WHY SHOULD EPDS BE USED IN PREFERENCE TO GREEN GUIDE RATINGS?
Many people in the construction industry remain familiar with Green Guide ratings as shorthand for the environmental impact of construction products.
However, with more detailed environmental impact reporting now available in the form of environmental product declarations (EPDs), decisions on sustainability can be made with more information than a simple summary rating can communicate.
‘The Green Guide’ is how the BRE’s ‘Green Guide to Specification’ is usually referred to, and it was created to support BREEAM assessments. It assigned relative ratings to a range of materials and components, across multiple environmental impacts, as well as giving a summary rating. Recent versions of BREEAM have phased out the use of the Green Guide and its ratings.
What is the biggest difference between Green Guide ratings and EPDs?
For both the Green Guide and an EPD, a construction product is assessed using life cycle assessment (LCA). A significant difference between the two is that a Green Guide rating doesn’t differentiate between the different life cycle stages of the product in question, whereas an EPD does.
Product specification that is carried out with environmental impact or sustainability in mind is more sophisticated now than when the first Green Guide ratings were introduced. Choices are more likely to be made based on specific environmental goals.
For example, one specifier might seek to reduce the upfront carbon on a project, and therefore focus on the earlier life cycle stages. Another specifier might be more interested in longer term carbon reductions and the circular economy, so be willing to accept slightly higher upfront impact in order to limit the impacts later in the project.
It is this increased scope of reporting, along with more specific environmental goals, that led to BREEAM 2018 requiring evidence in the form of EPDs rather than Green Guide ratings.
Potential issues when continuing to rely on Green Guide ratings
While we have seen an increase in the number of people requesting copies of our EPDs, we still get enquiries from people asking about Green Guide ratings. For example, contractors might ask if we have an A+ rating because they are pricing a specification that states a product should have one.
Aside from potentially being an outdated specification that has been copied and pasted, there are a variety of reasons why basing a specification decision on a summary rating is not appropriate.
Not all variants of different products and components were given Green Guide ratings, so historical ratings may not have applied to a particular product at any point. Lack of specificity is an issue when assessing environmental impact generally, as generic ratings and data do not necessarily reflect the performance and impact of a specific product from a specific manufacturer.
Furthermore, like assuming that a product with an EPD is automatically ‘sustainable’, having a ‘good’ or ‘bad’ Green Guide summary rating does not necessarily mean a product is either a ‘good’ or ‘bad’ environmental choice. What environmental impacts are you looking to mitigate, and how did the Green Guide rate the product in that specific area?
Similarly, a ‘bad’ rating would not necessarily communicate some of the potential benefits that a product could offer in terms of whole building performance. Intentional, deliberate product choices are based on a variety of factors that a Green Guide rating perhaps couldn’t communicate, even at the time they were more relevant.
Understanding of environmental impact and life cycle assessment has come on a long way in a short space of time, and specifications should be updated to reflect that better understanding. Green Guide summary ratings may have been useful for specifiers looking to make quick comparisons, but the construction industry is making a definitive shift towards EPDs that is being reflected in certification schemes.
For more information on EPDs and environmental impact, browse the Polyfoam XPS blog. Alternatively, visit our technical support page to download copies of our EPDs for floor and flat roof products, or other certification including responsible sourcing. For queries about the environmental impact of extruded polystyrene (XPS) insulation, you can also contact us.