Method Statement for Irrigation System

1. Description of Works

This Method Statement for Irrigation defines the general procedure implemented for the installation of the irrigation systems as per project specifications, quality, health, safety, and environmental requirements.

1.1. Introduction

This method statement for irrigation system shall be followed for the construction of any particular irrigation installations including the excavation and installation/laying of the main pipeline, lateral line pipe, valves, valve boxes, driplines, emitters, sprinkler pipes, etc. It will also include the jointing and pressure testing of pipes.

The objective is to specify the methodology of work and the requirement in terms of sequence, tools, equipment, labor, materials, logistics, quality, health and safety, and environment.

This method statement is subject to the requirements as stated in the following regulatory & statutory documents, applicable standards/specifications/building codes:

Project Specification – Irrigation Specifications, Irrigation System, Pipeline Installation

1.2. Definitions

QA Quality Assurance

QC Quality Control

MS Method Statement

PQP Project Quality Plan

HSE Health, Safety & Environment

PMCM Project Management – Construction Management

CSC Construction Supervision Consultant

HDPE High-Density Poly Ethylene

LDPE Low-Density Poly Ethylene

PVC Poly Vinyl Chloride

Psi Pound per Square Inch

ITP Inspection & Test Plan

FDT Field Density Test

MDD Maximum Dry Density

INR Notice of Inspection

RLM Red Line Mark-up

AWWA American Water Works Association

ASTM American Society for Testing and Materials

DIN Deutches Institut fur Normung

BS British Standard

ISO International Standard for Organization

OD Outside Diameter

ID Inside Diameter

PN Nominal Pressure

DN Nominal Pressure

PPE Personal Protective Equipment

Kw KiloWatt

NCR Non-Conformity Report

GPM Gallon Per Minute

LPS Liter Per Second

m/s Meter Per Second

SCH 40/80 Schedule 40/80

1.3. Reference

Contract Specifications
Project Specification-Specification for Irrigation System
Manufacturer’s Installation Instruction Guidelines

1.4. Duties and Responsibilities

Project Manager

• The representative of the management is responsible for the approval and compliance of the participating teams in performing this method statement for irrigation system. It is within his judgment that the executing parties (Construction Team, QA/QC Team & HSE Staff) can attain proper and safe implementation of this method statement.
• He is overall responsible for production quality, program, planning, surveying, testing, safety, and coordination.

Construction Manager

• Responsible for overall construction activities ensuring that all quality and safety procedures are implemented and required approved permits are obtained.

QA/QC Manager

• In charge of all quality assurance and quality control matters of the project.
• Overall responsible to ensure all activities are in compliance with project specifications and approved ITP.
• If any non-compliance he recommends to QA/QC Engineer to initiate internal NCR and coordinate with the construction team to close NCR.

QA/QC Engineer

• Ensure the proper implementation of the quality system and monitor the overall quality of the irrigation work is maintained.
• Conduct inspection and monitor tests.
• Determine and report any non-conformance and recommended corrective actions.
• Ensure that all personnel is aware of the quality requirement.
• Training of relevant personnel.
• Conduct surveillance and inspection duties at various stages to ensure compliance with QA/QC plan.

Site Engineer

• Supervise operations in accordance with the approved method statement for the irrigation systems, shop drawings, project specifications, material submittals, and schedules to achieve the acceptance of the project deliverables.

Site Foreman

• Liaise with the site engineer and supervisor for the work execution.

Site Supervisor

• Supervise closely, the activities designated to them and ensure that all instructions and safety procedures are followed and strictly adhered to.

HSE Manager

• Health, safety, and environmental (HSE) manager generally plan, coordinate and implement issues and directives within the organization.
• Ensure safe environmental working conditions for all employees.

HSE Engineer

• Ensure enforcement of safety procedures in accordance with the approved HSE Plan.
• Closely monitor the site engineer’s strict implementation of the method statement for the irrigation system, the use of proper tools and equipment to maintain safety, certifications of equipment and their adherence to safety regulations, reporting of any unsafe work, or stopping work that does not comply with ES&H procedures.
• Advises the health and safety requirements and monitors the Hazard controls implemented on site as per the method statement irrigation system.

Surveyor

• Obtain all data and information required for surveys.
• Determine methods to establish survey control.
• Use appropriate equipment to complete the assigned task.
• Keep accurate notes and records to describe and certify work performed.

Survey Aide

• Assist Surveyors in taking measurements, record measurements manually or electronically, and peg out boundaries.

Equipment Operator

• The only authorized person to operate any equipment to be used in the project.

Third-Party Laboratory Technician

• Performs the required testing and provides test results to certify that the work is in compliance with the project and contract requirements.

2. Resources

2.1. Plant and Equipment

Telehandler/Boom

Loader

Crane

Flat Bed Trailer

Forklift

Excavator

Tipper Trucks

Backhoe Loader

Boom Truck

Mini Excavator

Skid Steer Loader

Generator Set

Tower Lights

HDPE Pipe Butt Fusion

HDPE Pipe Electrofusion Set

Plate Compactor and/or roller

Survey Instruments

Water Tanker

Pick-up

Scaffolding

Movable Ladder

2.2. Workforce

Project Manager

Construction Manager

QA/QC Engineer

Site Engineer

Surveyor

Survey Aide

Foreman

Equipment Operator

Banksman

Pipe Fitter

Helpers/Laborers

Safety Officer

First Aider

Third-Party Laboratory Technician

2.3. Light Tools

Power Tools and Pipe

Cutters (Drilling machine, machine, hammer, etc.)

Hand Tools (Hack saw, hand shovel, hammer, spanner set, screwdriver set, pliers, file, knife, wrenches, etc.)

Test gasket, spades, blank flanges

Pressure Testing Equipment

Pressure Gauge

FDT Testing Equipment

Nylon Lifting/Slings

Wheel Borrow

Spirit Level

Measuring Tape

String Line

Feeler Gauge

Markers and Masking Tape

2.4. Materials

PVC pipes and fittings ( Solenoid valve, QCV, Air release valve, drain valve assembly locations)

HDPE pipes and fittings

TSE network connection filter and master valve

Solenoid valves

Inline filter on solenoid valve assembly

Geka coupling

Quick Coupling valves

Air /vacuum release valve

Drain Valve

Valve box

Inline drip tube

Online emitter

Drip tube compression fittings

Drip tube stake

Pumping system and accessories (vertical centrifugal pumps, manifolds, isolation valves, non-return valve, pressure gauges, pressure transducers, level sensors, dry run protection, pressure relief valves, pressure vessel)

Automatic self-flushing filter

VFD control system

Electric control panel and accessories

Decoder controller and filed decoder

Irrigation control cables and waterproof wire connector

Power cable for irrigation controller and pumping system

Water Meter

Warning tape

Selected backfill and sand bedding

PVC cement and cleaner

Gasket lubricant

Gate valve

Flange adaptor

S.S. nuts, bolts, and washers

Non-return valve

Ball valve

Concrete

Chamber cover

Level sensor

Pressure sensor

3. Site Planning & Preparation

a. Works shall be carried out under the supervision of the Site Engineer, Safety Officer, and QA/QC Engineer.

b. Work to be carried out in line with the approved Site layout drawing relevant to the area and the required trial pit related to the excavation must be inspected, and verified by the consultant prior to trench excavation.

c. Traffic will be managed by the Site Engineer/ Site Supervisor and the Safety Officer for any re-routing as well as the monitoring of equipment movements on site, transporting foundations, and lifting area.

d. Working area will be protected with plastic jersey barriers, safety signage, and safety tapes. Existing Structures, Utilities, Sidewalks, and Pavements should also be protected.

e. Any MEP or any other underground utilities required clearance shall be obtained prior to starting the activity.

f. Ensure that sufficient tools, materials, and manpower are available before commencing the work.

g. All relevant documentation (approved shop drawings, checklists, method statement irrigation system, material sample for pipes, fittings, and solvent cement/adhesives, etc.,) and materials applicable for the particular section of work will be checked by the Site Engineer/Supervisor prior to commencement of work.

h. The Site Engineer/Supervisor will give necessary instructions to the tradesman and provide the necessary approved shop drawings.

i. Materials shall be delivered in their original, tightly sealed containers or unopened packages, all clearly labeled with the manufacturer’s name, brand name, number, and batch member of the material where appropriate.

j. The material shall be delivered to the site in ample time to avoid delay in the job progress and at such times as to permit proper coordination of various parts.

4. Work Methodology-Method Statement for Irrigation System

4.1. Preliminary Activities and Approvals

a. All necessary work permits (excavation, hot works, cold work permit for pressure test, temporary road closure, etc.) shall be obtained prior to the commencement of works on-site and shall remain valid throughout the entire duration of the operations.

b. Excavation permit to be obtained for each area of excavation.

c. Check for existing utilities before excavations.

d. Road Closure (if applicable).

e. All interfacing activities shall be fully coordinated with the Supervision consultant.

f. Take proper measures to protect the joint from sand, rain, and direct sunlight.

g. CAT scan/trail pit to detect any existing utility services.

h. Material approval

i. Shop drawing approval

j. Approved method statement for irrigation system, checklist, inspection, and test plan.

k. Physical site verification to check all grades and determine that work may safely proceed, staying within the specified material depths.

I. Mockup approval.

m. Labor welfare facilities (shelter, toilet, cool drinking water, first aid, etc.)

4.2. Pre-Construction Activities

a. Calibration of equipment, gauges, etc.

b. Dust control, all existing facilities protection

c. Interface coordination between other disciplines shall be coordinated. Elevations and pipe routings will be determined by utilities and above-ground obstructions. Revised locations and elevations from those indicated as required to suit field conditions shall be submitted for approval.

d. Site warehouse/store room material and equipment shall be stored in separately marked approved warehouse /storeroom/laydown areas. Designated warehouse /storeroom/laydown area should comply with the requirement of proper storage of materials and equipment as per manufacturer/supplier and project specification for materials
/equipment storage.

e. Site management plan and access route-upon receiving approved shop drawing, all excavation routes /locations will be set out, and marked routes plan and access shall be divided by geographical zones. The information will be provided to the construction team for implementation.

f. Coordination with other contractors. The marked-out routes will identify the interface coordination which will be communicated with other contractors on site. The interface coordinator will be responsible for coordinating with other facility contractors. Coordinating with other related activities and other trade disciplines shall be the responsibility of the site engineer.

g. Traffic management-The required diversion routes will be marked on drawings including the required traffic signs.
Communication-Communication on site will be by GSM mobile phones. In case of emergency, announcements will be made through a portable public address system or air horn to evacuate people to designated areas.

h. Safety precautions shall be prepared.

• Checks the protective and safety equipment are ready.
• Personnel protective and safety equipment shall be performed.
• PPE shall be used by the person doing the task.
• Toolbox talks are to be convened and attended by personnel assigned to the job. The work crew will be given instructions on safety works procedures and all risks associated with the task and registered attendance.
• PPE, signage, barricades, safe access, and egress to the work area.
• Safety personnel and the designated responsible person will ensure that the above-mentioned is carried out and any other statutory requirements are compiled before the start of any work.

4.2.1. Material deliveries, handling, storage & preservation

Each pipe, fitting, and special appurtenance for the irrigation system shall be marked with permanent identification which shall include but not necessarily be limited to the following:

(a) Nominal diameter
(b) Name or trademark of the manufacturer
(c) Serial number
(d)Class of pipe, pressure rating in compliance with referenced standards
(e) Date of manufacture
(f) Type of service
(g) Details on fittings such as angle of change and taper

The acceptability of the pipes on delivery to the site will be based on the
results of tests carried out by one or more of the following:

(a) The manufacturer at the place of the manufacturer
(b) The consultant/inspector
(c) The third party on behalf of the consultant.

The consultant/inspector shall be permitted at all reasonable times to visit places of manufacture to witness tests.

Transport, handling, and storage of irrigation pipes and fittings shall be carried out as follows:

(a) In accordance with the manufacturer’s recommendations subject to the approval of the consultant/inspector.
(b) Effective precautions shall be taken to prevent damage to the pipe and fittings.

During transportation

(a) Pipes and fittings shall be well-secured and adequately supported along their length.

(b) Bolsters and binding of approved type shall be used.

(c) Nesting of pipes (placing a smaller pipe inside a larger) may be permitted pipes of certain materials and sizes provided that methods statements demonstrate that effective precautions will be taken to protect all pipe surfaces and coatings from damage.

(d) No pipe shall overhang the end of a vehicle.

(e) Pipes and fittings of plastic materials shall be covered.

Handling shall be carried out as follows:

(a) Pipes should be lifted singly and not handled in bunches.

(b) Pipes shall be handled only by means of:

(i) Approved hooks, of the type having a plate curved to fit the curvature of the inside of the pipe, on ends of sections
(ii) Fabric slings not less than 250 mm wide
(iii) Other methods approved for the pipe used

(c) Use of wire rope, chains, and forklift trucks will not be permitted.

(d) For strings of pipe longer than the standard length precautions shall be taken to avoid curvature and longitudinal stress in excess of allowable limits.

(e) Pipes and fittings of plastic materials

(i) Smaller than 300 mm diameter may be handled manually

(ii) Larger than 300 mm in diameter and greater than 4 meters in length shall be lifted using fabric lifting straps or large diameter rope slings positioned at a quarter of the pipe length from each end.

(iii) There should be enough slack in the slings to stay on the hook. Approximately 600 mm over the pipe

(iv) Steel chains or hooks shall not come into contact with the pipe.

(g) Pipes and fittings shall not be dropped or bumped.

(h) Pipes shall not be dragged over the ground.

(i) If rolled, pipes shall be rolled only over adequate timber bearers to prevent damage.

j) Where necessary, chocks shall be used to prevent lateral movement of pipes.

All pipes, fittings, and materials shall be stored in accordance with the manufacturer’s recommendations and the following:

(a) Pipes shall be stored in the open on a flat level area and raised above the ground on timber bearers so that the lowest point of any pipe or fitting is not less than 150 mm above the ground and shall be protected properly.

(b) timber bearers not less than 200 mm wide and 75 mm thick to be provided at 4 m intervals maximum. Pipe shall be stacked one above the other as follows:

(i) In accordance with the manufacturer’s recommendations but not to a greater number of tiers than the following:
< 600 mm diameter 4 tiers.

(ii) Suitable protective packing shall be placed between tiers to the approval of the consultant/inspector.

(iii) Wrapped pipes shall not be stacked.

(c) Spigot and socket pipes are stacked in such a way that successive pipelayers have sockets protruding at opposite ends of the stack.

(d) With pipes of different sizes and thicknesses stacked separately.

(e) With a maximum height of stacked pipes not exceeding 2 m, or that recommended by the supplier if less than 2 m.

Storage of jointing materials shall be as follows:

(a) Undercover

(b) Rubber ring gaskets shall

(i) be stored in their original packing

(ii) not be exposed to sunlight

(iii) be protected from exposure to greases and oils

(c) Gasket lubricants shall be stored so as to prevent damage to the container.

Pipes and fittings shall be protected in storage to the approval of the consultant by means of an impermeable membrane which shall cover the pipes and separate them from the ground on which they are supported.

The membrane shall be strong and durable in the prevailing climate conditions.

Pipes and fittings shall be subject to visual inspections after off-loading at the site and before Installation.

The following procedures shall be followed for dealing with damaged pipes and fittings:

a. Pipes damaged during transportation handling and storage shall be set aside and the damage brought to the attention of the consultant/inspector.

b. Pipes or fittings that show signs of corrosion or deterioration during storage shall immediately be treated to arrest and prevent the corrosion or deterioration or removed from the site, as the consultant directs.

c. Proposals for repair shall be submitted in writing for the consultant’s approval.

d. No attempt shall be made to repair the damage without the consultant’s approval.

e. If in the consultant’s opinion, the nature of any damage is such that the condition of the pipe has been impaired and cannot be repaired the pipe concerned shall not be incorporated into the works.

f. All rejected pipes shall be immediately removed from the site.

g. Damaged pipe shall be replaced or repaired by the contractor at his expense and such repairs shall be to the approval of the consultant.

Note: Material delivery inspection request is to be raised and to be submitted to the consultant for inspection for every approved irrigation material delivered to the site.

4.2.2. Preservation of Materials

Preservation application shall be basically as per manufacturer recommendation. Any material found without required preservation shall be noted in the inspection report.

The material controller shall arrange with the supplier for the proper preservation application or shall make arrangements for in-house application on a back-chargeable basis. No material shall be stored without proper preservation.

Fittings, flanges and valves, warning tape, flow sensor, disc filter, pump set and accessories, electrical items, controller and accessories, valve boxes, stud bolts, nuts, and washer emitter, shall be stored in a covered warehouse. The identification tag shall be hung on the item/ pallet on which the material is stored.

Flanges stored on wooden pallets, as far as possible, should have their face pointing down, to avoid damage to the flange face and reduce chances of corrosion.

Flange faces shall be protected with purpose-made caps or covers wherever possible.

All pipes shall be segregated according to grade and size when stored. Pipes stacked on wooden blocks shall be in such a way that they are separated from each other horizontally as well as vertically. All pipe ends shall be closed with temporary caps or blinds.

Weekly scheduled visual checks, of the stored items for preservation maintenance, shall be conducted by the store supervisor along with the material inspector. These visits shall be logged in a register maintained at each store.

4.3. Setting Out

a. Surveyor shall establish all control reference points and delineate the centerline of excavation. The width and depth of the excavation shall be marked as indicated in the drawings.

b. Verify all horizontal and vertical site dimensions prior to staking.

c. Stake out the location of all pipework, valves, and other irrigation works.

d. The proposed alignment of the pipeline shall be set out by staking out the locations of manholes, and chambers along the centerline of the carrier pipes.

e. Supervising consultant shall be notified of the setting out in sections of routes as mutually agreed and formally requested for a physical inspection by the submittal of an NOI (Notice of Inspection) which, shall be (accompanied by a drawing marked up with obstructions wherever they exist.

f. The setting out shall be completed once the Supervising Consultant issues his acceptance. To the alignment approve and sign off the accompanying drawings, if any.

g. Ground condition level shall be recorded, inspected, and approved.

h. Before starting work on the irrigation system, the contractor carefully checks all grades to determine that work may safely proceed.

4.4. Trenching and Excavation

a. Trenching will be carried out by mini-excavator and/or manually by hand wherein there are underground services to avoid damage to underground services and will be excavated as per the approved irrigation detailed shop drawing.

b. Irrigation sleeves/ducts under footpaths and roads shall be exposed and verified as well as all services in the adjacent areas.

c. Excavation and backfilling shall be in accordance with detailed drawings:

• Mainline shall be placed at 700mm deep and warning tape at 300mm above the crown of the pipe
• Lateral lines shall be placed at 400mm deep without warning tape above.
• Width of the trench should be as shown in the approved shop drawing.

d. Dune sand bedding layer of a minimum of 50mm is required under the irrigation pipe.

e. Sand surround to a minimum of 100mm around the irrigation pipe is required.

f. During excavation topsoil and subsoil shall, as far as is possible be separated and stored on groundsheets.

g. For the mainline, the trench depth shall be 700mm plus pipe diameter plus 50mm sand bedding. For the lateral pipes, the trench depth shall be 400mm plus pipe diameter plus 50mm sand bedding.

h. The bottom of the excavation shall be surveyed to confirm whether the reached grades are as per the levels indicated on the shop drawing.

i. Before spreading the sand bedding, ensure that the trench bases shall be level and free of sharp, irregularly shaped objects and debris.

j. Bedding for pipes shall be constructed by spreading and compacting sand bedding material over the whole width of the pipe trench. After the pipes have been laid, additional material shall, if required, be placed and compacted equally on each side of the pipe, and where practicable, this shall be done in sequence with the removal of the trench supports.

Joint holes can be excavated in the bedding but under no circumstances must the bedding be excavated at any other point along the length of the pipe barrel without written permission from an engineer.

k. Any pipe found “bridging” at any point will be removed and the bedding made complete and re-complete to the correct level.

I. Excess spoil shall be removed to an agreed on-site storage area as work progress.

4.5. Sleeves and Duct Installation

a. When appropriate (asphalt crossing ducts), the excavation for the road crossing and laying of ducts, concreting, and related work shall only be carried out on half the width of the road at one time, the other half being left available for traffic.

In this case, necessary warning signs on self-supporting tripods or cones shall be provided well ahead of the duct crossing works and all care and attention exercised to avoid the risk of accidents during the preparation and execution of the works.

b. Setting out, the excavation shall be carried out as per the above-mentioned method (setting out and trench excavation and bedding)

c. Prior to installation of sleeves/ducts the trench preparation shall be checked for the required elevation, and slope, and free from rock, stones, and other deleterious materials.

d. The sleeve shall be inspected for the size required as per the approved drawing and also for distortion, damages, etc.

e. Ensure all the control measures stated in the corresponding risk assessment are adhered to when carrying out the job.

f. Road crossing duct shall have a minimum of 150 mm diameter.

g. All dual systems shall be installed so that no undue strain is placed on cables when pulled in. The cable manufacturer’s recommendation shall be followed.

h. Duct runs crossing the roads shall be straight and wherever possible perpendicular to the axis of the road. Road crossing duct shall be extended beyond the road or shoulder line at each side of the road.

i. For all carriageway road crossing and for heavy vehicle traffic, the ducts shall be completely surrounded with concrete of grade C20 SRC concrete/as per project specification. The minimum concrete cover around the sleeve/duct shall be 100mm.

j. Duct shall be laid so as to drain naturally towards one or both ends, where adequate provision for drainage shall be made. Adequate precaution shall be taken to prevent the cable duct system from acting as a stormwater or groundwater drainage system.

k. Spare sleeves shall be laid as per project specification and engineer’s requirement.

I. To prevent the earth from blocking the ducts, the openings at both ends are to be protected with appropriate blanking caps.

m. A steel draw wire or nylon or polypropylene cord shall be inserted in each duct run immediately after its installation. A two-meter surplus length shall be left at each end of each run, neatly coiled and attached to the crossbar preventing the wire or cord from being drawn into the duct.

4.6. Installation of HDPE Irrigation Main Lines

a. Excavate trench for the mainline having a 700 mm cover min. (top of the pipe to the finished level) and having a width based on the pipe size.

b. Trench shall be clean and free from unwanted materials.

c. Spread the sand bedding in the trench 50 mm from the compacted subgrade/formation level.

d. Lay the mainline pipe along the center of the trench leaving the joints exposed.

e. Pipes shall be laid to line and grade shown on the drawings.

f. Spread the sand surrounding the pipe, according to the project specification and shop drawings.

g. On top of the sand surround, backfilling shall be done layer by layer not exceeding 250 mm unconsolidated thickness compacted to 95% MDD.

h. Please see Figure 1 below for the typical section of laying of the HDPE main pipeline.

4.7. HDPE Pipe Fusion Welding

Jointing Procedure
HDPE pipes shall be joined by Butt fusion/ Electro Fusion methods following manufacturer procedures. Pipe joining shall only be carried out by vendor-trained and certified personnel.

4.7.1. Butt Fusion Method

The most widely used method for joining individual lengths of large-diameter polyethylene pipe is by heat fusion of the pipe butt end .as shown in the figure. This technique precluded the need for specially modified pipe ends or couplings to produce a permanent and economical and flow-efficient connection.

Field-site butt fusion may be made readily by trained operators using developed butt fusion machines that secure and precisely align the pipe ends for the fusion process.

4.7.2 Electro Fusion Welding Method

Electrofusion welding works shall be carried out according to the polyethylene pipes & fittings technical catalog prepared in accordance with DVS 2207 (Internal standard) and the manufacturer’s recommendation.

This technique permits the joining, of pre-assembled pipes, to be carried out with minimum equipment.
The electro-fusion welding process involves the use of fitting. This basically an outer sleeve which the two pipe ends slide into. An internal stop prevents the pipe ends from meeting.

4.8. Hydrostatic Testing of Main Pipe Lines

a. Hydrostatic testing will follow the manufacturer-recommended procedure for the HDPE pipeline hydrostatic test/as per project specification, Type 1 Creep Test shall be used for HDPE pipes.

b. The section of the main pipeline to be tested shall be filled with TSE water and all air expelled. After the pipeline has been completely filled, the pressure shall be steadily and gradually increased until the specified test pressure has been reached. A pressure test shall be made at 150 % of working pressure at the point of the test, but not less than 125% of normal working pressure at the highest elevation.

No pressure drop for 4 hours at a pressure test of 1.5 times the maximum working pressure of 9 bars without exceeding the pressure rating of the piping system. All testing shall comply with AWWA M23-80, Polyvinyl Chloride Pipe Design, and Installation. Testing shall comply with AWWA specifications and requirements.

The disposal of the used water in hydro testing & water flushing should be carried out in the appropriate manner and subject to the approval of the engineer.

c. Instrumentation Calibration: Instruments shall be calibrated within six months from the date of calibration by the performing calibration and testing agency.

d. Calibration certificate for meter, gauge, fitting, specialty, and accessory meters used for the testing procedure according to manufacturer’s written instructions to be attached.

4.9. Mainline Flushing

On completion of the system hydrostatic test, the system is to be thoroughly flushed, the velocity of water being at least lm/s. Should the main water supply be unavailable or inadequate for this purpose at the time of flushing, then a swab of adequate size shall be used to remove all foreign matter from the pipeline.

This process shall continue until the pipeline is completely clean. Each control valve shall be opened separately and the terminal systems also be thoroughly flushed.

4.10. Installation of Conduits and Control Cables

a. UPVC Conduit pipe will be laid in a straight line along with the irrigation main lines above the crown of the pipes.

b. Pull box to be provided for every 50m to 100m straight line of the pipe or each bend/change in direction to facilitate easy cable pulling.

c. The solvent cement is to be applied to clean, dry surfaces in sufficient quantities to ensure bonding.

d. Long sweep elbows are to be used at bends.

e. Pull wire shall be installed in the conduit.

f. During the installation, the cable drums turning or rolling will be slowed down or stopped by wooden friction brakes so as to prevent the turns of the drum from becoming loose and scrapping on the floor.

g. Splicing using 3M wire connector: Firmly grasp wires, making sure installation ends are even and tightly bundled. (Wires may be twisted or untwisted). Lead stranded wires slightly. Slip the connector over the wire tips. Turn the connector onto wires in a clockwise direction until secure

h. Signal cable shall be installed in such a manner that ensures that it is not stretched /scraped/damaged/laid down under tension.

i. All cable joints will be made ensuring that at least one meter of cable is slack.

j. All cable joints shall be housed in a chamber/pull box.

k. All the wire connections/splices shall be waterproof.

I. Cables inside the conduit shall be loose for easy installation, operation, and maintenance.

m. Cable shall be laid to a minimum depth of 600mm in mainline trench lines and 400mm in lateral trench lines (where required, and where possible)

n. The signal cable does not lie directly adjacent to any 240V/415V power cable or another communication cable.

o. Crossing of signal cable at right angles should be avoided wherever possible. However if necessary, cables should clear each other by approximately 100mm and maintain minimum cover.

p. Signal cable shall be tested during the installation to ensure that there is no earth leakage and that continuity is present.

q. All power supply cables shall be steel wire armored and where necessary shield cables or ducts will be provided.

r. All electrical supply works carried out to local bylaw acceptance and shall conform to state /local safety directives, including voltage drop and test certificates.

4.11. Installation of Irrigation Controller, Earthing, and Surge Protection

a. Control equipment shall be installed exactly as per manufacturer specification.

b. Controller shall be secured to a concrete pad with approved anchor bolts. Chipping, cracking, or otherwise marring the finish of the enclosure when securing the concrete pad shall be avoided.

c. Earthing and surge protection shall be included as per manufacturer recommendation.

d. All electrical works from the power supply to the distribution point shall be carried out inclusive of necessary cables and switch fuses -all to IEE regulations.

e. Programming of Irrigation Controller: Using the controller schedule provided on the drawings, as a guide, the irrigation controller shall be programmed to correspond with the initial irrigation sequencing and duration of the cycles for each zone.

f. Irrigation schedule has to be modified to achieve a correct irrigation regime during establishment and maintenance in accordance with good horticultural practice, such modification shall be approved by the engineer.

g. Drilling of earth boreholes.

Place a ground rod in the drilled hole. Copper-bonded rods will be conjoined with threaded couplings as necessary to reach the required depth.

After the rods have been driven to the correct levels, connect the earthing rod using bolted and clamp-type connectors, and interconnection will be done as per approved drawings. Take a measurement of the earth resistance value with the drill submerged in the drilled hole.

After all the connections have been completed, backfill until the test level. Perform tightness tests for all connections.

Surge protection will be mounted to the Irrigation controller as per the manufacturer’s recommendation.

4.12. Irrigation Pumping Station

The pumping station manifold shall be skid mounted. It shall feature multistage centrifugal pumps.

All necessary ancillary equipment (nonreturn valves, isolation valve, pressure relief valve, pressure vessel, pressure gauges, pressure transducers, dry run protection, etc.) shall be included in order to ensure the correct operation of the pumping station shall be provided.

All necessary hoisting and offloading points shall be included on the pump station skid.

Suction shall be from a dedicated water storage tank.

Will liaise with the GRP tank manufacturer regarding the suction pipe works arrangement and follow all materials to facilitate complete and proper installation.

The delivery manifold shall include a water meter and self-flushing automatic filter the emitter/inline drip system required filtration size. An automatic filter water meter shall be installed according to the manufacturer’s recommendation.

The manifold shall be manufactured in 316-grade stainless steel or approved equal.

A butterfly isolation valve shall be incorporated on both the suction and discharge manifold to enable isolation from the water supply /feed into the irrigation mainline.

A pressure relief valve shall be installed on the discharge line with pipe works back to the water storage tank to release the excess pressure above the operating pressure.

The pump arrangement shall be managed by a variable frequency drive which shall maintain a constant pressure at a variable flow rate.

To install the pump station/assembly underground/basement, if necessary, it shall be dismantled and reassembled to effect full installation.

Will make provision to liaise with the main contractor undertaking the pump room fit-out regarding ingress/egress/ducting/ ventilation/drainage and installation of the tank.

Installation

Examine the condition of substrates and areas to receive irrigation pumps and manifolds for compliance with the requirements for installation tolerance and other conditions affecting the performance of all plumbing equipment.

Examine rough-in for piping systems to verify actual locations of piping connections before pump installations.

Check and verify the actual site condition before proceeding with the installations.

Prepare all the tools and equipment that will be required during the installation process.

The connection of the pipe must be carried out with utmost care; otherwise, the pumping medium can escape during operation, which can seriously endanger the operating personnel.

In a new installation, great care should be taken to prevent dirt, scale, welding beads, and other items from entering the pump. The suction system should be thoroughly flushed before installing the suction strainer and suction piping.

Suction and discharge piping should be of ample size and be installed in direct runs with minimum bends.

Short-radius elbows shall be avoided near the suction nozzle. If an elbow is necessary, it should be of the long radius type.

Suction and discharge piping configuration should be in accordance with the manufacturer’s recommendation.

Suction and discharge piping, fittings, and valves must be adequately supported and anchored close to the pump flanges to eliminate strains imposed on the pump casing, prevent excessive nozzle loads, maintain pump/driver alignment, and avoid pipe-induced vibration.

Check whether the piping is loosely laid so that no strain is placed on the pump.

Piping layout and installation shall provide adequate maintenance and operation accessibility.

Filed installed auxiliary equipment shall not interfere with the removal of the machine or driver.

Remove the covers of the pump flanges. Check whether the seals are correctly mounted.

Install a check valve and isolation valve in the discharged pipe. When the pump is stopped, the check valve will protect the pump against excessive back-flow pressure and will prevent the pump from running backward.

The check valve should be installed between the isolation valve and the discharge flange in order to permit its inspection.

A spool piece should be installed in the suction line so that the suction strainer may be installed and removed with a pressure gauge between the strainer and pump.

Pump and pipe flanges must be parallel; they should mate together without effort, and with the bolt holes properly in line.

Make sure that there are isolation block valves at the pump of each type of auxiliary piping.

Considering a slope in the suction piping to avoid high points.

In horizontal suction, line reducers should be eccentric (with the flat side of the reducer on top).

No obstruction within at least five pipe diameters of the suction should be fitted.

Do not install unsupported piping on the pump.

Make sure electrical connections do not impose any stress on the pump unit.

4.13. Water Storage Tank

GRP sectional water storage tank (please see example photo below) will be constructed according to the manufacturer’s recommendation with a dimension of 10m x 7m x 2m high as per the approved shop drawing with a minimum inflow of 14m³/hr.

Before the installation of the GRP water tank, the concrete plinth should be completed first.

a. Skid Base

Once the construction of the concrete plinth is completed, the skid base needs to be installed or placed on top of the concrete plinth. The skid base is made up of two elements; that is the main beams and the sub-beams. The main beam is made of I-beams or C-channels and the sub-beams are made of equal angles and C-channels.

The main beams are placed across the top of the RC plinth 1002mm from center to center. The sub-beams are placed across the main beams 1002mm from center to center. They are bolted to the main beams. The skid base must be tightened using HDG bolts & nuts.

The skid base should be leveled.

The top surfaces of the main and sub-beams should be flush.

The skid base should not be twisted and the deviation between diagonals should be as small as possible.

b. Base Panel

Arrange the Base Panel according to the drawing of “General Arrangement for Panel Type and Drill Code” which is provided with every tank shipment.

Place corner patch (Foam Sealant) at all four- (4) corners of each panel.

Then put a strip of Foam Sealant in between each panel.

Then place M10 x 45 bolts & nuts to join the panels to each other.

Repeat this process until all Base Panels have been joined.

Corner patch (Foam Sealant) at all 4 corners of each panel.

c. Wall Panel

Proceed with the installation of wall panels. Arrange the wall panels according to the drawing of “General Arrangement for Panel Type and Drill Code”. All the wall panels are hoisted onto the structure and installed on the structure.

Corner patches are placed at all angles of each panel.

Strip with foam sealant is then placed between each panel (horizontal and vertical).

For horizontal flanges of the wall panels, they have to be joined together with M10 x 45 bolts & nuts and frame angle.

For vertical flanges, the panels are joined together by using frame angle at the joints and M10 x 45 bolts and nuts to tighten.

After installing all four sides of the wall panels, one part column of the wall panel must not be erected. This portion is for access purposes, i.e. to install accessories, roof supports, and roof panels, and to prevent damages to the other panels.

d. Roof Panel

Arrange the roof panel and manhole cover according to the drawing of “General Arrangement for Panel Type and Drill Code”.

Then put a strip of foam sealant between each panel.

Connect the roof panel and the top side of the wall panel using HDG.

e. Finishing

Installing tie rods/HDG external reinforcement-Refer to tie rod arrangement/external reinforcement drawing provided with the tank shipment.

Close up the access (same as the wall panel process).

The water level indicator is connected to the bolt of the top tier and the bottom tier of the wall panel. Drill one no. of 12mm holes for the nylon string to be laid. The nylon string is to be tied to a float ball and indicator pointer.

The internal ladder is to be installed exactly at the access manhole and the top of the ladder is to be tied together with the HDG bracket at the roof panel. The bottom parts of the ladder use stainless steel brackets and tighten them with stainless steel bolts and nuts.

To Install the external ladder, drill two nos of 12mm holes at the top of the wall panel and align them with the access manhole. Then tighten the ladder using HDG bolts and nuts. The bottom parts of the ladder use HDG brackets and tighten them together to the bottom tier panel.

For pipe connection, the hole location is to be marked (by others); a Hand drill or hole saw (for small bore) and jigsaw (for large bore) are to be used to drill the hole according to the markings. It is recommended to drill the panel from both sides in order to ensure smooth edges.

4.14. Trench Backfilling

a. Once mainline levels are satisfactory, sand surround will be spread and compacted lightly using hand tampers on both sides of the pipes and 150mm above the pipe.

b. Backfilling shall not be commenced until Installation of the pipeline/duct/ cable conduit and associated pipe joints have been carried out.

c. Backfilling shall not be commenced until the parts of the works to be covered have achieved strength sufficient to withstand all loading imposed thereon.

d. Backfilling shall not be commenced until successful pipeline pressure testing shall be conducted.

e. For backfilling, selected backfill material shall be used above the pipes. The backfill shall be with a suitable friable material, free of large stones and sharp objects.

f. Selected backfilling material shall be used to backfill the trench. Backfilling material shall be deposited by 250mm thick layers and compacted with a compactor (manual/mechanical) as per site condition. Compaction shall be 90% MDD as per project specifications.

4.15. Installation of Warning Tapes

a. Trench marker tape/warning tape shall be laid 300mm above the mainline pipe.

b. The tape shall be laid continuously over pipelines and at joints and there shall be a minimum of one-meter overlapping.

c. Tape shall be terminated inside valve boxes to allow clipping of detector equipment to the tape.

4.16. Installation of HDPE Irrigation Lateral Lines

a. Excavate trench for the lateral lines having a minimum of 400mm cover (top of the pipe to the topsoil) and having a width based on the pipe size.

b. Trench shall be clean and free from unwanted materials.

c. Spread the sand bedding in the trench minimum of 50mm from the compacted subgrade/formation level as per project specification and approved shop drawing.

d. Lay the lateral line pipe along the center of the trench leaving the joints exposed.

e. Pipes shall be laid to line and grade shown on the drawings.

g. Spread the sand surround to a minimum of 100mm around the pipe, according to project specification and approved shop drawing.

h. Lateral lines with diameters of less than 90mm will be jointed by compression fittings as stipulated in the Project Specification.

i. On top of the sand surround, backfilling shall be done layer by layer not exceeding 250 mm, unconsolidated thickness up to the finished level for hardscape areas.

k. Under the soft landscape area, the backfill material shall be soil planting mix and it shall be water compacted.

l. All necessary wall/planter/paving penetration shall be identified and shall be ducted.

m. Pipeline installed within paving areas (between slab/paving etc.) must be ducted in position.

4.17. Valves Installation and Valve Chambers
4.17.1. General

a. Valves will be installed in positions at the location shown on the drawings, as per the manufacturer’s recommendations.

b. All remote control valves, manually-operated gate valves, quick coupling valves, air release valves, and flush valves shall be tagged and identified. All identifying numbers shall be consistent with like designations indicated on the irrigation controller schedule.

c. Valves shall be assembled neatly and installed so that they are accessible by hand to carry out maintenance.

d. TSE network tie-in connection points with necessary filtration and connection point master valve shall be provided.

e. Test and flush each line prior to valve installation.

f. All valves shall be checked for defects or damage.

g. All valves shall be thoroughly cleaned internally immediately prior to installation and all ends shall be kept closed with protective coverings when the valve is not being worked upon.

h. All installations should be neat and tidy.

4.17.2. Remote Control Valves

a. Solenoid Valves shall be incorporated into an irrigation chamber.

b. Valves shall be installed in one chamber or as indicated in the approved shop drawing. Chambers shall be installed at a suitable location away and not in the way of either pedestrians or maintenance machinery.

c. The solenoid valve shall not be installed within 40mm of the top of the valve chamber; all products in the chamber shall be easily accessed and a mock-up shall be provided for approval before installation.

4.17.3. Isolation Valve

a. Isolation Valves should be protected from damage during transportation, loading, and handling.

b. Lifting by means of any lifting device should only be done using the flange holes, lifting eyes, or appropriate straps. Never suspend the valve in a handwheel, gearbox, or actuator.

c. Before installation, a visual check must be performed. Special attention should be paid to checking the system, valve seat area, flanges, and coating. Look for defects, bent or out-of-place parts, dents, scratches, and other damages. Actions should be taken to repair or replace the valves if any defects are detected.

d. Bolts must be tightened in a criss/cross pattern. Actions should be taken to ensure even pressure on the gasket surface.

e. All valves shall be installed within appropriate irrigation chambers and c/w Denso tape coating or equal corrosion inhibitor. All flanges shall be stainless steel 316 grade.

4.17.4. Valve Boxes

a. All valve boxes shall be installed as detailed and where indicated on drawings. All valves and valve assembly shall be set parallel with the grade and as detailed in a neat and orderly fashion.

b. Shall be placed parallel to paving, kerbstone, walls, or similar structures and where more than one box, is parallel to each other.

b. All valve boxes will be installed with concrete blocks preventing the load of the chamber and associated traffic from touching the pipelines.

c. All chambers will have a textile membrane installed at the chamber base with 50mm pea gravel.

d. Signal cable will be clipped to the chamber to prevent obstruction of the products within the chamber.

e. Chambers shall be corrosion-resistant and supplied with a lockable cover.

f. Be suitably sized to enable easy access to all equipment and allow a minimum of 40mm clearance of the valve chamber lid above the manual watering point.

g. Valve lids shall be lockable and vandal resistant and marked nonpotable.

h. Where installed in hard paving, the chamber lid/chamber shall be a specialist product that enables the paving stone/slab to be inset.

4.17.5. Quick Coupling Valve

a. Quick coupling valve size shall be 1″.

b. Each valve shall include an isolation valve within the assembly.

c. QCV shall be firmly fixed to the riser pipe with a 100mm thick concrete base.

d. Round valve box shall be installed on the concrete base.

e. Valve assembly shall be easily accessible for operation and maintenance.

f. Swivel, key, and garden hose shall be provided for every 8 nos. of QCV installation.

4.17.6. Air Release Valve

a. Air valve shall be installed at the highest point of installation.

b. Valve shall be 2″

c. Each valve shall include an isolation valve within the assembly.

d. Valve assembly shall be easily accessible for operation and maintenance

4.17.7. Drain Valve-Mainline

a. Drain valve shall be 2″ in size.

b. Pipe shall be extended approximately 8 meters beyond the valve chamber to into a suitable drainage material/flooding will not be experienced.

c. Drain valve shall be installed on the lowest point of mainline installation to facilitate the gravity draining.

4.18. Installation of Driplines

a. Drip line shall be installed as per the manufacturer’s recommendations with regards to bank/angle & slope with regular flushing during the installation to remove debris.

b. Run length shall not exceed the maximum stated by the manufacturer.

c. An end crimp shall be fitted where necessary to close each end of the line.

d. Drip line shall be held in place by stakes at approximately 1.0 meter intervals, generally as per manufacturer’s instruction.

e. Drip line shall be tested visibly prior to mulching to ensure satisfactory operation.

f. All necessary wall/planter/paving penetration shall be identified and shall be ducted.

g. For the trees and palms, an online emitter, shall be installed as per the approved shop drawing.

h. All the emitters shall be installed on the PE distribution tube with the help of a drip punch. All the emitters’ locations and quantities are carefully selected based on the actual plant location.

i. Pressure compensating non-leakage dripline shall be provided for areas of ground cover shrubs.

j. The dripline emitters are pressure compensating, on leakage, and self-cleaning in operation spaced at approximately 30cm intervals at a flow each of approximately 2.3 liters per hour at 1.5 – 2.0 bar pressure.

k. Row spacing will be even and not exceed emitter spacing.

I. Drip lines shall be carefully uncoiled and laid in position without kinking. Any kinked section shall be cut from the line and subsequently re-joined with a line joiner section.

m. Drip lines shall be snaked as required for maximum coverage without the use of compression fittings. Sharp bends shall be avoided where there is a likelihood of causing kinks in the line.

n. Drip pipelines shall be installed on the ground as approved detail drawing & approved shop drawing.

o. Driplines shall be jointed by compression fittings as approved in the material submittal.

p. Drip stakes shall be provided at each point of change in direction of the drip line and spacing between drip stakes shall be not more than 10 meters.

q. Dripline installation includes all air valves and flush end caps for cleaning purposes.

4.19. Tie-in Connection into Primary TSE Network

a. The site-wide TSE network shall provide a minimum flow of 9m³/hr at 4.0 bar pressure to each one of the indicated and required connection points with a minimum of 3 No. connection points operating at any one time.

b. Necessary filtration (automatic self-flushing filtration) and connection point master valve control shall be provided in a chamber at each point provided.

5. Pre-Start Safety Briefing Arrangements

Refer to Risk Assessment in Appendix B.

5.1. Protective and Safety Equipment

All workers involved shall be equipped with adequate PPE as stated below:
a. Safety Helmet with Company Logo
b. Safety Boots
c. High Visibility Vest
d. Safety Goggles
e. Hand Gloves
f. Coveralls

5.2. Information to Personnel

a. Safety Induction
b. Job training
c. Superintendents Notices/Memos
d. Toolbox talks
e. START Card

1. Risk Assessment
   Please refer to the attached document in Appendix B.
2. Permit and Licensing Requirements
   Refer to Appendix C for the Permit to Work.
3. Drawings, Diagrams, Maps, and Survey Data
   Refer to approved Shop Drawings.

5.3. Special Safety Requirements for Method Statement of Irrigation System

a. All necessary personal/protective equipment (PPE), as well as harness, be provided.

b. Banksman, wearing distinctive vests, shall be assigned to help operators maneuver their equipment.

c. The equipment operators shall possess the required licenses and certificates.

d. Generated dust shall be controlled by periodic water spraying.

e. The project safety officer is responsible along with the project zone site engineer for ensuring that all operations are carried out with due regard to the safety of all project personnel & property.

f. All working activity shall comply with client safety procedures.

g. First aid material.

h. General management of protection/operation hazards is to be observed.

6. Environment and Quality Issues

6.1. Precautionary Measure

All precautionary measures shall be briefed to all workers prior to commencing the activity.

6.2. Disposal Requirements

All waste shall be disposed of as per the Construction and Environmental Management Plan, and as per government-approved disposal areas.

7. Inspection, Test, and Sampling-Irrigation System Method Statement

Request for Inspection and Testing will be submitted prior to and after the execution of irrigation works.

8. Quality Assurance Requirements Table

Ensure that work is executed as per the approved shop drawing, and work method statement for the irrigation system and that records are generated referring to approved ITP.

Best management practices shall also be considered which may be stated by the product manufacturer or suppliers.

Authority requirements will take precedence over all requirements in case authority approval is to be secured. For non-authority approval activities, the approved latest project specification will take precedence.

It is to ensure that regular toolbox training related to work quality is conducted and records are maintained.