Installation of CHW pipe

Scope of Installation of CHW pipe:

Installation of CHW pipe

 

To define the method of Installation of CHW pipe and valve packages and chemical flushing

Methodology and Sequence of Installation of CHW pipe

Pre-Installation Check

  • All operative shall attend safety induction meeting and wear five point PPE.
  • RAMS briefing shall be conducted to all operatives/foremen/supervisor before commitment of work.
  • Pre start briefing shall be done for operative on location before commitment of work.
  • All the power tool shall be PAT tested for every 3 months and colour coded.
  • Permit to work system followed if necessary for the work .work permit shall be obtained.
  • Ladder permit shall be obtained from ISG and tagged before use on site.
  • Mobile tower shall be erected by trained person and tagged.

Modification of chilled water pipe and valve packages:

  • Delivery of all material will be through the loading Bay Area and will be coordinated in advance. Shifting of material from store area to the work place area via manual handling or trolleys.
  • The relevant material for daily usage will be delivered to the site without disturbing the emergency exit area and followed by all safety measures.
  • All works on high level will be accessed through the use of mobile scaffold. Mobile tower shall be
    erected/dismantled /inspected by trained person.
  • Informing the Main Contractor about our work schedule prior to commencing work.
  • Existing pipes will be removed and re-fixed to match the proposed / approved drawing.
  • Non-existing points will be made by fixing (below 50mm dai) new pipes with the help of a threading machine & pipe wrench.
  • Tray shall be placed below the threading machine to collect the lubricant and disposal properly Pipe fittings, Supports & Hangars will be used as per standards while redesigning the pipes.
  • Drilling works will be done during the allowed time as per rules and regulations from the building management.
  • Calibrated torque wrench shall be installing pipe support.
  • Threading machine operating area barricaded with warning signage.
  • Existing valve package and associated chilled water pipe will be removed
  • Pipe and valve package will be insulated as per standards to avoid condensation
  • New chilled water pipe and valve packages will be installed with new approved materials
  • Once the chilled water pipes are installed we will proceed further in making a Pressure Test in order to ensure that there will be no leakages.
  • Pressure test permit after obtaining
  • Pressure testing area barricaded with warning signage
  • All the painting work doing by warehouse.
  • Leakages (if any) will be rectified after draining the system again.
  • Calibrated pressure gauge shall be used for pressure testing.
  • Pressure Test will be done again until we ensure that there are no leakages for at least 24 to 48 hours.
  • Full time supervision required in pressure testing area till completion of work. No one work carried in pressure testing area
  • After chilled water pipe pressure test we will move to chemical flushing procedure

Chemical Flushing for Installation of CHW pipe

  • Ensure that the hydro testing is completed and the system is leak free & filled with water.
  • Ensure availability of continuous supply of fresh water to water storage tank.
  • Confirm the availability of manpower at site for 24 hours operation.
  • Confirm the availability of chemicals at site.
  • Confirm that the Culligan temporary circulation pump is connected to the system at the tapping
    provided by Contractor
  • Confirm that the makeup line has been connected to the return line of the Culligan temp. Circulation pump through the temporary hose which is connected to booster pump to feed fresh water from Culligan temporary fresh water storage tank.
  • Confirm the drain line has been taken from the return line of the Culligan temporary pump and connected to waste water storage tank.
  • Confirm automatic air vent are installed at the topmost at the end of each loop of the branches.
  • The Flushing & Chemical Cleaning of each loop / section of pipe work comprises Five (5) important stages. The below stages will be typical for all 5 circuits.
  • Dynamic flushing
  • Chemical cleaning (Addition of Clean Guard – 70F02)
  • Final flushing and removal of chemicals
  • Addition of Passivation Chemical (Addition of Clean Guard – 70F03)
  • Addition of Corrosion Inhibitor chemical & Biocide (Addition of Corro Guard – 33L01 & Bio Guard 40H06)
  • The purpose of this Pre-flushing / Static Flushing is to remove the inert suspended matter such as iron fines, jointing compound, hemp, PTFE, welding spatter, welding slag, grit etc. Static flushing will be done until all suspended matter and loose debris is fully removed from the pipe work.
  • Ensure all prerequisites as mentioned in the initial stages have been met.
  • Fill the system with makeup water.
  • Fully vent the system to ensure no air is trapped within the pipe work.
  • Open the valve of the drain line from the return header of the circulation pump and keep the system in low circulation mode by running the circulation pump in low rpm.
  • Inspect, remove, and examine the strainers & Filters (which are inline during circulation) clean the same and reinstall them.
  • Return water will be passed through the filter to remove the Suspended solids and recirculated.
  • The purpose of dynamic Flushing is an advance stage of the flushing where the water is being drained through the various drain points. The makeup water is to be added at one side to maintain the pressure in the system.’
  • Once the major suspended debris is removed, increase the speed of the pump to the maximum,
  • Start the system circulation.
  • Systematically remove, examine and clean the entire strainer and reinstall the same.
  • Continue with the above step until no contaminants are noted in the strainer / bag filters.
  • Return water will be passed through the manual filter to remove the Suspended solids.
  • The purpose of Chemical Cleaning is the removal of impurities from the chilled water system by using cleaning chemicals.
  • The purpose for chemical cleaning is to remove oxide deposits from the metal surfaces.
  • The system will be dosed with the specified amount of Clean Guard 70F02 cleaning agent at a level of 1 Kg per cubic meter of system volume.
  • After the chemical dosing the system is left circulating continuously for a period of not less than 24 hours and not more than 48/72 hours prior to draining and flushing.
  • Clean Guard 70F02 will be circulated in the system until the sample indicate that no further  increase in iron level is occurring prior to start to flush, a reference sample should be collected by the contractor from the system in the sample bottle. At this point, draining and flushing will be commenced by the contractor and will continue until the iron level is less than 2 parts per million (ppm) and all traces of the chemical and sediment removed.
  • The purpose of Final Flushing is to take out all the left over suspended particles, mill scale, debris and metal oxides which are accumulated in the system during the chemical cleaning stage by continuously flushing with fresh water at the appropriate flushing velocities required.
  • Makeup and vent System to be flushed with clean and fresh water.
  • Set all valves to fully open or fully closed positions as required.
  • Systematically remove, examine and clean the entire strainer and reinstall the same.
  • Continue with the above step until no contaminants are noted in the strainer.
  • Continue flushing till the water is clear and the iron level is below 2 ppm
  • Passivation of chilled water system network using Passivation Chemical (Clean Guard 70 F 03) Once the system is spotless it should be properly passivated using passivation chemicals. Clean Guard 70F03 (Passivation chemical) is a gentle passivation of the metal surface.
  • System to be dosed with Clean Guard 70F03 at the rate of 1 kg per m3 and the system is to be circulated for the 8 hours. All the drain and flushing points of the system should be closed during passivation of the closed loop water circuit.
  • Back flushing of FCUs, AHUs and final circulation.
  • We will request the main contractor to inform the building management in order to connect the existing pipe to the new pipeline.
  • We will request the main contractor to inform the building management in order to open the chilled water main valve and thereby automate the chilled water system.