Normally we see double elbows or specialty flashings for drier vent terminations above roof. Would B vent cap be allowed? or does it have to much potential to trap lint?
504.4 Exhaust installation.
Dryer exhaust ducts for clothes dryers shall terminate on the outside of the building and shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination. Ducts shall not be connected or installed with sheet metal screws or other fasteners that will obstruct the exhaust flow. Clothes dryer exhaust ducts shall not be connected to a vent connector, vent or chimney. Clothes dryer exhaust ducts shall not extend into or through ducts or plenums.
A duct termination for a clothes dryer may not have any screening and is required to have a back draft damper at the termination. While the louvers aren’t “screens” they are tight enough to trap lint and it lacks a damper.
Thanks for the help. Great clear answer!