How are buildings classified?
In the Building Code of Australia (BCA), the National Construction Code (NCC) classifies buildings according to their primary use. Just like wind classifications, each classification comes with respective requirements with regards to safety, design, accessibility, etc. These technical specifications must be met by a building’s design.
Buildings are classified by number, from Class 1 to Class 10, some of which contain sub-classes. It can happen that a building is made up of parts with different functions.
In cases like these, the parts are individually classified. When a single building has multiple functions, it can also be given multiple classifications.
The buildings in Class 1 are houses. In particular, they are standalone structures that serve as residences.
Two types of sub-class in Class 1:
- Class 1a: any single residence, (house, townhouses or duplex, etc.)
- Class 2a: a boarding or hostel type of residence housing not more than 12 individuals, with a maximum floor area of 300 sqm
Apartment buildings are usually the ones in Class 2.
This classification contains residential buildings that have many units, where units are on different floors (Class 1 buildings can be multi-storey, but cannot have any other class of building above or below their residences aside from garages).
A one-storey residence with more than one unit with a common area could also fall under Class 2.
The buildings in Class 3 are actually the same as the buildings in Class 1b, but bigger in size and have a higher capacity.
They are meant for long-term living of people that are not necessarily associated with one another. Common examples are larger boarding houses, hostels, dorms, and the like.
The parts of hotels, hospitals, schools, or jails where people live can also be sorted into Class 3.
Anything Class 4 is actually just a part of a larger building. More specifically, it is a dwelling that sits inside a primarily non-residential building.
Most often, the Class 4 area of a building is the only residence within the larger structure. It is always located within a building in Class 5, 6, 7, 8, or 9.
Office buildings that are in professional or commercial use go into Class 5.
Company offices, law or accounting firms, government buildings, etc. are all Class 5.
Stores and restaurants of any kind would be listed in Class 6.
They are places where goods or services are sold to the public. Some common examples would be cafes, salons, supermarkets, malls, and the like.
Buildings and areas for storage and parking.
Two types of sub-class in Class 7:
- Class 7a: parking lots
- Class 7b: buildings that are used for either (1) storage or (2) the display of wholesale products
Class 8 buildings are used for business operations, such as manufacturing, adjustment, servicing, cleaning or packaging, etc. of products.
Most often, these buildings are simply factories. Mechanic workshops, food production buildings, and scientific laboratories are also in Class 8.
Class 9 has three sub-classes, but they are all generally buildings that are used by the public.
- Class 9a: these are healthcare buildings, such as hospitals or clinics (where people would need help in case the need for evacuation arises)
- Class 9b: these are buildings where gatherings can occur for social, theatrical, political, religious, etc. purposes, such as schools, sports buildings, dance clubs, churches, train stations, etc.
- Class 9c: homes for the aged
Buildings in Class 10 are basically those that can’t house people. They can actually also just be structures. It also has three sub-classes:
- Class 10a: single and double garage (3 cars or less), storage sheds, etc.
- Class 10b: fences, retaining walls, masts, swimming pools, etc.
- Class 10c: a private bushfire shelter on the premises of a Class 1a building (but not physically attached to it)
As you probably noticed, a single structure can have parts that fall under different classes. A grocery building (Class 6) could have a parking area (Class 7a).
As a general rule, the different parts of the building will be classified individually unless it takes up less than 10% of the space of the floor that it is found on.
In those cases, it will just be put in the same class as the majority.
Multiple Building Classifications
There may also be cases where a single structure or a single part of the structure has multiple uses, and would therefore have more than one class. They may be classified as Class 5 / 6 or Class 6 / 7 and the like.
Many buildings are constructed for the purpose of renting out space to tenants, so flexibility is actually desirable.
What About Special Cases?
A general practitioner’s “office” is Class 5 unless it performs treatment that would cause patients to be temporarily unconscious or immobile (any building that does so would fall under Class 9a).
Car repair or service centers are actually Class 6 buildings, but parts of them could become Class 8 if they are used exclusively for certain mechanical or electrical processes.
Labs are usually Class 8, but if they are attached to or found within a Class 9a building, then they will also be classified as Class 9a.