BCA - Building Code of Australia

The Building Code of Australia is produced and maintained by the Australian Building Codes Board (ABCB) on behalf of the Australian Government and State and Territory Governments. The BCA has been given the status of building regulations by all States and Territories. Find out about the campaign to make the building code available for free at:

The goals of the BCA are to enable the achievement and maintenance of acceptable standards of structural sufficiency, safety (including safety from fire), health and amenity for the benefit of the community now and in the future.
These goals are applied so that the BCA extends no further than is necessary in the public interest, are cost effective, easily understood, and are not needlessly onerous in its application.

The BCA contains technical provisions for the design and construction of buildings and other structures, covering such matters as structure, fire resistance, access and egress, services and equipment, and certain aspects of health and amenity.

The performance-based BCA Building Code

In December 1994, the ABCB requested its Office to produce a first draft of a performance-based BCA.

At that time, the advantages of a performance-based BCA were seen as allowing cost savings in building construction by:

permitting the use of alternative materials, forms of construction or designs to the prescriptive requirements;
the innovative use of materials, forms of construction or designs;
permitting designs to be tailored to a particular building;
giving clear information on what the BCA is trying to achieve;
allowing the designer flexibility in the use of materials, forms of construction or design provided that the intent of the BCA is met (in other words, allow for flexibility provided the performance required by the BCA is met); while still allowing acceptable existing building practices through the deemed-to-satisfy provisions.

The ABCB's Office produced a performance-based version of the BCA which was sent out for public comment during October to December 1995 and released in its final form during October 1996.

Hierarchy of the Performance-Based BCA

The performance-based BCA was drafted following consideration of numerous overseas models (including the New Zealand, British, Swedish and Dutch examples) to suit the Australian building regulatory environment. This has meant that the performance-based BCA substantially includes the technical requirements from the previous BCA90, with a 'performance hierarchy' built around them. The hierarchy of the BCA is shown below.

The following is an explanation of the terms used and how they operate in practice.

At Level 1 are the objectives. These represent the reason the community wants a matter regulated. They are primarily expressed in general terms, and usually refer to the need to safeguard people and protect adjoining buildings or other property. An example of an objective from the BCA is: The objective is to safeguard the occupants from injury or loss of amenity caused by inadequate height of a room or space.

At Level 2 are the functional statements. These set out in general terms how a building could be expected to satisfy the objectives (or community expectations). An example of a functional statement from the BCA is: A building is to be constructed to provide height in a room or space suitable for the intended use.

At Level 3 are the performance requirements. These outline a suitable level of performance which must be met by building materials, components, design factors, and construction methods in order for a building to meet the relevant functional statements and, in turn, the relevant objectives.

The performance requirements are the core of the BCA and are the only parts of the code with which compliance is mandatory. An example of a performance requirement in the BCA is: A room or space must be of a height that does not unduly interfere with its intended function.

Level 4 contains building solutions that set out the means of achieving compliance with the performance requirements. The BCA provides for two methods that can be followed to develop a building solution:

At Level 4a are the deemed-to-satisfy provisions. These include examples of materials, components, design factors, and construction methods which, if used, will result in compliance with the performance requirements of the BCA. An example of a deemed-to-satisfy provision in the BCA is: Ceiling heights must be not less than 2.4 metres in a habitable room.

At Level 4b are the alternative solutions. The key to the performance-based BCA is that there is no obligation to adopt any particular material, component, design factor or construction method. An approval authority may still issue an approval if it differs in whole or in part from deemed-to-satisfy provisions described in the BCA if it can be demonstrated that the design complies with the relevant performance requirement.

There are several means by which an approval authority can assess whether a building solution, complies with the BCA. These are referred to as assessment methods and include the following:

a. The use of clause A2.2 of the BCA. This clause allows the following evidence (in some cases subject to conditions) to be submitted in support of a proposal that a material, form of construction or design meets a performance requirement or a deemed-to-satisfy provision:

In keeping with the flexibility provided in the performance-based BCA, designers are not restricted to using a listed verification method. Any other method may be used if the approval authority is satisfied that it establishes compliance with the BCA. However, in making a decision, an approval authority may have regard to the relevant deemed-to-satisfy provisions or verification methods provided for in the BCA.

Where physical criteria are unable to be tested or modelled by calculation, the opinion of a technical expert may be accepted. This is referred to as the use of expert judgement.

The final assessment method is referred to as comparison to deemed-to-satisfy. This method permits a comparison to be made between the deemed-to-satisfy solution and the proposed building solution. If it can be demonstrated to the approval authority that the building solution complies in an equivalent or superior way to a deemed-to-satisfy provision, then it will be deemed to meet the relevant performance requirement.

Under this hierarchy an applicant can use any materials, components, design factors or construction methods which comply with the relevant performance requirement. For Australia, this is a significant move away from sole reliance on prescriptive requirements and is designed to encourage innovation and the use of new technology.

However, the BCA still caters for those who prefer specific guidance, or wish to continue to use traditional building methods. The deemed-to-satisfy provisions of the BCA continue to provide detailed prescriptive methods for establishing compliance with the performance requirements.

How the performance-based system is used

The BCA successfully combines a dual approach. It provides a strong degree of certainty, combined with a high degree of flexibility, so that:

if compliance is achieved with the deemed-to-satisfy provisions, a building proposal is deemed to have complied with the BCA; however
if a building proponent wants to take an alternative approach, they have the opportunity to do so - on the understanding that their proposal must achieve the performance requirements of the BCA.

The first step in using the performance-based system is to choose the means by which the building proposal will achieve compliance with the BCA. This will be by either:

If an alternative solution is chosen, the building proponent must ensure that an assessment method is chosen which satisfactorily indicates that the alternative solution will meet the performance requirements in the BCA. The nature of the assessment method will vary depending on the complexity of the alternative solution.

Publication of the BCA

The 1990 version of the BCA (BCA90) contained the technical requirements for the Classes of buildings in Australia, i.e. Class 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10.

At the same time that the BCA underwent the conversion to a totally performance-based building code, it was split into two distinct volumes, being Volume One for Class 2 to 9 buildings (commercial buildings) and Volume Two (Housing Provisions) for Class 1 and 10 buildings. The reason for this was that in Australia, domestic building works represent approximately two thirds of building expenditure.

The Housing Provisions are significantly different from Volume One. The clauses are written in plain English with diagrams to expand on and explain the code requirements. Non-mandatory explanatory information also accompanies clauses to assist users in understanding the requirements of the code. The code has been structured to follow the normal construction sequence, commencing with site works and progressing through the various construction stages to completion.

Administrative arrangements

The BCA is brought into operation by enabling building regulatory legislation in each State and Territory. This legislation prescribes or "calls up" the BCA to fulfil any technical requirements which have to be satisfied in order to gain approval of a building proposal. Each State's and Territory's building regulatory legislation consists of an Act of Parliament and subordinate legislation which empowers the regulation of certain aspects of the building process, and contains the administrative provisions necessary to give effect to the legislation. Administrative-type matters typically covered in the enabling or subordinate legislation include-

Plan submission and approval procedures.
Issue of building permits.
Inspections during and after construction.
Provision of evidentiary certificates.
Issue of certificates of occupancy or compliance.
Accreditation or approval of materials or components.
Review and enforcement of standards.
Fees and charges.

BCA's new format

In addition to the cd-rom and internet version of the BCA, the beginning of 2004 sees the release of the newly formatted hard copy BCA which is being produced as a B5 (176mm x 250mm) sized publication. The Board’s recent decision to move to an annual amendment cycle and the work that has been undertaken over the past 12 months to produce the BCA using XML technology have provided the ABCB with an opportunity to produce the BCA as an annual soft cover publication.

Each year the BCA will be known as BCA 2004 Edition, BCA 2005 Edition, etc. While remaining similar in term of style and layout, the publication will remove the need for subscribers to replace the large number of pages that are updated within each amendment cycle.

Discussions between ABCB and Industry representatives have identified that the B5 size is the most favoured of all the hard copy versions and, while the market research identified that some subscribers were unconcerned with product format, the majority of responses from a recent survey were favourable to the new compact and easier to manage product format.

In addition to seeking lower production costs, the ABCB Office has researched sustainability issues. There are many environmental benefits arising from the production of an annual bound version of the BCA. Moreover the proposed B5 size format will provide additional environmental benefits with a further 28% reduction in paper use.