(1) A building classified as Group B, Division 2 or Division 3 is permitted to be of combustible construction or noncombustible construction used singly or in combination, provided,
(a) except as permitted by Sentence 3.2.2.7. (1), the building is sprinklered,
(b) it is not more than 1 storey in building height, and
(c) it has a building area not more than 500 m2.