Method Statement of Split AC Units Installation

method statement for split AC

This method statement of split AC units installation ensures that specified materials are installed and agreed procedures are implemented during the execution of work. This MST defines the documentation and responsibilities for controlling the project quality and HSE requirements.


This method statement is intended to outline the activities and the methods used for the installation of split Air Conditioner (AC) units. All activities will be carried out in accordance with the contract details and in full compliance with the project specifications and references. The split Air Conditioner (AC) units methodology covers the equipment setting procedures and installation technique utilizing the method statement of pipes & fittings installation as well as the sequence of operation as set out in the given specification and approved drawings for the HVAC system.
After the system installation has been completed, the entire system shall be checked, inspected, and functionally tested by qualified and approved 3rd party specialists, as per the manufacturer’s recommended procedures.

The installation of split units has many advantages over traditional air-conditioners. The most obvious benefit is the quiet performance of the split unit system. The part of the air conditioner that makes the most noise is the compressor and the fan that cools the condenser. In a split system, the compressor and the fan for the condenser are located outside of the room being cooled and therefore the major sources of noise are removed.


Project Specifications
ASHRAE 15 and 34 and 62.1 Sections 4, 5, 6 & 7
Manufacturer’s Recommendation
Approved Material Submittals
Approved Shop Drawings


HSE Health, Safety and Environment
QA/QC Quality Assurance and Quality Control
MST Method Statement
RA 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
AHRI-Air Conditioning, Heating and Refrigeration Institute
ASHRAE-American Society of Heating, Refrigerating, and Air-Conditioning Engineers
NFPA-National Fire Protection Association
AC-Air Conditioner


A. General

  1. Project Manager (MEP) will be responsible to manage, execute, complete and handover 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 Method Statement in accordance with QA/QC and HSE requirements.
  2. Construction Manager will be responsible for managing construction activities and will lead and communicate site teams, subcontractors and vendors in assisting them from working within project schedule.
  3. HSE Manager will be responsible to plan, coordinate and implement issues and directives within the organization. He ensures safe environmental working conditions for all employees.
  4. 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 of Split AC Units Installation, and procedures in compliance with project specifications, codes and standards.
  5. HSE Officer will ensure enforcement of safety procedures in accordance with the approved HSE Plan. Will be closely monitoring the site engineer’s strict implementation of the Method Statement of Split AC Units Installation and 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. Site Engineer will be responsible for carrying out all construction related activities with compliance to HSE and QA/QC requirements as per contract specifications, drawings/documents, codes and standards.
  7. QA/QC Engineer will be responsible for conducting inspections as per PQP.
  8. Supervisor/ Foreman will be responsible for coordinating all works and workers relate to job.
  9. Electrician / other tradesmen will be responsible in assisting his superiors during all construction work related activities following HSE and QAQC requirements.
  10. Store in-charge receives and inspects all Incoming materials and reconciles with documents; processes and distributes documentation; reports, documents and tracks damages and discrepancies.

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 damaged material with adequate access for construction vehicles and/or lifting equipment.
• On receipt of equipment and accessories at the site, necessary precautions shall be taken for unloading, shifting, and storage as follows:
• Any equipment and accessories deliver at the site shall be carefully off-loaded by deploying necessary manpower in such a way that no damage shall cause to equipment.
• Equipment and accessories shall be inspected, handled, and stored properly upon receipt at the site.
• Equipment and accessories shall be stored in a place free of water, moisture, and dust and adequately covered to avoid any kind of damages. All materials to be stored are strictly in accordance with the authority’s requirements/manufacturer storage recommendation.
• Equipment and accessories shall be transported to the workplace using adequate manpower.
• While unloading, shifting, and storage, it should be ensured that there are no transit damages.
• Any discrepancies, damage, and 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 watermarks as any damage or watermark is not allowed during installation.

Material Inspection

For materials to be inspected after receiving at the site, these points are to be followed:
• Each material item shall be allotted a distinct and separate reference number and mentioned on the material requisition.
• Make sure that 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 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 will 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 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 & in one corner is strictly not allowed.


A. Tools and Equipment


a. Standard mechanical toolbox kit
b. Standard electrical toolbox kit
c. Pipefitter toolbox with complete hand tools
d. Measuring tape
e. Digital multimate (electrical)/meager
f. Electric drill with bits and grinder.
g. Open and box type wrench/spanners set
h. Chalk line/marking pen
i. Measuring tape
j. Ball hammer and cold chisel
k. Screwdriver set
I. Cleaning brush
m. Level bar/plumb bob
n. Step ladders/movable scaffolding


a. 2-3 Tons Forklift.
b. Hydraulic Trolley
c. Lifting Equipment (Shackles, Pad Eye, and Belt) – Third Party Certified.
d. Scissor Lift
e. Testing Equipment includes test pump and test manifolds, calibrated pressure gauges.

• 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.

B. Materials

Split AC Units

a. The material shall be used after being approved thru material submittals.
b. All materials to be used shall conform to the project specification and authorities regulations (where required).

C. List of Manpower

Construction Manager
Site Engineer
QA/QC Engineer
HSE Officer
HVAC technician
Trailer drivers
Mobile Crane/ Crane Operator
Forklift Operator

Methodology-Split AC Units Installation

A. Pre-installation

  • All relevant documentation, approved shop drawings, and material applicable to a particular section of works will be checked by Site Engineer prior to commencement of work.
  • Ensure that material received is in compliance with the project specifications/authorities regulations.
  • Ensure delivered equipment is as per approved Material Submittal and approved equipment schedule.
  • Ensure that all required materials and accessories are delivered, inspected, and approved by consultants and are readily available at the site to carry out the work.
  • All relevant documentation (includes MST-Method Statement of Split AC Units Installation and RA are approved, obtain necessary work permits, fill up STARRT cards after completion of daily toolbox talk), will be checked by Site Engineer prior to commencement of work.
  • The Site Engineer/Site Supervisor will give necessary instructions to tradesmen (Mechanical) 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 proper storing/handling of the equipment without damaging the surface.
  • Before starting the installation, ensure that area has been surveyed & coordinated.
  • Ensure all installation and testing of pipework and ductwork have been completed and approved by the consultant, prior to proceeding in the connection.
  • Relevant documents or certificates shall be presented at the time of inspection if required by the consultant.
  • Permission to start or civil clearance prior to installation has been given by the main contractor.
  • Installation activity shall only commence when all associated works by the civil have been completed.
  • Safe access shall be provided by the contractor thru work permits in coordination with the safety in charge at the site.
  • Check for other services, making sure that there is no interference between each service & adequate access to work and for future maintenance can be maintained.

B. Installation

Supports and Hangers Installation

  • Install supports or brackets for split AC units as per specification, approved shop drawing, and site conditions for each individual case (i.e. slab, floors, and walls, etc.).
  • Supports are to be fixed at correct levels checking the bracket material is compatible with the installation.
  • In line equipment is to be independently supported from the main structure.
  • Lift up the ceiling suspended split AC units using the third-party certified shackles, pad eye, and belt (instead of the crane).

Split AC Units Indoor Installation

  • Indoor type split units can stand or lie on the floor, or hang from the ceiling or wall. Allow space for wiring, piping, and service units.
  • For the installation of horizontal right conversion of the unit with slope coil installation to be followed.
  • For optimum condensate drainage performance in horizontal installation, the unit should be leveled along its length and width.
  • In a horizontal installation, the unit must not be installed with access panels facing up or down. All other units are factory built for horizontal left installation suspending unit from the ceiling, dimples in casing indicate the suitable location of screws for mounting metal supports.
  • Align holes with tubing connection and condensate pan connections and reinstall access panel and fitting panel. Make sure liquid and suction tubes are prevented from air leaks and cabinet sweating. Install after brazing.
  • For air duct connection, ensure to connect the supply air duct over the outside of the flange provided on the supply air opening. Secure the flange using the approved fasteners for the type of duct used and seal the duct-to-unit joint. If return air flange is required, install factory authorized, use flexible connectors between ductwork and unit to prevent transmission of vibration. When the electric heater is installed use heat-resistant material. The connector between ductwork and unit at discharge connection. Ductwork passing through unconditioned space must be insulated and covered with a vapor barrier.
  • Establish the reference level/datum point from where measurement will be made to the position of the service.
  • Installed approved supports, vibration isolators, brackets, and anchor fasteners as per project specifications, material submittal approval, and manufacturer instruction.
  • Permanent, accessible and sufficient clearances to be provided for servicing and maintenance of the equipment as per approved shop drawing and manufacturer’s instruction.
  • All installation and construction works require will be undertaken in accordance with manufacturer instruction and project requirements.
  • Maintain proper bottom of indoor split AC units as per approved coordination drawing.
  • Supervisor to ensure that there are no dents, distortion, or any possible damage during installation.
  • Condensate Drain Pipe (CDP) installation should be as per approved shop drawings, and project specifications.
  • After completion of split AC units installation work, identification of equipment will be performed.
  • See Detailed Indoor Split AC installation procedure and wiring diagram-“Split AC Unit Manufacturer’s Installation Detail” (attached)
  • The Site Engineer/Foreman ensures the cleanliness of the area.

Split AC Units Outdoor Installation

  • Ensure the proper location of the unit as per the approved shop drawing.
  • Ensure that vapors and liquid tube diameters are appropriate to the capacity of the unit.
  • Leave some slack between structure and unit to absorb vibration.
  • Ensure that tubing insulation completely surrounds the vapor tube.
  • If required use hanger straps that are 1 inch wide and conform to the shape of tubing insulation.
  • Insulate hanger strap from insulation by using metal sleeves bent to conform to the shape of insulation.
  • Unit shall be mounted to pad; tie-down bolts should be used and fastened through knockout provided in the unit base pan. Arrange supporting members to support the unit and minimize transmission of vibration.
  • For the floor/roof-mounted outdoor unit AC installation, close coordination with the civil team is required for the concrete base (detail is to be provided in the related shop drawing and ensure approval prior to installing the floor-mounted outdoor unit).
  • For the wall-mounted outdoor unit AC installation, please see the attached manufacturer’s installation detail.
  • When installing allow sufficient space for airflow clearance, wiring, refrigerant piping, and service.
  • Permanent, accessible and sufficient clearances to be provided for servicing and maintenance of the equipment as per approved shop drawing and manufacturer’s instruction.
  • All installation and construction works require will be undertaken in accordance with manufacturer instruction, project requirements.
  • Supervisor to ensure that there are no dents, distortion, or any possible damage during installation.
  • After completion of Split AC Units installation work, identification of equipment will be performed.
  • Detailed Indoor Split AC installation procedure and wiring diagram-“Split AC Unit Manufacturer’s Installation Detail”.
  • The Site Engineer/Foreman ensures the cleanliness of the area.

Split AC Units Wiring Installation

  • Before wiring, confirm the rated voltage of the unit as shown on its nameplate, then carry out the wiring closely following the wiring diagram.
  • Provide a power outlet to be used exclusively for each unit, with a power supply disconnect and circuit breaker for overcurrent protection provided in the exclusive line.
  • Ensure the installation of an electrical isolator (disconnect switch) for outdoor units and DP switch for indoor units.
  • To prevent possible hazards due to insulation failure, the unit must be grounded.
  • Each wiring connection must be done tightly and in accordance with the wiring system diagram. Wrong wiring may cause the unit to malfunction or become damaged.
  • Do not allow wiring to touch the refrigerant tubing, compressor, or any moving parts of the fan.
  • Ensure to comply with local codes on running the wire from the indoor unit to the outdoor unit (size of wire and wiring method, etc.).
  • Each wire must be firmly connected.
  • Be sure to connect the power supply line to the outdoor unit. The indoor unit draws its power from the outdoor unit.
  • Ensure field wiring complies with local regulation and electrical codes or as specified in the specification and voltage to the system is within limits. Operation of unit on improper line voltage constitutes abuse and could affect the units” reliability. Do not install the unit in the system where voltage imbalance may fluctuate above or below permissible units.
  • Detailed wiring procedure and wiring diagram is shown in ” Split AC Unit Manufacturer’s Installation Detail”.

C. Inspection and Testing

  • After completion of the work, the Site Engineer & Supervisor who perform an activity are required to raise an INR with complete attachment & information regarding the scope of the inspection, including necessary drawings highlighted to show the scope of the inspection. He shall systematically check and inspect their work. The inspection shall be performed according to a typical checklist and approved Inspection and Test Plans (ITP).
  • After Site Engineer & Supervisor completed their inspection and testing, INR shall be submitted to QA/QC Department who shall check and process the documents to have completed work inspected by Supervision Consultant for their approval.
  • Testing/running test of equipment installed shall be as per manufacturer’s instruction and witnessing by the supervision consultant prior to final approval. Details start-up and commissioning procedures are to be submitted in a separate method statement.
  • Manufacturers should be present during the start-up and commissioning of the equipment.
  • Raise INR for final inspection if no problem is encountered.

Note: INR must be processed and submitted to the supervision consultant 24 hours before the actual inspection and/or witnessing of the activity.

Health and Safety Analysis

A. Risk Assessment

Refer to Risk Assessment/Job Hazard Analysis.

B. Permit and Licensing Requirement

The required permit to work shall be obtained prior to commencement of work. This shall be coordinated with HSE. Site interface permits to be taken from other contractors before placing pipe at 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

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 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.
• Contractor must provide a safe place of works, with access and egress. Provide a safe working environment that is without risk to health.

Quality Assurance and Quality Control for Method Statement of Split AC Units Installation

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 project specification.
• The quality control requirement shall include related QCP’s, ITP’s and other related documents as applicable.

B. Quality Assurance Process

• The contractor shall notify the engineer 24 hours in advance prior to the start of the activity.
• 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, 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)


HSE Risk Assessment for Installation of Split AC Unit
Inspection and Test Plan for Installation of Split AC Unit
Checklist for Installation of Split AC Unit
Split AC Units Manufacturer’s Installation Detail

Split AC Unit Manufacturer’s Installation Detail –

How to install the split AC -watch this video.