This is a question from Australia, (I think I’m the only Australian member of BPA).
Our national building code is being updated in 2022. We currently do not address air tightness in our building code and the ‘code writers’ are reluctant to include it.
They state, "Unfortunately, air leakage testing of new dwellings in Australia has not been sufficiently extensive to develop an evidence base sufficient to allow the development of new regulation."
Does anyone know of any studies that may be available regarding air tightness of the building envelope?