I am installing a new range hood and my only option for venting is to run the 6" duct vertically from the first floor, up through a second floor closet, and then through the roof. This gives the shortest run, and also allows me to not have a large soffit running the length of my kitchen.
Anyway, the 6" duct will be in the closet. My questions are:
1. Does the 6" duct need to be enclosed in a "wall" or other structure, or can the vent be exposed in the closet? The 6" duct will be rigid, smooth 6" duct pipe (with all seams sealed).
2. If the duct does have to be enclosed, what are the requirements for enclosing the duct? Can I just build a small 2x2 wall and sheetrock it? Any weird requirements?