ICE
Oh Well
Cloth straps are listed for use a duct support. That is a mistake. The webbing folds and becomes a code violation. Used with metal duct or small diameter flex duct does not present a problem however, as you can see in the pictures, there is a limit to it's use. Under ideal conditions where the duct is supported every 4.5 feet and not sagging I suppose that the straps can do a good job with flex duct. That seldom happens.I thought the cloth straps were OK for flex ducts.
The third picture shows what appears to be a successful outcome. Even there, the middle strap might be folded and narrow. It is a challenge to inspect duct in an existing attic because unless you are willing to crawl on ceiling joist, it is likely that you won't see it all. So what to do? When this UL listed webbing first hit the market I turned it down. Yes I know that I was exceeding my authority.....but wait a minute....when I said no it stuck so I must have been within my authority... But then a person with more authority overrode my no with a yes.
I tried to convince the AHJ that this stuff is no good. I hit a wall and mostly gave up. I could only say no to strap that I saw was folded and ask for ideal conditions. There was still plenty of occasions to turn it down.
Last edited: