Help Interpreting SMACNA - Duct Construction Standard 1

[IBechir]

With reference to SMACNA Duct Construction Standard, in page 20 of Appendix A under the heading: 'Sample Shop Standards for 2" W.G. Pressure Class what are the 'brake shop' and 'coil line' referred to in the tables? Why are there separate tables for each?

Also how can a zee channel/bar be used to stiffen a duct joint?

Thank you,

 

[berkshire]

IBechir,
The brake shops, 10'-00" or 8'-00" are capable of producing sections of that length so accordingly have joints that far apart.
Read note A2 on page A19 .
A coil line is a machine that pulls material off a coil, shears, notches the ends, and bends the panels automatically, the sections are usually the width of the coil
In fact I would suggest re reading the entire Manual again, the questions you raise will then make more sense.
B.E.

You are judged not by what you know, but by what you can do.

 

[IBechir]

But why would both need to be specified in a shop standard? Isn't it enough to show the duct dimension, gauge and reinforcement type/spacing? Why should it be known if the duct came from a 'brake shop' or a 'coil line'? How is it important?

 

[berkshire]

IBechir
The seam locations are different. Refer to the letters next to the duct size, then go to Fig 1.5 in section 1.67. in the 1995 standard , (I have the second edition one here.), to see the longitudinal seam locations.
To answer your earlier question about, "How can a Z channel be used to stiffen a duct joint?" This is usually an intermediate stiffener, but it will stiffen the joint if placed on the duct within 3" of the joint. It is more common to use Standing S joints .
Remember too, that the schedules in the appendices are merely guides they are not gospel.

From the guide" The designer must apply construction standards appropriate for the requirements and scope of each project. Fabricators and installers must select features from the joint, seam, reinforcement and support options that will conform to the performance criteria identified in this manual ETC.. read full text on page 1.4.
B.E.

You are judged not by what you know, but by what you can do.