Part A6 Building classification

Classification is a process for understanding risks in a building or part, according to its use. It must be correctly undertaken to achieve NCC aims as appropriate to each building in each circumstance.

It is possible for a single building to have parts with different classifications. Part of a building can also have more than one classification. Where there is any conflict between what requirements the part should comply with, the more stringent requirement applies.

Where it is unclear which classification should apply, appropriate authorities have the discretion to decide. They base their decision on an assessment of the building proposal.

They will look at what classification the building most closely resembles. They will also take into account the likely fire load, plus, the likely consequences of any risks to the safety, health and amenity of people using the building.

Appropriate authorities will also look at any relevant court decisions or determinations of the State or Territory body responsible for considering appeals on building classification matters.

It should be noted that appeals body determinations and, in some States and Territories, certain court decisions are usually not precedent creating. Such decisions are determined on a case-by-case basis.

It should also be noted that State and Territory authorities responsible for building regulatory matters may have issued advice, interpretations or guidelines to assist practitioners in applying the correct classification to a building or part. Advice on such matters should be sought from the relevant authority.

Under A6.0 Exemption 1, if 10% or less of the floor area of a storey is used for a purpose which could be classified differently to the remainder of that storey, that part may be classified as being the same as the remainder. Laboratories and sole-occupancy units in Class 2, 3 or 4 parts are excluded from this concession. The reason is that laboratories are considered to have a high fire hazard potential and classifying them with the remainder of the building could, in a majority of cases, endanger occupants of the other parts of the building which have a lower fire hazard potential. Also, the intent is not to allow sole-occupancy units in Class 2, 3 or 4 parts to be regarded as another Class such as Class 6 and then not have any fire or sound insulation between the units and any other classification which may have a high fire load and could endanger the occupants of the Class 2, 3 or 4 part.

If A6.0 Exemption 1 is used, it should be remembered that it will still be necessary to use the occupant numbers in Volume One Table D1.13 for the particular use of the area. Likewise, the lighting and equipment levels, people occupancy and load profiles for the area of minor use for the purposes of Volume One Section J must be in accordance with the use of the area.

If the storey has a very large floor area, the 10% or less concession area may also be large, even though the rest of the building is classifiable as a building which ordinarily has a lower risk potential. An example of the application of this area concession could be as follows:

• If a single storey factory has an office that takes up 8% of the whole storey's floor area, the entire building (including the office) can be classified as being Class 8.
• However if that office area takes up 12% of the storey's floor area, that area must be classified as Class 5, and the remainder of the building as Class 8.

Under A6.0(3) a plant room, machinery room, lift motor room or boiler room, have the same classification as the part of the building they are in. These kinds of rooms do not need to be ancillary or subordinate to the part of the building they are in, that is, the 10% criterion is not applicable.

There are specific provisions for these kinds of rooms. For example, Volume One Section C requires some of them to be fire separated from the remainder of the building (e.g. see C2.13 with regard to elements of the electricity supply system).

Class 1 buildings are covered in Volumes Two and Three of the NCC. Class 1 buildings are not located above or below another dwelling, or another class of building other than a private garage.

A sole-occupancy unit used for residential purposes located over another sole-occupancy unit used for residential purposes will always be a Class 2 or Class 3 building (depending on the circumstances). It cannot be a Class 1 building.

A single Class 1 dwelling can be made up of more than one building. For example, it may include what is ordinarily called a house, plus one or more habitable ‘outbuildings’ such as sleepouts. Note that a habitable building such as a sleepout cannot be classified as a Class 10 building.

The height or number of storeys of a Class 1 building makes no difference to its classification.

Class 1b buildings used for short-term holiday accommodation include cabins in caravan parks, tourist parks, farm stay, holiday resorts and similar tourist accommodation. This accommodation itself is typically rented out on a commercial basis for short periods and generally does not require the signing of a lease agreement. Short-term accommodation can also be provided in a boarding house, guest house, hostel, bed and breakfast accommodation or the like.

Unlike a Class 1b building described in A6.1(2)(a), a Class 1b building described in A6.1(2)(b) does not have any floor area limitation. Therefore, if 4 or more single dwellings are located on the one allotment and used for short-term holiday accommodation, each single dwelling would be classified as a Class 1b building regardless of the floor area of each dwelling or the combined floor area of all of the dwellings.

See also Volume One Table D3.1 which contains an explanation of what is considered be "one allotment".

The Class 1b classification can attract concessions applicable to Class 3 buildings. These concessions allow people to rent out rooms in a house, or run a bed and breakfast, without having to comply with the more stringent Class 3 requirements. The reasoning is that the smaller size of the building and its lower number of occupants represents reduced fire risks.

Apart from their use, the primary difference between Class 1a and Class 1b buildings is that the latter is required to have a greater number of smoke alarms and in some circumstances, access and features for people with a disability.

A Class 2 building is one that includes more than one dwelling, each of which is generally solely occupied by one or more people to the exclusion of others.

Such buildings must not be otherwise classified as a Class 1 or Class 3 building or Class 4 part. See Figure 4 for a typical configuration of Class 1 and Class 2 buildings.

Figure 4: Section showing a typical configuration of Class 1 and Class 2 buildings (with non-combustible roof coverings)

Where a sole-occupancy residential unit is located above another sole-occupancy residential unit, the building containing the units can be either a Class 2 or a Class 3 building, depending on the other circumstances of the building proposal.

Class 2 buildings can be single storey attached dwellings. Where there is any common space below such dwellings, they are Class 2 (and cannot be Class 1) irrespective of whether the space below is a storey or not (see Figure 5).

Figure 5: Elevation showing a single storey of Class 2 with a common area below

Class 2 buildings can be attached to buildings of another Class. The attached Class 2 buildings need not be attached to one another, and need not be more than a single storey.

When two or more dwellings are attached to another Class, they cannot be Class 4 parts, as any building can only contain one Class 4 dwelling.

Class 3 buildings provide accommodation for unrelated people. The length of stay is unimportant.

Some exceptions to this classification include: certain bed and breakfast accommodation, boarding houses, guest houses, hostels, or lodging houses and the like which fall within the concession provided for Class 1b buildings.

Also, any sized building can be classified as Class 1 or Class 2 if it is used to house any number of unrelated people who jointly own or rent it, or share it on a non-rental basis with an owner or tenant.

It is not unusual for a manager's, owner's or caretaker's dwelling attached to a Class 3 building to be thought of as a Class 4 part of the Class 3 building. However, a Class 4 part of a building can only be part of a Class 5-9 building.

Accordingly, such dwellings are either classified as Class 1, Class 2 or Class 3, depending on the circumstances of the building proposal. However, a building could be a mixture of Class 3 and another Class.

Class 3 buildings include—

• the residential parts of hotels and motels; and
• hotel or motel caretakers', managers' or owners' flats, noting that under certain circumstances such dwellings could be Class 1, Class 2 or Class 3 buildings; and
• dormitory accommodation, in schools or elsewhere, noting that a dormitory is generally (but not always) considered to be a sole-occupancy unit; and
• bed and breakfast accommodation, a boarding house, guest house, hostel, or lodging house; and
• backpackers' accommodation; and
• a building which houses elderly people or other people who require special care. (In some States or Territories it is not acceptable for a Class 1b building to be used to house elderly people or other people who require special care - it is recommended the local building regulatory body be consulted.); and
• workers' quarters, including shearers' or fruit pickers' accommodation, or hotel workers' accommodation.

Class 4 classification applies to some types of accommodation located within a Class 5-9 building. The most common include a caretaker's flat within a building; and accommodation over or otherwise connected to a shop.

A Class 4 part cannot be located within a Class 1, Class 2 or Class 3 building. There can only be one Class 4 dwelling in a building. If there are two or more dwellings, they are Class 1, Class 2, or possibly Class 3. These Class 1, Class 2 or Class 3 parts need not be attached to one another, nor be more than a single storey.

Where a Class 4 part of a building is rented out for accommodation purposes, it retains its Class 4 classification. However, if any other part of the principal building is used for accommodation, for example, the attached shop is converted into an additional flat, both flats become classifiable as Class 2 or, depending on their use, possibly Class 3.

Class 5 buildings include professional chambers or suites, lawyers' offices, government offices, advertising agencies and accountants' offices.

A Class 6 building is a building where goods or services are directly sold or supplied to the public. Examples of a Class 6 building may include—

• a place where food or drink may be purchased such as a café or restaurant; or
• a dining room, bar area that is not an assembly building, shop or kiosk part of a hotel or motel; or
• a hairdresser’s or barber’s shop, public laundry, veterinarian; or
• supermarket or sale room, florist, showroom, or service station.

Service stations are Class 6 buildings. These are outlets used for the servicing of cars and the selling of fuel or other goods. The expression ‘service station’ is not intended to cover buildings where panel beating, auto electrical, muffler replacement, tyre replacement and the like are solely carried out. Such buildings should be classified as Class 6, Class 7 or Class 8 buildings as the appropriate authority sees fit.

There are three basic types of Class 7 building. The first is a carpark as defined in the NCC. The second is a building used for storage, often referred to as a ‘warehouse’. The third is a building used for the display of goods or produce for sale by wholesale. ‘Wholesale’ means sale to people in the trades or in the business of ‘on-selling’ goods and services to another party (including the public).

The most common way to describe a Class 8 building is as a ‘factory’. However, this can give a simplistic impression of the types of building which can fall within this classification.

For example—

• some laboratories, despite their often small size, have been included as Class 8 buildings principally because of their high fire hazard ; and
• buildings used for altering or repairing (except service stations, which are specifically included in A6.6 as Class 6 buildings); and
• potteries; and
• food manufacturers (but not restaurants, which are specifically included in A6.6 as Class 6 buildings); and
• buildings used for the packing or processing of produce, such as a farm or horticultural building.

Class 9a buildings are health-care buildings, including day-care surgeries or procedure units and the like. See definition of health-care building. Laboratories that are part of a Class 9a building are Class 9a, despite the general classification of laboratories as Class 8 buildings.

Class 9b buildings are assembly buildings. These buildings can include—

• theatres, cinemas and halls, churches, schools, early childhood centres, kindergartens, preschools and child-minding centres; and
• indoor cricket, tennis, basketball centres and sport stadiums; and
• nightclubs, discotheques, bar areas providing live entertainment and/or containing a dance floor, public halls, dance halls and other places of entertainment; and
• snooker halls; and
• bus and railway stations.

Regarding A6.9(2) E xemption 1, a building could be a mixture of Class 9b and another Class, or a Class 9b building could contain parts that are of another Class, but be taken as a Class 9b building because of A6.0 Exemption 1.

Class 9c buildings are residential care buildings that may contain residents who have various care level needs.

The Class 9c classification recognises that many residents progress through a continuum of care needs from low to high. Many older people enter residential care with low care needs (typically Class 3 facilities) but, as they age, require higher levels of care. In the past, such progression often necessitated the transfer of a hostel resident (Class 3) to a nursing home (Class 9a). This frequently had negative consequences for the health and well-being of the resident, for whom the hostel accommodation was home. It also led, at times, to the separation of couples with differing care needs.

Building designers should note that Class 3 buildings include hostels for the accommodation of the aged, and Class 9a buildings include nursing homes. It is important to be aware, however, that construction of Class 3 or 9a buildings may restrict the options available to the operators of a facility in relation to the profile of the residents they wish to accommodate. Where the potential exists for residents of varying care needs to be accommodated, consideration of the Class 9c provisions may be appropriate. The Class 9c classification allows for any mix of low and high care residents and is intended to allow the mix to change as the residents' care needs change over time, without the need to obtain any further consent or approval from the appropriate authority.

Multi-care level facilities are for residents who may require the full range of care services outlined by the Aged Care Act. Hence, it is not intended to restrict the resident type and provides maximum flexibility for service providers, residents and the community.

The NCC provisions for Class 9c buildings are based on minimal on duty on-site staff being available at any time. However, it is recognised that the staff numbers vary throughout the course of any one day, due to the care needs of the residents and the functioning of the facility. It is also recognised that the specific care needs of the residents may result in a greater minimum number of staff.

Class 10a buildings are non-habitable buildings. See Figure 6 for an indication of some Class 10 building configurations.

Figure 6: Examples of Class 10 buildings and structures

Class 10b structures are non-habitable structures. There is no requirement for Class 10 buildings to be appurtenant to a building of any other Class, for example, a small shed standing on its own on an allotment and a toilet block in a park.

A habitable ‘outbuilding’ which is appurtenant to another building is generally part of that building. Again, habitable ‘outbuildings’ cannot be classified as Class 10 buildings.

Typical outbuilding classifications include the following:

• A sleepout on the same allotment as a Class 1 building is part of the Class 1 building.
• A detached entertainment room on the same allotment as a Class 1 building, perhaps associated with a swimming pool, is part of the Class 1 building.
• A small toolshed, used for trade-related hobbies for non-commercial purposes or home repairs, on the same allotment as a Class 1 building, would be classified as a Class 10 building.

Provisions relating to Class 10c structures are only intended to address private bushfire shelters associated with a single Class 1a dwelling. These provisions are contained in Volume Two of the NCC.

Some States or Territories may exempt some Class 10 buildings or structures (often on the basis of height or size) from the need to have a building permit. Queries on this matter should be referred to the State or Territory body responsible for regulatory matters.

Difficult classifications

Class 2 or Class 3?

There is a fine line between a Class 2 building containing apartments or flats and a Class 3 motel building with units containing bathroom, laundry and cooking facilities, which may both be made available for short term holiday rental. When does a Class 3 motel unit become a Class 2 holiday flat and vice versa?

In general, an assessment will be based on the most likely use of the building by appropriate authorities.

Class 3 buildings, where the occupants are generally unfamiliar with the building and have minimum control over the safety of the building, represent a higher risk level and therefore require higher safety levels. In a case where the classification is unclear, a decision should be made according to the perceived risks inherent in the use of the building.

Class 6 or Class 7?

Class 7 buildings include those used to sell goods on the wholesale market, whereas Class 6 buildings are used to sell goods to the public.

Some establishments claim to sell goods to both the wholesale and retail markets. As a rule, however, if the general public has access to the building, it is considered a ‘shop’, and therefore a Class 6 building.

Hotel bars – Class 6 or 9b

As can be seen from the definition of a Class 6 building, it includes a hotel bar which is not an assembly building. The bar includes the bar area and associated standing and seating areas. This clarifies that the bar extends beyond the serving area to include standing and sitting areas where patrons may drink alcohol or other beverages and consume food. The exclusion of anassembly building means that a bar providing live entertainment or containing a dance floor is not considered to be Class 6, it must be considered as Class 9b. However, when that use is minor compared with the remainder of the bar, such as a piano bar or the like where patrons only listen to music and there is no dance floor, the appropriate authority should exercise judgement on the predominant use and therefore the appropriate classification of the bar.

A Class 9b building is an assembly building which is defined to include a building where people may assemble for entertainment, recreational or sporting purposes.

A building may have more than one classification (see A6.11)

Buildings used for farming purposes

Buildings used for farming-type purposes are often very diverse in nature, occupancy, use and size. In some States or Territories, appropriate authorities may classify farm buildings as Class 10a, which covers non-habitable buildings. They would only make this decision if a classification of Class 7 or Class 8 would not be more appropriate.

When making their decision they consider the building's size, purpose, operations and the extent to which people are employed in the building. For example, it may be appropriate to classify a shed which is used to store a tractor as a Class 10a building.

The NCC has definitions of "farm building" and "farm shed" which are certain Class 7 and 8 buildings used for farming purposes. Concessions to specific Deemed-to-Satisfy Provisions apply to farm buildings and farm sheds in recognition of their often low risk features, and it is recommended that reference is made to the definitions of "farm building" and "farm shed" for further guidance which may assist determination of an appropriate NCC classification.

For example, if people are likely to be employed to stack materials/produce in a storage building or remove materials/produce from a storage building then a classification of Class 7b may be appropriate. Depending upon whether the criteria in the definition of farm shed or farm building have been met, the associated Deemed-to-Satisfy Provisions in NCC Volume One Part H3 may apply.

Similarly if people are likely to be employed to pack or process materials/produce within a building, or employed to feed, clean or collect produce from animals or plants within a building then a classification of Class 8 may be appropriate. Depending upon whether the criteria in the definition of farm shed or farm building have been met, the associated Deemed-to-Satisfy Provisions in NCC Volume One Part H3 may apply.

However identification of low fire load, low occupant risk and low risk of fire spread should not be used as justification for choosing a less stringent building classification for a building under the Deemed-to-Satisfy Provisions. For example, if the intended use of a building is to grow or store a large amount of tomatoes, such as a large greenhouse, and there is likely to be only one to two persons in the building at any time, it is considered inappropriate to classify the building as a Class 10a under the Deemed-to-Satisfy Provisions and a classification of Class 7 or Class 8 would be more appropriate.

The Deemed-to-Satisfy Provisions for a Class 7 or Class 8 farm building or farm shed do not prevent the ability to consider or develop a Performance Solution for a particular building where the requirements may not be considered appropriate or are viewed as too stringent. Similarly if a Class 7 or 8 building used for farming purposes does not meet all the criteria to be considered a farm building or farm shed under the Deemed-to-Satisfy Provisions, this would not limit the ability to develop a Performance Solution which could contain features similar to those allowed under the Deemed-to-Satisfy Provisions for farm buildings or farm sheds.

For example, if a Class 8 commercial poultry building meets all the criteria to be considered a farm building under the Deemed-to-Satisfy Provisions other than the maximum floor area criteria, a Performance Solution could be developed to demonstrate that the concessions for a farm building under the Deemed-to-Satisfy Provisions are appropriate.

In regards to a farm building or farm shed where the purpose of the building is to park farm vehicles when not in use, as well as perhaps clean or polish the vehicle(s), it may be appropriate that this type of building is classified as a Class 7a.

However, a number of farm buildings and farm sheds are often not only used for the storage of farm vehicles, but to store supplies such as fuel, grain or hay. A Class 7a classification may still be appropriate where the majority of the shed's space is intended to be designated for the parking of vehicles. However, it may be more appropriate to classify some types of buildings as Class 7b, rather than Class 7a where a mixed use shed is intended.

Under A6.11 each part of a building (including the entire building) may have more than one classification. This means, for example, that it is permissible to classify part of a building as a Class 6/7 building, or a Class 5/6 building, or whatever is appropriate.

It is expected that this approach may be taken by a builder who is uncertain of what the precise use of a building will be after its sale, or to maximise the flexibility of the building's use.

Under A6.11 Application 1 where a building has more than one classification the more stringent Class requirements will apply.