This chilled water piping installation method of statement is prepared in order to outline the activities and the methods used for the installation of chilled water pipes and accessories. All activities will be carried out in accordance with the contract details and in full compliance to the Contract Specifications and documents. All work within the rights-of-way of the standards and specifications will be done in compliance with requirements issued by authorities.
Tools & Equipment Required For CHW Piping Works
Before starting the chilled water piping installation below mentioned tools shall be arranged and necessary measures will be taken for the safety of the equipment. Relevant entities which might require protection include any such works in the vicinity of the area of work or on the service access or discharge path. The construction team will ensure that any such requirements are documented.
- Welding Machine
- Cutting Equipment’s (oxygen, acetylene cylinders and cutting torch etc.)
- Threading Machine
- Lifting arrangement
- Tool Box
- Measuring Tape
- Spirit level
- Plumb Bob
- Steel Hammer
- Electric Drilling machine
- Hole Saw Cutter
Storage Of Pipes & Accessories
- All piping material while unloading shall not be dropped, but slowly lowered to the ground.
- Pipes shall be stacked on a flat surface with adequate supports.
- All pipes to be capped off and extra pipes to be removed for installation area to storage.
- 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 their use.
- Check and ensure all drawings used for installation are latest and approved for construction.
- Mark the pipe routing and support locations as per approved drawings, and 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 steel pipes before installing.
Installation of Chilled Water Pipes
- Drill the holes in ceiling/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 in future.
- Cut the pipes accurately to measurements determined at site, and prepare the pipe ends according to the type of joints i.e. Threaded joints, welded joints etc.
- Threading 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 rubber inserts between the pipe and support.
- Sleeves of suitable sizes shall be provided at wall crossings/openings.
- 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 and technical specification.
- Fix the blind plugs / temporary valves on all drain, air vent, pressure gauge, thermometer and test point’s trappings etc as per 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 and approved.
- Raise the inspection for chilled water piping installation to consultant. Obtain signoff for hydraulic pressure testing after the test is witnessed.
Pressure Testing of CHW Piping System
- The chilled water piping shall be tested according to the system working pressure (i.e. 1.5 times the working pressure) and/or 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 and as per consultant advice.
- 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 through a temporary pump and obtain the test pressure if no leakage is observed.
- 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 with water until no leakages throughout the entire piping system is observed.
- After no leakage is observed pressurize the system using hydraulic test pump up to full pressure.
- During pressurization observe the joints and entire piping system for leakages.
- Observe the pressure gauges readings for 4 hours and ensure there is no drop in gauge pressure. System pressure to be 1.5 times than the actual working pressure.