Life Cycle Analysis & Ecologically Sustainable Development
It is also a tool which building designers can use to achieve Ecologically Sustainable Development. LCA has also increasing relevance to Local Government and other regulatory bodies in developing guidelines to ensure Ecologically sustainable built environments.
Sustainable development is a goal for governments, businesses and communities around the world. Families too are making choices about their purchases and lifestyles.
CHAPPY is a Life Cycle Analysis (LCA) model that enables a student to calculate the environmental impact of his or her family. Image Life Cycle Analysis is an important tool for both analysing processes to find ways to improve them, and assessing materials and products. LCA consists of two components: inventory analysis and impact analysis.
Inventory analysis involves summarising the material and energy flows for a defined system. The "system" is the combination of processes and activities that manufacture a product or achieve an outcome. This typically includes all of the processes associated with the mining of resources, supply of energy, manufacture of the product, use of the product and disposal and recycle. The resultant inventory is a list of the resources consumed and the emissions associated with the system.
Impact assessment involves interpreting the significance of the resource consumption and emissions determined in the inventory stage. It should be noted that in life cycle assessment, these are restricted to environmental impacts. Energy and CO² emmissions are just two well known quantitative indicators for impact assessment. Other factors, which may be both quantitative and qualitative can include effect on biodiversity, air quality, soil quality, water quality, noise and other social and cultural impacts.
BlueScope Steel's LCA MODEL
BlueScope Steel began working on an LCA model in 1993. From the outset, it was determined the company's approach would be rigorous and stand up to international scrutiny. The BlueScope Steel model is used for both product and process assessment. It examines the material use and emissions in a product, from raw materials through to end of life. It also assesses the impact of products and processes on the environment - from the mining of the coal and ore which goes into the production of iron, through the steelmaking and manufacturing processes, to disposal by processes such as recycling at the end of a product's useful life. It does this by examining such things as: wastes generated during production; energy consumed during production and the use of the product; fresh water consumption during production; and the amount of recycling the product is capable of.
CASE STUDY: LCA in the Building Industry
Within the context of the Australian building industry, LCA can be applied to:
- Product assessment
- Eco labelling
- Process improvement
- Eco design
- New technology evaluation
Consider a building as an example. For the energy case, the analysis would consider the energy embodied in the building, and the energy consumed during the life of the building. The former depends on the materials used and the fabrication methods, while the latter depends on the orientation, window areas, window types and surface treatments, lighting systems, air conditioning systems, level of insulation, thermal characteristics of walls and roof, etc.
Figure 1 shows the results of an LCA for a typical project home with brick veneer on a concrete slab with steel framing and a steel sheet roof. The energy embodied in the building materials is small (around three per cent) compared with the energy used to operate it over its life. As most of this energy is consumed in lighting, heating and cooling, the most effective way of decreasing the life cycle requirements of a house is to use building materials and systems that can reduce the energy required to run the house. To that end, passive solar design principles, together with the use of energy efficient household appliances and lighting, are key factors in reducing energy consumption (and resulting carbon dioxide emissions from the generation of that energy).
In addition to energy, a comprehensive LCA will include a range of other environmental impacts such as greenhouse gas emissions and solid waste. A less than comprehensive LCA model can give misleading results. Examples would be where whole-of-life energy usage of a product is not included together with the embodied energy from the components and fabrication; or, alternatively, where only energy usage is incorporated (and other resource utilisation such as water and raw materials is ignored). Based on overseas developments and BlueScope Steel's experience with its own model, data should be specific to the situation and the materials being processed. For every product analysed, a large number of calculation steps are necessary for a meaningful answer.
Figure 1. Energy used in construction compared with utilisation for a typical house in Sydney.
Key Points to Learn From the Brief Summary of LCA
LCA shows us that the energy used in the construction of the building, which includes the EMBODIED ENERGY of the building materials is a SMALL FRACTION of the OVERALL ENERGY that will be consumed by the house over the period of its life.
When choosing building materials, designers should place high emphasis on using materials in ways to reduce the energy required to operate the building over its life time. The thermal benefits that steel roofing and walling can potentially offer may assist in doing this.
As an example, in a Commonwealth Scientific and Industrial Research Organisation (CSIRO) roofing study commissioned by BlueScope Steel, a typical dwelling located in Brisbane with a roof made from ZINCALUME® steel was compared to a similar dwelling with a red tile roof. It was found that the roof made from ZINCALUME® steel reduced the cooling bill to less than half when both dwellings were left uninsulated, as is common in such a climate. Even when both dwellings were insulated, the cooling bill with the roof manufactured from ZINCALUME® steel was approximately 15% less than the tiled roof.
Read more on ZINCALUME® steel for Roofing.
