NCC 2015 – an overview
This edition of the ABRB is published to coincide with the distribution of the 2015 National Construction Code (NCC) series. For readers who haven’t yet familiarised themselves with the changes in NCC 2015, this article contains a snapshot of some important changes.
CHANGES TO THE BCA
Continuing the increased use of performance
Previous editions of the NCC have included a number of changes as a result of an ongoing project to increase the use of ‘performance’. One key strategy in achieving this is the removal of qualitative terms in the NCC Performance Requirements, and their replacement with quantified terms (terms that can be objectively measured). Quantification occurs at the highest possible level, and this may be through the modification of Performance Requirements, or the introduction of Verification Methods as an alternative means of compliance (to the Deemed-to-Satisfy Provisions).
In recent years this has resulted in the quantification of confusing or subjective terms such as ‘slip-resistant’, or ‘non-skid’ along with a new Verification Method to demonstrate levels of safe evacuation illumination for emergency lighting systems. NCC 2015 continues the work of this project in introducing two new Verification Methods in NCC 2015 for ‘structural reliability’ and ‘weatherproofing’.
A building must have an inbuilt capacity to resist structural failure. This is commonly referred to as its ‘structural reliability’. The structural Performance Requirements of NCC Volume One and Volume Two describe a listing of structural actions that a building may reasonably be subjected to.
Both volumes subsequently contain Deemed-to-Satisfy Provisions that are deemed to provide acceptable resistance to failure from these actions by reference to the Limit State Design method. However, any designer wishing to demonstrate the structural reliability of a building outside of those specified by the Deemed-to-Satisfy Provisions is required to develop an alternative solution.
This new Verification Method is designed to assist engineers who may wish to follow this path. The Verification Method provides the minimum resistance targets for structural components and connections through a quantified reliability index, in order to demonstrate the building or structure meets the Performance Requirements for structural reliability.
Given the complexity of the calculation methodology of the Verification Method for structural reliability, a handbook has also been developed to assist those with the relevant engineering expertise expected to benefit by the use of this Verification Method.
Water penetration through the external building envelope has proven to be a major problem for countries like New Zealand and Canada. Although relatively few known problems currently exist in Australia, any underlying problems may take many years to become observable.
Industry observations by notification and survey – along with the distribution of warnings by some state and territory building authorities – provide an indication that problems may become apparent in the future. Construction practices in Australia are very similar to those of New Zealand and Canada too, furthering concerns that Australia may not be immune to future problems.
Although some Deemed-to-Satisfy Provisions currently exist in NCC Volume Two, this is not the case for Volume One, and the new Verification Method offers an optional means to verify whether or not a proposed external wall will meet the Performance Requirements.
The Verification Method is limited to an external wall which must meet a score achieved through a risk assessment methodology contained in the Verification Method. There are two test methods within the Verification Method, and the application of the test methods varies depending on whether the external wall is classified as a direct fix cladding wall, a cavity wall or a unique wall system.
It should be noted that Verification Methods in the NCC are provided to assist in demonstrating compliance with the relevant Performance Requirement. Verification Methods are not a mandatory component of the NCC, however they are one method of assessment which can be used to demonstrate compliance with the Performance Requirements.
Expanding the mandatory sprinkler protection provisions to include all residential aged care buildings
A tragic multi-fatality fire in 2011 along with other fires in the last 30 years in residential aged care buildings has caused concern in the community, and resulted in the ABCB commissioning research into the causes along with the consideration of the role of sprinklers in preventing such fires. This has resulted in an expansion of the mandatory sprinkler protection provisions to include Class 3 and Class 9a residential aged care buildings.
Although the causes of the examined fires revealed that behavioural factors were major contributors, it was considered that mandatory sprinkler protection to all classes of residential aged care buildings will meet community expectations of higher protection levels for the vulnerable occupants of those buildings.
A new Australian Standard for termite management systems results in amendments and new provisions in the NCC
In NCC 2014, the reference to ‘termite barriers’ was replaced with ‘termite management systems’. The change aligned terminology with the intended review of the AS 3660 series of Australian Standards for termite management. NCC 2015 includes further changes to the termite risk management provisions now that the review of the AS 3660 series has been completed.
In addition to the alignment of terminology, there is a requirement for all chemicals to be included on the appropriate authority’s pesticides register, and a new Acceptable Construction Practice for the installation of sheet metal as a termite management system has been included along with an option for chemical systems to be assessed under AS 3660.3 (Termite Management – Assessment criteria for termite management systems).
The NCC will adopt a two year phase-in period for the new Standards, during which the existing 2000 edition of AS 3660.1 will remain as an option for satisfying the termite management provisions until the completion of the phase-in period. This allows time for industry to adapt to the new edition of AS 3660.1 and, if necessary, for testing to AS 3660.3 to be undertaken.
Continuing to improve the useability of the NCC
NCC 2015 includes the restructuring, simplification and enhancement of two commonly used parts of the NCC; Part J5 – Air-conditioning and Ventilation Systems in Volume One and Barriers to prevent falls (previously Balustrades and other barriers) in Volumes One and Two.
Part J5 Air-conditioning and Ventilation Systems
Since the change in stringency of the energy efficiency provisions in Section J of BCA 2010, concerns have been raised by industry about the difficulty in understanding and applying the provisions. Part J5 has been restructured and improved, and expanded guidance material has been provided to assist users in understanding Part J5.
The review and restructure of Part J5 has also incorporated some technical changes to resolve outstanding technical issues that had been previously raised by industry. Some of these changes include clarification of the exemptions allowed in the defined term ‘air-conditioning’ and the increase of the fan motor power allowances for car park ventilation systems.
Barriers to prevent falls
For a number of years, users of the NCC have commented on the growing complexity of the balustrade provisions in the NCC. The relevant provisions in Volume One have now been simplified and tabulated while the less complex Volume Two provisions have been restructured. In both volumes, all references to ‘balustrades and other barriers’ have been simplified to the general term ‘barriers’. Changes to Volume One also include the relocation of all openable window barrier provisions to D2.24 – Protection of openable windows.
CHANGES TO THE PCA
PCA 2015: Stage 2 — making NCC harmonisation a reality
PCA 2015 contains a number of improvements to the code which are being introduced as the second stage of the Board’s work program to harmonise building and plumbing requirements between NCC volumes, and to elevate matters of public policy from referenced documents to the PCA. These changes build on the significant progress made in the 2014 edition, which was stage one of what is the most significant revision to the PCA since 2004.
This year, NCC harmonisation becomes a reality for PCA users, with each part of the code now including new information outlining at a glance those critically important elements of the BCA that can have an impact on many plumbing and drainage works. This will save time and reduce your chances of getting caught out by those provisions which can cross-over between the volumes. You will find this new information at the end of the Deemed-to-Satisfy Provisions for each part, in an explanatory information box marked ‘Cross-volume considerations’.
While the cross-volume consideration boxes look a little different to the already familiar explanatory information introduced in the 2012 edition, it is important to note that they are nonetheless only advisory and are provided to guide you in the right direction for related BCA content.
Users of the BCA can soon look forward to similar useful information being provided in that code to help identify which parts of the PCA may impact on building work. Development of new cross-volume consideration information for the BCA is already underway, with proposals expected to appear in the NCC 2016 public comment draft, which will be released in early June 2015.
The process of elevating matters of public policy from referenced documents into the PCA is also nearing completion, with three new Deemed-to-Satisfy Provisions transferred into the PCA from the current AS/NZS 3500 Parts 1 and 4. These include B1.6 and B2.6, which set a maximum water efficient flow rate for shower, basin, kitchen sink and laundry trough outlets, and B2.5 which describes hot and cold tap layouts, so as to provide consistency and safety for the vision impaired. Explanatory information has also been added below Performance Requirement BP1.2 to provide information on how to address unintended heating of cold water pipes, which can be an issue in some parts of Australia.
Others changes include an amendment to the overarching objectives of parts B4 and E1 regarding suitability of these services, and a minor restructure of the general requirements provisions to clarify for which buildings you can use AS/NZS 3500.5 Plumbing and drainage – housing installations.
WaterMark: Introducing the WMTS
No doubt many of you are familiar with the review of the WaterMark Certification Scheme being undertaken by the ABCB; an initiative which has of course occupied time and resources, both at the ABCB and among many of you who are in one way or another involved with the scheme. However, the review is not all that has been going on.
Over the last year or so, the ABCB office has also been progressing in the conversion of the current Australian Technical Specifications (ATSs) to a new format called a WaterMark Technical Specification (WMTS). The technical content of the new WMTSs will be unchanged from the old ATSs; with the purpose of the conversion only being to reflect that the ABCB is the new owner of the documents. The WMTS have been published by the ABCB directly and are freely available online through the ABCB website.
Lastly, just a reminder that all other WaterMark related information is also now available on the ABCB website, including the Schedule of Specifications, the list of Exempt Products, and of course the product database itself.