Method Statement Title: Flushing and Chemical Cleaning of Chilled Water Piping System
1.0 Scope :
The scope of this method statement is to define the procedure for Flushing and chemical cleaning of chilled water piping system.
Note
- Refer to method statement Ref. ETA/MS/M-002 for Installation and Hydrostatic Testing of Chilled Water Piping System.
- A separate method statement Ref. ETA/MS/M-014 shall be submitted for startup and commissioning of Chemical dosing System.
2.0 Material :
- Chemicals for cleaning and chilled water treatment.
2.2 Chilled water piping system.
2.3 Circulation pumps.
3.0 Preparation :
The following preparation checks / works shall be carried out prior to commencement of flushing and cleaning of chilled water system.
3.1 Check the installation of piping system is completed including supports, vibration isolation, jointing etc. as per approved layout drawings.
3.2 Check and ensure the system is hydrostatically pressure tested and verify test certificate.
3.3 Check all in-line valves are in full open position and drain valves are closed.
3.4 Check the provision of air vents at location as per approved drawings.
3.5 Check and ensure sufficient quantity of chemicals are available as per requirement.
3.6 Place warning signs and warning tape as required.
4.0 Flushing & Cleaning :
4.1 Close all the branch lines for initial flushing of the main liners.
4.2 Fill the system with clean water and drain the water after 30 minutes.
4.3 Refill the system with clean water and run the chilled water pump for 2 hours.
4.4 Open the drain valves in the main lines and drain the water completely.
4.5 Clean the strainers
4.6 After the pre-cleaning of main lines is completed as above, the branch lines shall be cleaned step by step by the same process.
4.7 During the above flushing process the drain valves shall be kept open while the pump is running, until the water appears clean.
4.8 The process of flushing as described will be continued until all branch and main lines are clean.
4.9 Remove all strainers, clean and refix.
4.10 Close all the drain valves
4.11 Refill the system with clean water and add chemicals in required quantities as per Specialist supplier’s instructions (See specialist supplier’s details).
4.12 Samples of solution shall be collected from various parts of the system to ensure the chemical solution has reached all parts of the system.
4.13 Run the pump and circulate the water (with chemicals added) for a minimum period of 24 hours and maximum period of 72 hours as per specialist supplier’s recommendations.
- After system has been treated in accordance with the attached culligan procedure, the system will be drained into tankers and disposed of into DM approved waste disposal facility, such as the waste dump at Jebil Ali by NMX.
4.15 After the cleaning process is completed as described above the cleaning solution shall be flushed out.
4.16 The entire system is re-filled with fresh and clean water and treated with corrosion and scale inhibiting treatment chemicals as approved. Specialist contractor shall collect samples and conduct tests until satisfactory results are obtained as required.
Note
After satisfactory completion of flushing and cleaning as described above, the specialist supplier shall check the same and proceed with the testing, commissioning of the chemical dosing system.
5.0 Safety :
- The area shall cordon off with and warning signs shall be placed as required during the process of flushing and cleaning.
- Only competent personnel shall be engaged for flushing and cleaning.
- All PPE shall be used as required by the technicians involved in the activity.
- Safety officer shall check and ensure all safety precautions are followed as per the project safety plan.
- Chemicals shall be stored in a proper place due to health hazard.
6.0 Inspection :
6.1 The inspection request shall be raised for Main Contractor and Consultant to witness the flushing and cleaning process.
6.2 Work Inspection Request (WIR) shall be retained as records.
6.3 Certification of the system cleanliness by the specialist supplier M/s.Culligan shall be documented and recorded.
7.0 Reference :
- Specification Sections 15200.
7.2 Approved technical submittals
7.3 Approved drawings
7.4 Manufacturer’s instructions
8.0 Attachment :
- Specialist supplier, M/s.Culligan’s procedure & Checklist formats.
