Challenges of Complying

National Building Code of Australia, which includes the Building Code of Australia (BCA), carried out aimed at reducing production of greenhouse gas emissions to find a specific energy efficiency measures in Section J Volume 1 Requirements vary for different climate zones and for different building classes. Some provisions for residential care facilities (RACF), and other elder care are particularly stringent. Proper application of the methodology early in the design process is necessary to ensure an effective outcome. This article explores how.

Energy efficiency is important for several reasons of compliance - energy efficient buildings can provide improved thermal comfort and reduce operating costs. This is clearly how important it is that high availability of facilities in the nursing industry.

BCA provisions covering many aspects of construction - building fabric (including the roof, ceiling, walls and floors), glass sealing, ventilation and air conditioning, artificial lighting, hot water and access for maintenance. Of these, the first two tend to be locked in early in the design process so that it is important that they be dealt with in advance. In most states, compliance with Section J report is not required until the construction certificate (or equivalent) is required. However, this level of development approval is granted, and changes to the building envelope is more difficult. Issues include the development agreement amendment and convincing clients that their expectations need to change.

Regardless of when the consultant is engaged in energy sustainability, considered to satisfy (DTS) provisions of the BCA are likely to be a challenge. There are several reasons for this. First, the DTS requirements are expressed as minimum R-value. This is the thermal resistance to the building element to be reached. For example, a wall built of brick in a double with no additional insulation can have a total R-value of less than 0.5, but the BCA requires at least 2.3. Lining the inside wall with insulation will reduce the available floor area. Adding insulation keeps the surface of cavities, but adds the cost of construction. So, what is best for each part of RACF?

Second, the R-value is only an indicator of the performance of building types. Other factors such as thermal mass, shading and vents are equally important. BCA attempts to get some of these factors into account, but their treatment is understandably pretty basic.

Third, the glass estimate is based on the use of glass calculator that estimates roughly type of window required for effective design. He believes the window size, orientation, some types of blinds, area and construction class. Glazing energy charges for RACF and related structures is the lowest of all.

Even with these limitations, assessment of DTS is the place to start. It will identify challenges and to allow early consideration of design trade-offs. DTS under RACF will more than likely have a much smaller window that is what good design aesthetic requirements. It can even be counterproductive as a small window will mean increased use of artificial light - especially if the glass is determined by a low SHGC (solar heat gain coefficient). In my experience, it is not uncommon for DTS under RACF to have high performance double glazing (Uw under 3.0) and SHGC less than 0.3. Such glass is very expensive and will admit a bit of natural light.

Fortunately there is a way around these important issues. It is to employ an alternative solution. Those involved in BCA Section J is called JV3 - verification using a reference building. With this methodology, computer simulations are used to determine the annual energy consumption in the building of DTS line (reference building). Proposed project will comply with the condition that it does not use more energy than the benchmark.

JV3 time provides tremendous flexibility and supports a better design. Music and shading can be optimized for each facade. Isolation can be finetuned to boost the performance of the whole building. Most importantly, energy-efficient design can be developed to retain key architectural requirements.

Experience with many buildings have been shown to have better design results JV3 sure when it is applied. Furthermore, the cost modeling and analysis is more than offset by improvements in RACF design and construction costs.

David is the director of Gradwell Gradwell Consulting, NSW based sustainability consultancy that has completed more than 880 score reports and certificates.