METHOD STATEMENT FOR IRRIGATION WORKS CHAPTER 3 l HOW TO DO IRRIGATION WORKS l IRRIGATION COMPANIES IN DUBAI
PRESSURE TEST
Prior to pressure test, the pits will be backfilled exposing only the joints for inspection. Only sufficient material to prevent pipe movement will be backfilled over the pipe prior to testing. The pipes will be brought to operating temperatures before the pressure test. A pressure test will be carried out as per project specification. Testing will not be carried out against closed valves. The pipe will be charged slowly from the lowest point with air cocks in open position. They will be closed in sequence from the lowest point only when water discharges from them visibly free from air. The fully filled pipe will be left overnight to allow any residue air to settle out. Any water shortage will be made up to fill the void. Then pressure testing can be started by pumping slowly until the pressure reaches the specified limit. At the end of the pressure test, water loss will be calculated as per the project specifications. Also, a visual inspection of the joints will be carried out in presence of the consultant to confirm no leaks are visible. If any part of the irrigation system fails the test, it will be corrected/repaired and a new test will be carried out.
WARNING TAPES
On completion of the pressure test, the pit is backfilled up to the specified level for the installation of the solenoid cable conduits. Before backfilling, warning tapes as per the specification are positioned above the main lines. The warning tapes should be detectable by electromagnetic means using low output generator equipment.
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| HARD & SOFT LANDSCAPE COMPANY DUBAI |
LAYING CONDUIT FOR SOLENOID CABLE
After backfilling up to the required level, conduits for the solenoid cables are placed in the pit. The size of the conduit is determined as per the number of cables that are supposed to pass through them. The conduit pipes are joined together using solvent cement. Where ever there is a change in direction of the cables or at specified distances, pull boxes are provided. Dummy ropes are installed inside the conduits while installation for pulling the solenoid cables at a later stage.
INSTALLATION OF VALVES
Solenoid valves, quick coupling valves and air release valves will be assembled at the store prior to bringing to site. Then the valves are fitted with suitable fittings and connected to the main line using solvent cement. These valves are positioned inside valve boxes which are installed at the specified levels. Isolation valves are connected to the line using flanges. Valve chambers for the isolation valves will be cast in concrete as per the specification.
LAYING OF SOLENOID CABLES
The solenoid cables are pulled through the conduit pipes from pull box to pull box using the dummy ropes placed inside the conduits earlier. Wherever joints are required, the cables are joined using waterproof wire connectors as per specification. The cables will be ferruled for identification during pulling. After pulling the cables, the same will be tested for continuity using the specified instrument. Upon completion of the test, the cables will be connected to the valves and the controller.
