As of today, Australia has a new building code as the 2019 version of the National Construction Code (NCC) came into force this morning.
Practically, this will involve changes in fire safety and energy efficiency requirements as well as amendments in other areas.
Beyond this, however, the Code is being reshaped amid a transition away from qualitative performance requirements toward performance requirements which are quantitative in nature.
All up, the Australian Building Codes Board (ABCB) estimates that 40 percent of performance requirements under NCC 2019 will be quantified either directly or through a verification method. Indeed, the 2019 update alone saw quantified values directly inserted into four performance requirements and the introduction of 28 new verification methods. Beyond that, the Board is aiming to have most of the remaining performance requirements quantified in the same manner by NCC 2022.
For several reasons, this will deliver important benefits.
As many readers will know, compliance with the NCC is achieved whereby the design and construction of buildings meets minimum standards and requirements in regard to safety, occupant health and amenity and environmental sustainability. These standards are known as performance requirements.
As many will also be aware, performance requirements can be met through either deemed-to-satisfy solutions (DTS solutions) or performance solutions (formerly known as alternative solutions). The former approach follows a set recipe under which the NCC specifies a combination of materials, components, design factors and construction methods which – if used – are deemed to meet the performance requirements. The latter approach involves solutions which are unique to each situation and sees architects and engineers use professional judgement to specify solutions which they feel represent the best way by which to satisfy the performance requirements for the individual situation in question.
Given the flexibility which they afford, greater use of performance solutions will facilitate innovation and enable best possible methods and materials to be applied in given situations.
Where performance requirements are qualitative rather than quantitative, however, there can be ambiguity about whether or not particular design solutions will satisfy the requirements and will receive approval.
Where this happens, ABCB chief executive officer Neil Savery says architects and engineers can be discouraged from using performance solutions. This is especially the case where the subjectivity involved means that practitioners and consenting authorities are unable to agree on what is necessary for compliance with a particular requirement.
Moreover, Savery says unquantified requirements involve greater risk that an inappropriate level of performance could be inadvertently accepted.
By contrast, he says greater quantification will deliver benefits across several areas.
“As many of the performance requirements are qualitative in nature, it can discourage practitioners from using them for performance solutions and involve delays in obtaining approvals,” Savery wrote in a response to questions from Sourceable.
“Quantifying these requirements will provide objective levels of performance for practitioners to target and consent authorities to assess against. This will encourage both increased use of performance solutions and the levels of competency in using a performance-based code. It will also help ensure a level playing field and reduce the risk of misinterpretation.”
Asked about specific examples of performance requirements which have been newly quantified in NCC 2019, Savery talks of three areas.
First, there is air conditioning. On this score, Performance Requirement JP1 now provides an absolute performance target for the energy use of air-conditioned buildings.
Next, in respect of natural lighting, P2.4.4(a) now provides a measure of the minimum amount of natural light that must be provided to a room.
Finally, when it comes to sound transmission, a new verification method, FV5.3, now quantifies the required level of sound attenuation of a floor in a residential care building.
All this, Savery says, helps to promote certainty over required outcomes and flexibility about how performance requirements can be achieved.
In respect of air conditioning, Savery says the change to JP1 will ensure that designers have a specific and clear performance target. This, he says, will help to free them up to innovate across all aspects of design in a manner which is unconstrained by prescriptive requirements for the energy efficiency of individual building components such as insulation, windows, shading, lighting, air conditioning or lifts.
On natural daylight, he says the greater clarity provided by the new P2.4.4(a) will help to free practitioners from constraints associated with prescriptive requirements contained in DTS provisions for features such as windows or roof lights. Instead, practitioners will be more readily able to demonstrate they meet this minimum amount of natural light using creative measures.
In regard to sound transmission, Savery says the new verification method will mean that as long as compliance with FP5.4 is demonstrated with the use of the methodology documented in FV5.3, practitioners will have flexibility to innovate in how they attenuate sound through the floor and will be unconstrained by prescriptive requirements.
Around Australia, greater use of performance solutions will help to encourage innovation and deliver greater flexibility in design and construction.
With more performance requirements being quantified, practitioners will be able to use more performance solutions with higher levels of confidence.