The purpose of below Method Statement is to define step by step procedure for Installation of Air Handling Units AHU’s through the guide line contained herein so as to ensure that the job execution complies with the project requirements and serves the intended function to satisfactory level of the client & end users.
Following Tools & Equipment’s shall be arranged:
- Fork Lift or Crane with capacity & arrangement in line with the Manufacturer’s recommendations, pallet mover and as required at site.
- Hydraulic Trolley
- Portable hand tools.
- Portable Drilling Machine/ Grinding Machine & Angle Cutter.
- Spirit Level / Level Threads
- Scaffolding with platform.
Material Handling & Storage
On receipt of the Air Handling Units and accessories at site, necessary precautions shall be taken for
unloading, shifting & storage, as follows:-
- All Air Handling Unit received at site shall be inspected and ensured that the materials are as per approved material submittals in terms of their make, model type, point of origin and capacity.
- Upon arrival at site, the Air Handling Unit shall be off-loaded carefully at site by the Site Engineer / Site Supervisor using necessary manpower and required equipment to ensure that no damage is caused to the Air Handling Units.
- At site all the Air Handling Units will be stored in a clean / dry place and adequate covering by tarpaulin sheets will be done to protect the equipment from deposition of construction dust till it is finally shifted to its location.
- Any discrepancies, damage etc., found will be notified and reported for further action suitably.
GENERAL INSTALLATION REQUIREMENTS
- Ensure that the proper clearance is available from civil side before commencement of works.
- Ensure that the work area is clean and safe for carrying out the activities.
- Prior to start of works, it shall be ensured that the relevant shop drawings and coordination drawings are approved and issued for construction.
- It shall be ensured that no contradiction with other previously installed services, and if there is any shall be cleared.
- It shall be ensured that the material issued is as per the approved material submittal.
INSTALLATION PROCEDURE FOR AIR HANDLING UNIT AHU’s
- The following procedure shall be followed for the installation of Air Handling Units.
- Visually inspect the exterior casing of the Air Handling Units for any damages during transporting and transferring of the units.
- Materials shall be submitted for Consultant approval before proceeding with installation.
- Cut all banding (if applicable) loose from skid but do not remove the skids until the unit is shifted to the installation area.
- Site Engineer shall ensure that the installation of the Air Handling Unit is carried out in accordance with manufacturer’s installation recommendations and specification.
- Prior to start of installation, refer to the approved shop drawing related to the area of installation and ensure that required material is available at site as per approved material submittals.
- Ensure that the equipment and accessories are stored properly and there is no damage or deformity of any kind during transportation of material from site store to the working area.
- After inspecting the work area, ensure that it is totally ready for installation. Then the required equipment shall be moved to the place of installation.
- Check the equipment weight to ensure that the rigging equipment can handle that safely.
- Before installing the unit check whether proper space is available for unit servicing, installing and removing air filters or not.
- Proper marking shall be done for the unit location / supports as per approved shop drawing. Ensure the unit model number location shall be same as indicated on the drawing.
- Ensure that the orientation of AHU’s is matching with direction of supply and return duct.
- After inspecting the work area / foundation, ensure that it is totally ready for installation. Then the required equipment shall be moved to the place of installation.
- Under direct supervision of the Site Engineer / Site Supervisor, lift the air handling unit, transfer it to the allocated places as per approved shop drawing, position it on to the plinth using the crane if required or rolling as appropriate and feasible.
- Assembling of the air handling unit shall be done by aligning the sections by using the matching bolt of each sections and proper gaskets supplied by manufacturer, then tighten the bolts and make sure that the complete unit is resting properly on the rubber pads / spring isolators. Use proper gaskets as supplied by manufacturer while assembling the modules.
- Manually rotate the fan wheel to ensure free movement of the shaft and bearings. Check the base is free from corrosion and galvanized coating is applied, If required.
- Inspect the coils for fins damage.
- Check all the filters are fixed properly.
- Duct work shall be connected to AHU’s with Flexible Duct connector as per approved material submittal for supply, return and fresh air duct connections. Duct thermostat ( sensor ) and test point shall be installed as per approved shop drawing.
- Connect the piping net work to the air handling unit as per the approved drawing.
- Pipe work shall be connected to AHU’s with flexible connection. And ensure that all valves and control devices has been installed.
- Condensate drain pans shall be connected with pipe by using approved material submittal. Condensate drain pipes shall be directly connected to the traps and all condensate drain pipe shall be insulated as per approved method statement. Appropriate trap shall be provided as per approved drawings.
- Flushing & cleaning of system shall be done as per method statement which shall be submitted separately.
- Equipment, pipe identification, tagging & labeling shall be carried out after completion of all works as per approved material submittal / Specification.
- The V belt shall be checked for proper tension.
- All control devices , frequency drives application shall be as per approved BMS submittal.