site according to contract drawings or any other drawings
on approved by the engineer.
12 PROTECTION OF PIPES
Marker Posts
Pre-cast concrete marker posts (grade 20 concrete) shall be placed along the pipe traces especially at
turning points, special nodal points, branch off, etc. Similar arrangement shall be made for each valve
chamber and where it is not possible having marker posts, marker plate shall be introduced.
Marker Tapes
Marker Tape shall be installed in the trench, 300mm above the crest of the pipe.
13 SAMPLING AND TESTING
All testing will be carried out at the independent laboratory.
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13.1.1 Hydro testing has to be done as
per theMethod
SFS 3115
standard
andPipe
Wiik
Statement
for HDPE
Laying
procedure shared. Mutually agreed,
section wise hydro testing has to be
13.1 TESTING AND DISINFECTION
done before the trench is back filled.
The final test can be done with
All pipes will be hydrostatically tested according
to the approved
All tests
backfilled
trench allmethod.
in one final
go.will be
conducted on the pipe lines in sections after the trench is backfilled, buy before pavement
13.1.2 Pipe flushing has to be
construction.
done before Hydro test
All pipe lines will be thoroughly checked for foreign matters before testing all wash out valves
hydrants will be closed when the pipe line is ready for testing. The pipe line will be slowly
filled by water, allowing all air pockets to be released, until the pipe is completely filled and
under working pressure at which condition it should be allowed to stand for 24 hours, any
apparent defects in the pipeline will be noted and rectified. For this purpose pressure pump
and standard equipment will be used with the coordination of the engineer.
13.2 DISINFECTION
After successful completion of pressure testing, sterilizing process will be commenced. The
concentration of chlorine solution applied will be according to the specification and the
engineer’s directions. The water used for pipeline testing and disinfecting operations will be
disposed without causing any damage to adjacent property.
13.3 PIPES
Pressure testing of the pipes shall be done as per the Engineer’s requirements.
Pressure testing checklist shall be used for monitoring the pressure testing process. The results shall
be recorded to the hydrostatic pressure testing monitoring form.
The length of the sections to be tested shall be decided by considering,

The availability of suitable water

The number of joints to be inspected, and

The different elevation between one part of the pipeline and another.
Pressure testing shall be carried out in such lengths as convenient and approved by the engineer, but
in any circumstance these lengths shall not be greater than 1000 m.
14 BACKFILLING AND COMPACTION

Backfilling and compaction shall be done layer by layer.
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14.1 For above
ground pipe lines
covering of soil
has to be
included.
Original
Method Statement for HDPE Pipe Laying

The thickness of the top layer of soft material free from stones greater than 25mm size shall
be deposited in 150mm layer from top of the bedding to a depth not less than 300mm from
the crown of the pipe.

The other two layers shall be 300mm thick and excavated soil shall be used after the
engineer’s approval.

Compaction shall be done using a roller compactor/vibrator and excessive/unsuitable
material shall be removed from the site.

If the pipe is to be laid on carriageway of RDA/PRDA roads, clear sand shall be used for
backfilling up to 300mm from the crown of the pipe.

Under the wet conditions, clear river sand/other clear granular material approved shall be
used to obtain require compaction.

Road reinstatement shall be done where required.

Backfill shall be compacted to a dry density not less than 95% of the laboratory modified
proctor density.
14.1 PIPE BEDDING
Pipe bedding shall be placed as per construction drawing with materials complying with the
requirements. Water level in the trench shall be kept to a minimum while placing the bedding
material. Bedding shall be levelled and compacted to achieve the required level of compaction.
Required bedding angle shall be provided by using hand tools.
The backfill material shall be compacted with plate compactor/compacting rammer. Soil thickness of
each layer shall be 150mm maximum at loose stage.
14.2 PIPE SURROUNDING
Soil shall not be dumped directly on the pipe. Protective timber board shall be provided to cover the
pipe to avoid damaging it due to the soil dump. Uncompacted/ partially compacted soil remaining in
previously placed layers shall be moved to adjoin fill and compact. Hand compaction shall be applied
in stages to compact pipe surrounding as well as a reasonable height above the pipe crown as per the
manufacturer’s recommendation (if required).
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Method Statement for HDPE Pipe Laying
14.3 BACKFILLING THE REMAINING PART
Maximum depth of each uncompacted soil layer shall not be exceeded 150mm and the number of
passes shall be eight. Compaction tests shall be done and the test results shall be available at the site
office.
15 REMOVING OF TRENCH SUPPORT
Removing of trench support shall be done simultaneously with the backfilling. Lowest bracing shall be
removed once completed the backfilling up to that level. So on for bracings for higher levels. The
Contractor shall be responsible for removing all the supporting systems that are used for the pipe
laying process. Relevant authorities shall be informed soon after the completion of pipe laying in
order to undertake the permanent reinstatement of the carriageway.
16 TEMPORARY ROAD REINSTATEMENT
Aggregate base course for a thickness as specified and indicated in the drawings shall be placed and
levelled it in the trench after carrying out backfilling and then it shall be compacted using approved
equipment to 100% of MDD up to the top level of existing road surface. Compaction tests shall be
carried out through approved laboratory and test results shall be submitted for the approval of
Engineer. Prime coat of bitumen emulsion (CSS 1) at the rate of 1 lit/m2 shall be applied and blinded
with sand as necessary. Contractor at his own cost shall maintain the roads so reinstated until they
permanently reinstated after completing pipe laying work including pressure testing of pipelines and
testing of the backfill of the trenches to the approval of the Engineer.
17 PERMANENT ROAD REINSTATEMENT
At the time of permanent road reinstatement is commenced, it shall be required to remove a top
layer of ABC up to required depth in the trench so as to accommodate a layer of asphalt concrete in
permanent road reinstatement and then remaining layer of ABC shall be compacted using approved
equipment to achieve 100% of MDD. Tack coat at a rate of 0.5 lit/m2 shall be applied. Then asphalt
concrete shall be laid and compacted using approved equipment to reach the required density and
shall be finished up to the top surface level of existing road. Compaction test/any other required shall
be carried out through approved laboratory and test results shall be submitted by the contractor as
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Method Statement for HDPE Pipe Laying
directed by Engineer. Upon completion of the reinstatement conforming to the specification, the
contractor shall arrange with Engineer to carry out a final inspection and measurements.
18 RESOURCE ALLOCATION
Required equipment and manpower shall be allocated for each pipe laying group. However
machinery/equipment allocation, number of workers and work allocation method shall be decided
depending on the site conditions, type of the pipe and the diameter of the pipe etc. There will be a
technical qualified personnel of each working gang and competent enough to handle the job.
19 HEALTH AND SAFETY
The care shall be paid for the work underneath electric lines. Safety supervisor shall visit the sites
randomly and without any prior notice for safety inspection of the sites. Person-in-charge of each
group shall be responsible for following every safety measure introduced by the safety supervisor.
Safety supervisor shall conduct weekly safety toolbox meetings and explain the safety procedure to
the employees.
Special attention shall be paid for the pipe laying along the road. Traffic arrangement shall be
discussed with the relevant police station prior to the commencement of work. Road safety shall be
among the considerations of the safety precautions.
19.1 ENVIRONMENTAL PROTECTION
The identification of the potential treats to environmental impacts is necessary. The main issues to be
addressed are:

Discharge of water into existing stream

Erosion and sediment control

River bank and bed protection

Dust control

Noise and vibration control

Air pollution control

Hazardous and solid waste management
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Method Statement for HDPE Pipe Laying
The environmental management plan will be prepared. Plan will address the site preparation and
clearance, temporary access, trench excavation, material and equipment transportation etc, which
will help to respond to the quality of people living standards.
20 QA/QC PLAN
Quality of the pipe laying process shall be monitored through the pipe laying trenching log. The
contractor shall maintain the quality of the construction work to match the quality of the ISO format.
Ceylex Engineering quality manual shall be maintained for quality assurance for the project.

The specific QA/QC program will be established so as to ensure that the project requirements
will be met for all elements of design, material/service procurement, fabrication, assembly,
shipping and installation.

Document control
Document control covering the requirement for the preparation, review, approval and
distribution will be established to ensure that those documents and changes thereto are
controlled and distributed as required to locations where applicable work is being performed.

Procurement control
The procurement of material, equipment and services will be controlled to assure
conformance with specified requirements.

Materials and equipment control
Controls will be established to assure that only correct and accepted items are used and
installed

Inspection/testing
The objective of inspection and test is to ascertain that equipment and materials are
manufactured and erected strictly in accordance with QA/QC program as well as client
document.

Quality assurance records
Records that furnish documentary evidence of quality, if required by the client, will be
specified, prepared and maintained

Audits
Planned and scheduled audits will be performed to verify compliance with all aspects of the
QA/QC program to evaluate its effectiveness.
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