In a first for our industry, Think Brick Australia commissioned a Total Life Cycle Assessment (LCA) of the brick industry to quantify the environmental impact of clay bricks.
The results show that the external walling materials of a house, including clay brick, have very little impact on the overall greenhouse gas emissions caused by a house and provide important learnings about LCA methodologies that may one day be used to regulate the industry.
In 2008 Think Brick Australia commissioned Energetics to undertake a full Life Cycle Assessment of the Australian clay brick industry. This involved collecting data directly from the industry on clay extraction, manufacturing processes, transport requirements, construction elements, and end-of-life disposal.
The study - the first of its kind for depth and breadth - also included the modelling of operational energy consumed by the houses constructed. This allowed for a comparison of total emissions created by a house over its lifetime (rather than just the emissions created during the manufacture of the materials).
The Key Findings were:
• Improving the design and operation of a house is currently the best way to significantly reduce greenhouse gas emissions
• The walling material(s) make very little impact on the overall greenhouse gas emissions caused by house
Comparing building material requires measuring the four stages of a building total life cycle:
• Extraction & manufacture
• Transport & construction
• Operation of a lived-in house (over at least 50 years)
• Demolition & disposal
The embodied emissions of a typical Australian house represent only 11% of the total emissions over a 50-year life cycle, regardless of walling materials.
In particular, this study highlighted that analysis of emissions based only on the manufacture of building materials and/or the construction of a house does not capture the breadth of information to properly develop public policy.
The best way to capture this information is to use the total life cycle analysis methodology employed by the Energetics study.
Life Cycle Assessment (LCA) is a method of evaluating the environmental impact of products or services across their 'life cycle'.
LCA measures the environmental impact of products by analysing all the inputs (ie raw materials, water, energy) and outputs (i.e. the end product, waste, emissions) that occur as a result of that product being manufactured, transported, 'built' or assembled, used and maintained, and eventually, disposed of.
According to the Australian Sustainable Built Environment Council (ASBEC) the building sector is responsible for almost a quarter, or 23 per cent, of Australia's greenhouse gas emissions. More than 50% of those emissions come from residential housing. The source of these emissions is the energy we use to live in our homes (heating, cooling, lighting, TVs etc.).
The unknown factor in ASBEC's research is how many emissions exist within the building fabric itself (i.e. walls, floors, roofs etc.). To date, the 'embodied energy' of the buildings has not been substantially quantified. As Australia continues to evolve its understanding of carbon emissions and improve the performance of our buildings it is likely embodied energy (or more accurately, embodied emissions) will be under the spotlight. The only way to substantially quantify embodied emissions is using the LCA methodology.
At its most basic level LCA is a measure of building material and construction efficiency. Despite that, LCAs can differ in what they actually measure, even if they do follow the ISO 14040 Standard. See Total v Partial Life Cycle Assessment below.
The International Standards Organisation (ISO) sets world-wide standard for many activities, including Life Cycle Assessment. Although not all LCAs have to follow these standards, it is necessary to do so before publishing any comparative results. Recognising the need to address the total life cycle of product and to fully understand the environmental impact of building and occupying houses, Think Brick Australia has used an international best practice total Life Cycle Assessment methodology to more accurately compare the advantages and disadvantages of different building materials. In a first for our industry, Think Brick Australia commissioned energy consultants Energetics to conduct an ISO 14040 fully compliant and peer reviewed total Life Cycle Assessment to quantify the environment impact of clay brick. View the results and conclusions or alternatively read the full report. Visit the Think Brick Australia blog to comment and read more information on the methodology used and the policy implications of the findings.
As highlighted in the image at the top of this page, there are four different LCAs that can be undertaken. According to the ISO 14040 standard, all of these are correct. The problem this creates is that comparing different building materials LCAs requires ensuring they are a like-for-like comparison.
To date, most building material LCAs only use what is commonly referred to as a 'cradle to gate' methodology (illustrated in green). This assesses the environmental impact of the building material within the 'boundary' of the product's extraction and manufacture. (See the detailed methodology discussion for more information on the subject of 'boundaries').
Other LCAs go further and use what is commonly referred to as a 'cradle to grave' methodology (illustrated in blue and orange) for either the single unit of building material, or a section of that material assembled in a building (i.e. a square metre of wall).
While this is a more complete analysis of environmental impact, it does not recognize that building materials directly influence the operational emissions of a building (predominately through heating and cooling).
As such, a Total Life Cycle Assessment is required. As illustrated in pink, this methodology uses thermal modelling to quantify the operational emissions from living in a building. Given that the operational emissions can contribute nearly 90 percent of the total emissions from a building it is fundamental to include these emissions when analysing the environmental impact of buildings.
This is why Think Brick Australia has undertaken an international best-practice, fully compliant and peer reviewed LCA study to quantify the total environment impact of not only clay bricks, but also buildings made using clay bricks. For a more detailed discussion of the methodology, see Think Brick Australia's LCA Methodology.