NCC Tutor lesson - Understanding building classifications

Slide 1:

Welcome to Understanding building classifications.

Slide 2:

The focus of this presentation is building classifications, which are essential to understanding and using the NCC correctly. There is one set of building classifications in the NCC, and they are used within all Volumes.

You have probably referred to different building classifications as you go about your work, or heard others talking about them, for example, talking about whether a building was a Class 1a building or a Class 1b building, or discussing whether a particular kind of building met the requirements for a Class 6 building. 

Most of the requirements in the NCC apply to a specific classification - or specific classifications - of building, so you need to be able to identify which classification/s any relevant building belongs to, and know where to go when you need an authoritative decision on which classification is most appropriate for a building, when there are arguments for it failing under more than one classification.

That’s what you will learn about in this presentation.

Slide 3:

What you will learn. Where to find information about building classifications. The 10 building classifications in the NCC. Building classifications for mixed use buildings and buildings with more than one classification. Applying this to different types of buildings.

Slide 4:

Where to find information about building classifications in the NCC. 

Building classifications are in Part A6 of the Governing Requirements in each volumes.

The text is identical in all volumes. (As is all of the Governing Requirements).

If they know/have read the information on building classifications in one volume, then they have read what it says in the other volumes as well. 

Part A6 contains the formal definitions of each building classification, and some explanatory information, which discusses distinctions between the classifications and gives a lot of useful examples.

The Building classifications handout is another resource they can use. It contains more explanations and examples that can be helpful, especially when trying to distinguish between 2 possible classifications. 

It is available from the ABCB website.

Slide 5:

So, What are the NCC building classifications? Buildings are built to serve different purposes, so the way that they are designed and constructed also varies. Therefore, the requirements that they must meet also vary, in terms of things like size, space, facilities, light, how you enter them and exit from them, fire safety and structural strength. 

Building classifications within the NCC reflect this variation in the purpose of different buildings, and the Performance Requirements that they must meet.

Consider a single family home versus an apartment block versus a backpacker hostel versus a hotel. We might sleep, relax and otherwise live in all of them, but a single family home would not successfully fill the purpose of a hotel or backpacker hostel, nor would it make for comfortable accommodation for multiple families.

An office block versus a warehouse versus a factory versus a small retail shopfront. People might work in all of these buildings, but the work they are doing varies along with the number of people who might work in each one, the number of visitors we might get, and the other materials we might keep in the space. A typical office block would make an inconvenient warehouse and a warehouse would be an uncomfortable office or shopfront, in most instances.

Because buildings have different purposes, they also need to perform differently, as a structure. They will be different sizes and shapes, they will need different numbers, sizes and shapes of rooms, they will need different amounts of light and warmth, and will need different facilities, such as bathrooms, electrical connections and lifts. They will vary in their energy and water use, their requirements for safety and security, including ways to get in and out of the buildings, and they will vary by their need to resist fire and their structural strength.

Consider the facilities required for safe evacuation of a single storey shop/retail building versus a multi-storey office block. Any door or window in a single storey shop may be able to be used for escape from a fire or other hazard, so there are often multiple routes for evacuation. The same is not true in a multi-storey building, where the windows are usually not able to be used for evacuation. This means that dedicated escape paths (usually fire stairs) are needed in multi-storey buildings, but not usually in single-storey buildings. The numbers of people who are likely to be in each building are also very different, resulting in different requirements for services to suppress a fire in order to allow time for people to escape.

A hospital versus a school hall. Facilities to allow for safe evacuation of people from the building would be different in these 2 buildings, because of the assumption that a large number of people in a hospital might have difficulty evacuating on their own. They may not be able to walk, use stairs or move without bringing equipment with them. While evacuating a school hall of primary school aged children might not be as easy as evacuating adults, we can assume most of them will be able to walk out of the building without assistance (although they will probably need shepherding by adults).

The NCC manages this variation in building purpose and requirements by grouping buildings by their function and use, assigning a building classification to each grouping, and specifying particular Performance Requirements for particular classifications of buildings.

Sub-classifications (e.g. 1a, 1b) are treated as separate classifications, so effectively there are 16 building classifications/sub-classifications. A Performance Requirement might apply to Class 1a, or Class 1b, or it might apply to Class 1, which means that it applies to both Class 1a and Class 1b.

Volume One is usually thought of as covering the “commercial” building classifications.

Volume Two is thought of as covering the “residential” building classifications. They may have heard people in the industry referring to Volume Two as the “Housing Provisions”.

This separation is not hard and fast. In particular, there are some disability access provisions in Volume One that may also apply to Class 1b buildings, which are otherwise covered in Volume Two. 

Slide 6:

How well do you know the difference between building classifications?

Class 1. Class 1a; single dwelling/house, detached, row/terrace, duplex. Class 1b, boarding house, guest house, hostel less than 300m squared, usually fewer than 12 people. 

Class 10. Class 10a; non-habitable building, Shed, carport, garage. Class 10b; structure, Fence, mast, antenna, retaining wall, pool. Class 10c; private bushfire shelter, associated with a Class 1a building only.

Class 2. Class 2 Apartment building, typically multi-storey, multi-unit residential building where people live above and below each other. Also single-storey dwellings with a common space below them, such as a garage

Class 3. Class 3 Residential building (not a Class1 or 2 building or Class 4 part of a building), For long-term or transient living by unrelated people. Hotel, motel, hostel or guesthouse, dormitory, workers’ quarters, residential care facility. 

Class 4. Class 4 Residential part of a non-residential building, could be a sole dwelling or a residence e.g. caretaker’s residence, can only be located in a Class 5 to 9 building

Class 5. Class 5 office building, used for professional or commercial purposes, offices of lawyers, accountants, architects, government agencies.

Class 6. Class 6 building used for the sale of retail goods or services, retail (to the public) not wholesale, shop or shopping centre, barber or hairdresser, market, showroom, funeral parlour

Class 7. Class 7a carpark, Class 7b storage or warehouse, used as a warehouse, wholesale display (of goods or produce) 

Class 8. Class 8 Process-type building. A building where a process or handicraft is carried out for trade, sale or gain, Factory, mechanics workshop, abattoir or food processing plant, Small or large laboratory

Class 9. Class 9a health care building, Public or private, hospital, day care, surgery, nursing home, Class 9b assembly building, School, children centre, sports centre, night club, transport hub, Class 9c residential care building, Aged or residential care facility.

Slide 7:

What class is a Hardware store? Equals Class 6. Furniture factory equals Class 8. Mosque equals Class 9b. Bed and breakfast equals Class 1b.

Slide 8:

What class is a Kindergarten? Equals Class 9b. Shearers’ hut equals Class 3. Multi-storey carpark equals Class 7a. Residential care facility equals Class 9c.

Slide 9:

Which of the following is a Class 1a building? Single, detached dwelling above a single garage for that dwelling?

An apartment complex. A row of terrace houses, with common fire walls between them, each with an attached garage. A 3 storey building with a shared underground garage and a residential sole occupancy unit on each storey, not including the garage.

Options 1 and 3 are both Class 1a buildings. Options 2 and 4 are both Class 2 buildings.

Slide 10:

Which class is each of the following buildings? Accommodation for visiting doctors in a rural hospital?

Six single dwellings on one block that are used for holiday stays?

A row of terrace houses, with common fire walls between them, and a common underground garage?

A caretaker’s flat in a warehouse or office building?

Option 1 is a Class 3 building. Option 2 is a Class 1b building. Option 3 is a Class 2 building. Option 4 is a Class 4 part of a building.

Slide 11:

What about Volume Three? Volume One covers class 2-9 buildings. Volume Two covers class 1 and 10 buildings. Volume Three covers plumbing and drainage requirements for all building classifications.

Slide 12:

Mixed use buildings. Each part is classified separately according to its purpose. Each part must meet all the Performance Requirements for its particular classification. Generally, if a part of a building that has a different purpose is less than 10% of the total floor area of the storey it is on, then it is not given a separate classification. The classification of the rest of the building, or space it is within, applies. In the NCC, this is provided as an exemption to clause A6G1.

For example, in a single storey warehouse with an office that is 15% of the total floorspace, the office space has a separate classification – Class 5 – and that space must meet the Performance Requirements for a Class 5 building. 

If the office space was only 5% of the total floorspace, then it would be classified, along with the rest of the warehouse, as a Class 7b building, and would have to meet the Performance Requirements for a Class 7b building.

If the warehouse had 2 storeys and the office was 15% of the ground floor, but only 7.5% of the total floorspace, then the office space would still be considered a Class 5 part of the building, because it is the percentage of the floorspace of the storey it is on that matters, not the total percentage.

The 10% rule doesn’t apply to …

Laboratories. A laboratory (usually a Class 8 building) is considered to have a high fire risk which must be appropriately managed. Treating a laboratory like another class of building would potentially mean that fire hazard management measures might be inadequate for the risk the laboratory poses to users of the building.

A sole-occupancy unit in a Class 2 or 3 building or a Class 4 part of a building. When any space is used for people to live in, the NCC mandates Performance Requirements to manage fire risks and ensure adequate sound insulation. Treating an SOU like another class of building could mean reducing these requirements, which would result in a living space that failed to comply with requirements and lacked necessary amenities.

9b early childhood centres. Early childhood centres generally pose a different set of risks, especially in emergency evacuation, than other building classifications. Treating an early childhood centre like another class of building could mean that the fire safety measures do not match the risk and occupancy characteristics of this building classification.

More discussion of the 10% rule and exceptions to the rule can be found in the Explanatory information in Part A6 of any volume of the NCC.

Slide 13:

What about a shopping centre with shops in the ground floor and 2 floors of car parking above = Class 6 (retail shops) and Class 7a (carpark).

A church with an attached priest’s residence = Class 9b (church) and Class 4 part of a building (residence).

A hospital with a child care centre = Class 9a (health care building) and Class 9b (childcare centre = assembly building).

A boiler room or machinery room in the basement carpark of an office building = Class 7a as no special classification is needed for a boiler room or machinery room (regardless of their size or percentage of the floor space). HOWEVER, there are specific Performance Requirements for the construction of these kinds of rooms, e.g. fire separation requirements. See Volume One for the specific Performance Requirements. If you have time and the trainees are interested, you could ask the trainees to look at Volume One and find the location of these special provisions for boiler rooms etc.

Slide 14:

Can a whole building have multiple classifications?

Yes, it's possible if the building is designed to serve multiple purposes.

If a builder wants to build a building that has flexibility in its use, i.e. can be used for different purposes. For example, a building with a number of units in an industrial park. The building owner/developer might want to be able to sell or rent the units in the building for a variety of purposes such as office space for small businesses (Class 5), retail space for businesses that sell to the public (Class 6), storage space (Class 7b).

This is permissible but the building must meet all the specific requirements for any class and the most stringent requirements of all the classes.

For example, a storage space might not need to have a lot in the way of facilities, such as bathrooms, because typically few people work in these spaces. 

However, an office or retail space requires a minimum number of bathrooms (determined by the expected number of users and size) because there is an expectation that some people will typically spend long periods of time in the space, and that a larger number of people will use the space. 

Therefore, the units would need to meet the more stringent facility requirements for Class 5 and Class 6 buildings.

Slide 15:

What if a building's classification isn't obvious? Building classification is a risk management issue. The risk associated with a building’s intended purpose needs to be assessed so that the building can be classified appropriately and built to meet the most appropriate Performance Requirements.

When deciding on a building’s classification, the appropriate authority reviews the building proposal and might consider the intended purpose of the building, and/or different parts of the building. Building classification that the building most closely resembles, likely fire load of the building, likely risks to the safety, health and amenity of the people who might use the building, relevant decisions or determinations by appeals courts in the relevant state or territory. (Note that not all appeals court decisions set precedents.)

The definition of appropriate authority is slightly different in NSW. Some building regulatory authorities in some states and territories issue their own guidelines for building classification.  A building surveyor is one of the main appropriate authorities to classify a building, but it could also be a council and that this should be confirmed with the local regulator.

Slide 16:

How would you classify a retail shop with a residence at the back? Retail building equals Class 6. Residence equals Class 4 part of a building.

Slide 17:

How would you classify a building that could be used as a warehouse or for light industrial activities?

Both Class 7a and Class 8

Slide 18:

How would you classify a building with squash courts, a small sports association office, and a cafe taking up 30% of the building? Sports centre equals Class 9b. Cafe  equals Class 6 .Office - Class 9b.

Slide 19:
What class is a Pottery studio equals Class 8. Service station equals Class 6. Railway station equals Class 9b. Warehouse equals Class 7b.

Slide 20:

True or false?  You are building a small hostel (Class 1b) on the coast. You can find all the relevant Performance Requirements in Volume Two of the NCC. If you chose false, yes, that’s right. You need to refer to Volume Three for plumbing and drainage provisions.

Also, some of the disability access and fire provisions in Volume One may apply to a Class 1b building.

Slide 21:

A boarding house or hostel could be a Class 1b building or a Class 3 building. What key factor/s determines its class?

Height in storeys. A Class 3 building is typically a high-rise building while a Class 1b building is typically a low-rise building.

Who will live/stay there. A Class 3 building is designed to accommodate unrelated people while a Class 1b building may accommodate related or unrelated people.

How many people it can accommodate and total floor area. 
A Class 1b building would normally not accommodate more than 12 people, and would have a total floor area of no more than 300 m².  If bigger than this, it would be classed as a Class 3 building.

If you chose, Option 3, yes, that/s right. If you chose, Options 1 or 2, that’s incorrect. Both Class 1b and Class 3 buildings are designed to accommodate unrelated people.

Slide 22:
True or False?
A class 1a residence cannot be built over or under another structure of any other class, except for a pirate garage
If you chose True, yes, the statement is true. 
If a residence is built over any other type of structure it would be a sole-occupancy unit of a Class 2 building.
This is the case, even if the other structure is a common garage space.

Slide 23:
Summary. Class 2-9 buildings. NCC Volume One. “Commercial” provisions. Class 1 and 10 buildings. NCC Volume Two. “Housing Provisions”. Volume One disability access provisions may also apply. Plumbing and drainage provisions for all building classes. NCC Volume Three

Slide 24:

Key Points

Building classifications are found in the Governing Requirements, Part A6 in all volumes.

A mixed use building may have parts that have different classifications. The 10% rule usually applies.

An entire building can have more than one classification, if it is designed or intended for more than one potential purpose.

If building classification is unclear, refer to the appropriate authority in the relevant state or territory. 

Slide 25:

Thank you for your time. That brings our presentation on Understanding building classifications to a close. If you’d like more information please visit abcb.gov.au