Specifying efficient use of materials and considering their impact from manufacture to disposal.
Life cycle assessment
Life cycle assessment calculates the potential environmental impacts of materials, products and services across a defined life cycle. LCA is recognised in international building environmental rating tools such as Green Star.
Knowing about LCA and how it works can help designers and specifiers to select building products and services that have a lower environmental impact.
LCA models the use of materials and energy and calculates environmental impacts as a result of this use during extraction, processing, manufacturing, transportation, use, reuse, maintenance, recycling and eventual disposal.
Depending on the scope of an LCA, it can quantify potential impacts across this entire life of a product or just one part, such as manufacturing. When using LCA data it is important to understand what the analysis covers and what has been left out.
Examples of environmental impacts that can be calculated using LCA:
- Global warming (greenhouse effect) that part of climate change caused by the emission of greenhouse gases.
- Ozone depletion ozone helps reduce harmful levels of solar radiation reaching the earths surface. Ozone can be destroyed by the release of ozone-depleting substances.
- Acidification of land and water release of acidifying pollutants such as sulphur dioxide, nitrogen oxides and ammonia can contribute to this.
- Smog can be aggravated by release of volatile organic compounds and carbon monoxide.
- Non-renewable resource depletion (fossil fuels).
- Non-renewable resource depletion (other).
- Eutrophication impacts due to nitrogen and phosphorus going into waterways.
Providers of construction materials or products who use LCA can publicly declare the environmental performance of their materials or products in an Environmental Product Declaration (EPD) or environmental profile. This provides a summary of information about the environmental impacts associated with a material or product, including results of an LCA.
There are a number of international life cycle assessment tools and websites, for example:
- Ecospecifier (Global)
- Greenspec (United Kingdom)
- Gabi is a widely used database for building material examination. ISO Standards
ISO 20400:2017 Guidance on Sustainable Procurement, explains how companies can source the goods and services they need while reducing environmental damage and benefitting wider society.
The process for undertaking LCA is set out in the ISO standards ISO 14040 (2006) and ISO 14044 (2006), with more specific detail concerning the application of LCA to building products in ISO 21930 Sustainability in building construction Environmental declaration of building products (2007).
ISO 21930 is part of a suite of developing standards concerned with sustainability in building construction and construction works.
Others are as follows:
- ISO 15392: Sustainability in building construction General Principles (2008).
- ISO 21929-1: Sustainability indicators Part 1: Framework for development of indicators for buildings (2011).
- ISO 21931-1: Framework for methods of assessment of environmental performance of construction works Part 1: Buildings (2010).
Published European standards include:
- N 15643-2 Sustainability of construction works. Assessment of buildings. Framework for the assessment of environmental performance.E
- EN 15978 Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method.
- 5804 Sustainability of construction works. Environmental product declarations. Core rules for the product category of construction products. EN 1
LCA in New Zealand
In New Zealand, BRANZ and other organisations are working on life cycle assessment. A good place to start with this is the New Zealand whole building whole of life framework.
BRANZ has developed LCAQuick Office, a Microsoft Excel tool to help designers understand LCA and its outputs and how to use it. Work on developing a similar tool for residential construction is underway.
Updated: 10 June 2019