AMDP uses two types of duct reinforcement, internal tie rods & external angle reinforcements, located at duct joints and mid-panel on duct and fittings per SMACNA standards. We use tie rods when warranted unless otherwise requested.
Reinforcements must be fastened (tack welded, spot welded, riveted, screwed, or bolted) at 8” intervals maximum. When ends are tied, the 3/4” interval may be omitted. When reinforcements occur at the same location on adjacent sides at 4” W.G. (1000 Pa.) static and greater, tie the ends. 4.5