(1) Except as provided in Sentences (2) and (3), a repair garage shall be separated from other occupancies by a fire separation having a fire-resistance rating of not less than 2 h.
(2) Ancillary spaces directly serving a repair garage, including waiting rooms, reception rooms, tool and parts storage areas and supervisory office space, need not be separated from the repair garage but shall be separated from other occupancies as required in Sentence (1).
(3) The fire separation referred to in Sentence (1) shall have a fire-resistance rating of not less than 1 h, where,
(a) the building is not more than one storey in building height,
(b) the building is operated as a single suite, and
(c) the only occupancy other than the repair garage is a mercantile occupancy.
(4) Where a building containing a repair garage also contains a dwelling unit, an air barrier system conforming to Subsection 9.25.3. shall be installed between the dwelling unit and the suite containing the garage to provide an effective air barrier to gas and exhaust fumes.
(5) Where membrane materials are used to provide the required airtightness in the air barrier system, all joints shall be sealed and structurally supported.