A material issue

This Issue This is a part of the Materials and specifications feature

By - , Build 130

Current BRANZ research will develop ways for manufacturers to better understand the environmental impact of their products – an important consideration as building materials increasingly come under the environmental spotlight.

A building’s greatest environmental impact is incurred during its occupation, through energy and water use, waste generation, cleaning, maintenance and renovation activities. The production of the building’s materials – or embodied impact – typically contributes between 10–20% of environmental impact.

This has led to a focus on reducing the impacts of buildings during use through, for example, better insulation and improved energy efficiency. This approach is reinforced in the New Zealand Energy Strategy 2011–21.

Five key drivers for change

Now, however, there are five key reasons why the environmental impact of building materials and products in New Zealand is likely to come under increasing scrutiny.

IMPACTS OF CONSTRUCTION SIGNIFICANT

Construction materials and products have a considerable effect on the environment, from raw material acquisition and manufacture through to end of life. They are estimated as being responsible for 50% of total material resources taken from nature and 50% of total waste generated.

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MATERIALS CONTRIBUTION SET TO RISE

As the overall environmental impacts associated with building use are likely to reduce over time with improved performance, the percentage contribution made by the materials to the life cycle environmental impacts of buildings will increase.

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BUILDING GREEN CASE GROWING

Local and overseas studies indicate there are several benefits of building green. For example, reports on commercial buildings have demonstrated benefits for their corporate tenants and owner-occupiers such as:

  • improved public image
  • lower operating and maintenance costs
  • increased employee satisfaction and productivity improvements ranging up to 20%
  • reduced risk from improved coordination through the design-build process, providing potential savings of 2–5% on capital costs
  • better understanding of potential indoor environmental hazards
  • up to a 30% increased market value through lower operating costs and more satisfied tenants.

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BUILDING ENVIRONMENTAL RATING TOOLS

The New Zealand Green Building Council’s Green Star suite of tools and Homestar™ award points for use of more sustainable materials, such as those licensed by Environmental Choice New Zealand.

The US building rating tool, LEED, has been piloting the award of points for materials with accompanying Environmental Product Declarations (EPDs), which disclose the life cycle environmental impacts of a material or product in an independently certified report (see Build 126, page 92).

This is part of an increasing global trend for greater transparency of information about the environmental impacts of materials and products.

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KEY EXPORT MARKETS

A lack of robust, publicly available information about the environmental impact of New Zealand building materials and products in a format readily understood by clients, architects and specifiers could impact on exports.

Financially, construction materials exports are important to the New Zealand economy, contributing over NZ$3 billion annually.

Many of New Zealand’s export markets, including Australia, China, Europe, Japan and the US, are paying more attention to the life cycle environmental performance of materials used in construction – through the use of building environmental rating tools, for example.

BRANZ found sector wants to improve

In November 2011, BRANZ completed the first stage of its environmental profiling research, resulting in the discussion paper Environmental profiling of New Zealand building material products: Where to for the New Zealand building sector? This reported on:

  • the needs of the New Zealand building sector in relation to environmental profiling
  • environmental profiling tools used internationally and what New Zealand can learn from these
  • the development of two draft Environmental Product Declarations (EPDs) as a possible means to provide the transparent, robust environmental data sought by the building sector
  • recommendations to further develop environmental profiling in New Zealand.

The research, reported in Build 119 (pages 82–83) and Build 126 (page 92), found that the New Zealand building sector wants to improve its position on environmental profiling by using a consistent life cycle methodology that would create a level playing field for comparison of products and materials.

What exactly does this mean?

Firstly, the environmental impact of materials should be assessed across the whole life of a building including extraction of resources, manufacture, transport, construction, use in the building and end of life. This is important because some materials may have a greater impact in one part of the life cycle compared with alternatives, but have a smaller impact in other parts of the life cycle.

Focusing on just one part of the life cycle, such as manufacture or end of life only, may not necessarily lead to a fair comparison of alternatives, as it does not consider the overall picture.

Assessment across the full life cycle – a life cycle assessment (LCA) approach – helps to ensure that environmental savings in one part of the life cycle are genuine and not achieved by shifting environmental impacts to another part of the supply chain or life cycle.

Secondly, a range of impacts should be considered rather than focusing on a single impact, such as greenhouse gas emissions, or a single attribute, such as recycled content. This allows a more complete understanding of how a material or product may impact on our environment and us and reduces the chance of unexpected surprises.

Developing a life cycle assessment plan

Building on its earlier work, BRANZ has now commenced the second stage of this research with the aim of developing an LCA plan for the New Zealand building sector.

The project, funded by the Building Research Levy, is scheduled to run until September 2012. Its objectives are to:

  • establish an agreed LCA methodology for the New Zealand building sector, based on relevant New Zealand and international protocols
  • recommend an approach to the recognition of environmentally preferable materials in New Zealand building environmental rating tools
  • develop a business case, using case study examples from New Zealand and internationally, to help the building sector better understand the benefits of environmental profiling.

A building sector advisory group has been established to assist with the research, representing different stakeholders including manufacturers, designers, government and others.

BRANZ is planning consultation on the plan later in 2012 to obtain feedback from the New Zealand building sector.

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For more

If you are interested in this project, please email Dr Dave Dowdell at [email protected].

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