Protecting Ductwork on Roof

[Kwanjuju]

I am working on a job where I'm being forced to run duct horizontally out of an RTU prior to turning down into the building.

What is the proper way of protecting ductwork installed a roof? I was told something about what sounds to be a pitched covering to prevent water from pooling on the ductwork, but we don't have a detail of anything like that.

 

[tys90]

We just note to pitch it to prevent ponding, means and methods from there.

Double wall duct or some pvc jacket should also be considered.

 

[SAK9]

For exposed ducts it is better to insulate them internally so that there may be no issues with water ight cladding,rivetting, sealing etc.It will be aesthetically pleasing as well.