HVAC Duct Work & Accessories Installation Method Statement
This method statement cover on site installation of pre-fabricated duct-work systems manufactured from hot dipped galvanized steel sheet to S.M.A.C.N.A.
2. SCOPE OF WORK
This method statement is to define the method to be used to ensure that prefabricated ducting, bracketing, and in line equipment installation and final connections and workmanship are correct and acceptable, and conforming to the contract documents and General Specifications
Material to be submitted for review by the Client- see latest Revision of the Material Procurement Schedule.
3. RESPONSIBLE PERSONNEL
- Construction Manager
- Mechanical Superintendent.
- Warehouse Controller
- Q.C. Engineer/Inspector
4. METHOD – PRE-INSTALLATION
- All materials drawings and other documentation relevant to a particular section of works will be checked by the Construction Department prior to the commence of work ensuring that these are of the correct type as reviewed by the Client.
- Before commencing any construction works, pre-inspections will be carried out on all materials prior to them leaving the storage area
- Prior to the commencement of any construction works, areas and access will be inspected by the Construction Team to ensure that they are in a suitable condition for construction works to commence. The Client will be invited to attend this inspection at his discretion.
- A close co-ordination with other trades will be carried out on site prior to commence work.
- A safe and protective storage area will be allocated on site, in close co-ordination with the employer.
5. METHOD OF INSTALLATION
- Supervisor will instruct tradesmen regarding the execution of the works and will distribute all necessary approved construction drawings of the latest revision.
- The supervisor will also check that tools and equipment available are in compliance with the contract requirements.
- Ensure horizontal ductwork is adequately supported at equal distances in accordance with Construction Drawings with all brackets fixed to the vertical face of ribbed beams of the structure.
- Care will be taken during setting out, that ductwork runs between ceiling module lines so as to maintain maximum flexibility for any future relocation of lighting fixtures or other services.
- Ductwork supports unless otherwise indicated will be installed to provide a minimum space of 15mm between finished covering and adjacent work, and 100mm clearance from suspended ceiling.
- Supports or hangers will be placed within 300mm of any 45° – 90° bend.
- Screwed drop rods will have thread adjustment in either direction available after leveling of ductwork and associated plenum box’s.
- Ducts will be supported within 300mm of mating flanges or joints.
- As indicated on relevant approved construction drawings where more than one duct can be supported on one hanger – the size of the hanger will be assessed on the sum of the maximum widths.
- Ductwork passing through non fire rated walls and floors will be adequately supported on either side.
- All locknuts are tightened correctly. At all open end’s check for debris then cover with suitable material to prevent any ingress of debris vermin, or moisture.
- Supervisor to ensure that there are no dents, distortion or buckling of ducting during installation being aware that damaged sheet metal work will be rejected.
- Supports are to be fixed at correct levels checking the bracket material is compatible with the installation and the correct method used for thermal insulation.
- Ducting to be installed allowing sufficient space for expansion/contraction and thermal insulation.
- Fixing of flanges to ductwork will be by the approved details and in compliance with the specification requirements: a) Clean both flange faces to be joined. b) Add gasket jointing material to flanges to be mated. c) Using only undamaged rust free bolts nuts and washers join mating flanges together and tighten bolts. d) Clean any excess jointing material from flanges.
- Continuously check horizontal and vertical alignment of ductwork and compliance with contractors drawings and specification requirements by using spirit level plumb or other suitable instrument.
- In line equipment is to be independently supported from main structure and not blockwork walls or sub-structure.
- Silencers, fire dampers, balancing dampers & other plant items will be installed as per contractors drawings, and will be supported adequately.
- Supervisor to check before end of work day’s by recording in his diary (as necessary) that: a) The correct type supports installed, b) Supports are adequately supporting the ductwork and associated plant equipment.
- Test holes to be provided and plugged ready for commissioning and control equipment.
- Ensure terminal equipment is installed as specified.
- Supervisor to ensure that all completed installations look neat and tidy, and that there is adequate spacing between ductwork and in line equipment allowing access for operation and ease of maintenance, to approved contractors drawings and manufacture’s recommendations.
- The supervisor in charge and the QC officer shall continuously monitor the activities (by recording the defects or snags into his House Process Inspection List) to ensure that all components indicated on the approved contractors drawings have been installed and that the installation is in accordance with the contract requirements.
6. SAFETY AND ENVIRONMENTAL CONSIDERATION
Ductwork check list.
8. REFERENCE DOCUMENTS
- Particular Technical Specification Vol 2. Mechanical
- S.M.A.C.N.A .Specification for Ductwork Construction and Installation 1985
- Painting & Identification See CONP-09-07
- For Second Fix Accessories, see separate Construction Quality Plan No. 07 ( i.e. For Grilles, Louvers etc.)
- See Construction Quality Plan On Site Ductwork Manufacture
- Contractors Drawings