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Mat 01 Environmental Impact of Materials

Number of credits available Minimum standards
25 No

Aim

To encourage the retention and enhancement of existing elements and where new materials are required the use of materials with lower environmental impacts over their lifecycle whilst optimising the thermal performance of key building elements.

Assessment criteria

Up to 25 credits available:

  1. The BREEAM Domestic Refurbishment Mat 01 calculator is used to determine the number of credits awarded. Credits are awarded according to the impact of new materials according to their Green Guide Rating and their impact on improving the thermal performance of the dwelling for the following elements:
    1. Roof
    2. External walls
    3. Internal walls (including separating walls)
    4. Upper and ground floors
    5. Windows
  2. Up to a maximum of 25 credits can be awarded through achieving a combination of the credits available for each element ,

Table - 27: The number of credits available for each element

Elements

Green Guide Rating credits available

Thermal performance credits available*

Roof

5

3

External walls

5

3.8

Internal walls (including separating walls)

5

-

Upper and Ground Floor

5

1.2

Windows

5

2

* Thermal performance credits are only available to retained elements undergoing refurbishment to recognise thermal improvements made to existing retained elements.

  1. Retained elements, where no work is being carried out on them, are assessed against the Green Guide Calculator. Typically they will be counted as being very low impact by the calculator. A maximum of 5 credits are available with elements rated from A+ (6) to E
  2. Retained elements undergoing refurbishment (e.g. the installation of solid wall insulation) are assessed against the Green Guide Calculator. A maximum of 5 credits are available for refurbished elements depending on their Green Guide rating from A+ (6) to E.
  3. New elements such as new windows, a newly constructed roof or walls are assessed against the Green Guide to Specification with a maximum of 3 credits available depending on their Green Guide rating from A+ to E
  4. Additional credits are awarded for retained elements undergoing refurbishment as detailed in the calculation procedure (Mat01: Calculation Procedure B 7) depending on the thermal improvement made as a result of refurbishment based upon the U value of elements before and after refurbishment.

Assessment Procedure

Criteria

Procedure

Criterion

All Credits

1 - 6

  1. Determine the Green Guide rating of elements, using:
  • Green guide calculator for retained elements undergoing refurbishment (e.g. new roof coverings etc.) and retained elements, where no work is being carried out
  • Green Guide Calculator for new building elements (e.g.new external walls etc.)
  • Green Guide for Specification for windows
  1. Determine the U value for retained elements before and after refurbishment to assess the number of thermal performance credits awarded using the BREEAM Domestic Refurbishment Mat 01 calculator
  2. Refer to the definition for Mat 01 Calculator.
  3. Obtain a copy of the output from the Mat 01 calculator.
  4. Refer to the relevant definition for Retained materials; New materials; Green Guide to specification; Using the Green Guide to Specification; Online Green Guide Calculator; Green Guide Calculator; Green Guide Element Number.
  5. For more information on the calculation procedures refer to Appendix B-6

Compliance Notes

Ref

Terms

Description

CN1  

Element not present

Where the refurbishment does not contain an element listed above the BREEAM Domestic Refurbishment Mat 01 calculator allows the element to be excluded from the assessment. In such instances the BREEAM Domestic Refurbishment Mat 01 calculator will re-calculate the number of credits awarded based on the remaining applicable elements.

CN2

Flats

Where the assessment covers only some of the floors in the building, (e.g. ground floor flats), the roof and/or ground floor must be indicated as an element not present in the Mat 01 calculator where relevant. Where the assessment includes all floors in a block of flats, the flats should be assessed against this issue on a whole building level.

CN3

Element consisting of more than one specification

Where more than one specification is present for a given element, the Green Guide rating and area for each specification should be entered into the BREEAM Domestic Refurbishment Mat 01 calculator. The calculator will then determine the total credits score on the basis of each specifications rating and area as a proportion of the whole element.

CN4

Finding exact Green Guide Ratings

Whilst exact matches in specifications are not always found, it should be possible to identify a similar specification and use its rating for the purposes of assessment. Where no similar specification can be found, guidance should be obtained from BRE on the appropriate rating (also see CN5).

CN5

No similar Green Guide rating available

Whilst exact matches in specifications are not always found, it should be possible to identify a similar specification and use its rating for the purposes of the assessment. Where the required component is not listed in the Green Guide Calculator, a Bespoke Green Guide Query proforma will need to be submitted, from which BRE Global will calculate the rating and confirm the result.

Where no similar specification can be found for a newly constructed element, the online Green Guide calculator can be used to determine a bespoke Green Guide rating. The calculator can be accessed via www.thegreenguide.org.uk. If a required component is not present via the online Green Guide calculator, a Bespoke Green Guide Query proforma will need to be submitted, from which BRE Global will calculate the rating and confirm the result.

CN6

Environmental Profile Certification of products

Products with certified Environmental Profiles and with a “product specific” Green Guide rating can be used to demonstrate compliance with this BREEAM issue. Products are certified with a “product specific” Green Guide rating as part of a relevant elemental specification, e.g. a manufacturer’s concrete block as part of an external wall specification. This rating can be used in the same way as a generic Green Guide rating for this BREEAM issue.

Where a certified product forms part of a different specification, for the same or different element type (i.e. different to that described on the Environmental Profile certificate), the guidance within Appendix B concerning Environmental Product Declaration types should be followed. This procedure outlines how BREEAM gives additional recognition for materials with robust Environmental Product Declaration types.

A copy of the Environmental Profile Certificate and its appendix (which contains characterised data, normalised data and the Ecopoints score) can be sourced from the manufacturer or via the Environmental Profiles listing on www.greenbooklive.com.

CN7

Roof lights, patio doors and glazed conservatories

For the purpose of this issue any doors with a large expanse of glazing (>30% of the door area) and patio doors where glazed areas make up >70% of the door area, should be assessed as windows. Similarly, glazed areas of conservatories and roof lights should be assessed as windows (8).

CN8

Environmental Product Declaration

Where an independently verified third-party Environmental Product Declaration, covering part of or the whole life cycle, is available for a material/product that forms part of an assessed building element, this can be used to increase the contribution of that element to the building’s Mat 01 performance (refer to Appendix B for more information).

CN9

Environmental product declarations and Environmental Profile Certification

BRE’s Environmental Profile Methodology is an example of an independently verified third party EPD. Products are certified with a “product specific” Green Guide rating as part of a relevant elemental specification, e.g. a manufacturer’s concrete block as part of an external wall specification. This rating can be used in the same way as a generic Green Guide rating for this BREEAM issue.

Where a certified product forms part of a different specification, for the same or different element type (i.e. different to that described on the Environmental Profile certificate), the guidance within Appendix B concerning Environmental Product Declaration types should be followed. A copy of the Environmental Profile Certificate and its appendix (which contains characterised data, normalised data and the Ecopoints score) can be sourced from the manufacturer or via the Environmental Profiles listing on www.greenbooklive.com.

CN10 Determining the U Values U-Values should be based on the data shown in section 3 of the SAP assessment used for Ene 01, Ene 02 and Ene 03. If RdSAP was used, the U values should be provided by your Accredited Domestic Energy Assessor.

Schedule of Evidence Required

Ref Design Stage Post-refurbishment Stage

All Credits

All Req.

  1. Specification providing a detailed description of each applicable element and its constituent materials.
    AND
  2. Design drawings or specification detailing the location and area (m2) of each applicable element.
    AND
  3. A copy of the output from the Mat 01 calculator tool, including Green Guide ratings and element numbers for each specification assessed.
  4. And where relevant:
  1. Copies of Environmental Product Declarations
  2. A link/reference to the EPD’s Product Category Rules
  3. Online Green Guide and or refurbishment calculator output
  4. Environmental Profile certificate(s) (or certificate number)
  1. Where Post Refurbishment assessment only OR where documentary evidence differs from that provided at the Design Stage, then provide detailed documentary evidence, as listed for Design Stage, representing the dwelling/s as refurbished.
    OR
    A building/site inspection report and photographic evidence confirming dwelling/s have been refurbished in accordance with the detailed documentary evidence provided at the Design Stage.
    OR
    Written confirmation from the developer that the dwelling/s have been refurbished in accordance with the detailed documentary evidence provided at Design Stage.


OR
On-site measurements (methodology detailed in BRE IP 23/93 (6)) in the same rooms assessed at Pre-refurbishment stage (required when scale model measurements were carried out at Pre-refurbishment Stage)

Additional information

None.

Relevant definitions

BREEAM Domestic Refurbishment Mat 01 calculator
A calculator required to determine the number of credits achieved for this BREEAM issue, based on each applicable element’s Green Guide rating and the improvement from the pre refurbishment U value. See Calculation procedures below for a description of how BREEAM Refurbishment determines the number of credits achieved for each material element.
Ecopoint
The Ecopoint used in the Green Guide online is single score that measures the total environmental impact of a product or process as a proportion of overall impact occurring in Europe – 1—Ecopoints is equivalent to the impact of an average European Citizen. Green Guide ratings are derived by sub-dividing the range of Ecopoints/m2 achieved by all specifications considered within a building element.
Environmental Product Declaration
BS EN ISO 14025:2010 defines an environmental label or environmental declaration as a claim which indicates the environmental aspects of a product or service. BS EN ISO 14020:2001 goes on to state that environmental labels and declarations provide information about a product or service in terms of its overall environmental character, a specific environmental aspect, or any number of aspects. BRE’s Environmental Profile Methodology and Green Guide to Specification is an example of an EPD. Life Cycle Assessment (LCA) is the tool underpinning EPD and the LCA should conform to the requirements of the BS ISO 14040 series.1 2
BRE Environmental Profile Methodology
Subsequent product certification involves calculating the ‘cradle to grave' environmental profile of a building material, product or system, and services. This is a measure of all key environmental impacts, during extraction, processing/manufacture, use (including maintenance and refurbishment) and disposal, over a 60-year study period. Once certified, environmental profiles are reviewed on an annual basis to ensure they remain valid, and are recalculated every three years.
Frequently updated lists of building materials, products and systems assessed and certified under the Environmental Profiles Certification Scheme can be viewed at www.greenbooklive.com . The listing also includes the Green Guide rating for the approved products.
Where a product specified is claiming certification against the BRE Environmental Profiles Methodology, a copy of the certificate or the certificate number and certifying body from the relevant manufacturer should be acquired or, alternatively, they can verify the claim via Green Book Live listings. A reference to the BRE Global Approved certificate number should be included in the assessment report.
Green Guide to Specification
The Green Guide to Specification is an easy-to-use comprehensive reference website and electronic tool, providing guidance for specifiers, designers, and their clients on the relative environmental impacts for a range of different building elemental specifications. The ratings within the Guide are based on Life Cycle Assessment, using the Environmental Profile Methodology (www.thegreenguide.org.uk ).
Online Green Guide Calculator
BRE Global has created the Green Guide Calculator for elements to enable those licensed to use the facility to quickly and efficiently generate Green Guide ratings for a significant proportion of specifications not listed in the Green Guide to Specification Online. The Green Guide Calculator database is based on the components currently used to create specifications within the Green Guide to Specification Online. These components can be selected and combined to generate instant Green Guide ratings for a multitude of different retained or refurbishment specifications. The refurbishment rating extends the Green Guide rating from A+ to A+6 (where A+1 is the equivalent to A+). The extended Green Guide A+ range provides finer scale differentiation for refurbishment specifications, with typically 85% of refurbishment specifications being rated within the A+ band.
Green Guide element number
A unique BRE Global reference number given to a Green Guide rating for any particular building element type specification. Both the standard Green Guide ratings; Green Guide Ratings and those calculated using the Online Green Guide calculator will have an element number. Element numbers may change from time to time due to updates in the Green Guide Data. As a result a note of the element numbers used to give Green Guide rating advice on the BREEAM assessments should be kept for auditing purposes.
Retained Elements undergoing refurbishment
An existing element being refurbished such as an existing solid wall undergoing upgrade with internal wall insulation.
New Elements
A building element installed or constructed from scratch e.g. new windows, roof, external walls etc.
U value
The overall heat transfer coefficient of a material which describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area under standardised conditions. A smaller U value is better at reducing the heat transfer.


BREEAM Refurbishment – Domestic Buildings
Reference: SD5072 – Issue: 3.2
Date: 29/02/2016
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