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1 Sustainability TECHNICAL BULLETIN No. 7 | Version 2 | 17 May 2010 BlueScope Steel Ltd. (BlueScope Steel) has made a commitment to continually improve the company’s environmental footprint and the sustainability of its products and services. This is the seventh in a series of technical bulletins relating to sustainability issues that directly or indirectly impact the steel value chain. In writing these bulletins BlueScope Steel wishes to inform and educate the market, based on the latest available and verifiable information. This technical bulletin details how thermal mass can be used to help create energy efficient thermal comfort across Australia’s diverse climate zones. Thermal mass is the term used to describe the ability of materials to absorb and store heat. There are a number of ways that both high and low thermal mass materials can be used to help create energy efficient buildings. In many climate zones reverse mass construction can be a sustainable choice, while in hot, arid or tropical regions, lightweight construction may be more appropriate. Regardless of climate zone, a low mass roof is usually preferable. Steel is a lightweight, low thermal mass material, therefore, can be used in both low and reverse mass designs. Other technical bulletins in this series related to the use of thermal mass, and other steel products, to help provide indoor thermal comfort and create a sustainable built environment include: 1. Zero-Carbon and Carbon Neutral Developments; 2. Urban Heat Islands 3. Voluntary Green Buildings Ratings Tools in Australia; 5. Mandatory Sustainability Requirements for Residential Buildings in Australia; and 8. Steel in Sustainable Buildings. 1. Energy Efficiency and Thermal Mass Increasing energy efficiency – which reduces energy demand – is one of the easiest and most effective ways to increase environmental, social and economic sustainability. Because 50%1 of Australia’s energy needs are met by coal-fired power plants, in most regions a decrease in energy demand would likely reduce the amount of greenhouse gases (GHGs) and other pollutants released to the atmosphere. Reducing GHG concentrations is key to slowing climate change and its associated effects such as increased species extinction rates, changes to rainfall patterns and sea-level rise. A reduction in particulates in the air may positively affect the health of local communities – particularly infants, the elderly and those predisposed to asthma or bronchial complaints. Energy efficient buildings should provide occupants with thermal comfort with reduced dependence on mechanical heating and cooling systems, which not only saves energy, but also saves money. Further, because Sustainable Building Solutions: Thermal Mass

2 meeting peak demand is already a challenge for most Australian supply grids, if energy demand at peak-time can be reduced, the need to develop additional power stations – which are expensive and potentially sources of GHGs and pollutants – may also be deferred. There are numerous design features, fixtures and fittings that can be utilised to gain energy efficiency in new buildings, significant retrofits or renovations: thermal mass is one of these tools. Thermal mass is the ability of any material to absorb and store heat energy, and can be thought of in terms of how much energy is needed...

3 made from high thermal mass materials that store large amounts of heat during the day, the heat released into the dwelling in the evening may result in uncomfortable sleeping conditions. In areas occupied during the day, high thermal mass materials, such as slab-on-ground, can be used to create cool living or working spaces, but as in warmer temperate areas, attention must be paid to how the heat will be dissipated in the evening. In hot, arid areas that experience cool evenings in winter – such as Alice Springs – incorporating thermal mass into the walls or floors can also help reduce...

4 sparsely planted, shorter trees can create turbulence and enhance wind flow. One-room-thick designs – which have windows and doors on both (or all) sides of the room – optimise opportunities for capturing the breeze and removing heat from a room during the evening. In private homes, high ceilings and overhead fans can enhance air circulation with minimal additional energy use. If mechanical extraction is necessary, as may be the case in commercial buildings that are unoccupied at night, the energy efficiency of the system selected becomes very important to the overall sustainability of...

5 Literature Cited 1. Australian Bureau of Statistics (2007) Australia’s Environment: Issues and Trends 2007. Australian Bureau of Statistics, Canberra. 100pp. 2. Reardon, C., McGee, C. and Milne, G. (2008) Passive Design: 4.9-Thermal Mass. In, Your Home Technical Manual. 4th ed. Department of the Environment, Water, Heritage and the Arts, pp 114-118. 3. Sustainable Energy Authority Victoria (2007) Sustainable Energy: Thermal Mass. Victorian Government, Melbourne. 6pp. used most efficiently. For example, if a building is to be occupied intermittently i.e. a home where the occupants are at...