1. INTRODUCTION
This Method statement describes in detail the Installation of Natural Gas Pipeline. This includes addressing programs for implementing commitments regarding the quality of Natural Gas Pipeline works.
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2. OBJECTIVE
This method of statement shall be used
as a guideline to assist ABC personnel to fully
understand their responsibility on how to execute their work in a safely and
efficient manner throughout the project.
3. WORK SCOPE
This procedure is applicable to all
Natural Gas pipeline installation at Zubair and aims to:
To ensure that all works carried out
comply in all respect with the Act and Regulations and by laws of the
followings:
- Client Standard
- Code of Practice for the Installation of
Fuel Gas Piping Systems and Appliances
- Occupational Safety and Health Act and
Regulation 1994
Not limited to the above act and regulations,
the duty to comply extended to any other authority having jurisdiction over the
scope of works.
4. WORK ACTIVITIES
- Storage management
- HDD work
- Soil excavation work
- Soil backfill work
- MDPE pipe and fittings installation
- Carbon steel pipe and fittings installation
- Anti-corrosion tape wrapping work
- Coring work
- Sleeve insertion works
- Gas cock installation
- Leakage testing
- Housekeeping
5. WORK PREPARATION
5.1. Pre-job meeting
Pre-job meeting shall be held prior to
the commencement of any work activities at site in order to ensure all parties involved
are well informed of the work process and the associated safety hazards.
Toolbox talk and JSA shall be held with the workers prior to commencing work.
5.2. Manpower
ABC shall be represented by: -
Engineering
Manager – He is responsible of all activities related to the project. He
is available on request or as per job requirement.
Project
Manager – He is responsible of the execution of the project. He is available
full time at site.
Project
Executive – He assists Project Manager in the execution of the project. He
is available on request or as per job requirement.
Site Supervisor – He is responsible
of the manpower planning onsite. He is responsible to obtain all permits
required prior to the job, holds toolbox talk and JSA with workers and ensures
work complies with the design. He is also responsible for chairing daily
progress meeting onsite. He shall act as the immediate authorized person in the
absence of the Project Manager.
Welder – He is responsible
of MDPE pipes and fittings fusion, carbon steel sch40 pipe and fittings welding
and conducts leakage testing.
Fitter – He is responsible
for general works at site.
- Management : 3 person
- General Workers : 7 person
- Total no. of workers at site : 8 person
5.3. Machinery, Tool & Equipment
ABC shall
provide good working equipments in order to complete the work safely. ABC shall supply but not limited to the following equipment’s:
-
- Electro-Fusion Welding Machine
- Pipe Clamp
- Diesel Generator
- Welding Set
- Thread Machine
- Drilling Machine
- Speed Cutter
- Rotary Hammer
- Grinder
- Hacker
- Coring Machine
5.4. PPE & Safety Equipment
ABC shall
supply sufficient & comply with the mandatory requirements of standard PPE
i.e.
- Safety helmet
- Safety shoes
- Safety glasses
- First aid box
1. JOB EXECUTION
6.1. Storage management
ABC
shall erect site storage facilities to store all work materials, tools and
equipments. The store shall act as ABC site
office.
6.2. Horizontal Directional Drilling (HDD) work
To carry out Horizontal Directional
Drilling (HDD) work for underground MDPE pipe installation across the main
road.
- Prior
to carrying out HDD works, ABC shall discuss and verify with the main contractor and
consultant the area/path to be drilled. Drilling path designed with
consideration to the position of existing utilities, accessibility of
drilling rig and geographical site, and shall be at least 3 feet below the
road. Details of utilities shall be marked on plan, should necessary final
adjustment will be made at site.
- Radio
detection shall be used to finalize the path. Trial hole shall be
excavated to verify the base of the underground utilities. Warning signs
and colored bunting shall be erected at locations of overhead power
cables. Work area shall be barricaded with warning signs erected.
- Horizontal
distance and cross sectional profile of the proposed bore shall be
determined with measuring tape and dumpy level. Drilling path shall be
marked on the ground.
- High
viscosity drilling fluid shall be used to prevent the collapse of borehole
during drilling. Drilling fluid viscosity shall be monitored and
maintained at Funnel Viscosity 40 secs/quart.
- A
(1.5 m x 1.0 m) x 1.0 m depth pit shall be dug at the entry& exit
point to cater for cuttings &fluids.
- Commence
drilling operations by attaching a 3” diameter fluid jet drill head with
sensor to the drill rod. Drilling trajectory shall be monitored at every
3m by Digitrak Electronic tracking system.
- Locator
technician shall inform drilling operator should drill head strays off
course. Adjustment shall be made by the drilling operator.
- At
exit pit, drill head shall be removed and replaced with a fluid jet
reamer.
- Reamer
shall be retracted through the drilled hole – at doing so borehole will be
enlarged and more cuttings will be removed. Different diameter reamers
shall be used to enlarge borehole in steps to a max of approx. 30 percent
than pipe size.
- MDPE
pipe will be laid on rollers after being string up.
- After
final reaming, pipe will be attached to the last reamer & swivel &
will be pulled into borehole.
- Upon
installation pipe ends shall be capped to prevent foreign particles ingress.
Site shall be cleaned and reinstated and drilling rig demobilized.
6.3. Soil excavation work
To conduct soil excavation work to lay
underground MDPE pipe and underground carbon steel pipe (c/w anti-corrosion
tape).
- Prior to carrying out
excavation works, LWG shall discuss and verify with the main contractor and
consultant the area/path to excavate.
- Permit shall be applied
and made available at site. Toolbox talk shall be held prior to starting
work.
- JCB excavator shall be
mobilized, unauthorized personnel kept out of the excavation area.
- Trench shall be excavated
as per approved drawing. It shall be prepared as such that the pipe lays
on a firm, continuous bearing on the bottom.
- Excavator demobilized
and site cleaned in preparation for pipe laying.
6.4.
MDPE pipes and fittings installation
- Welders shall make sure
that all pipes and fittings are dry, free from burrs, suspended matter &
oil.
- Prior to joint the pipe with
electro-fusion machine, MDPE pipe shall be aligned properly by clamp.
- For more detailed
information on electro-fusion joint of MDPE pipes and fittings, refer to
attachment B.
6.5. Carbon steel pipes and fittings installation
Pipes shall be cut to desired length
based on shop drawing: -
- Pipe length shall be
measured by measuring tape and marked at the desired
length based on endorsed shop drawing.
- Speed cutter (on Portable Cut-Off
Saw) shall be set on clean, dry, stable surface, without the
presence of flammable elements and connected to the power supply.
- Wear proper apparel. Do
not wear loose clothings, gloves, necklaces, rings, bracelets or other jewelries’
which may get caught in moving parts. Nonslip footwear is recommended.
Wear protective hair covering to contain long hair.
- Safety glasses shall be
used. Face or dust mask shall also be used.
- Pipe shall be laid on
the speed cutter, pipe marked position adjusted to speed cutter cutting
wheel.
- Pipe position shall be
fixed at 90 degree with the base of speed cutter and hold down by clamps.
- Before using the tool on
pipe, let it run for a while. Watch for vibration or wobbling that could
indicate poor installation or a poorly balanced wheel.
- Switch on, wait until
wheel attains full speed and lower gently cut the pipe on marked position.
- Watch out for flying
sparks when operating. They can cause injury or ignite combustible
materials.
- Do not overreach. Keep
proper footing and balance at all times.
- Do not touch the
workplace immediately after operation; it is extremely hot.
- Never leave tool running
unattended.
- Turn power off.
- Do not leave tool until
it has come to a complete stop.
- Power off and disconnect
power supply.
All underground, floor/wall embedded
carbon steel pipes should be wrapping with anti-corrosion tape to keep the
pipes corrosion free.
- The pipe surface shall be free of mud,
oil, grease or any others foreign material that will prevent the joint
coating system from bonding to the steel pipe surface.
- Visible oil and grease shall be removed
with suitable solvent.
- The steel surface shall be dry prior to
the application of the joint wrap tapes.
- KEROSENE shall NOT be used for cleaning
the pipe joints.
- Wrapping shall be applied under hand
tension or using a hand-wrapping machine capable of maintaining even,
constant tension across the width of the tape.
- The wrapping shall be 55% over lap.
To fabricate male screw end on pipe,
pipe shall be threaded by threading machine:-
- The threading machine shall
be set on clean, dry, stable surface, without the presence of flammable
elements and connected to power supply.
- Wear proper apparel. Do
not wear loose clothings, gloves, necklaces, rings, bracelets or other jewelries
which may get caught in moving parts. Nonslip footwear is recommended.
Wear protective hair covering to contain long hair.
- Be sure switch is OFF
before plugging in. Carrying tools with your finger on the switch or
plugging in tools that have the switch ON invites accidents.
- Do not overreach. Keep
proper footing and balance at all times. Proper footing and balance
enables better control of the tool in unexpected situation.
- Insert the pipe into the
Threading Machine so that the cutting mark is located about 12 inches to
the front of the speed chuck jaws.
- Insert work pieces less
than 2 feet long from the front of the machine. Insert longer pipes
through either end so that the longer section extends out beyond the rear
of the Threading Machine.
- To avoid equipment
tip-over, position the pipe supports under work piece.
- Tighten the rear
centering devise around the pipe by using a counter clockwise rotation of
the hand wheel at the rear of the Threading Machine. This prevents
movement of the pipe that can result in poor thread quality.
- Secure the pipe by using
repeated & forceful counterclockwise spins of the speed chuck hand wheel
at the front of the Threading Machine. This action “hammers” the jaws
tightly around the pipe.
Shielded Metal Arc Welding (SMAW) or
stick welding is a process which melts and joins metals by heating them with an
arc between a coated metal electrode and the carbon steel pipe:-
- Wear welding mask /welding goggle and
welding glove.
- Arrange cables to one side and away from
the operator.
- Do not coil or drape cables around body.
- Keep welding power source and cables as far
away from operator as practical.
- Connect work clamp to pipe as close to the
weld as possible.
- Bevel the pipe end into
30 Degree by using grinding tools. And also remove oxidation and
mill scale.
- Align the pipe/fitting in jointing position with 1.5mm gap between 2
elements.
- Set-up the welding machine with proper amp and select an electrode.
- Electrode
angle should be 75° - 80° according to welding position.
- The electrode outer
coating, i.e. flux, assists in creating the arc and provides the shielding
gas and slag covering to protect the weld from contamination.
- The electrode core
provides most of the weld filler metal.
- Weld the joint by
moving electrode along the pipe end bevel at the correct speed, the metal
deposits in a uniform layer will seal the joint (bead).
Pneumatic leakage testing shall be
conducted by welder prior soil backfilling for MDPE pipe and cement patching
for embedded carbon steel pipe.
- Testing pressure is determined by 1.5x of operating
pressure or minimum 5 psig.
- Testing shall be witnessed by main
contractor / consultant.
- Testing record must be documented and
endorsed by main contractor / consultant.
Nail bracket shall be applied to all embedded
carbon steel pipes for temporary positioning before cement plastering: -
- Fabricated
pipes shall be aligned into pipe groove.
- 2
pieces of nail (approx 3mm Ø x 25mm length) shall be derived into the
wall/slab and nail head secured with slim wire to hold pipe in centre.
- Care
to be taken not to scratch/damage pipe.
6.6. Coring works
To core floor slab / beam by Coring machine to
allow pipeline to be installed through.
- Prior
to carrying out coring works, LWG shall discuss and verify Coring position
and obtain permit from main contractor and consultant.
- Mark
core position and fit/mount the Coring machine in position by using wall
plug.
- LWG
shall equip the Coring machine with proper size of core bit and provide
current supply.
- Switch
on the Coring machine and spray water on the core hole during process.
- Turn
off coring machine after bit core is through the slab/beam.
- Dismantle
the wall plug and clean the coring site.
6.7. Sleeve insertion works
- Tools and equipment’s
to be prepare e.g. measuring tape, PVC pipe etc.
- The level of PVC to be
inserted at the wall slab shall be measured and marked.
- PVC pipe shall be cut using
pipe cutter and pipe’s butt sealed with masking tape.
- The completed PVC pipe
shall be inserted into the floor beam mold.
- Tighten the PVC pipe
with the wire at the mesh wire.
6.8. Soil backfill work
To conduct soil backfilling work after the
installation of underground MDPE pipe & underground carbon steel pipe.
- Upon installation, the
underground piping shall be covered with sand bedding.
- Tracer wire, warning slab,
protection slab shall be laid to mark the position/as protection to the
installed piping system.
- On top of the protective
concrete slabs, the trench shall be filled and compacted with soil.
Drawings as per Attachment A.
- GI. B pipe sleeve is
required as a protective sleeve for road-crossing pipes.
6.9. Gas cock installation
Gas cock shall be installed at each gas outlet
after the pipeline system installation is complete.
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