Unless otherwise specified, all the dampers and duct accessories installation shall be according to the approved shop drawings and contract mechanical specifications.
Drawings, plans, schematics and diagrams indicate general location and arrangement of ductworks, install the dampers as indicated unless deviations to the layout are approved on coordination drawings.
This duct accessories and dampers installation method statement covers all types of dampers including backdraft dampers, manual volume control dampers, fire dampers, combination fire and smoke dampers, and motorized dampers.
Before installing the dampers, examine areas and conditions with requirements for installation tolerances and other conditions that may affect the performance, operation and maintenance of dampers.
Install all the duct accessories according to applicable details in SMACNA’s “HVAC DUCT CONSTRUCTION Standards – metal and Flexible” for metal ducts and in NAIMA AH116, “Fibrous Glass Duct Construction Standards,” for fibrous-glass ducts.
Dampers installation shall be according to manufacturer’s installation instructions and applicable portions of details of construction as shown in SMACNA standards.
Install dampers of materials suited to duct materials, i.e. use galvanized-steel dampers in galvanized-steel ducts.
Install volume control dampers VCD in lined duct with methods to avoid damage to liner and to avoid erosion of duct liner. Install backdraft or control dampers (as identified on the drawings) at inlet of exhaust fans or exhaust ducts as close as possible to exhaust fans unless otherwise indicated.
Volume control dampers shall be installed at points on supply, return, and exhaust systems where branches extend from larger ducts.
Where dampers are installed in ducts having duct liner, install dampers with hat channels of same depth as liner, and terminal liner with nosing at hat channel.
HVAC Duct Security Bars Installation
Construct duct security bars from 0.164-inch (4.18- mm) steel sleeve, continuously welded at all joints and 1/2-inch (13-mm) diameter steel bars, 6 inches (150-mm) o.c. in each direction in center of sleeve.
Weld each bar to steel sleeve and each crossing bar.
Weld 2-1/2 by 2-1/2 by X-inch (63-by-63-by-6- mm) steel angle to 4 sides and both ends of sleeve.
Connect duct security bars to ducts with flexible connections.
Provide 12-by-12-inch (300-by-300-mm) hinged access panel with cam lock in duct in each side of sleeve.
Access Door Installation
Install duct access doors on sides of ducts to allow for inspecting, adjusting, and maintaining accessories and equipment at the following location:
Downstream from manual volume dampers, motorized dampers, and backdraft dampers.
Adjacent to and close enough to fire or smoke dampers, to reset or reinstall fusible links.
Access doors for access to fire or smoke dampers having fusible links shall be pressure relief access doors and shall be outward operation for access doors installed upstream from dampers and inward operation for access doors installed downstream from dampers.
Access door sizes vs Hinges
Access doors less than 300 mm square: No hinges and two sash locks.
Access doors up to 460 mm square: Two hinges and two sash locks.
Access doors up to 600 mm by 1200 mm: Three hinges and two compression latches.
Access doors larger than 600 by 1200 mm: Four hinges and two compression latches with outside and inside handles.
Label access doors according to specification Section “Identification for HVAC Piping and Equipment” to indicate the purpose of access door.
Install duct test holes where required for testing and balancing purposes.
Steps for Installation of VC Dampers
Before installation check any physical damages on the dampers.
Determine the position of the damper to be fixed on the duct from the construction drawing and check site conditions.
Fix the VCD in available space by flange or nut/bolt and apply duct sealant.
Examine the location for requirement of installation tolerances and clearances as specified in the drawings.
Manually move the volume control damper (VCD) to the desired position in a way that damper channel frame matches the duct flange.
Installation Method Statement For Fire Dampers
Before installation check any physical damages on the dampers
Determine the position of the fire damper to be fixed on the duct from the construction drawings.
Fix the damper with flange or nut/bolt and apply duct sealant.
Examine the location for requirement of installation tolerance and clearance as specified with the drawings.
Fire dampers should be installed in all fire rated walls, floors and partitions.
Installation of fire dampers should be completed as per specification and manufacture recommendations.
Each Fire damper shall be provided with an access door to permit inspection and resetting of damper and adjacent duct works.
Provide duct access doors for internal access to all fire dampers for sizes bigger than 300 mm width of the duct.
Motorized Fire Damper Installation Procedure
Before installation check any physical damages on the motorized dampers.
Determine the position of the damper to be fixed on the duct from the construction drawings.
Fix the damper with flange or nut /bolt and apply duct sealant.
Examine the location for requirement of installation tolerances and clearances as specified in the drawings.
Provide duct access doors for internal access to all dampers.
All fire dampers Installed will be as per applicable local and international standards.
Inspection and Testing of Dampers
During installation, ensure that each damper complies with the specification requirements.
Notify the main contractor / consultant in advance at least 24 hours before inspection time.
Set dampers to fully open position before testing, adjusting, and balancing.
Provide test holes at inlet and outlet and elsewhere as indicated.
Check that fire and smoke dampers installation is according to the manufacturer’s UL listing.
Make sure the installation of necessary interfacing cables for fire and smoke dampers with the fire alarm system.
Check that access doors are installed with swing against duct static pressure.
Follow-up inspections will be carried out as the work progresses until completion of a particular phase of installation.
Operate fire, smoke, and combination fire and smoke dampers to verify full range of movement and verify that proper heat-response device is installed.
Operate remote damper operators to verify full range of movement of operator and damper.
Adjust volume control devices as required by the duct testing and balancing procedures to achieve required air flow as-per the contract specifications and performance parameters.
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