As many of you already know, the NCC has moved to a three-year update cycle, with the next version of the NCC planned to come into effect in May 2019. As part of this process the ABCB is conducting a line-by-line review of the Code with the scope to make it shorter, simpler, more flexible, but also more stringent where justified by economic criteria.
Below we summarise some of the proposed changes to Section J with particular emphasis to Part J1 to J3. We also note that the proposed changes are not definitive, as the ABCB is still in the process of reviewing and consulting with industry in preparation for issuing a draft NCC 2019 and beginning a formal consultation period in February 2018.
The first proposed change relates to the inclusion of Green Star and NABERS simulation protocols as part of the Performance Solution approach. This means that if your project has undergone simulation as part of one of those voluntary certification schemes and has achieved specified improvements over a base case, there won’t be the need to conduct a separate simulation to demonstrate compliance with Section J. The reasoning behind this change is to allow more flexibility into the compliance process, avoid unnecessary doubling up in simulation requirements, and encourage the industry to adopt Performance Solutions more frequently rather than relying on DTS provisions that may not benefit all types of design.
While there will be a push for broader use of the Performance Solution methods, the DTS provisions are also being reviewed and not surprisingly, the glazing requirements of Part J2 are a main area of focus. This is because windows play an important role in the energy efficiency and comfort of a building, and also because the length and complexity of the current Part J2 often leads to compliant solution actually been found non-compliant when investigated further. While the specifics are still under review, the key messages are that Part J2 will be significantly simplified; and that façades with no external shading will be allowed very small windows compared to façades that integrate a combination of appropriate shading and performance glass, where WWRs of about 80% could be achieved. Another important change related to glazing involves the possibility to ‘trade-off’ between façades, meaning that from 2019 we may be able to compensate façades with high WWRs with façades with low WWRs to achieve overall compliance (something that we currently do following the Performance Solution verification method by engineering calculations).
In relation to building fabric, wall insulations requirement will remain mainly unchanged or in some cases decrease slightly. However, thermal bridging requirements will be made clearer with the likely introduction of compliant construction methods. Light-coloured roof will also likely be mandated in most climate zones. Further, air-infiltration will be addressed with the likely introduction of maximum air-changes per hour (likely to be around 7) and blower-door testing as a voluntary measure to demonstrate compliance. Finally, energy efficiency requirements for all building services will also become more stringent.
These changes are projected to increase the energy efficiency of the Australian building stock by around 40% and thus contributing to the Nation’s goal to reduce emissions to 26-28 percent on 2005 levels by 2030. While some may view these changes as extreme, it is important to remember that the requirements of Section J haven’t be significantly revised or increased since 2011 leaving Australian buildings exposed to a number of risks ranging from low levels of occupant comfort to high energy demands and reliance on active systems to maintain safe operational parameters. In the words of Dr. Paul Bannister (the leading technical advisor and author of much of the research that is supporting the changes to Section J) ‘from an international point of view these changes won’t put Australia at the head of the pack, but will bring us back in the game and are a step in the right direction to ensure our buildings perform today and into the future’.