During delivery of materials all Chilled Water Piping material while unloading shall not be dropped, but slowly lowered to the ground. For pipes, wooden supports shall be placed beneath at equal distance. Pipes shall be stacked on a flat surface with adequate supports. End caps of pipes shall be in place until removed for installation. Any items found damaged or not suitable as per project requirements shall be removed from site. If required to store temporarily, they shall be clearly marked and stored separately to prevent any advertent use.
- Check and ensure all drawings used for installation are latest and approved for construction.
- Mark the pipe routing and support locations in the trench as per approved drawings.
- Check the co-ordination of piping layout with other services and decide pipe route with minimum bends/offsets.
- Check and ensure sufficient clearance around pipe for applying insulation / cladding as applicable.
- Clean and apply primer / red oxide on all seamless black pipes.
Chilled Water Piping Installation
- Drill the holes in trench wall for fixing supports.
- Fix the anchors and threaded rods with clevis hangers / structural supports as applicable. Threaded rod length shall be sufficient to allow for leveling of piping.
- Cut the pipes accurately to measurements determined at site.
- Prepare the pipe ends according to the type of joints i.e. Threaded joints, welded joints / grooved coupling joints.
- Threading and grooving as applicable shall be done as per fittings / coupling manufacturer’s recommendations.
- End preparations for welded joints shall be done as per approved welding procedure.
- After the end preparation clean the pipe ends and ensure no material and dust is left inside.
- Qualified and approved welders with certificates shall be engaged for welding works.
- Install the pipe sections at heights as per approved drawing in a neat and tidy manner.
- Insert the wooden saddle between the pipe and support.
- Sleeves of suitable sizes shall be provided at wall crossings.
- Install the valves in locations as per approved drawings.
- Install the piping connections with valves and accessories wherever equipment’s are installed as per approved drawings.
- Fix the blind plugs / temporary valves on all drain, air vent, pressure gauge, thermometer and test points trappings approved drawings.
- Check and ensure proper supporting is provided as per approved drawings.
- While installation is going on of the pipe work, the insulation will be fitted to the pipe work. But all fittings and joints will be left exposed until the pressure testing and inspection is completed.
- Raise the “IR” for piping installation to consultant. Obtain sign-off for hydraulic pressure testing.
Pressure Testing Procedure
- The chilled water piping shall be tested according to the system working pressure and PN ratings of the pipes, pipe fitting and valves used in the piping.
- The piping may be tested in sections or in total, depending on site requirements.
- Estimate the piping volume and make arrangement for required quality of clean water.
- Arrange for temporary piping / hose pipe connections for filling and draining the water.
- Fix the temporary valves at air vent / drain points and pressure gauges.
- Fill the piping system with clean water.
- If leakages are observed, arrest the leakage immediately. If leakages are major, isolate the leaking portion with nearest isolating valve and / or stop the water filling.
- Rectify the leakages and again fill wit water.
- Ensure no leakages throughout the entire piping system.
- Observe for the leakages and pressurize the system using hydraulic test pump.
- During pressurization observe the joints and entire piping system for leakages.
- Observe the pressure gauges readings for 8 hours and ensure there is no drop in gauge pressure.
- Raise the “WIR” for witnessing the pressure testing to obtain sign-off with clearance for insulation only after satisfactory pressure testing.