What is NCC BCA Section J?

The National Construction Code Volume 1, through Section J of the Building Code of Australia (BCA) specifies the energy efficiency measures that must be followed during the design process of a proposed commercial development. The objective of the Section J is to reduce greenhouse gas emissions of a building by reducing the energy consumption of the building. In order to meet these requirements, a report is compiled which outlines the performance requirements of the proposed development to comply with section J of the NCC volume 1. There are 2 venues documented under the BCA for compliance with the Section J requirements. The first method is to comply with all the Deemed to Satisfy (DTS) requirements of the section J. The other method is through the methodology specified under the JV3 part of the Section J which uses computer modelling to demonstrate compliance of an alternative solution to a DTS.

NCC / BCA Section J Compliance

Classes 2-9 of Section J categories of building compliances listed below:


  • Class 2 – a building containing two or more sole occupancy units like residential flat buildings.
  • Class 3 – a residential building providing long-term or transient accommodation for a number of unrelated persons, including boarding houses, backpackers quarters, residential part of a hotel, motel, school, health care or detention centre child or aged or disabled accommodation.
  • Class 4 – a dwelling in a class 5, 6, 7, 8 or 9 building
  • Class 5 – office building
  • Class 6 – public sale or service buildings like showrooms, restaurants, shops, markets, dining
  • Class 7 – carparks, storage space warehouses
  • Class 8 – a process building like laboratories, workshops
  • Class 9a – hospitals and health care
  • Class 9b – assembly building like workshops and labs
  • Class 9c – residential care buildings

Individual residential units of a Class 2 residential flat building developments also must comply with the NCC requirements for residential developments. In NSW, this means compliance with BASIX and NatHERS requirements which is being mandated by the NSW Department of Planning. A BCA Section report for class 2 includes  the requirements for the common areas of a proposed development and it also have some requirements which are applicable to individual units. For more information about BASIX and NatHERS certification, please visit our BASIX and NatHERS  pages.

Frequently Asked BCA Section J Questions

What is the difference between DTS and JV3?

The requirements of each section of the National Construction Code are detailed under various sections of the Buidling Code of Australia in form of Deemed to Satisfy Requiremens. A building must meet all the applicable requirements of relevant parts of the BCA in order to be compliant with the NCC requirements. In addition to the DTS requirements of the BCA, a performance based alternative solution is also permissible under the NCC to demonstrate compliance with the requirments of the building code. For compliance with the section J of the NCC, the methodology and protocol to formulate an alternative solution using authorised computer modelling is documented under the JV3 part of secion J.

BCA Section J DTS

The ‘Deemed-To-Satisfy’ (DTS) approach aims to achieve compliance by ensuring all components of Section J are individually met. These components include prescriptive examples of materials, products, design factors, construction and installation methods which should satisfy the performance requirements of the National Construction Code. They fall under 9 main sections of the National Construction Code (NCC) :

  • Part J0 – Energy Efficiency
  • Part J1 – Building Fabric
  • Part J2 – Currently Blanks as of NCC 2019 & 2022
  • Part J3 – Building Sealing
  • Part J4 – Currently Blanks as of NCC 2019 & 2022
  • Part J5 – Air-conditioning and Ventilation Systems
  • Part J6 – Artificial Lighting and Power
  • Part J7 – Heated Water Supply and Swimming Pool and Spa Pool Plant
  • Part J8 – Facilities for Energy Monitoring (J8.1 to J8.3)

The DTS assessment process is also dependent on additional external factors including the building class which the development falls under, the specific climate zones and floor areas of different building zones. The DTS provisions are generic in nature and does not take into account the particular geometry or unusual conditions of a building. This form of assessment and reporting is used where the development can be subjected to a degree of modification. The process is simple in its compilation procedure and is therefore faster and is an economically expedient solution to demonstrate a development’s compliance with the section J of the NCC.

BCA Section J JV3

For the purpose of compliance with the NCC Section J requirements, an alternate method to the DTS approach is the JV3 Assessment method. This approach allows for inclusion of non-compliant provisions in a building and still, demonstrate compliance with the requirements of the NCC Section J as a whole. Using a JV3 alternative solution, we can bypass the undesirable and expensive DTS requirements and replace them with more effective and inexpensive solutions which will improve the overall performance and economics of a particular development.

The most problematic and, hard to comply part of the section J is glazing performance requirements and floor insulation. Removing these requirements are the most common request from Eco Certificates and as a result, our BCA Section J reports are always initially optimised toward the least performance requirement for glazing. This allows us to introduce the least amount of changes during a JV3 assessment and reduce the cost of any necessary upgrades like addition of solar panels.

In certain circumstances, installation of lower performing glazing systems and removal of floor insulation or other downgrades to the element performances actually results in improved overall performance compared to a DTS compliant building. This is due to the nature of a DesignBuilder comprehensive computer simulation which considers all possible interactions and relations of various building components with each other and recognising the conflicting effects of solar radiation during cold and warm seasons.

A NCC BCA Section J Assessment can change the design

Most councils in Australia require a NCC / BCA Section J Report to be submitted as part of the documentation for the Construction Certificate stage. Although it is almost never on the Development Application checklist of required documents, Eco Certificates recommends that designers and developers acquire a BCA Section J Report at the DA stage. In some cases, the requirements of the Section J, and particularly the glazing requirements, may trigger the need to modify the building design and if this is identified just before the CC stage when all other studies are completed, it could cause delays and unnecessary expensive re-designs. 

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