A. Contractor shall study all drawings and specifications and familiarise with the structural and architectural details and the work of other trades.
B. Contractor shall ensure that the work under this section will not interfere with those of other trades and are compatible with the surrounding finishes; prior to placing orders, fabrication and installation.
C. Contractor shall co-ordinate with the electrical trade for the exact power requirements and the location and type of interface(s). Information as required by MEW for obtaining approvals shall be furnished.
D. Necessary templates, patterns, setting out plans and other items shall be furnished to relevant trades for incorporation or leaving necessary provisions in the work.
E. Conflicts in requirements with other trades shall be resolved by the Contractor. Only those which cannot be solved, without changes to structure or those which involves major changes to system design shall be referred to the Engineer.
F. Acceptability of sizes and locations of the points of connection (POC) shall be checked and confirmed to the plumbing trade.
G. Piping layout and the installation of the irrigation heads shall be co-ordinated with the planting plans; accomplishing changes / modification necessary to attain a harmonious installation.
3.02 PIPING INSTALLATION - GENERAL
A. Piping shall be routed in an orderly manner, maintaining gradient.
B. Factory manufactured fittings shall be used where changes in pipe direction occur. Bending or forming of rigid piping shall not be permitted (flexible polyethylene lines for drip system excluded).
C. During progress of work, the ends of piping shall be kept closed with factory manufactured plugs to prevent the entry of foreign matter.
LANDSCAPE IRRIGATION SYSTEM 02810-10 Project No.: KW.11.0209 11 March 2013
D. Piping, control valves, quick coupling valves and other system components shall be installed within the planting bed, unless otherwise noted or directed by the Engineer.
E. Threaded pipe fittings shall be assembled using Teflon thread sealing tapes.
F. Piping trenches shall be wide enough to allow a minimum of 100 mm (4 inch) between parallel pipe lines. The depth of the same shall be to provide a minimum cover from finished grade as follows:
1. Pressurised supply lines ... 450 mm (18 inch) 2. Non-pressurised distribution lines ... 300 mm (12 inch) G. Piping shall not be installed one over the other, in the same trench.
H. Trenches shall be back-filled with clear agricultural soil and manually compacted, to a dry density equal to that of the adjoining soil, to the adjoining finished grade. If settlement occurs after completion of the work, necessary adjustments shall be made to piping and the system components, as directed by the Engineer. I. Schedule 40 galvanized steel sleeves / UPVC duct shall be used for irrigation piping crossing roads and
similar areas subjected to traffic loading.
3.03 PIPING INSTALLATION - PARTICULAR FOR UPVC PIPING
A. Only approved (recommended by the piping manufacturer) solvent cement shall be used for making the joints.
B. Solvent joints shall not be made in humid or dusty atmosphere.
C. Prior to making the joint, the required penetration and fitting alignment shall be marked in a clearly visible manner on the pipe end, for later verification.
D. Pipelines shall be filled only after allowing a minimum period of twenty-four (24) hours from the time of making the joint.
3.04 VALVES
A. Valves shall be same size as pipeline, except where shown otherwise on the contract drawings. B. Valves with flanged ends shall be used in valve pits, irrespective of size.
C. Valves shall be installed with stem upright or horizontal, not inverted; except with written permission of the Engineer for each location.
D. Ball / gate valves shall be used for shutoff and to isolate equipment, part of systems or risers.
E. Appropriate valve gland packing, sealing and gasket materials shall be selected for the temperature, pressure and chemical properties of the water encountered.
3.05 ELECTRICAL CABLING - PARTICULAR REQUIREMENTS
A. Low voltage cables shall be installed in the same trench as the pressure supply lines or in a separate trench as approved by the Engineer.
B. When more than one cable is placed in a trench, these shall be bound together with dead locking type plastic cable ties at intervals not exceeding 1,000 mm (40 inch).
C. 300 mm (12 inch) of extra length of cable shall be provided at each termination.
D. Continuous single length of cable shall be used between controller and the control valves. Where splices are essential (generally not permitted), the same shall be executed only after obtaining written approval of the Engineer, providing a valve box with identification at the splice. Connector housing shall be filled with jelly (sealant) after connections are made.
E. Grounding wires for the controllers / control valves shall be coloured green / green and yellow.
F. Crimped on brass terminal lugs shall be used for termination of cables and terminals shall be numbered with slip-on ferrules for quick identification.
G. Cables shall be sized such that the voltage available at the valve shall be within 24 ± 2 volts. 3.06 AUTOMATIC CONTROLLERS
LANDSCAPE IRRIGATION SYSTEM 02810-11 Project No.: KW.11.0209 11 March 2013
A. Internal transformer shall be selected to suit the local system power supply parameters and to furnish the power supply at the control valve at 24 ± 2 volts.
B. Two (2) nos. keys shall be furnished for each of the controllers along with an identification tag, registered with the suppliers.
C. Power supply to the controller shall be obtained from the standby power supply system, where possible. 3.07 IRRIGATION HEADS
A. Irrigation heads shall be located and adjusted to minimise splash of water on non-planted areas.
B. Spacing recommended by the manufacturer shall not be exceeded, in respect of irrigation heads, under any circumstance.
C. Turf sprinkler and rotor heads shall be set to finished grade.
D. Schedules and details on drawings shall be referred to for the installation details of other types of heads. E. Irrigation heads shall be installed on branches with offsets, swing joints etc. even if they are not specifically
indicated in the drawings.
F. Approved type spikes or similar rigid supports shall be provided for all irrigation heads.
G. Irrigation heads shall not be installed, until after the complete piping system has been thoroughly flushed. 3.08 VALVE BOXES
A. Co-ordinated valve identification schedule shall be submitted for the approval of the Engineer. The approved schedule shall be used for locating the control stations in the as-built drawings.
B. Approved, identification codes shall be painted on the valve boxes in 50 mm (2 inch) high lettering with white, resin based epoxy paint.
3.09 INSPECTION, TESTS AND ADJUSTMENTS
A. During the manufacture (at Contractor's premises only), installation and after completion of works; the system, sections of the system or its components shall be tested by the Contractor / specialist Subcontractor in the presence of the Engineer, as directed below or else where. Contractor shall procure all testing instruments and accessories and bear all costs in connection with the same.
1. Basic materials for conformity with the specified standards
2. Controller for start, operating period and cut off; tolerances, alarms etc. 3. Control valves for water tightness; cut-in and cut-out; pressure and flow 4. Electrical wiring for continuity and dielectric resistance
B. Following shall be balanced and regulated, prior to start of planting: 1. Irrigation program - flow matched with the source capacity 2. Control valve discharge pressure
3. Irrigation heads throw and direction 3.10 TESTING OF SUPPLY PIPING
A. Irrigation water supply piping starting from the main isolating valve up to the control valve, shall be pressure tested by this section.
B. Piping shall be filled with clean water, leaving all high points open to allow purging of air.
C. System shall be pressurised using manual pumps in increments of 25 % of the test pressure. A standing period of 10 minutes shall be allowed after each pressure increment. Pressure testing using motor driven pumps will not be permitted.
D. System shall not be over-pressurised under any circumstance. If the test pressure is close to the maximum permissible working pressure of any of the system components, calibrated pressure relief valves shall be installed in the tested circuit.
LANDSCAPE IRRIGATION SYSTEM 02810-12 Project No.: KW.11.0209 11 March 2013
E. Piping system shall be tested with water at a pressure of 1,034 kPa (150 psig) for a minimum period of 4 hours. Circuit temperature shall be recorded along with the pressure readings and pressure fluctuations due to temperature variations allowed for in computations.
F. Joints shall be checked for leaks by swabbing with a dry tissue. Drop in pressure to the order of 10 kPa (1.5 psig) per hour shall be considered as acceptable.
G. Leakage through the seat shall be considered as reasonable grounds for rejecting the control value. 3.11 TESTING OF DISTRIBUTION PIPING
A. Because of the limitations in conducting a pressure test on the piping system, this requirement is waived; but the piping shall be tested for line and gradient.
B. Integrity of the pipe joints, in respect of pressure tightness, shall be subject to scrutiny and piping with leaking joints shall be repaired / replaced.
3.12 SYSTEM FLUSHING
A. On completion of the piping, but prior to the installation of the heads, the complete system shall be thoroughly flushed to remove all debris.
3.13 IRRIGATION SYSTEM PROGRAMMING
A. Plant watering shall preferably be done before sunrise and after late in the evening to facilitate the optimum use of the landscaped areas. This restriction shall not be applicable to systems which do not have surface sprays and which are watering areas not used for sitting.
B. Alternate programs shall be furnished for summer and winter so as to economise the water use without sacrificing the basic intent.
3.14 SYSTEM DEMONSTRATIONS
A. Services of a competent engineer shall be provided by the Contractor to supervise the commissioning of all equipment and to train the Owner's personnel in all aspects of the same during a five (5) working days period, during normal working hours. All expenses in connection with the above shall be allowed for by the Contractor.
B. System demonstrations shall be conducted only after the substantial completion of the project. A minimum of one week's written notice shall be given and the Owner's written consent obtained, prior to such demonstrations.
3.15 GUARANTEE (Defect Liability) AND MAINTENANCE
A. Requirements of the General Conditions of Contract shall be referred to and complied with as appropriate. END OF SECTION