Method Statement For VRF SYSTEM

CONTENTS

1. SCOPE
2. PURPOSE
3. RESPONSIBILITES
4. SAFTY
5. PROCEDURES
6. COMMESIONING

1. SCOPE:

The scope of this method statement covers installation of the VRF System (Refrigerant Piping Network, Piping Fittings and Transmission Networks) for all floors in accordance with specifications and drawings.

• PURPOSE:

The Purpose of this method statement is to describe the materials which will be used and work procedure for VRF System.

• RESPONSIBILITES:

• TIBA Project manager or his engineers are responsible for ensuring that this method statement is fully implemented upon approval by supervision consultant.
• TIBA Quality Control Engineer is responsible for the proper implementation of the quality control procedures including inspection and testing of materials.

• PROCEDURES:

• General procedure

The fixing of all air conditioning equipment, installation of all refrigerant pipe work and full commissioning shall be performed by a specialist refrigerant installer who shall be authorized to install VRF equipment

Accredited installer will ensure that all personnel are instructed to comply with the prevailing site rules/directions.

Accredited installer shall clearly state on his tender submission the specialist sub-contractor he intends to employ to carry out the work if not in their direct employment.

Full access shall be afforded to site during the installation stage of the project to allow them to verify that installation methods are fully in accordance with the supplier requirements and that the equipment’s warranties will not be invalidated. All works including labor, materials, plant, tools and equipment will comply with the standard.

Furth more all of the following points should be adhered to.

• Accredited installer retains the responsibility to advise of any aspects which, based upon experience, would appear to be inappropriate and or likely to lead to operational problems.
  •  Accredited installer will adhere to the health & safety at the site, and all other relevant attendant legislation.

• Accredited installer will ensure that all personnel are fully competent in the work they are tasked to perform and any claim to stated qualifications are valid.
  • Accredited installer will ensure that all personnel are instructed to comply with the prevailing site rules /directions.

• Accredited installer will use calibrated and regularly checked tools. Electrical tools will be calibrated and checked annually.

• Upon completion of the works, accredited installer will ensure that all debris is removed and the site is left clean and tidy to the satisfaction of customer.

• Refrigeration Pipe work

Supply and installation of all interconnecting refrigeration pipe work should be carried out by an Accredited Installer )TIBA ((certificate of approval must be submitted prior the installation commencement – the refrigeration pipes will be supplied by the manufacturer), the certificate of approval to be issued through the supplier or manufacturer representative. All pipe work must be suitable for R410a as applicable. Longest possible lengths of copper pipe should be utilized to minimize joints on site furthermore all of the following points should be adhered to.

• All copper pipes up to 2 1/8” outside diameter (O/D) shall be fabricated from refrigerant quality tube to the project specification. Tube shall be fully annealed (soft) up to 5/8” outside diameter (O/D) only. Tube shall be delivered to site internally degreased and shall be stored in clean dry conditions with ends sealed until required for installation. Outdoor support for pipes shall be covered tray, indoor pipes supports shall be hanger support each 1.5 meter.

Fig. 1- Minimum copper pipes thickness

• All due consideration and allowances shall be taken to keep pipe work clean and dry during the installation works. Ensuring that all pipe work unfinished ends capped off at all items.

• Flared joints must only be used when connecting to the manufacturers’ equipment.

• Pipe work to properly fixed and supported using a recognized and approved hanger support by the supplier and the engineer.

• Pipe work shall be suitably identified and labeled, where specified. Brazing shall be carried out in accordance with Refrigeration Association Specification for Brazing. At all times, when brazing, a small amount of dry nitrogen must be purged through the pipe to prevent oxidation and scaling internally. Any component susceptible to heat during the brazing process that may be damaged must be protected.

All Completed R410 a system will be strength and leak tested with dry. If the system is found to be leaking free. The final pressure reading for both strength leaks testing is to be witnessed and entered into the supplier checklist.

3. Steps strength and leak test:

1. 3 bar (N2) for 3 min or more ( for contractor checking before submit to consultant )
2. 15 bar (N2) for 3 min or more ( for contractor checking before submit to consultant )
3. 40 bar (N2) for approximate 24 hours ( for inspection from consultant side )

• On completion of strength /leak testing an evacuation is to be carried out for more than 2hr and bring the system to (- 30mmHg) and the system will remain under this condition for more than 15 minutes.
  • The  inspection request will be submitted as follow:
• For copper pipe installation.
• Strength and leak tested for copper pipe at 40 bar (N2) for approximate 24 hours with copper pipe brazing.
• For copper pipe insulation.
• For indoor unit installation.
• For outdoor unit installation.
• Testing flared joints and connecting the copper pipes to the indoor unit.

• Electrical work

Electrical work contractor shall include for the design, shop drawing, material submittal and installation (unless otherwise specified). Including connecting all items of mechanical equipment. Electrical work contractor shall provide and install all wiring, cables, cable trays, termination points, and local means of Isolation, control wiring etc., to mechanical plant items to ensure that all items of equipment and controls fully function in accordance with manufacturers’ recommendations.

• All electrical cables and data/control cables used for power distribution will comply with the project specification and manufacturer recommendations. The control cables from the outdoor units to the indoor units shall be installed along the refrigeration pipes and will be provided inside EMT conduits.

•  Appropriate glands will be fitted to each item of equipment in accordance with environmental conditions.

• The whole installation will be in full accordance with the project regulations in every respect with particular attention to clipping, earthling of equipment, gladding off, final connections and isolating.

• On completion the installation should be tested in accordance with the requirements of inspection and testing section of the supplier Regulations. Inspection shall include physical check that all equipment has been securely fixed and that all electrical connections are mechanically sound.

• Where necessary, to prevent damage to components of equipment, the equipment shall be disconnected for the duration of the relevant tests.

• A disconnect switch of isolating the electricity supply shall be fitted adjacent to and within reach and sight of the equipment.

• When running interconnecting control wiring it is essential to avoid the risk of electronic control signals being corrupted. Care should therefore be taken to avoid running control cables too close to power cables.

• Thermal insulation

Thermal insulating material used within any building shall be classified as noncombustible also free from substances which in the event of a fire would generate appreciable quantities of smoke or toxic fumes. Insulating materials shall be as defined by the building regulations and as per approved material submittals.

• Thermal insulating will be fitted to all the pipe work installations detailed herein all materials used will be ‘non-combustible’. All insulation materials adhesives and finishes will be suitable in all respects for continuous use without degradation throughout the range of operating temperatures and within the environment indicated.

Accredited installer will apply identification banding in all instances. Labeling will include the wording ‘Refrigerant under pressure’