The purpose of this mechanical method statement is to identify the requirements/methodology for installation of refrigerant copper piping as per the contract specification, drawings and as per the applicable regulations if any.
This method statement is applicable to all activities related to installation of refrigerant copper piping for Ducted Split and Decorative Units.
The implementation of this document will ensure that the work is carried out and complies with the project specifications & manufacturer and legal requirements.
Necessary Tools & Equipment
Below is list of mandatory tools and equipment that shall be needed for the installation of copper piping.
- Mechanical hand tool
- Cutting Tools
- Drilling Machine
- Heating Machine
- Lever-Hand Bending
- Pipe Support
Roles and Responsibilities
Mechanical Project/Site Engineer shall:
- Ensure that the activities are carried out according to the Specifications, drawing and approved method statement.
- Ensure that all required submittal are made in a timely manner.
- Arrange all materials and tools required for installation as per agreed project schedule.
- Provide all necessary information and distribute the responsibilities to his copper pipe installation team.
- Monitor that all in process tests are carried out and approval is taken from client’s representative
- Also monitor and ensure that the work is performed in accordance within the time and cost constraints.
Foreman for Mechanical shall be responsible for:
- Carrying out the work and the proper distribution of all the available resources in coordination with the Site Engineer on daily basis.
- Continuous coordination and following Site Engineer’s instructions to meet quality requirement during the job execution.
- Incorporate all the QC and Safety requirements as requested by the client’s representative.
- Report to Site Engineer the accomplishments and problem encountered on daily basis.
QA/QC Engineer shall be responsible for ensuring that execution of works are complying with approved method statement; specifications, approved shop drawings and ensure ITR are submitted based on ITP requirements.
Sequence of Work for Copper Pipe Installation
Material received at site shall be inspected and stored according to manufacturer recommendations.
Material shall be stored in covered / dry space.
All copper material should be never walked upon.
Material shall be stacked on flat surface.
Material shall be covered with polythene sheets before installation.
All safety precautions shall be followed as per the established Project Safety Plan.
Safety helmets, goggles and gloves shall be worn.
All PPE shall be worn as appropriate according to the nature of the job
Work area shall be maintained neat and clean on daily basis.
Indoor/outdoor Decorative and Ducted Split unit copper pipe sizes shall be noted.
Bends in the pipe route shall be noted and accordingly bends shall be prepared.
All types of bend shall be prepared through lever-type hand bender and step wise procedure is described below.
With handles at 180 degrees and the tube holding clip raised out of the way, insert the tube in the forming wheel groove.
Place the tube-holding clip over the tube and bring the handle into an approximately right angle position, engaging the forming shoe over the tube.
The zero mark on the forming wheel should then be even with the front edge of the forming shoe.
Bend by pulling the handles toward each other in a smooth continuous motion.
The desired angle of the bend will be indicated by the calibrations on the forming wheel.
Remove the bent tube by pivoting the handle to a right angle with the tube, disengaging the forming shoe. Then release the tube-holding clip.
Brazing Method for Copper Tube Jointing
Joining method employed shall be brazing for greater joint strength.
The following joining process shall be used:
Measuring and cutting:
Accurately measure the length of each tube segment.
Cut the tube to the measured length.
Cutting will be done through disc-type tube cutter.
Reaming shall be done to full inside and outside diameter of the tube to remove small burr created by cutting operation.
Reaming shall be done using round files.
Abrasive clothes shall be used for cleaning pipe and fittings
Flux is applied to dissolve and remove any traces of residual oxides from the surfaces to be joined, they protect the metal surfaces from re-oxidation during heating and they promote the wetting of the surfaces to be joined by the brazing filler metal.
The brazing filler metals generally are BCuP (Brazing-Copper-Phosphorous) and BAg (Brazing Silver).
Heating is applied using oxy/fuel torches. First preheating of the tube is done and then tube and fitting are heated.
When the brazing filler metal starts to melt, heat is applied at the base of the fitting socket to help draw the brazing filler metal in by capillary action.
The flame shall be in continuous motion and shall not be allowed to remain at one point long enough which can result in burning of tube and fitting.
When joint is complete, continuous filler is visible completely around the joint.
If the filler metal fails to flow, or has the tendency to ball-up, it indicates oxidation on the metal surfaces or insufficient heat on the parts joined.
In case the filler metal refuses to enter the joint and tends to flow over the outside of either part of the joint, it indicates that this part is overheated or that the other part is under heated.
When the joint is complete, allow it to cool naturally.
Flux residues are removed by washing with hot water and brushing with a stain less steel wire brush.
Once piping is approved and pressure tested it shall be insulated by using approved insulation materials and finally connection to indoor and outdoor units shall be done.
Quality Control Procedure
Prior to start of works related subcontractor and material approvals will be verified by the Project engineer.
Once the area is ready for installation of refrigerant copper piping, Project Engineer will coordinate with QA QC Engineer for the internal inspection.
Once accepted by QA / QC installation of refrigerant copper piping will be done as per method statement.
After installation of refrigerant copper piping is completed Project Engineer will raise work inspection request WIR to QA QC Engineer and QA QC Engineer upon his satisfaction will forward the subject ITR for consultant/client inspection and approval.
During installation of refrigerant copper piping, HSE Engineer shall ensure that all health, safety and environmental requirements are carried out by the in-charge Site Engineer.
All activities for the installation of copper refrigerant piping will be carried out under full supervision of concerned project engineer, foremen and HSE Officers.
HSE Control Measures
Working at Height / Access to Roof
- Fixed ladders must have fall-arrest systems or safety hoops fitted.
- Ensure that ladders are inclined at 75ᵒ (ration of 1:4) and that they are secured, top and bottom.
- Provide suitable barriers to segregate working areas.
- All required work permits should be obtained before start up of work at height.
Copper Pipe Installation
Suitable PPE should be worn at all the time.
Personnel shall ensure that correct handling practices are used at all times.
Use of proper cable stand and Equipment.
Close Supervision is required by supervisors/foreman.
Workers should be trained for safety requirements.
Area should be barricaded and relevant sign boards should be displayed.
Do not allow any unauthorized persons to enter the work area.
Explain and implement the manual lifting procedure while doing any manual lifting works.
Keep fire extinguishers with charged hose near the working place.
All workers should be trained motivated with specific requirement about safety while working with chemicals.
Emergency contact numbers and emergency response plan should be made available at site and should be briefed to the workers through tool box meetings.
Fire fighting protection such as Fire Extinguishers should be made available at site for use in emergency situation.
Use of Power Tools
Always use tested and certified electrical tools.
Tools shall be secured properly while working at height, strong tool bag/ pouch or similar container should be used to hoist tools from the ground/store to job location etc.
Ensure that the tools are in perfect working condition and suitable for the job
Should not use damaged Tools and should check tools before using them.
Use proper guards. Ensure tightening mechanism of the tool.
All workers shall wear proper PPE while using the power tools.
Ensure proper earthing of the equipment.
For working in the process area industrial sockets shall be used for power supply
The damaged cable shall not be used for the power supply.
All the cable connections shall be tightened properly to prevent sparking.
Low vibration tools should be used and such equipment should be properly maintained.
Wearing anti-vibration gloves can also reduce the harmful effect of vibration while using power tools.