Method Statement for Installation Irrigation System .
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Method Statement for Installation Irrigation System .

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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.

 See risk assessment template for installation irrigation system.

See Checklist Template for Installation Irrigation System. 

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