Section J forms part of the Building Code of Australia, and it deals with energy efficiency for class 2 through class 9 buildings, as defined in the BCA. That includes detached houses and apartments as well as commercial and industrial buildings.
It’s an important policy objective for the Australian government and other governments around the world right now. The energy conservation requirements in building codes both in Australia are abroad are tightening up, and it’s changing the way we do things in the construction industry.
Section J is divided into eight subsections:
- Part J1 – Building Fabric
- Part J2 – External Glazing
- Part J3 – Building Sealing
- Part J4 – Air Movement
- Part J5 – Air-Conditioning and Ventilation Systems
- Part J6 – Artificial Lighting and Power
- Part J7 – Hot Water Supply
- Part J8 – Access for Maintenance
J1 to J4: Building Envelope Requirements
Part J1 concerns the building fabric, or wall section. It includes the cladding material used in the outside of the building, as well as the insulation and any other materials that are part of the wall construction and that help to limit the passage of heat. A pre-submission section J assessment will indicate the materials used in the building’s walls and call out any additional methods or requirements necessary to achieve the minimum standard as required by section J1.
Section J2 governs glazing – glass – and it gives requirements for the building’s windows and/or glass curtain walls. A glazing calculator is used to show the level of performance needed in order for the glazing to meet the minimum standard. Section J3 deals mostly with how the walls control rainwater, providing guidelines for the design and construction of face-sealed, redundant and rain screen-style walls, as well as requirements for roof flashings and sealing around other openings.
J4 to J7: Ventilation, Plumbing and Mechanical Systems
Section J4 has requirements for facilitating natural ventilation and cooling through operable windows, vents and other direct openings. Sections J6 to J8 are prescriptive, that is, they give minimum requirements for system efficiency, based on an energy efficiency model that includes the building’s planned usage, characteristics, and local climate. In many projects, these parts of the report are used as a basis for the mechanical and plumbing design.
All new buildings need to comply with Section J in order to receive development approval from the Local Authority. It’s important to think about the Section J requirements early in the decision making process, and it’s best that these issues be considered before the general building design is discussed with the Local Authority.