3.12.2.1. Requirements for Stations (1) Except as provided in this Subsection, the requirements in Subsections 3.2.1. and 3.2.2. do not apply to a rapid transit station. (2) The requirements in Sentence (3) shall apply to (a) a rapid transit station erected entirely below the adjoining finished ground level, and (b) the underground portion of a rapid transit station. (3) Except as permitted in Sentence (4), an underground station or an underground portion of a station in Sentence (2) shall be of noncombustible construction, and (a) floor assemblies shall be fire separations having a fire-resistance rating not less than 2 h, (b) roof assemblies below ground level (i) shall have a fire-resistance rating not less than 2 h, or (ii) a fire-resistance rating is not required where steel tunnel liners are left in place to form part of the assembly and the tunnel liners are in direct contact with soil, and (c) all loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (4) An interior stair extending to street level is permitted to be protected by a combustible roof. (5) Where a rapid transit station is erected above and below the adjoining finished ground level, the above ground portion of the station shall be of noncombustible construction and shall conform to the requirements in Sentence (10). (6) Where a rapid transit station is erected entirely above the adjoining finished ground level and is a stand-alone building, the station shall be of noncombustible construction and shall conform to the requirements in Sentence (11). (7) Openings for stairways and escalators used by passengers are permitted to penetrate the fire separations required in Sentences (2) to (6). (8) Elevator shafts are permitted to penetrate the fire separations required in Sentences (2) to (6) provided they are enclosed by (a) a fire separation having a fire-resistance rating not less than 1 h, or (b) wired glass assemblies conforming to the Supplementary Guidelines. (9) Openings for other than stairways, escalators or elevators are permitted to penetrate the fire separations required in Sentences (2) to (6) provided the openings are protected by a closure having a fire-protection rating not less than 45 min. (10) The building shall be of noncombustible construction, and (a) floor assemblies shall be fire separations with a fire-resistance rating not less than 2 h, (b) mezzanines shall have a fire-resistance rating not less 1 h, (c) roof assemblies shall have a fire-resistance rating not less than 1 h, and (d) all loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (11) Except as provided in Sentence (12), the building shall be of noncombustible construction, and (a) floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h, (b) mezzanines shall have a fire-resistance rating not less than 1 h, (c) roof assemblies shall have a fire-resistance rating not less than 1 h, and (d) all loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (12) A building classified as Group A, Division 2 occupancy that is not more than 1 storey in building height, and in which the building area is not more than 3 200 m2 if not sprinklered, or 6 400 m2 if sprinklered, is permitted to be constructed with a roof of heavy timber construction and have columns of heavy timber construction. 3.12.3.Safety Requirements Within Stations