Method Statement Title: Installation of Fresh Air Handling Units (Floor Mounted)

Method Statement Title: Installation of Fresh Air Handling Units (Floor Mounted)

1.0       Scope

1. This method statement applies to the installation of floor mounted air handling units as per the Specification Section 15700.

• Purpose

• Purpose of this method statement is to outline the method of storage and installation of Floor mounted Air Handling Units.

• Material

• Fresh air handling units.

• Pipes and fittings as per approved submittals/drawings.

• Ducting and accessories as per approved submittals/drawings.

• Electrical cables, control panel, other accessories if any, as per approved drawings and submittal.

• Method

• Receiving

• On arrival at site all Air Handling Units (AHUs) shall be checked for quantities, type and model number, physical damages, orientation of coil connections, access doors, etc.

• Upon delivery material on site inspection shall be carried by R&P/NMX/MACE.

• Upon satisfactory inspection the AHUs shall be stored properly with protective covering.

• Preparation

• Check the AHUs foundation and ensure it is as per approved drawings.

• Check the area around the foundation and ensure access to the AHUs from all sides as applicable.

• Ensure availability of sufficient slope to the drainpipe, for easy draining of condensate drain.

• Check the foundation surface and it shall be smooth finish to avoid any dust accumulation.

• The foundation surface shall be even in all directions.

• The foundation surface shall be cleaned before installation of AHUs.

• Mark the AHUs position on the foundation for centralisation.

• Place the anti vibration ribbed rubber pads of correct thickness as per approved drawings/submittals.

• In case of multiple rubber pads the pads shall be placed one above the other, with the ribs at right angle to each other.

• AHU sections are assembled at site/location by factory trained personal.

• Installation

• Shift the AHUs to the place of installation in safe manner using fork lift/crane as applicable. Sufficient manpower will be engaged as required for safe shifting and installation.

• Ensure that the correct AHU is shifted to the place of installation.

• Air inlet, outlet, fresh air connection and chilled water connection orientation are as per approved drawings.

• If the AHUs are shipped in multiple sections, the AHUs will be assembled strictly as per the manufacturer’s instructions.

• Remove the movement arrestors provided inside AHUs at Fan and impeller which are fixed during transportation.

• The AHUs are placed correctly on foundation with vibration isolator rubber pads at right location.

• The AHUs will be properly levelled and parallel to room walls/other installations.

• AHUs shall be inspected again for any damage during hoisting/shifting and installation by R&P/ETA.

• Upon satisfactory positioning of AHUs any open air/water outlets of AHUs shall be closed properly and area shall be cleaned, complete protection in areas where other trades are working.

• Air, Chilled water, Electrical and Condensate Drain connections

• Air side connections

• Ducting connection shall be done as per approved shop drawings.

• Provide flexible duct connections as applicable/as approved submittal.

• Provide proper supports as per approved drawings.

• The weight of ducting shall not act on AHUs panel.

• Before making final connections to AHUs ensure inner area of AHUs is clean, especially the impeller of the fan.

• Chilled Water connections

• Chilled water connections shall be made as per approved drawings.

• Ensure supply and return connection is made properly.

• Provide pipe flexible connection and other piping accessories as per approved drawings and submittals.

• The piping shall be free of any strain and shall not exert any load on, AHUs panel/AHUs.

• Provide vibration isolators to piping supports as per approved submittals/drawings.

• Install the control valves, strainer, commissioning set correctly as per direction of flow as per approved drawings.

• Ensure proper operation of valve handles and sufficient space for valve installation.

• The location and orientation of the gauges and commissioning sets shall allow for easy accessibility and readability of readings.

• Electrical connections

• Electrical power connections shall be done as per approved drawings.

• Cables shall be installed and terminated as per approved method statement Ref;ETA/MS/E/015.

• Condensate drain piping connections

• Condensate drain piping shall be terminated at the nearest floor drain.

• Provide the `U’ trap in the condensate drain piping.

• Ensure provision for cleaning of `U’ traps.

• Ensure proper slope to enable easy draining.

• Ensure trap is deeper than ESP of  fan – eg., 70mm > 650pa

• Cleaning

• Clean the interiors of AHUs including the impeller, drain tray.

• After completion of installation, it shall be checked and certified by the supplier/manufacturer and inspected by R&P/ETA.

4.6       Testing

• The piping connections to AHUs shall be pressure tested to 1.5 times the working pressures. Coils not included in test.

• Strainer shall be cleaned after pressure testing and initial flushing of chilled water piping system.

• Flow test of the AHUs drain tray, condensate drain pipe and ensure water is drained out completely.

• Inspection

• Work Inspection Request (WIR) shall be raised for consultant’s inspection.

• QC inspection shall be carried out as per the installation checklist and manufacturer’s instructions.

• Inspection shall be recorded in the approved format and signed off by R&P.

• Safety

• All safety precautions shall be followed as per established project safety plan and procedure.

• Only experienced and skilled technicians shall be engaged for carrying out AHUs installation work.

• The people involved in the installation shall use PPE such as safety helmets, safety shoes, harnesses, gloves, etc as required.

• Safety officer shall check and ensure that all safety precautions are followed.

• Safety officer shall check and ensure that all scaffolding and ladders used at site are having duly signed tags.

• Reference

• Manufacturers catalogue.

• Approved submittal.

• Shop drawings.

• Specification section 15700.

• Records

• `Work Inspection Request’ (WIR) duly signed by the Consultants.

8.2       Air Handling Unit installation checklist signed off by R&P.