The Green Guide is an accredited environmental rating scheme for buildings that contains more than 1500 specifications used in various building types. It is a good example of a practical tool where materials and components are arranged on an elemental basis so designers and specifiers can compare and select from comparable systems or materials as they compile their specification. Across nine building element categories (e.g. walls, windows, roofs, and landscaping), the guide provides an extensive catalogue of building specifications covering most common building materials.
The data is set out as an A+ to E ranking system; A+ represents the best environmental performance/least environmental impact, and E the worst environmental performance/most environmental impact. BRE also provides a summary environmental rating.
For example, Canadian cedar weatherboarding receives an A+ rating based on:
- breather membrane;
- plywood (temperate EN 636-2) sheathing;
- timber frame with insulation;
- vapour control layer;
- plasterboard on battens; and
- paint.
A rating of C would be given to an extruded aluminum curtain wall containing:
- three transoms per floor;
- laminated sealed glass unit; and
- coated aluminum spandrel panel with pentane blown polyurethane (PUR)/polyisocyanurate (PIR) insulation.
The Green Guide rating covers 13 separate issues including:
- climate change;
- water extraction;
- mineral resource extraction;
- stratospheric ozone depletion; and
- fossil fuel depletion.
By evaluating the performance of materials and building systems against these specific environmental impacts—which have also been ranked on an A+ to E basis—it is possible for the specifier to select materials on the basis of personal or organizational preferences or priorities, or make decisions based on the performance of a material against a particular environmental impact. This methodology shows transportation impacts alone become insignificant when impacts from industrial practices are factored in.
To provide the data necessary to conduct a lifecycle analysis of a product, assembly, or entire building, manufacturers must first provide data about materials and products via an Environmental Product Declaration (EPD). These are created following a standardized format (i.e. ISO 14025, Environmental Labels and Declarations: Type III environmental declarations–Principles and procedures) for communicating the environmental performance applicable worldwide.
An EPD includes information about the environmental impacts associated with a product, such as:
- raw material acquisition;
- energy use and efficiency;
- content of materials and chemical substances;
- emissions to air, soil, and water; and
- waste generation.
Under new legislation (entitled “Loi Grenelle 2”), France now requires EPDs to be in place for a host of product categories ranging from cosmetics to furniture.
This data is located in large lifecycle inventory databases around the world (customized to specific geographic areas) that are accessed by the various software tools. The primary barrier to mainstream adoption of LCA in product specification is willingness of manufacturers to publish data about their products. For some manufacturers, the information is proprietary; for others, there is disagreement about what should be included and how materials are to be assessed. At the end of the day, as specifiers increasingly seek to understand the impacts of their choices, pressure to provide EPDs will likely increase.
Rigorous lifecycle assessment methods require significant time and financial resources. For specifiers, it is often difficult to justify the development of several design alternatives for the purposes of objective comparison. Nevertheless, at a time when demands on natural resources from human activity (2.7 ha [6.67 acres] globally per capita required to serve current needs) already exceeds the capacity of the global productive ecosystem capacity (about 1.8 ha [4.44 acres] globally per capita) by about 50 per cent, it is more important than ever to ensure choices are made to create a positive outcome.
Therefore, instilling lifecycle assessment thinking at the macro level is an easy first step that offers immediate benefits. In the early design phases, a whole-building analysis can help with basic questions like those about structural system selection.
In later phases, product-to-product comparisons can help fine-tune a building’s environmental performance. For example, being familiar with the relative embodied energy values for commonly used materials can broaden the palette of material options. Lifecycle assessment also offers valuable indicators that assist in the efficient allocation of limited dollars to the most critical and practically attainable strategies for achieving the highest building performance.
Mainstream adoption of LCA will only happen when building owners are motivated either by regulations or by market demand for this information. However, with so many accessible tools available, LCA thinking can start today, informing designs from schematic stage forward.
Helen Goodland, BA, Dip. Arch, RIBA, MBA, LEED AP, is the executive director of Light House Sustainable Building Centre. Located in Vancouver, Light House provides consulting, researching, and education services. It has been working with the building and B.C.’s forest industries to raise the profile of lifecycle analysis (LCA) as a standard by which all materials can be compared objectively. Goodland has more than 25 years of experience as an architect and sustainability consultant. She can be reached via e-mail at helen@hsbc.com.
