(1) If access is provided through a fire separation between a storage garage and a Group A, Division 1 or Group B occupancy or a retirement home, the access shall be through a vestibule conforming to Sentence (3).
(2) In a building more than 3 storeys in building height, access through a fire separation between a storage garage and a Group A, Division 2, 3 or 4, or a Group C occupancy, shall be through a vestibule conforming to Sentence (3).
(3) If access is provided through a vestibule, as required by Sentences (1), (2) and 3.3.5.4. (1), the vestibule shall,
(a) be not less than 1.8 m long,
(b) be ventilated,
(i) naturally to outside air by a vent that has an unobstructed area of not less than 0.1 m² for each door that opens into the vestibule but not less than 0.4 m², or
(ii) mechanically at a rate of 14 m^3/h for each square metre of vestibule floor surface area, and
(c) have openings between the vestibule and an adjoining occupancy provided with self-closing doors with no hold-open devices.