Lynn2202 wrote:I'm specifically looking for the required size of the vent and if it must be constructed with a double wall and insullation.
Your question has a complex answer, so I will start here:
- The vent size within the condo will be the standard 4 inch size (unless the designers of the system increased the size for whatever reasons they had).
- The vent size for the main riser is dependent on the engineering done regarding the number of inlets on each riser, the connection to each riser, the size (CFM rating) of the roof mounted exhaust fans, and other considerations,
- The riser would have been required to have been constructed and sealed at all joints, then enclosed in at least a 2 hour rated shaft enclosure.
- The dryer duct within each condo is not allowed to be in the plenum, thus each condo dryer duct should have been sealed off from the plenum, typically by enclosing in metal framing chase/soffit which is then covered with gypsum board which is bedded and taped to seal the dryer duct off from the plenum.
- The dryer duct within each condo would have either been 26 gage or 30 gage sheet metal.
Those are the basics for that riser and the condo branch duct to each dryer connection.
Hopefully in there somewhere I answered your questions.