Enhancing the Building Rating System in Australia

Background

Developed in 2003 by the Green Building Council of Australia (Russell, 2011), the Green Star rating system assesses eight different environmental management categories, namely: daylight and lighting, volatile organic compounds, energy efficiency and improvements, sustainable improvements, sustainable transportation, water efficiency, sustainable materials, building conservation and ozone-depleting potential (Portalatin et al., 2010). By evaluating how some case buildings in Australia are using sustainable materials to reduce carbon emissions to a minimum level, the present paper aims to develop proposals that could be employed in practice to enhance the Green Star rating system.

Case Study 1: Pixel Building

Pixel’s project objective was “to design and construct the world’s first carbon-neutral and water balanced office building with regard to both operational and embodied carbon emissions” (Sustainability Victoria, 2012, p 1).

In terms of sustainable materials intended to minimise carbon emissions, the strategies included:

1. Using the Pixelcrete” concrete, which has been shown to halve the embodied carbon of the mix when compared with traditional 40MPa concrete mix designs,
2. Making significant design effort to a large proportion of the building envelope so that it can be removed and reused in order to minimise the future carbon footprint once the building is demolished,
3. Using unique external shading material to minimise solar thermal loads,
4. Gas with carbon intensity of 0.21 kgCO2e/kWh was selected over the traditional Victorian brown coal powered grid electricity, which has a carbon intensity over six times greater (1.34 kgCO2e/kWh ),
5. Using a gas fired absorption chiller that employs ammonia refrigerant as it has no ozone depleting potential or any possibility of legionella, and
6. Designing renewable energy systems into the building, consisting of fixed and tracking photovoltaics and wind turbines on the roof, in addition to a small amount of biogas produced from an anaerobic digester connected to the vacuum toilet black water system (Sustainability Victoria, 2012).

Case Study 2: VS1

With a Gross Floor Area of 35 350 m2, the VS1 building in Victoria Square “has a strong focus on water conservation and energy reduction and is expected to achieve a reduction of approximately 70 per cent in portable mains water consumption, and a reduction of approximately 50 per cent in green gas emissions and energy costs compared to a typical office building” (Green Building Council of Australia, n.d).

In terms of sustainable materials intended to minimise carbon emissions, the strategies included:

1. Using low VOC off-gassing carpets, paints, sealants and adhesives,
2. Using low formaldehyde off-gassing joinery,
3. Recycling of over 90% of construction and demolition waste,
4. Non PVC piping, conduits, sub-mains, flooring and blinds,
5. Replacing 20 per cent of Portland Cement in concrete with fly ash,
6. Using a fritted western veil in front of the building skin to minimise solar loads,
7. Using ETFE roof over full-height central atrium to facilitate natural light into the heart of the building,
8. Using automated blinds on east, north and west facades to control glare,
9. Using exhaust riser for printer and photocopy rooms, and
10. Employing humidity sensors in supply air ducts to control humidity and minimise potential for mould growth (Green Building Council Australia, n.d.).

Case Study 3: 55 St Andrews Place

With a net lettable area of 6000 square metres, Melbourne’s 55 St. Andrews building was voted as the 2007 sustainable refurbishment of the year (Wild, n.d.).

The main objective of the project, according to Clark (2009), “was to transform a poorly performing building, from both an energy efficiency and indoor environment quality perspective, into a building that meets current best practice for greener office spaces” (p. 28).

In terms of sustainable materials intended to minimise carbon emissions, the strategies used by the project designers and developers included:

1. Replacing punched window glazing with clear glass to enhance daylight potential, improve comfort and reduce air conditioning needs,
2. Installing external automated blinds to control solar load before it enters the building,
3. Replacing the large expanse of full height tinted glazing in the office area with an insulated 1.2m high spandrel panel and new Low-E glass (except in the new naturally ventilated resource room where the existing glazing was retained and glass louvre door added) to improve comfort and increased daylight levels,
4. Reducing construction waste by reusing as many materials as possible, and
5. Avoiding PVC and other materials that are known to have substantial off-gassing (Clark, 2009).

Where new materials were used, the developers always made sure that

1. New pipework and communications cabling had no PVC content,
2. Carpet tiles had low VOC emissions and no PVC backing,
3. Sheet flooring used linoleum with no PVC content, and
4. Joinery used particleboard and MDF with low formaldehyde content (EI and EO standard) (Clark, 2009).

Case Study 4: The Cundall Office

“The first office building in the Southern hemisphere with LEED-Platinum certification, Cundall Sydney Office (fitout), was opened in 2003 in St. Leonards, Sydney, and participated in the green building movement in the country” (Atabekyan, n.d.).

Atabekyan, A. (n.d.). Cundall Sydney Office, Sydney, Australia.

In evaluating the 400 square metres facility for possible ranking, the Green Star used totally different credits that were extremely specific to tenancy issues. While BREEAM did not address fitout design issues, Green Star looked at each type of furniture, and LEED lumped the furniture all together (Wild, n.d.).

In terms of sustainable materials intended to minimise carbon emissions, the strategies used included:

1. 50% diversion of construction and demolition debris,
2. 10% recycled content building materials,
3. 5% regionally extracted, harvested, recovered, or manufactured materials,
4. 40% existing interior non-structural elements reuse,
5. 30% salvaged, refurbished, or used furniture,
6. 5% salvaged, refurbished, or reused building materials, and
7.  5% rapidly renewable materials (GBIG, 2013).

Proposals for Enhancement

In a recent review of the Green Star rating system, users requested for simple energy calculators to be made available online for project teams, along with a list of elements that should be included in the energy model (Green Building Council of Australia, 2013). From the case studies, it is evident that energy generation and use, along with the materials used for such generation, is a critical component in any sustainability efforts. In view of the fact that carbon dioxide and other greenhouse gases are emitted whenever fossil fuels are burned to produce energy for the buildings (International Energy Agency, 2012), it is fundamentally important to introduce separate calculations of energy use and greenhouse gas emissions minimisation in future Green Star rating tools. These calculations should be principally based on the type of materials used in the buildings to generate energy.

From the case studies, it is clear that the use of PVC materials, high VOC off-gassing, paints, sealants and adhesives and other materials with high concentration levels of acetaldehydes and formaldehydes is directly related to an increase in the carbon emissions into the atmosphere. Available literature shows that tested furniture coating is “the strongest source of formaldehyde concentration levels when compared to levels resulting from the tested wall surface latex paint and composite flooring material” (Srebric, 2010 p. 7). Although the Green Star rating system looks at each type of furniture in assigning credits, it is proposed that more comprehensive rating components be developed to individually measure these potentially hazardous chemical pollutants and materials and assign credits according to the contribution of the material or chemical to the carbon footprint not only in the operation phase of the building’s life cycle but also in the maintenance and deconstruction phases.

As indicated in the literature, “there is little dispute now that buildings are substantial CO2 emitters and contribute substantially to climate change” (Reed et al., 2009 p. 1). This view has been reinforced by the case studies, whereby it is evident that some types of building concrete (e.g., Pixelcrete) have the capacity to substantially reduce the embodied carbon of the mix when compared with other traditional concrete mix designs. Consequently, the Green Star rating system should strive to establish a global set of benchmark parameters for sustainable materials used in the building industry, with a starting point of zero net emissions for optimal credits. Such parameters, in my view, will not only allow buildings to be effectively and efficiently compared within each country and also between each country, but also contribute substantially to a reduction on the carbon footprint as developers will be in the know on which materials are considered sustainable as well as their rating potential.

Lastly, as a general proposition, the developers of some of the most used rating systems (e.g., BREEAM, LEED, and Green Star) should seek to develop similar metrics that will assist international stakeholders and markets in comparing buildings in different cities using an ‘international language’, with the overall goal of having a common set of criteria and targets that could be used to facilitate the reduction of carbon emissions into the environment.

References

Atabekyan, A. (n.d.). Cundall Sydney Office, Sydney, Australia.

Clark, D. (2009). The refurbishment of 55 St Andrews Place, Melbourne: Turning a sparrow into a peacock. Web.

GBIG. (2013). Cundall Sydney Office Fitout. Web.

Green Building Council of Australia. (n.d.). Victoria Square.

Green Building Council of Australia. (2013). Green Star review 2012-13: Helping us build a better rating system. 

International Energy Agency. (2012). CO₂ emissions from fuel combustion highlights. Web.

Portalatin, M., Koepe, K., Rostoski, M., & Shouse, T. (2010). Sustainability “how-to-guide” series: Green building rating systems. IFMA Foundation. Web.

Reed, R., Bilos, A., Wilkinson, S., & Schulte, K.W. (2009). International comparisons of sustainability rating tools. JOSRE, 1(1), 1-22. Web.

Russell, M.D. (2011). Enhancing building rating systems based on carbon footprinting. Web.

Srebric, J. (2010). Opportunities for green building (GB) rating systems to improve indoor air quality credits and to address changing climatic conditions. Web.

Sustainability Victoria. (2012). Carbon neutral offices: The Pixel building case study. Web.

Wild, S. (n.d.). Green rating tools comparison, evolution and future. Cundall. Web.