BCA Section J Structure
With introduction of the version 2010 of the Building Code of Australia, BCA Section J has undergone significant changes compared to its previous version and more than any other section of the BCA. The energy efficiency provisions of the BCA 2010 are now more stringent and more specific systems and technologies are being recognized. For the first time renewable energy is also recognized in the BCA Section J aiming to reduce the GHG emissions of a building resulting from the consumption of energy.
BCA Section J 2010 Structure
BCA 2010 is the most recent and current version of the BCA in effect which has undergone major modifications compared to the previous version of the BCA. Visit BCA Section J 2010 changes page for a brief overview of these changes. The following parts and sub sections are now comprise the energy efficiency provisions required by the BCA Section J 2010:
Section J Energy Efficiency: At the fist pages of this section, objectives, performance requirements and verification methods for compliance with the energy efficiency requirements of the BCA are being described. What is new in BCA Section J 2010 version is the consideration of renewable or low GHG emission fuel type for energy generation for a building operation. The only verification method in this section is Verification Using a Reference Building. The proposed building and a reference building are both being modeled and simulated using a building thermal simulation program complying with ABCB Protocol for Building Energy Analysis Software and by using Annual Energy Consumption Criteria addressed at Specification JV of the BCA Section J. The annual energy consumption of the proposed development shall not be higher than that of a reference building to demonstrate its compliance with energy efficiency requirements of the BCA.
Part J0 Energy Efficiency: In this part of the BCA Section J performance requirements of class 2 to 9 buildings are described. For sole occupancy units of class 2 buildings or a class 4 part of a building each unit must achieve a minimum 5 stars NatHERS rating and the average of all units in a multi unit development must be at least 6 stars. For class 2 to 9 buildings other than sole occupancies addressed before, performance requirements of the BCA Section J Parts 1 to 8 shall be satisfied. This part of the BCA Section J also requires that ceiling fans which are addressed in NatHERS thermal simulation of sole occupancy units to have certain specifications.
Part J1 Building Fabric: This part of the BCA Section J applies to building elements that form the envelope of a class 2 to 9 building minus a couple of exceptions. Regardless of the utilization place of an insulation, there are several general criteria that must be followed for selection and installation of thermal insulation. Part J 1 sets the minimum R Value performance of insulation elements for Roofs and Ceilings construction, Walls and Floors for each climate zone. Unlike BCA Section J 2009, the 2010 version does not nominates different R Values for different classes of buildings and only considers the climate zone of the development in determining the R Values. There is a new table in 2010 version for adjusting the minimum R values required for loss of ceiling insulation due to removal of insulation for installing building elements like ducts, skylights, lighting etc. U-Value and SHGC performance of roof lights is also addressed in this part. BCA Section J 2010 also recognizes the insulation requirements of the envelope walls which are not external walls of the building for the first time.
Part J2 Glazing: BCA Section J Part J2 sets the minimum energy efficiency performance requirements of building glazing elements. The glazing assessment of a building is based on the principle of air conditioning energy value through each glazing element which is the amount of energy lost based on the performance of the glazing element which is calculated for each 8 major geographic directions. The sum of air conditioning energy values of all glazing elements for a single facade in each direction for each storey of a building shall not be more than a number which is obtained from multiplying that particular facade area by a coefficient. This coefficient has a different value for each climate zone and each class of the building. BCA Section J 2010 for the first time assesses the performance of glazing elements for the internal fabric of the building. This part also sets the requirements of a shading element in order to be able to addressed in the BCA Section J report compilation.
Part J3 Building Sealing: This part of the BCA Section J 2010 sets the requirements for a building sealing in order to prevent unwanted air infiltration which is one of the major sources of energy loss in buildings. Sealing requirements for chimneys and flues, roof lights, windows, doors, exhaust fans and evaporative coolers are addressed in this part of the BCA Section J 2010. Construction of roof, walls and floors must also follow the requirements of this part.
Part J4 is Blank: This part of the BCA Section J is left blank in 2010 version and its previous provisions in BCA Section J 2009 are now being addressed in other parts of the BCA 2010. Part J4 is named Air Movement in BCA 2009 and deals with air movement units energy efficiency requirements, ventilation openings, ceiling fans and evaporative coolers.
Part J5 Air Conditioning and Ventilation Systems: Energy efficiency provisions for HVAC systems and their peripheral systems are listed in this part of BCA Section J 2010. This part addresses areas like sealing and insulation requirements of air conditioning systems and their heating and cooling systems, maximum allowed fan and pump power, time switch requirements, energy efficiency rating of various systems and exhaust system specifications.
Part J6 Artificial Lighting and Power: While for sole occupancy units of class 2 buildings and class 4 parts of the buildings there is a fixed W/m² allowed for illumination power density, other classes of buildings have different values for each functional space of the building in this part of the BCA Section J. For other than sole occupancy units each space in the building is allocated a certain maximum illumination power density which is different for each functional space and the sum of the design illumination power of all spaces shall not exceed the maximum allowed. The maximum illumination power density of each space can be adjusted (increased) by installation of certain energy efficiency mechanisms and also for small spaces. This part of BCA Section J 2010 also has comprehensive provisions for interior artificial lighting and power control, interior decorative and display lighting, artificial lighting around the perimeter of a building and power supply to boiling water and chilled water storage units.
Part J7 Hot Water Supply and Swimming Pool and Spa Pool Plant: This part of BCA Section J 2010 is considering the energy efficiency of spas and swimming pools for the first time. This part has deemed to satisfy provisions for hot water supply, swimming pool heating and pumping and spa heating and pumping.
part J8 Access for Maintenance and Facilities for Monitoring: Requirements for provision of energy consumption monitoring meters is introduced for the first time in BCA Section J 2010 in addition to previous requirements for access and maintenance.
Specifications: The Specifications parts of BCA Section J 2010 are extensively elaborating on the technical properties and requirements of Construction Materials, Roof and Ceiling Construction, Wall Construction, Floor Construction, Ductwork Insulation and Sealing, Insulation of Piping Vessels, Heat Exchangers and Tanks and Lighting and Power Control Devices. These specifications are being referenced throughout various parts of BCA Section J and must be addressed in a BCA Section J report when it is relevant.