METHOD OF STATEMENT

HVAC System
Purpose & Scope
The purpose of this method statement is to outline the method of storage, insulation and installation of HVAC
Supply / Return / Exhaust ducts including fixing of dampers, fire dampers and access doors and Installation of
Full Inverter based cooling only VRV (20 HP @ 16 TR) and High Static Ductable Type indoor unit of 06 TR
capacity each

Reference & Standards

 Approved Shop Drawings 
 SMACNA Standards
 ASHRAE Standards

Tools & Equipment


 Tool Box 
 Drilling Machine
 Spirit Level
 Grinder 

Method Statement for Firefighting System

 Ensure that all materials to be used and equipment to be installed should be checked by the Project
Engineer / Supervisor against equipment data sheets and approved drawings.

 All materials and equipment shall be inspected by Quality Control Department prior to shifting to work
site.

 The latest revision of the Approved Shop Drawing should be available at the installation area.

 Project Engineer / Supervisor will ensure that safety requirements have been complied with and are in
place.

 Project Engineer / Supervisor will orient and familiarize all the workers and assistants involved in the
installation regarding relevant approved drawings, technical submittals, installation procedures and
details, acceptance criteria.

 Locate where accessible for servicing and replacement.

Materials

 Pre fabricated ducts made of G.I. Sheet

 Duct mate flanges and corners for ducts.

 Threaded rods & MS. angles for supporting system.

 Thermal insulation as per approved submittal.

 Adhesive for fixing duct insulation.

 Duct Sealant.

 VCDs, Fire dampers, Motorized dampers and Access doors

Method

 When off-loading, the ducts shall be carefully lowered to ensure no damage to edges or duct surface.

 All ducts shall be stored on plywood or similar material to safeguard duct from any abrasions.

 Insulation material shall been stored in proper storage place and shall not be Exposed to direct sunlight.

 Duct Sealant and adhesive for insulation shall be stored in enclosed area in closed cans as per
manufacturer’s recommendations

Refrigerant Pipe Network

 Air Conditioning design and installation instructions and standards will be followed holistically. All pipe
work must be suitable for given refrigerant 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 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 are capped off at all times.

 The number of joints bends and sets are to be kept to a minimum. Butt joints will not be accepted;
properly swaged joints must be formed. Bends and sets are to be machine pulled to an approved radius
where possible.

 Flared joints must only be used when connecting to the manufacturer equipment.

 Pipe work to be properly fixed and supported using a recognized industry approved support system.

Drain Pipe work

 A condensate line shall be installed to each fan coil unit. This shall be installed and insulated as per the
standard specification. Minimum size of condensate pipes to be 15mm plastic and insulated. Condensate
shall be pumped from each fan coil, drains to run 1:80 minimum falls.

 Pipe work will be adequately supported in such a manner as to permit free movement due to expansion
and contraction.

 Pipe work should be graded to fall throughout, run to waste, and should be accessible for cleaning.

 On completion, a leak and function test must be carried out.

 Gravity drains will be installed whenever possible.

Electrical Work
 The contractor shall include for the design and installation (unless otherwise specified), including
connecting all items of mechanical equipment. The Contractor shall provide and install all wiring, cables,
conduit, trunking, cable trays, termination points, local means of isolation, control wiring etc., to
mechanical items to ensure that all items of equipment and controls fully function in accordance with
manufacturers’ recommendations

 All electrical cables used for power distribution will comply with the latest Electrical Standards

 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 Safety Regulations in every respect with
particular attention to clipping, earthing of equipment, grounding off, final connections and isolating.

 Earth bonds on refrigeration, cold water and drainage pipe work to be applied throughout.

 On completion the installation should be tested in accordance with the requirements of Inspection and
testing 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.

Insulation
 Thermal insulating material used within any building shall be thick nitrile rubber insulation

 Thermal insulation will be fitted to all the pipe work installations detailed herein.

 The materials and method of installation will comply with all relevant ASHRAE standards.

 In all cases where pipes pass through fire compartment walls, fire resistant and non-flammable
insulation/foam will be packed between the pipe sleeve and the pipe. All insulation will be supplied at the
thickness specified in relevant HVAC standards.

Ductwork, Grilles and Diffusers

 Unless specified otherwise all sheet metal ductwork will be manufactured and installed in accordance
with SMACNA standards.

 Ductwork shall be manufactured using hot dipped galvanized steel sheeting

 Bends and fittings for rectangular ductwork will be of the square type with internal turning vanes.

 Circular ductwork will generally be of the “spirally wound” type utilizing standard sizes as specified in
 DW/144.

 Bends in circular ductwork shall be a minimum of 0.5D throat radius.

 Branches onto main ducts will be by “shoe” type connections with a 45° leading edge.

 All ductwork will be adequately supported from the building structure using one of the methods
approved by DW/144 appropriate to the size of duct.

 All ductwork systems will be fitted with sufficient volume control dampers to enable system balancing. To
prevent noise regeneration final trimming to 10% only of airflows to be carried out using the opposed
blade dampers fitted to terminal devices.

 Fire dampers are to be fitted to ductwork passing through designated fire barriers, these dampers to be
fitted with HEVAC installation frames where passing through structural walls.

 Flexible ducting shall be used to form the final connection to the air terminal device. The maximum
length not to exceed 1.5 meters and incorporate a change in direction of not greater than 90°.

 Flexible ducting will be manufactured from aluminum/polyester/aluminum laminate enclosing a high

tensile steel wire helix.

 Joints between flexible and rigid ductwork to be secured by worm drive clip with the rigid ductwork
spigot incorporating a ‘swaged’ end.

 Insulation will be applied to the following ductwork systems: - Fresh air intake ductwork, ventilation
return air ducts passing through unheated spaces - All conditioned air ductwork (unless an architectural
feature and adequate control is provided to prevent condensation forming on the ductwork).

Pre-commissioning
The following items must be checked prior to any systems being switched on.

 A marked up scale site drawing showing all VRF units and refrigeration pipe work, address settings (for
units and remote controllers and BC branch connections) and model/serial numbers must be produced.

 All control wiring and remote controllers must be complete and connected but final connection left
disconnected.

 Before the Power Supply to Outdoor Unit is turned on, the mains wiring must be checked phase to
neutral, neutral to earth. Once this is complete the mains isolator can be switched on to allow the
crankcase heater to warm up the oil (minimum 24 hours).

 All power supply wiring to Indoor Units must be complete, tested and left switched on at Indoor Unit
isolators.

 All Indoor Units must be clearly marked with marker pen or similar indication and label indicating address
and branch controller connection and model/serial number.

 Condensate pipe work must be completed and tested.

 Total lengths of liquid line pipe work installed, must be confirmed by installation Engineers and marked
on drawings for additional refrigerant charge calculation.

 Sufficient supply of refrigerant in dumpy cylinders must be on site adjacent to the Outdoor Units ready
for use.

 Now charge refrigerant into pipe work based upon the additional refrigerant charge calculation.

 Outdoor Unit service valves must now be opened.

Safety :

 Safety precautions shall be followed with inline established project safety plan