(1) A building classified as Group A, Division 1 is permitted to conform to Sentence (2) provided,
(a) it is not more than 1 storey in building height,
(b) it has less than 40% of the area of the building as 2 storeys for the purpose of,
(i) development of productions including preparation of scenery and costumes and rehearsal of performers,
(ii) organization of performers, scenery and sound equipment,
(iii) preparation by performers for a performance,
(iv) managerial functions, or
(v) toilets, rest rooms and similar public facilities,
(c) it has no occupancy above or below the auditorium other than one that serves it or is dependent on it,
(d) it is not more than 600 m2 in building area, and
(e) the occupant load is not more than 600.
(2) The building referred to in Sentence (1) is permitted to be of heavy timber construction or noncombustible construction used singly or in combination, and,
(a) floor assemblies shall be fire separations,
(i) with a fire-resistance rating not less than 45 min, or
(ii) of heavy timber construction, and
(b) loadbearing walls, columns and arches shall,
(i) have a fire-resistance rating not less than that required for the supported assembly, or
(ii) be of heavy timber construction.