Rectangular Duct Design per SMACNA
Rectangular Duct Design per SMACNA
(OP)
Hi All,
I have question about rectangular sheet metal duct welding.
When joining the sheet metal to form a rectangular duct, is it required to use a continuous longitudinal seam weld at the welded corners (See Figure 16, SMACNA 1980), or is intermittent seam weld acceptable. Use of continuous seam weld seems like on overkill. What is the common standard practice in duct world ?
Thanks
StrainStress
I have question about rectangular sheet metal duct welding.
When joining the sheet metal to form a rectangular duct, is it required to use a continuous longitudinal seam weld at the welded corners (See Figure 16, SMACNA 1980), or is intermittent seam weld acceptable. Use of continuous seam weld seems like on overkill. What is the common standard practice in duct world ?
Thanks
StrainStress





RE: Rectangular Duct Design per SMACNA
RE: Rectangular Duct Design per SMACNA
RE: Rectangular Duct Design per SMACNA
Most other ducts use folded seams, i.e. Lockform, Snaplock.
There is a system that uses a pocket and flange that is tack welded about every 12 to 18 inches with a 1" stitch.
As Drazen and Chicopee say don't do it unless you have to.
B.E.
You are judged not by what you know, but by what you can do.
RE: Rectangular Duct Design per SMACNA
RE: Rectangular Duct Design per SMACNA
Yes the longitudinal seam machine was an odd duck, I have only ever seen one used in a shop, It looked a bit like an end-cap machine, it turned a pocket on one side and a flange on the other. In use a sealant gun laid a bead in the pocket, then the duct was folded, assembled and tacked with a Mig welder.
I think the snaplock superceded this system.
B.E.
You are judged not by what you know, but by what you can do.