The Green Guide was published in 2008 and covers the ‘cradle-to-gate’ environmental impact using ISO methodology to consider the weighted effect of 13 environmental impacts (water, resource, energy, potential for recycling etc., but not transport to site) to produce Ecopoint assessments for components.
By combining these it creates environmental ratings for complete system specifications based on a 60 year period.
For example, a warm roof of PVC on all insulation types on a profiled steel deck achieves an A+ rating. A similar specification with FPO membrane is also A+. The A+ to E scale divides the range of Ecopoints evenly so a product type such as windows (with a small range) may only differ by 0.5 Ecopoints/m2 across the range, whereas roofing varies by over 1.5EcoPoints/m2 (so E is four times worse than A+. Therefore ratings for different product types should not be compared. There are moves to build this method into a whole-building rating (similar to that for energy performance.
BREEAM, the BRE Environmental Assessment Method, takes this a stage further by setting environmental standards for complete buildings of different types (retail, office, residential). A manufacturer cannot claim BREEAM compliance because it is a total building assessment. The August 2008 version enhances the influence of energy credits to 19%.
BREEAM will be withdrawn in phases to enable a full revision to bring it into line with EN15804, the new European Standard for Environmental Declaration of Building Products.