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FAQs - The Green Guide


Green Guide to Specification 2008

1. How do I access the Green Guide ratings online?

The Green Guide ratings are publicly available. All you need to do is register your details.

2. I have already registered with other BRE websites, including BREEAM, do I need to register again?

Yes, you will need to register separately.

3. Can I buy a printed copy of the Green Guide to Specification?

The printed edition of the Green Guide to Specification 2008 (Ref BR 501, ISBN 978-1-84806-071-5) is available to buy from BRE Bookshop, please see link below.

4. Where can I buy it?

You can buy it from BRE Bookshop http://www.brebookshop.com/details.jsp?id=321573


5.  uPVC steel reinforced windows achieve an "A" rating. However the functional unit specifies that it is "based on the BFRC domestic window model". Does this mean that the window manufacturer should be registered under BFRC?

The window manufacturer does not have to be registered under BFRC.
"Based on the BFRC domestic window model" means that the quantities of materials that were used when creating the specification for the domestic window came from windows designed to meet BFRC performance requirements.

6. What is Life Cycle Assessment or LCA?

LCA is a form of systems analysis in which a product, system, process or service is assessed against environmental impact categories over a defined time period. LCA is the modelling approach which underpins the Green Guide to Specification.  

7. What are generic LCA data and models?

The Green Guide ratings are representative of ‘generic' UK-supplied construction products and materials. In this regard they represent the typical product available to builders and developers.

Information presented in the Green Guide is typically derived through working with UK trade associations to generate generic models drawn together with information from many product manufacture sites. These LCA models are representative of the manufacture activities which supply the typical UK product.

The Green Guide also uses background LCA data and models to represent activities such as transportation, energy supply and raw material process related activity etc. Greater clarity on these models can be found from reviewing the Environmental Profiles Methodology

8. How does the Green Guide to Specification relate to Envest?

Both the Green Guide to Specification and Envest use the Environmental Profiles Methodology to generate environmental impact information.

However, Envest reports impact information using Ecopoint scores, and the Green Guide converts Ecopoint score information to Green Guide ratings. A UK Ecopoint is a single score that measures total environmental impact as a proportion of overall impact occurring in the UK. It is calculated by taking the normalised data from a BRE Environmental Profile, applying a weighting factor to each impact and then adding all the weighted impacts to give a total - The Ecopoints.

Also, a key difference between the two tools is that Envest enables the user to ‘construct' an entire virtual building and measure its impacts, whereas the Green Guide works on an elemental basis.

9. Who is the Green Guide targeted at and at what point within the construction process should it be applied?

The Green Guide is primarily developed to provide building architects and specifiers environmental impact information to support the material/product specification and selection process. However, it can be used at any stage in the construction value chain.

The Green Guide may also be a useful source of information to material manufactures who want to understand the environmental attributes of the products and materials they are producing

10. What are the next steps for the Green Guide to Specification?

With the launch of the Green Guide online, BRE Global and its industry stakeholders and partners are embarking on an exciting phase in which information can be more readily disseminated and evolved over time.

In June 2008 BRE Global launched the basic Green Guide online as a free to view service. The scope of this service will be enhanced over the coming year, and will incur subscription costs. Coverage is expected to include:

  • Accessibility of numerical LCA data on specifications and the capability to switch between Green Guide ratings and numbers
  • Environmental impact specific numbers including information on resource efficiency and carbon footprint
  • A specification and material search function
  • Access to proprietary and manufacturer specific LCA data and its influence on Green Guide ratings
  • Per ton generic material environmental impact information
  • Graphical interfaces and displays
  • A ‘build your own specification' tool
  • A mixing desk in which material supply and production options can be examined

11. If I am required to do a whole building assessment can I use the Green Guide?

The Green Guide is developed to look at environmental impacts of discrete building elements. If a whole building assessment is required the user should access Envest.

12. I'm interested in a building element category not included in the Green Guide. Am I able to get a Green Guide rating?

If a building elemental category you are interested in is not included in the Green Guide then it is not possible for BRE to generate a rating. It is intended for the scope of the Green Guide to broaden to include additional elemental categories

13. I have a specification I'd like to see represented in the Green Guide. How can I get it included?

If you are a licensed assessor for BREEAM, EcoHomes or the CSH, and are working on a registered project, then BRE will provide a rating for the specification you are interested in.

14. The construction material I manufacture is not in the Green Guide. What is its environmental impact?

If a construction material is not in the Green Guide then BRE will need to undertake a full LCA of the manufacturing process and the supply chain before its impact can be determined. The completion of this work is subject to normal contractural conditions. To ensure its inclusion in the Green Guide it will be important that the study is representative of the product supplied to the UK market. This may require input from a number of manufacture activities and such a project is best undertaken in partnership with the relevant UK trade body. A further route for inclusion in the Green Guide is also available through the Environmental Profiles Certification Scheme

15. How do I calculate the profile mass for Aluminium Windows?

The basis for the Green Guide Ratings is the average mass/metre length.

Domestic elements: First calculate the mass of aluminium (excluding beading) for the British Fenestration Rating Council (BFRC) standard domestic window; width 1.23m x height 1.48m; casement to one side. Divide this mass by 11.09 (the total length in metres of the frame) to give the average mass for 1 metre of profile.

Commercial elements: First calculate the mass of aluminium (excluding beading) far a fixed pane window - 1.0m x 1.0m. Divide this mass by 4 (the total length in metres of the frame) to give the average mass for 1 metre of profile.

16. Why is the same element sometimes given different ratings?

Some elements may be assessed separately for one or more different building types due to differences in the functional unit for each building type, and the type of specifications typically used for that building type.

The functional unit ensures specifications are compared on a like-for-like basis against the identified performance criteria. The functional unit is based on a 60-year study period which includes the necessary manufacture and construction of materials, any repair and maintenance necessary during use, and finally disposal at end of life in the LCA assessment.

The Green Guide Ratings themselves represent where a particular product assessed within an Element Specification sits within the larger range of Ecopoints. Each element type is assessed individually and can apply to one or more different ranges based on building type.

The best and worst generic ecopoint value (i.e. the published elements created for the Green Guide to Specification), within a particular category make up the range. This range is subsequently divided into 6 equal parts; making the A+, A, B, C, D and E Ratings. A+ being the product with the best environmental performance, and E the worst.

As each building element category therefore has a range, or set of ranges based upon the applicable building types, the same ecopoint score may give a different rating depending on the building type.