The requirements of the BCA (Building Code of Australia) relating to energy efficiency represent the minimum acceptable building standards as determined by wide consultation with governments, industry and the community. These minimum acceptable standards once contained in the BCA are applicable to all new buildings.
For completely new buildings, the application of the BCA is straightforward as it is applicable to all aspects of the construction. For new building work associated with an existing building, the BCA is generally only applicable to the new building work, to those parts of the building directly affected by the new building work or to those parts where the building's use is being changed.
Energy efficiency provisions were introduced into the Building Code of Australia (BCA) in stages. The first was in 2003 for Class 1 and 10 buildings (residential buildings). This was followed in 2005 by provisions for Class 2 and 3 buildings and Class 4 parts of buildings. The range of buildings became complete in 2006 when provisions for Classes 5 to 9 buildings (commercial) were also added. At the same time, the provisions for Classes 1 and 10 buildings were made more stringent. In 2010 the stringency of the provisions in all classes was increased.
The BCA energy efficiency provisions were developed on the basis of them being cost effective for a long term building owner using certain defined financial criteria.
ELEMENTS OF ENERGY EFFICIENCY
These are some of the key elements of a building which are analysed under the Energy Efficiency provisions.
THE BUILDING FABRIC
The thermal performance of the building fabric is of paramount importance in any building, as once established, it is unlikely to diminish while that of active systems such as air-conditioning and lighting may diminish depending upon the quality of maintenance and changes over time. Although not an energy user itself, the fabric and glazing has a major impact on the services that are, i.e. the air-conditioning and the lighting.
Glazing is probably the most important building element in a commercial building as even the best glazing barely performs as well as an un-insulated wall. All new glazing in a building must comply with the current BCA glazing requirements as it is new building work.
Shading is an integral part of the performance of the glazing but there may be site constraints or planning requirements that prevent external shading from being provided. In such instances, the required level of performance may still be achieved with unshaded glazing and if not an Alternative Solution could be proposed with a reduced level of glazing performance compensated with over performing other aspects of the building or the engineering systems.
Buildings need to be sealed to avoid the loss of conditioned air or the entry of uncontrolled outside air, particularly in the more extreme climates.
New building work must comply with the BCA sealing provisions. Sealing is a provision that, in practice, applies to a complete space. When compliance of the new building work contributes little to the thermal performance of the space, some strategy to improve the situation could be considered, such as an Alternative Solution, measured against the principles of viability, cost effectiveness and practicality.
AIRCONDITIONING & VENTILATING SYSTEMS
Air-conditioning and ventilating systems may consist of new systems that are installed in a new building or in an extension. They may also be partly new and partly existing systems within the existing building. New systems and new elements in new parts of a building and new elements and systems in existing parts of a building must all comply with the BCA services provisions.
Some air-conditioning provisions in the BCA relate to the system while others relate to the equipment. System related aspects include outside air economy cycles, controls, time switches and fan motor power. If these are part of the new building work then they must comply with the BCA provisions.
New items such as a boiler, chiller, fan, package air-conditioner, pump, piping insulation (for new piping) and the like must comply with the BCA provisions. New piping and ductwork, whether within a new or existing part of a building, must comply with the BCA provisions. Existing piping and ductwork serving areas that are not being changed is not required to comply.
ARTIFICIAL LIGHTING & POWER
Artificial lighting and power systems are similar to air-conditioning and ventilating systems in that new elements and new systems in new parts of buildings must comply with the BCA provisions, as must new elements and new systems in existing parts. However, unlike air-conditioning and ventilating systems, most lighting components are within, or adjacent to, the space being served, which means that they are generally more accessible and therefore more easily upgraded. This makes lighting easier to make compliant.
It also makes lighting a candidate for consideration as part of an Alternative Solution in order to compensate for some other element that may be more difficult to make compliant.
HOT WATER SUPPLY
Hot water supply systems (those for supplying hot water for washing and food preparation) are similar to air-conditioning systems in that they have central components and reticulated piping systems. However, they are different in that the BCA requirements only cover a heat trap, insulation on the piping and high efficiency outlets. New hot water supply systems and new work on existing systems must comply.
Further information on Energy Efficiency may be obtained from:
Sustainable Energy Development Office
Department of Housing & Works
Australian Building Codes Board
Australian Greenhouse Office