(1) Except as provided in Sentences (2) and (3), a storage garage shall be separated from other occupancies by a fire separation having not less than a 1.5 h fire-resistance rating.
(2) Except as permitted in Sentence (3), storage garages containing 5 motor vehicles or fewer shall be separated from other occupancies by a fire separation of not less than 1 h.
(3) Where a storage garage serves only the house or the individual dwelling unit it is attached to or built into, it shall be considered as part of that house or dwelling unit and the fire separation required in Sentence (2) need not be provided between the garage and the house or dwelling unit.
(4) Where a storage garage is attached to or built into a building of residential occupancy,
(a) an air barrier system conforming to Subsection 9.25.3. shall be installed between the garage and the remainder of the building to provide an effective barrier to gas and exhaust fumes, and
(b) every door between the garage and the remainder of the building shall conform to Article 9.10.13.15.
(5) Where membrane materials are used to provide the required airtightness in the air barrier system, all joints shall be sealed and structurally supported.