Source: Noson, Perbix, SSD
To brace ducts.
Provide transverse and longitudinal bracing in accordance with the SMACNA Seismic Restraint Manual Guidelines for Mechanical Systems.
- Steel angles—size varies with ducts
- Machine bolts—1/2" diameter
- Sheet metal screws—No. 10
- Provide angle braces sized in accordance with the SMACNA guidelines. Attach together with machine bolts. Maximum spacing is 40' for transverse bracing and 80' for longitudinal bracing.
- Provide screws at 18" on center maximum from the bracing to the duct.
- Attach bracing to the structure above in accordance with the SMACNA guidelines.
- Bracing is required at ducts exceeding 6 square feet in cross-sectional areas, and for round ducts exceeding 28" in diameter.
- No bracing is required if the top of the duct is 12" or less from the support above. See SMACNA guidelines for hanger requirements.
- Walls, through which ducts pass, can be substituted for transverse braces. Provide blocking around the duct.