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Sustainability Speak
BRE Green Guide to Specification
The Green Guide:
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Owned by BRE Trust;
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Last updated in June 2008 (4th Edition);
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Strongly linked to the Code for Sustainable Homes (CSH);
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The Construction Products Association (CPA) had an important data input role;
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Both the CSH and BRE Environmental Assessment Method (BREEAM) (August 2008 is the latest version), use the Green Guide as the means to rate materials for credits – based on the embodied impacts of those materials;
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More than 1200 specifications, used in various types of building, are examined in the new edition;
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6 different generic types of buildings are considered, namely:
o Commercial, such as offices
o Educational
o Healthcare
o Retail
o Residential
o Industrial
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ISO (International Organisation for Standardisation) methodologies are used for life-cycle assessments, i.e. ‘cradle to grave’ (60 year ‘life’ assumed) or ‘cradle to cradle’ (recycled materials);
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13 different criteria are weighted and added up to give EcoPoint scores, i.e.:
o Climate change
o Water extraction
o Mineral resource extraction
o Stratospheric ozone depletion
o Human toxicity
o Ecotoxicity to fresh water
o Nuclear waste (higher level)
o Ecotoxicity to land
o Waste disposal
o Fossil fuel depletion
o Eutrophication (harmful enrichment with nutrients)
o Photochemical ozone creation (ground level ozone is classified as a damaging trace gas)
o Acidification
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The BRE’s ‘Environmental Profiles Methodology’ is used, and is the basis of the online Green Guide – www.thegreenguide.org.uk;
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Gives the relative performances – environmental impacts – of materials and components, arranged on an elemental basis, so that designers and specifiers can compare and select from ‘comparable’ systems or materials as they complete their specifications;
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The elements covered (not exhaustively) are:
o External walls
o Internal walls and partitions
o Roofs
o Ground floors
o Upper floors
o Windows
o Insulation
o Landscaping
o Floor finishes
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There are 6 ‘bands’ for EcoPoints – A+ to E – but the difference between the best (A+) and the worst (E) can be relatively small in absolute terms, i.e. an E-rated element (material and/or component) can still be part of an overall building solution achieving high rating levels in the CSH and BREEAM;
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Specifying materials or products solely on one criterion, such as embodied carbon or recycled content, can lead to sub-optimal overall sustainability choices;
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Specifiers must understand that the embodied environmental impacts, as measured in the Green Guide, are only part of (and not the same as) the overall sustainability as measured in BREEAM and the CSH;
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The CPA and BRE would like to move towards a system where the EcoPoint scores of each material/product are added up at the whole building level, rather like energy performance, ideally through the CAD system.
BRE Global
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