(2)For the purpose of this Act, "use group" or "occupancy" shall mean the purpose for which a building or part of a building is used or intended to be used. For the purpose of classification of a building according to occupancy, occupancy shall be deemed to include subsidiary occupancies which are contingent upon it. The classification of occupancy shall include residential, educational, institutional, assembly, business, mercantile (retail), mercantile {wholesale), industrial, storage and hazardous. The principal occupancy shall be the occupancy covering more than 50 per cent of the floor area of a building. In case no single occupancy covers more than 50 per cent of the floor area of a building, the building shall be classified as "mixed use building". The classification of buildings based on principal occupancy, shall be as follows :"residential building", "educational building", "institutional building", "assembly building", "business building", "mercantile building (retail)", "mercantile building (wholesale)", "industrial building", "storage building", and "hazardous building".
