The question of what is a sustainable construction product is a complex one and can be interpreted in many different ways. A frequent request to CPA is for a list of ‘the best or most sustainable products’. This is analogous to asking for the best music. The answer to both questions is ‘it depends’ on what is required. Often the enquirer is referring to products that capture renewable energy, or capture and store rainwater, or make a house more energy efficient. Another enquirer may wish to know which product has had the least impact on the environment; others want to know whether a product has been sourced in a responsible way. For some, only locally sourced materials meet their requirements.
In all cases it needs to be remembered that the construction product is a component within a building or structure, in essence the building or structure such as a bridge is the final product. What may be a sustainable solution for one project may not be the optimum sustainable solution for another project. A construction product can similarly be the most sustainable choice in one scenario but the very same product may not be the best sustainable choice for another project.
The first step therefore is a consideration of the construction project type. Is it a small project where a product is being replaced like for like such as a window, or is it a major project constructing a row of houses, a school, a multi-story office block or a railway. The choice of materials and products will depend on the performance required. The expected lifespan of the building and end of life options can radically affect the choice of products. For instance shop fitting, where lifespan is measured in years or even months rather than decades, is an area where high impact materials have to have good re-use or recycling routes in order to compete with lower impact materials; whereas a multi-storey office block or an apartment block must have products with strength and durability and may be expected to exist for decades if not several centuries. Assessing the benefits of products and materials in building performance terms is thus often now entwined with the environmental, and increasingly social and economic, impacts in their manufacturing and use.
To assess this complex area, there has emerged over the past two decades a set of national initiatives that have now evolved into a suite of European standards that provide the rules for measuring and reporting the sustainability performance of construction works, these cover environmental, social and economic and apply at the building level and at the product level. These are called the CEN TC 350 suite of European standards and apply across the European Union. Information can be found here. Construction products are part of the single European market and should Member States wish to regulate on the sustainability performance of products then they must use existing European standards.
For products, the environmental impact of a product is measured through a life cycle assessment (LCA) process. This gives rise to an environmental profile often formally called an Environmental Product Declaration (EPD). This is a set of numbers measuring an indicator such as impact on global warming or toxicity and can be used to input to design tools to decide the best material and product option to deliver a required sustainability performance.
The methodology for creating an EPD is now formalised through a formal European standard called EN 15804. EPD providers; i.e., those companies that provide a service to manufacturers to develop an EPD, now follow this standardised methodology. In the UK, the main provider of environmental profiles is BRE which has been providing profiles for 20 years largely because of the Green Guide to Product Specification. BRE now use the European standard.
The European standards on the measurement and reporting of sustainability performance are of great relevance and importance to CPA members. The Association thus works collaboratively with members to ensure they have good involvement with the direction and development of the standards.
CPA also works to ensure that knowledge of the mature landscape of environmental and sustainability reporting is known to those in the wider construction community, such as contractors and designers, and also to policy makers
The reporting of environmental performance has been a driver for many manufacturers to assess the impact of their manufacturing process from raw material extraction through the manufacturing process and in use and to make improvements often resulting in greater efficiencies and lower costs. This has led to innovations to reduce embodied carbon, water usage, and impact on a range of emissions and resource extraction. Such innovations are expected to improve a product’s BRE Green Guide rating and potentially lead to better scoring for the material element in a BREEAM rating scheme or similar. Making more with less resource, be it material, energy or water, is also likely to have beneficial impact on the economic bottom line of manufacture.
- The Association has published a Guide to Understanding the Embodied Impacts of Construction Products which provides a helpful introduction to the scope and methodologies used within the sector to produce third party environmental impact information.
- Information about the CEN TC 350 suite of European standards on measuring and reporting the sustainability performance of construction works including construction products can be found here.
- The European Standard for producing Environmental Product Declarations - EN15804 - can be purchased from BSI here.
- The BRE Green Guide to Building Specification provides a simple rating system of the environmental impacts of building materials. The rankings are based on Life Cycle Assessments (LCA), this initially used “BRE's Environmental Profiles Methodology 2008” but this is now modified to align with the European standard for producing Environmental Product Declarations (EPD) – EN 15804.