All buildings erected after 1 January 1974 must have a building classification, which is determined in accordance with the Regulations. Buildings erected prior to this date may have a classification assigned to them. The classification assists in determining the requirements for fire safety, weatherproofing, sanitary facilities, room sizes and other matters. The owner of a building must not permit the building to be occupied unless the building is constructed, maintained and operated in accordance with the classification appropriate to its use. Purchasers of buildings or persons renovating premises should ensure that the classification of the building is appropriate to its use.