Residential Units with Natural Ventilation

Re: 1) Unless smoking is prohibited in the whole building, which some rental properties have done, each unit is considered a "smoking room" and has to meet the credit requirements for door sweeps, sealing of plumbing, HVAC, and electrical penetrations in the walls, dedicated direct exhaust for each unit and verification with blower door testing. Yes, prohibiting smoking in all common areas will comply if smoking is also prohibited on any exterior balconies or decks that are w/in 25' of an operable window or intake vent, which is probably true of most exterior decks. 2) The blower door test is to verify that smoke will not migrate from unit to unit -which can certainly happen. This can be challenging to prevent, especially in metal stud framed construction. For party walls between units, make sure electrical outlets and other penetrations don't share a stud cavity or other chase that allows air to move between units. Extra effort may be needed to instruct and supervise that sub contractors and installers are providing adequate air sealing at all penetrations, fixtures, etc. Pocket doors can be problematic; gaskets may be needed on fixture, outlet and switch covers, etc. In our experience, the blower door has usually been set up at the unit entry door. I believe it's acceptable to cover with plastic & tape the exterior windows and kitchen & bath vent fans since these are connected to the outside and not to other units, but you'll want to verify that. The test is thus determining the air leakage in and out of the unit through the boundary it shares with other units, which is a good indicator of ETS transmission between units. Hope that helps!