BCA Definition of Class 2 and Class 3 Buildings

AUST  Hendry building surveying consultants endeavour to clarify the differences in classification and use of Class 2 and Class 3 buildings as designated in the Building Code of Australia in this article.

Traditionally, we have not experienced difficulties in assessing the use of Class 2 or Class 3 buildings under the Building Code of Australia. A certain degree of clear thinking has been necessary and this process is usually assisted by requiring a “statement of use” and an explanation of the operation and management of a facility from the user perspective.

Misunderstandings do occur in the description of use of a building and our experience indicates this can be attributed to the terminology differences between planning schemes and Building Code of Australia.

Traditionally, we view Class 3 buildings to be of long or short term accommodation, with shared facilities, where a person may or may not own their sole occupancy unit. We usually expect to see some form of shared facilities in a Class 3 building. However, shared facilities such as laundry facilities under the BCA are permitted in Class 2 buildings and this can lead to some confusion as to the building’s correct classification, Class 2 or Class 3. Typically, a Class 3 building has shared facilities consisting of:

  • Kitchen and dining room
  • Laundry facilities
  • Toilet and bathrooms

The toilet and bathroom facilities can be provided within the sole occupancy unit of a Class 3 building. However, we consider that an experienced building surveyor will easily “cut through” such circumstances.

Whilst we are aware that a Class 2 use is usually permanent accommodation for its occupier, contemporary motels and hotels have rooms arranged as separate sole occupancy units where one may, in fact, be a Class 2 classification and the other a Class 3 classification, although these may be combined together at certain times resulting in a single Class 2 sole occupancy unit. This arrangement is achieved by creating a “common private entry lobby” opening off the main public corridor which can also be part of the public corridor. When both sole occupancy units are used individually, the private lobby is, in fact, part of the public corridor but is then closed off when the two units become a single unit.

Notwithstanding this arrangement, the fire separation aspects etc. for the Building Code of Australia are complied with no matter how the rooms are used, so it is simply a use/ classification issue, Class 2 or Class 3. We have, in the past, adopted a multiple classification for those buildings (sole occupancy rooms) described above and determined compliance with both classifications. i.e., the building may have a Class 2 and Class 3 classification. Once Class 2 and Class 3 has been applied, the actual use is irrelevant to a certain degree as fire safety for occupants and health/ amenity issues are satisfied and complied with under the Building Code of Australia. Planning scheme and health registration requirements must always be satisfied.

Our opinion is that it is critical to establish the classification and use (Class 2 or Class 3) of a building at the design stage as one cannot check compliance with the Building Code of Australia unless this occurs. Any change during construction is treated as a departure from the building approval plans for which a new approval (planning and building) would be required for the new Class 2 or Class 3. Thus, any change is managed through the approval process.

When a building is completed, an occupancy permit must be issued which sets out the approved use applicable to that building or parts of that building, i.e. Class 2 or Class 3 classification. There is, to some degree, no way of preventing an owner of not meeting the specified use of a building but this is, in itself, an offence under building control and planning legislation. Also, particular non approved and registered uses can contravene the Health Act, other local Council by-laws, State and Federal legislation. It is normal to expect a building to undergo a change of use during its life provided it has been dealt with as required by legislation and the Building Code of Australia, therefore the obligation resides with an owner who must ensure that they comply with both building health and planning approvals issued for their building.

It is correct to assume that an incorrect classification of a building may lead to an erosion of fire safety, health and amenity and this could occur if a Class 3 use is incorrectly classified as a Class 2 building and vice versa.

The prime areas of concern, should this occur, relates to the fire separation between rooms (sole occupancy rooms/ units) and public corridors and the flow-on effects of this and the provision of accessible rooms and facilities. This scenario becomes an obvious issue where a Class 2 dwelling, which has say 5 large bedrooms, is subsequently provided with double bunk accommodation where separate rent is payable by the individuals resulting in the “sole occupancy unit” test not being met, but really is a Class 3 use. The requirements applicable to a Class 1b classification under the BCA may be a guide as to how one should view the classification of this particular “sole occupancy unit”.

The bottom line, however, is to ensure that the use is clearly established at the outset, but should this prove to be overlooked or ignored by the owner, then it simply becomes an enforcement issue for non-compliance. Consequently, the expertise, nature of engagement, conduct, frequency of site inspections undertaken, production of reports and details to owners, etc. are key components of ensuring that such circumstances do not unknowingly occur.

In conclusion, our opinion is that the Building Code of Australia is satisfactory in the classification of buildings of Class 2 or Class 3 usage but may need clearer guidelines and requirements designed to define the application to those classifications; such as, a limit on the occupancy in a Class 3 sole occupancy room or more clearly define a Class 2 dwelling, notwithstanding that there is an overlay here with health registration laws, other local Council by-laws, State and Federal legislation.

Of particular interest to us is that Clauses C2.14, C3.11 and Specification C1.1 Tables 3, 4 and 5 in the Building Code of Australia must be read together in order to establish all of the requirements for walls bounding public corridors, lobbies and the like without acknowledgement that the stairway is an extension to a public corridor and must also be captured as part of these provisions. This results in interpretations such as allowing a void to connect floors and public corridors in Class 2 and Class 3 buildings without recognising the implications of the separation requirements. The atrium provisions can sometimes be exploited to “allow” this type of design.

Another concern arises when a Class 2 or Class 3 use is constructed above another commercial use which does not require any smoke hazard management provision whereas the Class 2 or 3 part does. That is to say the Class 2 or 3 use is compromised because the commercial use is below the level of requiring any smoke hazard management provision, other than when they share the same fire stair. Our view is that a review of specific provisions of the Building Code of Australia may well go hand in hand with the better application of the Building Code of Australia to determining the correct use of the building.

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