Method Statement for Refrigerant Piping Installation

Method Statement for Refrigerant Piping Installation

Purpose

This method statement for Refrigerant Piping Installation and Testing defines the sequence of activities, utilization of resources, and execution of the works in compliance with applicable safety, quality procedures, and project specifications.

Scope

This method statement is intended to outline the activities and methods used for the installation and testing of refrigerant piping. All activities will be carried out in accordance with the contract details and in full compliance with the contract specifications and documents reference. All work within the rights-of-way of the standards and specifications will be done in compliance with requirements issued by authorities.

References

Project specifications
ASHRAE standards
Manufacturer’s recommendation
Approved material submittals
Approved shop drawings

Abbreviation

HSE – Health, Safety, and Environment
QA/QC – Quality Assurance/Quality Control
MST – Method Statement
RSK – Risk Assessment
ITP – Inspection and Test Plan
PQP – Project Quality Plan
INR – Inspection Request
PPE – Personnel Protective Equipment
MEP – Mechanical, Electrical & Plumbing
STARRT – Safety Task Analysis Risk Reduction Talk

Responsibilities

A. General

  1. The Project Manager (MEP) will be responsible for managing, executing, completing, and handing over the construction activities within approved budgets and resources in compliance with project requirements as specified in project specifications. He will be overall in charge of implementing the Method Statement for Refrigerant Piping Installation and Leak Testing in accordance with QA/QC and HSE requirements.
  2. The Construction Manager will be responsible for managing construction activities and will lead and communicate with the site supervisor, subcontractors, and vendors to assist them in working to the project schedule by conforming to QA/QC and HSE requirements at the site.
  3. The HSE Manager will be responsible for planning, coordinating, and implementing issues and directives within the organization. He ensures safe environmental working conditions for all employees.
  4. The QA/QC Manager will be responsible for supporting the project team in implementing and maintaining Quality Management System for the project through PQP, ITP, Method Statement for Refrigerant Piping Installation and Leak Testing, and procedures in compliance with the project specifications, codes, and standards.
  5. The HSE Officer will ensure the enforcement of safety procedures in accordance with the approved HSE Plan. He will be closely monitoring the site engineer’s strict implementation of the Method Statement for Refrigerant Piping Installation and Leak Testing & Risk Assessment, the use of proper tools and equipment to maintain safety, certifications of equipment and their adherence to safety regulations, reporting of any unsafe work or stopping work that does not comply with HSE procedures.
  6. The Site Engineer will be responsible for carrying out all construction-related activities in compliance with HSE and QAQC requirements as per contract specifications, drawings/documents, codes, and standards.
  7. The QA/QC Engineer will be responsible for conducting inspections as per PQP.
  8. The Supervisor/Foreman will be responsible for coordinating all works and workers relate to the job.
  9. The Electrician/other tradesmen will be responsible for assisting his superiors during all construction work-related activities following HSE and QA/QC requirements.
  10. The store-in-charge receives and inspects all Incoming materials and reconciles them with documents; processes and distributes documentation; reports, documents, and tracks damages and
    discrepancies.

B. Interfacing with other Operations

Other mechanical, electrical, plumbing works, architectural, civil, and structural requirements

C. Duration, Phasing with the Subcontractors

All works associated with construction work referred to in this method statement shall be completed as per the project schedule.

D. List of Subcontractors

Subcontractors for MEP: Specialized sub-contractor as approved by government authority.

E. Handling, Storage, and Transportation

During transport, handling, and storage special care shall be taken not to damage the materials.
Materials shall be cleaned from any foreign matter deposited during transport.

All material storage locations should be on suitably firm, level ground, free from damaging material with adequate access for construction vehicles and/or lifting equipment.

On receipt of copper pipes, fittings, and accessories at the site, necessary precautions shall be taken for unloading, shifting, and storage as follows:

Any copper pipes, fittings, insulation, and accessories delivered at the site shall be carefully offloaded
by deploying necessary manpower in such a way that no damage shall cause to the pipework.

Copper pipes, fittings, insulation, and accessories shall be inspected, handled, and stored properly upon receipt at the site.

Copper pipes, fittings, insulation, and accessories shall be stored in a place free of water, moisture, and dust and adequately covered to avoid any kind of damage. All materials to be stored are strictly in accordance with the authority’s requirements/manufacturer storage recommendation.

Copper pipes and fittings shall be transported to the workplace using adequate manpower.

All insulation materials shall be inspected for thickness and density.

While unloading, shifting, and storage, it should be ensured that there are no transit damages.

All insulation material shall be stored in a dry place and adequate cover shall be provided to ensure that they are not directly exposed to weather as per the manufacturer’s recommendations.

Any discrepancies, damage, etc. found to the materials will be notified and reported to QA/QC Engineer and Project Engineer for further action.

Materials found not suitable for site use should be removed from the site immediately.

Protect from water marks as any damage or watermark is not allowed during installation.

F. Material Inspection

For materials to be inspected after receiving at the site, the following points are to be followed:

Each material item shall be allotted a distinct and separate reference number and mentioned
on material requisition.

Make sure that the material is approved/examined by the consultant and QA/QC and associated
documents/test certificates are approved.

The Store In charge shall ensure that all approved supplies be delivered to the site as per the
approved material submittal; with the manufacturer’s seals, labels, or other proof of origin
intact.

These labels and seals shall not be removed until the material is required for use and shall be
retained for inspection by the consultant and QA/QC.

Store-in-charge shall initiate material inspection for all incoming material to QA/QC and the
material shall be inspected against reference documents and as per approved material
submittal.

Moreover, the physical condition of the material shall be checked. Afterward, an INR shall be
raised by QA/QC to the consultant and an inspection will be carried out by the consultant.

Materials, which do not conform to the given specification/approved material submittal, shall
be rejected. Any discrepancy or damages shall be notified and reported for further action.

For any materials inspection, the items shall be segregated as per their type/sizes and placed
items separately.

Each item shall have an identification posted on a laminated paper with the description of the
items are clearly written on it.

There shall be appropriate spaces between the material items so that the engineer/inspector
can freely go around them and inspect the materials thoroughly.

Stacking the materials all over each other and in one corner is strictly not allowed.

Resources

A. Tools

a. Hacksaw/pipe cutter
b. Electric drill with bits and grinder.
c. Open and box type wrench/spanners set
d. Chalk line/marking pen
e. Measuring tape
f. Ball hammer and cold chisel
g. Screwdriver set
h. Cleaning brush
i. Level bar/plumb bob
j. Coarse files
k. Battery drill machine
l. Pop riveter
m. Step ladders/movable scaffolding
n. Oxy/acetylene welding equipment
o. Portable torch
p. Portable “Butane” gas tank
q. Flaring tools

B. Equipment

a. 2-3 tons forklift.
b. Hydraulic trolley

Testing Equipment includes a test pump and test manifolds and calibrated pressure gauges.

Note:
All testing equipment and measuring tools to be used shall have a valid calibration certificate prior to usage.

All lifting equipment and machines shall be 3rd party verified with valid certificates.

C. Materials

Material approved includes but is not limited to the following:

  • Copper pipes & fittings
  • Soldering lead
  • Copper tube cutter
  • Teflon tape

a. The material shall be used after being approved thru the material submittal process.
b. All material to be used shall conform to the project specification and authority’s regulations (where required).

D. List of Manpower

Construction Manager
Site Engineer
QA/QC Engineer
HSE Officer
Supervisor
Foreman
Welders/Installers
HVAC technician
Surveyor
Helpers

Trailer drivers

  • Mobile Crane / Crane Operator
  • Forklift Operator
  • Riggers

Mobilization

A. Preparing and Planning

The contractor shall ensure that all gate passes, permits, tools, materials for safety precautions, manpower, and equipment are available before the commencement of work.

The site team shall make sure that access roads are always clear from any obstructions and site is always accessible.

B. Site Clearance

Before commencing the work, the area shall be cleared of all debris, materials, or other obstructions.

C. Traffic Management

The Site Team with the assistance of the Safety Officers shall coordinate logistics and materials movement through the site following the direction and road signs displayed on site. The required diversion routes shall be marked on drawings including the required traffic signs.

The Work Permits and Operator Certificates shall be compiled and filed for reference by authorized personnel.

Temporary traffic signs, barriers, and flagmen will be deployed to control traffic flow in accordance with and Traffic Management of the HSE Plan.

At the end of each ramp, there will be a transition area to give the driver the opportunity to watch the access roads before joining thereto.

D. Pre-construction Safety Meetings

A meeting shall be scheduled prior to the beginning of the work and before any subcontractor starts on the project.

Safety awareness meetings will be conducted every working day morning/every other day to brief the workforce on the safety prevention measures. The equipment check for safety shall be recorded/ documented during the daily Safety Awareness Meeting.

Traffic safety will be discussed to emphasize these meetings. Each worker will be instructed to
follow specific safety requirements related to his trade. They will be required to follow installed
safety signs, observe barricades and use PPEs.

The contractor Safety Team will perform hazard risk analysis by identifying all steps, and hazards identified in those steps, with a focus on the relationship between the work task, the tools, and the work environment. After identifying uncontrolled hazards; the contractor will take steps to eliminate or reduce them to an acceptable risk level.

General Contractual Safety, Health, and Environmental requirements.

• Roles of the contractor, subcontractors, authorized representatives, and all project workers.
• Accident reporting requirements.
• Specific details of the work to be performed along with the use of personal protective equipment.
• Emergency procedure.

E. Operating Procedures

A site investigation has to be carried out to develop safety precautions and measures prior to the commencement of the work. After such investigation, relevant sign boards will be displayed and barricades will be installed where and as necessary, such as but not limited to the following:
• Relevant information, advanced signs, warning, and mandatory signs will be placed as required.
• Radio Communication system would be used where normal communication is impossible.
• After completion of the work, safety cones and barricades have to be removed accordingly.

Methodology

A. Pre-installation

All relevant documentation approved shop drawings, and material applicable to a particular section of work will be checked by Site Engineer prior to the commencement of work.

Ensure that the material received is in compliance with the project specifications/authorities’ regulations and is approved.

Ensure that all required materials and accessories are delivered, inspected, and approved by the consultant and are readily available at the site to carry out the work.

All relevant documentation (including MST and RA are approved, obtain necessary work permits, and fill up STARRT cards after the completion of the daily toolbox talk), will be checked by Site Engineer prior to the commencement of work.

The Site Engineer/Site Supervisor will give necessary instructions to tradesmen (Mechanical/HVAC) and provide necessary approved construction/shop drawings.

The Site Engineer/Site Foreman will check that proper tools and equipment are available to carry out the work and are in compliance with contract specifications.

The Site Engineer will explain to his team about HSE precautions to be observed.

Ensure to remove scales and dirt inside and outside of the pipes. Prepare the piping connection to equipment with flanges or unions.

Ensure proper storing/handling of the copper piping without damaging the surface.

Before starting the installation, ensure that area has been surveyed & coordinated.

Confirm that appropriate openings required through walls, beams, and slabs are available.

B. Installation

Supports and Hangers

Install supports or brackets for refrigerant piping as per project requirement, approved shop drawing, and site conditions for each individual case (i.e. Slab and Walls, etc.).

Refrigerant piping supports shall be installed with maximum horizontal and vertical spacing as specified, and the allowable minimum pipe elevation from the finish floor level.

Riser support for vertical refrigerant piping shall be as per the detail shown on the approved shop drawing.

As indicated on approved construction drawings where more than one pipe can be supported on one hanger, the size of the hanger will be assessed on the sum of the maximum widths and weight of filled pipes.

Supports are to be fixed at the correct levels and check the bracket material is compatible with the installation.

Install hangers to provide a minimum of 13mm space between the finished covering and adjacent work.

Provide trapeze hangers where several pipes can be installed in parallel and at the same elevation.

In-line equipment is to be independently supported from the main structure.

Refrigerant Pipe Installation

Establish the reference level/datum point from where measurement will be made to the position of the service.

Clean the surfaces, Ream pipe, and tube ends. Remove burrs, bevel plains, and ferrous pipes.

Proper tools are to be used for making cutting the refrigerant pipe at the site.

Installation of all refrigerant piping connections/specialties shall be in accordance with the manufacturer’s recommendation instructions.

Provide non-conducting dielectric connection wherever jointing dissimilar metals.

Route piping in an orderly manner and maintain gradient. Route parallel and perpendicular to the wall.

Group piping whenever practical at common elevation, without stressing pipe, joints, or connected equipment when using one hanger to support more than one pipe.

Provide clearances in hangers and from the structure and other equipment for the installation of
insulation and access to valves and fittings.

Provide access where valves and fittings are not exposed. Coordinate the size location of access doors.

Where pipe support members are welded to structural building framing, scrape, brush clean and apply one coat of zinc-rich primer on welding.

Locate the expansion valve, and sensing bulb downstream of the evaporator on the suction line connection.

Install valves with stem upright or horizontal but not inverted.

Maintain proper bottom of refrigerant pipe as per approved coordination drawing.

Refrigerant pipes penetrations across the wall and slab shall be sealed with approved material
as agreed with the Consultant/Engineer. The sealant installer or supervisor shall be certified and all completed locations shall be tagged along with signature and stamp.

Any changes in pipe sizes as per site conditions shall be conveyed to the Consultant/Engineer
supported with calculations for review and approval, and to be incorporated in as-built drawing.

Check for above false ceiling clearances for refrigerant piping and other MEP services, and
allow sufficient ceiling space for ceiling panel removal.

Care will be taken during setting out that refrigerant pipework runs between ceiling module
lines so as to maintain maximum flexibility for any future relocation of lighting fixtures or
other services.

All open ends check for debris and then cover with suitable material to prevent any ingress of
debris, vermin, or moisture.

Supervisor to ensure that there are no dents, distortion, or buckling of refrigerant pipework
during installation.

Continuously check horizontal and vertical alignment of refrigerant pipework in compliance
with approved drawings and specification requirements by using spirit level plumb or other
leveling instrument.

Refrigerant pipe penetrations through walls and slabs will be provided with sleeves as per
project specifications.

Provide proper sleeves including fiberglass to fill the gap with firestop material for refrigerant
pipework which passes through a fire-rated wall or slab.

Insulation of refrigerant piping shall be as per approved material submittal and insulation manufacturer’s instruction.

Provide oil traps as per approved shop drawing and or equipment manufacturer instruction. Oil traps shall be constructed using short-radius pipes.

Refrigerant piping charging and purging/disposal of the system shall be as per equipment manufacturer instruction and ASHRAE standards No. 15 procedures.

After completion of refrigerant pipe installation work, identification of refrigerant pipework will be performed.

For further details on the installation and testing of refrigerant pipework, adhere to “Refrigerant Piping Manufacturer’s Installation and Leak Testing Detail”.

The Site Engineer/Foreman ensures the cleanliness of the area.

Joining Method

All welding works shall comply with the provisions in ASME B 31 series, “Code of pressure piping”. Ensure that welder executing the works has valid AWS certification or equivalent.

Whenever welding of steel pipes will be part of the system, the filler metals shall comply with AWS D10.12 for welding materials appropriate for wall thickness and chemical analysis.

Observe the manufacturer’s recommendation on which method should be used on each designated fitting joint.

Soldering Method

Solder filler metal shall comply with ASTM B 32, lead-free alloys including water flushable flux according to ASTM B 813.

Using a suitable brush apply water flushable flux adequately, but not excessive to both the outside of the tube and inside the fitting socket.

Insert the tube into the fitting until it reaches the tube stop and then wipes off any excess flux. Heat the assembled joint evenly on all sides.

Apply Solder to the mouth of the fitting. When the correct temperature has been reached the solder will flow freely and be drawn into the point. Briefly re-apply the blow torch and wipe off any excess solder.

Allow the joint to cool without disturbance. Clean the joint generally. Wiping off any external flux residues. This will prevent, unsightly stains or (in extreme cases) corrosion of pipe work. Flush out the pipe work.

Brazing Method

Brazing filler metal shall comply with AWS A5.8, B Cup series, copper-phosphorous alloys for general duty brazing unless otherwise indicated; and AWS A5.8, Bag1, silver alloy for refrigerant piping.

Using a suitable brush apply approved water flushable flux adequately, but not excessive to both outside of the tube and inside the fitting socket.

Insert the tube into the fitting until it reaches the tube stop and then wipes off any excess flux. Heat the assembled joint evenly on all sides.

Heat the assembled joint evenly on all sides (red heat in poor daylight).

Apply the approved filler rod to the mouth of the fitting. Allowing the alloy brazing to melt and flow into the annular gap. Allow the joint to cool without disturbances. Clean the joint generally and flush out the pipe work.

Inspection and Leak Testing

After completing the segment of piping installation, The Site Engineer/Supervisor shall systematically check and inspect their work as per approved shop drawings. Any rectification/modification shall be immediately done prior to raising an INR.

After a satisfactory inspection of piping installation by the Site Engineer/Supervisor, the INR has to be raised by them with a complete attachment & information regarding the scope of the inspection, including necessary drawings highlighted to show the scope of the inspection. The inspection shall be performed according to a typical checklist and approved Inspection and Test Plans (ITP).

The needed attachment will be forwarded by the Site Engineer/Supervisor to the QA/QC Department who shall check and process the INR documents of completed works for Supervision Consultant installation inspection and approval.

Right after satisfactory installation inspection by Supervision Consultant, completed work shall be under leak test. All pipes (risers and horizontal installation) shall be subject to leak test in accordance with ASME B31.5.

All pipe joints shall be left uninsulated until the leak test has been satisfactorily approved by Supervision Consultant.

Make sure to pressurize liquid pipes, gas pipes, and high/low-pressure common pipes. Set DIP (Dual In-line Package) switches as vacuum mode and never perform air purging using refrigerant.

Vacuum drying using a vacuum pump shall be made at the service port of the outdoor unit service valve by evacuating the system for two hours at -105 Kpa (-76 mmHg); after this period, close the service valve then observe any rise in vacuum gauge for one hour.

In case of any trapped moisture inside the pipe after performing two hours of evacuation, apply vacuum break pressure of 0.5 Kg f/cm² (7.3 psi) using nitrogen gas and re-evacuate the pipelines with a vacuum pump for one hour at -105 Kpa (-76 mmHg vacuum drying).

Check and repair for pipe leakage if the system cannot be evacuated to -105 Kpa (-76 mmHg) within two hours; then repeat the vacuum drying and vacuum break until no further notice of leakage is observed.

Finally, maintain the system in a vacuum state at -105 Kpa (-76 mmHg) for one hour and see to it that no drop or rise in vacuum gauge reading.

Leak testing shall withstand for 24 hours without pressure drop using nitrogen to 551 psi. Check pipe joints by applying soapy water or liquid detergent with a soft brush, and see to it that no drop is registered in the calibrated pressure gauge; otherwise, immediately repair the leaking portion of pipelines under test and repeat the steps.

Before applying the pressure/leak test with dry nitrogen, ensure that all safety precaution is in place and check that all pipe ends are closed with test plugs except for the filling point.

Clean the pipes for any dust or debris on the joint surface for easy identification of leaks if there are any.

After approval of installation and leak test, connect refrigerant piping lines to outdoor and indoor units and start charging the system with the manufacturer’s recommended refrigerant and operating pressure. Further manufacturer’s recommendation is stipulated in Appendix.

Note: INR must be processed and submitted to Supervision Consultant 24 hours before the actual inspection and/or witnesses.

Health and Safety Analysis

A. Risk Assessment

Refer to Risk Assessment/Job Hazard analysis in Appendix.

B. Permit and Licensing Requirements

The required permit to work shall be obtained prior to the commencement of work. This shall be coordinated with HSE. Site interface permits are to be taken from other contractors before placing pipe at the tie-in point to reconfirm IL and coordinates.

C. Pre-Start Safety Briefing Arrangements

C.1 Protective and Safety Equipment

All workers involved shall be equipped with adequate PPE as stated below:
Safety Helmet with Company Logo
Safety Boots
High Visibility Vest
Safety Goggles
Hand Gloves
Coveralls
Proper safety harness

C.2 Information to Personnel
Safety Induction
Job training – All the personnel involved in this task shall be provided training and only
trained personnel shall be authorized to work around this area.
Toolbox talks
STARRT Card

C.3 Special Safety Requirements

All necessary personal/protective equipment (PPE), as well as harness, be provided.

Rigging team, wearing distinctive vests, shall be assigned to help operators maneuver their equipment.

The equipment operators shall possess the required licenses and certificates.

The required permit to work shall be obtained prior to the commencement of work.

The project safety officer is responsible along with the project zone site engineer for ensuring that all operations are carried out with due regard to the safety of all project personnel & property.

Working at height to be monitored with due care.

In case of working at night, please refer to Method Statement for Night Works.

The contractor must provide a safe place of work, with safe access and egress. Provide a safe working environment that is without risk to health.

Quality Assurance and Quality Control

A. Quality Assurance Requirements

The contractor shall provide the required documents for the consultant’s approval prior to initiating the execution of this activity as per the project specification and requirements.

The quality control requirement shall include related QCPs, ITP, and other related documents as applicable. Refer to Inspection Test Plan

B. Quality Assurance Process

The contractor shall notify the engineer 24 hours in advance prior to the start of activity and comments from the site Instruction will be complied with to the satisfaction of the consultant.

The contractor shall consult the public utility authorities not less than one month before it is proposed to commence work to ascertain whether any underground installations will be affected by the proposed work, in which event the contractor shall make all necessary arrangements with the public utility authorities to safeguard the installation.

C. Follow-up and Evaluation

Follow-up on quality performance shall be carried out through an in-house monitoring system such as progress reporting to the planning department, and daily, weekly and monthly reports generated by the planning department to closely monitor site performance in general and reflect on quality performance in specific.

All the above shall be conducted in close coordination with the quality department to monitor any deviations from the normal quality requirement and induce corrective actions whenever required to eliminate non-conformance or quality deviations.

All remedial actions to be taken, if any, shall take into account the official schedule which is to be used as a guideline for performance and most importantly under the close supervision of the quality control department.

D. RECORDS

Checklists (CKL)
Inspection Request (INR)
Inspection and Test Record (ITR)

Attachments

Appendix:

HSE Risk Assessment for Installation and Testing of Refrigerant Piping
Inspection and Test Plan for Installation and Testing of Refrigerant Piping
Checklist for Installation and Testing of Refrigerant Piping
Refrigerant Piping Manufacturer’s Installation and Leak Testing Detail

tag: Method Statement for Refrigerant Piping Installation and Leak Testing