HVAC Metal Duct Hangers and Support Installation

This article is about HVAC Metal Duct Hangers and Support Installation as per International Codes and standards.

Support for Rectangular ducts when suspended from above shall be installed on two opposite side of each duct.
(UMC Para. 603.1.2 )”
Supports for Rectangular Ducts shall be riveted, bolted, or metal screwed to each side of the duct at not more than the intervals specified in Table 6-E of UMC (See attachment 1)
(UMC Para. 603.1.2 )”
Horizontal round duct 40 inches or less in diameter when suspended from above shall be supported at intervals not more than as set forth in Table 6-E of UMC (See attachment 1) with one hanger installed.
Ducts shall be equipped with tight fitting circular bands extending around the entire perimeter of the duct at each specified support interval
Circular bands shall not be less than one inch wide nor less than equivalent to the gauge of the duct material it supports
Each circular bands shall be provided with suitable means connecting to the suspending support
Ducts shall be braced and guyed to prevent lateral or horizontal swing
Horizontal Duct shall have a support within two feet of each elbow and within 4 feet of each branch intersection (SMACNA Para 4.1.1)
Concrete Inserts shall be installed before the concrete is poured (SMACNA Para. 4.2.1)
Concrete fasteners shall be installed after the concrete has been poured and the forms have been removed (SMACNA Para. 4.2.2)”
The Support system shall not cause corrosion by galvanic action at points of contact with the duct
(UMC Para. 6.104.5 Appendix “”A””)
Note: Corrosion by galvanic action occurs when dissimilar metals are in contact with each other.
The support system shall not penetrate enclosures containing fluids or electrical wiring in such a manner to create a hazard
(UMC Para. 6.104.6 Appendix “”A””)”
The support system shall not penetrate a bearing member in such a manner as to cause excessive loading on the member
(UMC Para. 6.104.7 Appendix “”A”” ).
When Ducts are supported from wall they shall be located against the wall or maximum of 2″ away from wall. Weld, bolt or No. 8 (Min) screw may be used as fasteners. (SMACNA FIG 4-8 Note No. 2).
Fastener (for supporting ducts from wall) shall be located within 1″ of the duct edge (wall side) and within 2″ of the duct outer edge. Minimum of 3 on 24″ width and up is required in addition to ones from edges. (SMACNA FIG 4-8)
Rectangular duct risers from floor shall be supported by angles or channels secured to the sides of duct with welds, bolts, sheet metal screws, or blind rivets. Fasteners shall be located within 2″” of the duct edges, locate others at evenly spaced intervals as shown on Construction Drawings. (SMACNA Para 4.2.10)
Note: 1-If the spacing of the fasteners are not specified / shown, then spacing shall be as instructed by Saudi Aramco.
2- Angle sizes and their spacing shall be as shown on the Construction Drawings, if they are not shown / specified, then sizes and spacing shall be as instructed by Saudi Aramco.”
Round Ducts riser from floor shall be supported by split band support by supplemental angle or channel spanning the slab opening or as recommended by the manufacturer. Minimum of two fasteners in each half of band is required.
Note: No. of fasteners and spacing shall be as shown in Construction drawings. If Construction drawings do not address the number of the fasteners and/or spacing of them then the number of the fasteners and spacing shall be as instructed by Saudi Aramco (SMACNA FIG 4-9)”
Angles shall be at 12 feet intervals for rectangular and round duct risers. (SMACNA Para 4.2.10)