Government Business

We are all being encouraged to specify and use construction materials and products that minimise environmental impact. To help with this an updated online version of the BRE Green Guide to Specification was launched in June.
    
In the Green Guide online, building materials and components are assessed in terms of their environmental impact across their entire life cycle – from ‘cradle to grave’, within comparable specifications. This accessible and reliable information is of great assistance to all those involved in the design, construction and management of buildings as they work to reduce the environmental impact of their properties.  
    
The new online version provides a more flexible and adaptable medium; as and when new information becomes available, the on-line Green Guide will be updated. It contains more than 1,200 specifications used in various types of building. Since the previous edition, information on the relative environmental performance of some materials and components has altered, reflecting both changes in manufacturing practices, the way materials are used in buildings, and our evolving environmental knowledge.

Examining impact
The Green Guide is a listing of generic building products and elements with environmental ratings. It examines the relative environmental impacts of the construction materials commonly used in six different generic types of buildings including: commercial buildings: offices; educational; healthcare; retail; residential; and industrial.
    
The environmental rankings in the Green Guide are based on Life Cycle Assessment (LCA) studies. Materials and components are presented in their typical, as-built elemental form. They are compared on a like-for-like basis, for 1 m² of construction, as components that fulfill the same or very similar functions: important variables such as the mass of a material required to fulfill a particular function are therefore taken into account. For example, a direct comparison between the Environmental Profile of one tonne of structural steel and one tonne of structural concrete would be misleading, as less steel is required to achieve the same structural performance.
    
It should be noted that in the Green Guide it is not possible to take operational performance into account in terms of the potential energy-saving benefits of materials with a high ‘thermal mass’ or high insulation values. Whilst high-mass materials such as concrete or other masonry specifications can, if used appropriately, reduce the energy consumption of a particular building, the goal and scope of this work has not included the complex quantification of such potential.
    
The LCAs that underpin the information in the guide take into account the environmental impacts of the winning of the raw materials, manufacture, assembly, maintenance and repair, demolition and waste management at the end of life.

It's elemental
Materials and components in the Green Guide are arranged on an elemental basis: External walls; Internal walls and partitions; Roofs; Ground floors; Upper floor construction; Floor finishes; Windows; Insulation; and Landscaping.
    
This means designers and specifiers can compare and select from comparable systems or materials as they compile their specification. Furthermore, it is meaningless to compare the environmental profiles of say, concrete floors and a particular type of paint; ratings are therefore based only on product performance within each respective element group.
    
Across all building element categories the guide provides an extensive, but not complete catalogue of building products. It is therefore intended that the number of products profiled will continue to increase with subsequent editions and through updates to the online Green Guide. It is fully expected that other building elemental categories will also be added in time.

Environmental ratings
Although the environmental ratings in this guide are underpinned by extensive quantitative data, it was felt that these numerical values and comparisons would be of interest only to specialists rather than those involved in the day-to-day procurement of building projects. This data has therefore been translated into a simple environmental rating system to enable specifiers to make meaningful comparisons between materials and components.
    
Based on life cycle assessments, the guide looks at six different buildings types, over 200 materials and 1,200 specifications. Instead of the former ‘A’ to ‘C’ system, there is now more differentiation in ‘A+’ to ‘E’ gradings. A+ equals good environmental performance/least environmental impact, with A, B, C, D and E ratings increasing in their environmental impact.
    
The environmental issues included reflect the generally accepted areas of concern related to the production of building materials used in the UK. They were arrived at through the industry consultation and consensus process that took place during the development work of the guide: Climate change; Water extraction; Mineral resource depletion; Stratospheric ozone depletion; Human toxicity; Ecotoxicity to water; Nuclear waste; Ecotoxicity to land; Waste disposal; Fossil fuel depletion; Eutrophication; Photochemical ozone creation; and Acidification.
    
The online version of the Green Guide provides ratings against all these environmental impacts, together with an overall summary rating.

Making informed decisions
By evaluating the performance of materials and building systems against these specific environmental parameters, it is possible for the specifier to select specifications on the basis of personal or organisational preferences or priorities, or take decisions based on the performance of a material against a particular environmental parameter.
    
Perceptions regarding best environmental practice are subject to change as our understanding increases and a clear consensus regarding what is most important and practically achievable emerges. Designers should be aware, for example, of the ongoing debate concerning the merits of recycling and how recycling may not always represent best environmental practice, especially where high value and polluting energy resources are consumed to recycle low value material.
    
BRE suggests that the merits of recycling should be judged on a case-by-case basis, looking particularly at key issues for each individual material and location. For example, the relatively low impacts of some reclaimed materials can be adversely affected if they have to be transported over very long distances when compared with new materials, which may be produced more locally.

Environmental profile
The Environmental Profile (i.e. LCA) of a building material is only one of many factors that needs to be taken into consideration when compiling a specification; cost, durability, appearance, development control issues, buildability, function and operational issues (including the benefits of using high thermal mass materials), maintenance and availability are all important and potentially decisive issues. The most successful approach to specification is one where underlying objectives and priorities are clearly established in the early stages of a project as this can then help determine the appropriate balance between these sometimes conflicting requirements.
    
Even in the best buildings, compromise is an inevitable part of design and specification; ‘green’ considerations will no doubt be subject to this same process of trade-off in achieving the right balance of priorities for a particular project. It is hoped that by thoughtful consideration and the careful use of this guide, designers and client organisations will at the very least begin to ‘move in the right direction’ towards reducing the environmental impacts of construction projects.

Controlling risk
Many in the property sector are becoming more aware of the need to further reduce exposure to ‘environmental risk’. Whilst the most common construction and development related risks have been associated with polluting activities or the failure of specialists to deal with specific environmental hazards, the future scope of environmental liability may have far-reaching implications for the construction industry.
    
The impact of the construction process in terms of energy use or levels of emissions on global conditions could be identified as a major ‘indirect’ environmental hazard. As such, it is possible that these issues will become potential legal liability flashpoints and that designers, specifiers and materials manufacturers will be obliged to take this into account in the design and construction process.
    
Property investors and funding institutions, under pressure from shareholders and insurers, are also seeking a ‘greener’ and more ‘socially responsible’ approach to the design and procurement of buildings and many property-owning organisations are signing up to Corporate Social Responsibility (CSR) initiatives. A more carefully considered, environmentally aware approach to the specification of materials is important in being able to demonstrate that projects are well managed and are protecting shareholders interests through minimising the risks associated with environmental impact.

BREEAM and the Green Guide
The Green Guide is heavily linked to BREEAM (Building Research Establishment Environmental Assessment Method). BREEAM is the world’s leading and most widely used environmental assessment method for buildings, with over 110,00 buildings certified and over half a million registered. It sets the standard for best practice in sustainable design and has become the de facto measure to describe a building’s environmental performance.

The Materials section within the BREEAM criteria accounts for 12.5 per cent of the final score. The Green Guide is an essential resource to those looking to obtain credits within the materials section of BREEAM, as BREEAM requires the use of A rated Green Guide products to obtain credits. For more detailed information regarding how the BREEAM and the Green Guide tie in to one another please visit www.breeam.org to download the 2008 BREEAM Assessor Manuals.

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