What is BCA Section J?
The National Construction Code employs Volume 1 Section J of the Building Code of Australia (BCA) to stipulate energy efficiency measures that must be taken during the proposed development of a building plan. It’s objective is to reduce greenhouse gases through sustainable actions via reduced energy consumption. In order to meet these requirements, a report must be generated based on the proposed design of the development, and this is what is created by us. The two main approaches to achieving this, namely through a ‘Deemed-To-Satisfy’ (DVC) approach or through Verification using Energy Modelling.
BCA Section J Compliance
Classes 2-9 of Section J list out categories of building compliances listed below.
- Class 2 - Multi-residential, units, apartments
- Class 3 - Boarding houses, backpackers quarters
- Class 4 - Aged Care facilities with residential dwelling
- Class 5 - Office buildings, front offices of factories/warehousing facilities
- Class 6 - Showrooms, restaurants
- Class 7 - Carparks, storage space warehouses
- Class 8 - Laboratories, workshops
- Class 9a - Hospitals
- Class 9b - Workshops/Labs in schools
- Class 9c - Aged care buildings
Class 2 multi-residential developments, including units and apartments, also require BASIX and NatHERS certification in conjunction with a Section J report. For more information on BASIX and NatHERS certification, visit our BASIX / NatHERS information pages.
What is the difference between DTS and JV3?
The National Construction Code which absorbs the Building Code of Australia, has an overarching compliance level which has certain performance requirements that need to be met. In order to do so, certain compliance solutions have been devised in the form of 2 main approaches - Deemed-To-Satisfy Approach and the JV3 Method.
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 (J0.1 to J0.3)
- Part J1 – Building Fabric (J1.1 to J1.6)
- Part J2 – Glazing (J2.1 to J2.5)
- Part J3 – Building Sealing (J3.1 to J3.7)
- Part J4 – Air Movement (not applicable)
- Part J5 – Air-conditioning and Ventilation Systems (J5.1 to J5.4)
- Part J6 – Artificial Lighting and Power (J6.1 to J6.6)
- Part J7 – Heated Water Supply and Swimming Pool and Spa Pool Plant (J7.1 to J7.4)
- Part J8 – Facilities for Energy Monitoring (J8.1 to J8.3)
The DTS assessment process is also dependent on additional external factors including the Class the development falls under, the specific climate zones and area space of the development’s floor. The DTS provisions are generic in nature and does not take into account the outerlying scenario of the development. This form of assessment and reporting is used where the development can be subjected to some 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 BCA.
An alternate method to the DTS approach is the JV3 assessment method. This method involves the testing of a computer simulated 3D model to calculate temperature and energy consumption while using the DTS provisions as a reference. Once a theoretical figure is reached through calculation, this is compared to the annual energy consumption allowance to ascertain what is agreeable under the NCC.
This method can also be used to allow flexibility in the initial stages of the design process, when accounting for glazing surfaces, the type of building fabric and energy based services including air conditioning/heating and lighting.
A BCA Section J Assessment Can Change the Design
Most councils in Australia require a 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 developres acquire a BCA Section J report at the DA stage. In some cases the requirements of the BCA Section J, particularly the glazing requirements, might trigger the need to modify the building desing and if this is knows right before the CC stage when all other studies are completed, it could cause delays and unnecessary expensive re designs.