Method Statement for Installation Irrigation System.
Scope of Work.
The Scope of this method statement covers the Landscaping
Irrigation works.
Equipment to be used for Irrigation Works.
- Round Point Blade Shovel
- Square Point Blade Shovel
- Trenching Shovel/Spade
- Tamper Bar, Pry Bar, Digging Bar • Broom
- Pipe Cutter
- Work Gloves
- Latex Gloves
- Pipe Wrench
- Measuring Tape
- Riser Extractor
- Hack Saw
- Wire Cutters
- Screw Drivers
- Sledgehammer
- Garden Hose
- Hose Sweeper Nozzle
- Trencher Machine
Materials to be used.
- Upvc pipes and fitting – as per material approval. • PVC Glue – as per material approval
- Pipe support rollers
- Pipe cutters
- Digital thermometer with probe
- Timer
- Indelible Marker pen for marking beads.
- Bead gauge
- Saw and saw guide.
- Pipe end cover
- Spirit level.
Irrigation Procedure.
Material Handling.
Care and attention should always be applied when handling
pipes; this should be done not only for the
protection of the pipes but also the safety of the handling
personnel.
Pipes should never be dropped onto hard or uneven
surfaces.
Pipes should never lie thrown from vehicles.
Pipes should never lie dragged or rolled along the
ground.
Where possible, pipes should always be unloaded individually
and by hand.
There are occasions where pipes may already
be bundled into frames; in this
case, proper lifting equipment (lift
truck etc.) should be used.
Where pipe weight exceeds practical personnel handling then
rope or web sling should be used with
mechanical lifting equipment’s
Metal Chains, Hooks or Ropes should never be used.
Transportation.
Bundled Pipes.
Pipes supplied in factory bundles should be stored on flat
even ground able to withstand weight of both
pipes and lifting apparatus.
Pipes should be kept away from sharp projections, stores, or
other jagged cut crops.
Bundle strapping should remain in position until such time
that the pipe is to be used.
Height should not exceed three bundles.
Loose Pipes.
Pipes should be stored on flat even ground able to withstand
weight of pipes and lifting apparatus.
Pipes should be kept away from sharp projections, stones, or
oilier jagged outcrops.
Socket pipes should be stacked with the sockets of alternate
layers facing in opposite directions and with
socket ends protruding.
Different sizes of pipes should be stored separately. Where
this is not possible, larger and/or thicker walled pipes. Should be placed at
the bottom of the stack.
Pipe stacks should not exceed 3 meters in height.
Never place pipes in contact with lubricating or hydraulic
oils, gasoline, solvents, or other aggressive
materials.
Keep pipes away from intense heat.
Exercise special care when handling pipes in humid or wet conditions, as the pipes may become slippery.
PROTECTION FROM ULTRAVIOLET.
A first-in, first-out stock rotation system of pipe and
fittings usage should be adopted.
For hotter climates, as experienced in the Gulf it is
recommended that pipe Should be kept under cover always during storage -higher UV levels
can otherwise 'bleach’ the pipe.
Covering also protects against excessive heat build-up
(which could lead to pipe deformation), Therefore, it is recommended that Pipes
should be protected from direct sunlight whilst ensuring good ventilation storage in containers is not recommended.
EXCAVATION OF TRENCHES AND PITS.
General.
Before the start of the construction works, obtain all permits from the main
Contractor, comply with their
requirements, and shall obtain Engineer’s approval for the method of pipe
construction with special relevance to the maximum length of open trench.
The trenches shall be excavated to the required line and
level as shown on the Drawings or as approved
by the Engineer, and shall, always, be drained and braced to ensure safe
and efficient pipe laying.
DEPTH.
The entire pipe shall have a cover as per drawing, measured
from the top of the pipe to the finishing road level except where the pipe may
be lifted or lowered when crossing the other services as instructed by the
Engineer.
Where trenches are required to be deeper than the general
depth mentioned above, shall dig the trench
to this required depth with a gradual slope necessary for the proper
laying of the pipeline.
Pipelines shall not be closer than 300 mm (12") to
other pipelines, services or structure or as directed by the engineer.
The trench width is dependent on the nature of the ground,
depth, and pipe size. The clear width of the
trench at any level shall be minimum of one pipe diameter,
plus 300 mm (± 50 mm).
In all cases the trench shall be excavated sufficiently to
ensure efficient laying and jointing of
the pipes.
PIPELINE BEDDING.
The pipes shall be bedded on good dry approved bedding
material free of lumps or stone chippings.
If the material in the trench bottom is considered
unsuitable or unstable, it shall be removed to a depth of 100 mm and the bottom
of the trench shall be filled with a 100-mm layer of suitable approved fill
material.
All bedding material shall be subject to prior approval of
the Engineer.
METHOD OF EXCAVATION.
Wherever practical, mechanical excavation methods shall be
used.
Where shoring is used to stabilize excavations, the shoring
shall be removed progressively to ensure that
adequate backfilling is carried out without leaving voids.
All excavated material shall be placed to avoid any danger
or hindrance to others.
SCOPE.
The scope of this Method statement is to ensure that all
excavation works for the purpose of Irrigation
Pipe lying are carried out using the approved procedure, which complies
with the project specifications.
This Method Statement covers the following scope of works:
-
Trenching works for Lateral UPVC Pipes.
Supply & install
Inline PC drip
network complete with
pressure compensating, self-flushing type including accessories, stakes,
end caps, joiners.
Supply, install, testing & commissioning of UV resistant
linear low density polyethylene tube 16mm Día with necessary fittings and
accessories for Palm trees.
Supply & Install valves including valve boxes, excavation, disposal, backfilling, block work support, gravel infill, brass male x PVC union adaptors, valve box, valve label, electrical & mechanical connections. As detailed in specifications and as shown on detail drawings.
Control System by Others.
Prior Activate.
The routing of the pipes will be determined following
approved coordinated shop drawings.
All rocks and deleterious material will be removed from
trench bed.
Where trenching is difficult due to sand, water will be
applied to get the proper.
Trench shape. Necessary shoring, sheeting, and bracing will
be used to protect against the collapse of side
slopes.
Make sure the extent of all trenches in open cut is the
minimum necessary or practicable for the
construction of the Works.
Do not exceed the maximum total length of 500meters for open
trenches for pipelines.
Do not make battered trenches in public highways, private
gardens or within 30 meters of any building or
other structure.
Form that portion of the trench, which extends from the
formation to a point 300 millimeters above the
crown of the pipe when laid in its correct position, with vertical
sides the minimum
practicable distance apart, unless otherwise specified by the pipe
manufacturer and/or accepted by the Engineer.
Procedure.
Trench width & depth will be as per approved detail shop
drawings.
The trench bottom will be composed of stable & uniform
selected backfill sand with no protuberances that might cause point loading of
the pipes. Sand bedding to be as per approved detail shop drawings.
Additional excavation will be carried out at the position of
the pipe socket to ensure proper joint assembly and pipe support.
PIPE LAYING.
General
In general Polyethylene pipes shall be handled and laid
according to an approved Standard and/or manufacture’s recommendations
Laying.
All pipes, fittings, valves etc. shall be carefully lowered
into the trench with suitable equipment in a manner that will prevent
damage.
At the close of a day or whenever pipe laying is not in
progress t h e open ends of the installed
pipe shall be closed by an
approved cap or blank
to prevent the entrance of ground
water or any other foreign matter.
Under no circumstances shall pipes be used for the storage
of tools etc.
To ensure that the pipeline is always clear and free of all
foreign matter until taken over by the main Contractor. Sufficient backfill
shall be placed on the pipe to prevent floatation. Any pipe that has floated
shall be removed from the trench and re- laid in a dry trench.
The Engineer's decision is final about the suitability of
the weather for pipe laying.
Additional excavations must be carried out to provide extra
space around couplings.
These shall be large enough to allow unhindered jointing of
the pipes. All pipes shall be laid and maintained to the agreed alignment and
grade ensuring that the pipe is properly bedded along its whole length.
Fittings and valves shall be at the required locations. No
deviation shall be made from the agreed alignment or grade except with the
written consent of the Engineer.
Temporary supports, adequate protection, and maintenance of
all underground and surface utilities encountered during construction of the
Works shall be furnished.
Whenever it is necessary to determine the locations of existing underground utilities, after an examination of available records, shall make all explorations and excavations as may be directed by the Engineer to determine these locations Only such tools and equipment as' have been approved by the Engineer shall be used by the Contractor to execute the work in a safe and efficient manner.
BACK FILLING.
General.
Approved fill material free from clay, rocks and other unacceptable material shall be compacted by means of hand
tools around the pipe up to 30 cm above top of pipe in layers of not more than
20 cm.
If in the opinion of the Engineer the materials excavated
from the trench are not suitable for this purpose, shall supply suitable
materials, to be approved by the Engineer.
The materials shall be made damp, if necessary, to attain
adequate compaction around and under the pipes and fittings.
The balance of the backfill to the final ground level shall
contain no stones more than 15 cm (6") in their largest dimension and
shall not contain more than 25 percent of stones.
All backfill shall
be compacted in a manner approved by the Engineer.
The trenches or any other excavated shall only in a manner
approved fill, and shall be used for dumping unwanted excavated material, which
shall be disposed of away from the site as directed by the Engineer.
Any depressions caused by settlements due to the trench excavations and backfilling shall be made good using approved fill material.
Backfilling of trenches in Existing.
In general, Clause 5.1 shall also apply for backfilling of
trenches and excavations in the proposed roads and road crossings, where
approved fill material shall be used.
The backfill around the pipe and up to 30 cm above the top
of the pipe shall be done by means of hand tools, for the rest of the filling a
compaction as per approved density by the modified proctor
test (ASTM D1557) shall be required.
The approved filling materials shall be deposited and spread
in 150 mm thick layers. Each layer shall be compacted by means of approved
mechanical vibrating rollers.
The formation shall be shaped to an even and uniform well
filled surface true to the required gradients.
VALVE.
Valves on horizontal section of pipe work shall be installed
with the spindle vertical.
All valves shall be installed as accessible as
possible.
All open ends of pipe work left during construction shall be
covered using purpose made caps or blind flanges, such temporary ends shall
suitably support during testing. Valve identifications tags shall be wired to
all valves.
Air release values shall be installed at high points in the
system if required Engineer. Gate values, Air values and Solenoid values shall
be installed as shown on the drawings.
VALVE BOXES AND CHAMBERS.
Value boxes shall be bedded in cement and mortar on concrete
or concrete block chamber and shall be flushed with surrounding surface.
The block chamber shall have in situ a concrete base, and
block shall be laid in stretcher bond. Beds and vertical joint shall
be filled with mortar as the block are laid and joint shall be flush cut as the
work proceeds
IRIRGATION EQUIPMENT.
Equipment shall be installed to achieve optimum irrigation
efficiency and to accommodate the requirements of the landscaping.
All irrigation equipment such as spray heads and emitters
shall be installed only after the laterals and risers are flushed
thoroughly.
The installation shall be as per the irrigation detail
drawings. The top of the sprinkler case shall be flush with final grade level.
Riser assemblies shall be snag free of leaks. The half circle spray heads should be
installed at least 30cm away from the kerbstone.
ELECTRICAL INSTALLATIONS.
Installation of Cable.
Measuring, marking off and cutting of all cables to length
before installation or laying.
Temporary sealing, protection and support of cables being
installed or laid, and testing of cables for insulation before jointing or
termination.
Preparation of all necessary materials for the placement,
support or carriage or all cable runs. These shall include earth trenches,
sleeves ducts, cable trays, ladders, trucking, racks, clamps, saddles,
etc.
If a cable passes through foundation walls or other
underground structures, the necessary ducts or openings shall be provided in
advance for the same.
Sealing of cables using fire retardant cable sealing
material in ducts, sleeves, or trenches to prevent ingress of water.
Testing of cable insulation, phasing, and continuity.
All outdoor terminals shall be shrouded, and the termination
shall be covered with heat shrink shrouds.
Cable termination shall be made with proper size cable lugs.
Copper strands shall not be cut to use with under size lugs. Cables in the
panels shall not be connected directly to the terminals or circuit breaker or
isolators but shall be connected through terminal block.
Terminal board/bock shall be leveled and refer to drawings
accordingly.
Each cable shall be tagged at the termination point, fitted
over- sheath, providing cable number ad circuit identification.
Cores of control wire shall be provided with ferrules and
sleeves with markings.
Spare cores of control or power cables shall be terminated
on the terminal blocks with identification level and tagged spare.
JOINTING OF CABLES.
Cable sealing and jointing shall be in accordance with the
best current practice.
Cables with metal
sheaths or armoring shall be terminated or jointed with metal sheaths or
armoring solidly bounded to the metal joints or terminal boxes to provide a low
resistance path fault condition.
An identical type of cable shall be used for extension.
Obtain Engineer’s prior to approval for the job.
On the Engineer's approval, joint on the incoming cable may
be allowed, the length of the additional piece of cable shall not less than 15
meters.
CABLE PULLING.
When the cable is being laid in ground or pulled through
trenches, cables pulling shall be by manual means and sufficient wooden roller
supports shall be provided by over bottom of the trench to prevent damage to
the cables.
CABLE TRENCHING.
Before the cables are laid, trench shall be partly filled
with soft and pebble free sand to a depth as per the approved drawing.
At the road crossing and other places where cable enter
pipe sleeves, adequate sand bed shall be
provided so that the cables do not slack
or suffer damages from the pipe ends
back filling.
CABLE MARKERS.
Cables markers shall be installed over the cable route every
50m and at points of change of direction, or the joints, if these exist.
ELECTRICAL TEST.
Each electrical equipment cable and complete system shall be
thoroughly inspected and tested before finally placing into service.
All tests shall
be made in
compliance with respective
regulations, recommendations, and standards.
INSTALLATION OF SOLENIOD VALVES AND GATE VALVES.
Before installation of solenoid the irrigation lateral line
should h a flushed enough to prevent any
remaining dirt or particles inside the pipe.
Solenoid valves will be installed as per drawing and
standard details. Plastic valve boxes with the block work chamber will be
provided.
Aluminum or plastic identification nameplates will be
provided for the valve boxes and pull boxes.
FINAL COMPLETION OF THE ENTIRE INSTALLATION AND COMMISSIONING OF THE SAME
Is safe to say that, except for a few very minor items and
very minor procedures, with reference to the civil works mainly, not being
fully described as per this “Method Statement”, that we may conclude this
statement by closing with the following:
Testing of the
all the system
components such as
electrical components, system
control components and devices, valves,
pumps, etc. will be subject to the appropriate, relevant, and individual testing procedures , where
possible, prior to commissioning of
the entire project
installation.
Once the procedures
are successfully completed, a written report will be submitted to the
Project Consultant for his perusal and
preparation for final handing-over of the project.
Prior to final handing-over, the entire site will be
cleaned, and all construction rubbish will be removed, and the site prepared to
be 100% tidy.
After successful handing over, all snags attended and
rectified, comprehensive, and fully compliant
'As-Built Drawings and O & M Manuals' will be handed over to the
Project Consultant for his perusal, comments and correction.
After re-submittal of
the same with corrections, the project will be finally handed over and
the ‘Defect Liability Period' will be initiated for a period of one year from
the applicable date.