Material Use

Life cycle assessment provides a systematic way to consider the impact of a material or component over its full life – from extraction to processing/ manufacturing to construction/installation to use to eventual disposal.

The life cycle assessment process is set down in ISO standard AS/NZS ISO 14040. Under this process, a product, building system, or whole building can be assessed to determine the environmental impact it will have over its whole life. The process involves: compiling an inventory of relevant inputs and outputs (for example, raw materials and energy); evaluating the potential environmental impacts associated with those inputs and outputs; and interpreting the results.

Typically, a life cycle assessment will examine: acidification; eutrophication; ozone depletion; photochemical ozone creation; human toxicity; and eco-toxicity.

There are many life cycle assessment tools and databases available, including:

• New Zealand tools and resources such as the BRANZ lightweight wall cladding tool, the Environmental Choice NZ scheme, and the NZ Institute of Architects’ materials charts
• International tools and resources such as Ecospecifier and Greenspec
• The eight-step eco-hierarchy process which you can use to carry out your own life cycle analysis.

The ideal life cycle assessment tool will:

• use a standardised methodology
• consider the material through all stages of its life, and provide lifetime comparisons
• be easy to use
• be robust, but still accessible for non-specialists
• provide meaningful, accurate information that is relevant to New Zealand
• provide information that is independently verified
• be updated frequently.