Mat 01 - Life Cycle Impacts - BREEAM Knowledge Base

Assessing basement external walls - KBCN0241

Only the external walls above ground level are required to be assessed under 'external walls'. The external walls below ground (i.e. within a basement area) perform a specialist function, these are not comparable with other external walls in a building. These are included in the 'basement retaining walls'.

20/08/2021 Scope clarified in accordance with the New Rules of Measurement (NRM) by the Royal Institute of Chartered Surveyors (RICS).

Astroturf (artificial grass) - KBCN0106

This is not be considered as hard landscaping and should be excluded from the assessment of this issue.

Boundary Protection - KBCN0753

Only boundary protection specifically forming the site boundary should be included in the calculations. This may not necessarily be located on the boundary of ownership, but is the physical barrier which ostensibly encloses the development. Any other freestanding walls or fencing within the site can be excluded.

Building LCA tools recognised by BREEAM - KBCN1118

The following document shows the building LCA tools that are recognised by BREEAM for each BREEAM scheme. Only submissions from the tools listed here will be accepted as part of a BREEAM assessment. These recognised tools may be either an IMPACT Compliant tool or another type of building LCA tool that has been evaluated by BREEAM and considered suitable for carrying out building LCA according to BREEAM’s scheme specific requirements. To apply for a new tool to be evaluated, please contact: [email protected] Where more than one version of the same tool is listed for a given scheme version, the most recent version of the tool (that is available at the point building LCA work commences on the project) should be used. It is acceptable to use subsequent, more recent releases/versions of a recognised tool (that have the same name as shown in the table). View Building LCA tools recognised by BREEAM.

Table updated to new downloadable format, with new layout and new recognised LCA tools and corrections added 01/03/2024
Table updated to include new recognised LCA tools and corrections 10/11/2023
Table updated to include new recognised LCA tools and corrections 22/07/2022
Table updated to include new recognised LCA tools 12/03/2021
KBCN updated for clarity regarding subsequent tool versions on 10/03/2021

Exemptions from hard landscaping and boundary protection - KBCN00062

Where a third party, such as the local authority, enforces strict constraints on the materials that can be used by the project for hard landscaping or boundary protection, and these materials do not achieve a Green Guide rating of A/A+, it is possible to exempt these materials from the assessment of this issue, on the condition that robust evidence confirming this is given. In this instance the developer does not have control over the materials specified, therefore it is not appropriate to include them in the assessment.

Gabion as boundary protection - KBCN000008

A gabion can be excluded from the assessment if it acts as a retaining wall or any other form of a supporting structure. If it acts purely as a boundary and a generic Green Guide rating cannot be found for a specification, the BREEAM assessor will need to submit a Bespoke Green Guide Query proforma detailing the specification details.

GN08 – Scope of IMPACT compliant tools and data submission requirements - KBCN0621

Scope of IMPACT Compliant (or equivalent) Tools and Data Submission Requirements - BREEAM UK New Construction 2011 and 2014 Introduction This Guidance Note relates to complying with the exemplary level criteria for route 2, as defined under the Mat01 issue of the BREEAM New Construction 2011 and 2014 versions. It provides information about IMPACT and the level of detail (the Quality Requirements) and file transmission requirements for the Building Information Model (BIM) from IMPACT compliant (or equivalent) tools. It also outlines criteria for demonstrating the equivalence of a proposed alternative to IMPACT compliant tools for BRE Global approval. View full Guidance Note (licenced assessors only) View all Guidance Notes (licenced assessors only)

Green-roofs - KBCN0263

When assessing green roofs, only the structural elements of the roof construction need to be considered i.e. the waterproof layer and above can be excluded. Where Green Guide is being used to assess the issue, it is likely that the online Green Guide Calculator will need to be used to provide a rating for the roof construction. HQM - For the purpose of HQM, green roofs fall under 3.3 Specialist roof systems therefore should be included in the IMPACT model.

IMPACT compliant software - KBCN0809

For a list of all IMPACT compliant software please see How to get IMPACT on the IMPACT website.

LCA modelling for multiple BREEAM assessments - KBCN0960

Multiple buildings' assessments Site-wide approaches are not acceptable and each BREEAM assessment needs to have its own Life Cycle Assessment model (using an IMPACT compliant software tool or equivalent). This applies in all cases, including when the buildings are on the same plot and are built to the same specifications. Developing assessment-specific LCA models ensures that material quantities are accurate, refer to the actual building (and building type) and account for external works included within the scope of the specific assessment. Single building with multiple assessments within it Where multiple assessments are conducted for different parts of a building, it is acceptable to have a single LCA model covering all assessments. In this case, an explanation of the allocation process used should be provided and the following guidance applies:

Common elements (e.g. roof, foundations, external walls etc): apportion a percentage of the total impact of the element to each assessment based on their percentage share of the total GIFA (e.g. if an assessment accounts for 10% of the total GIFA, 10% of the element’s impact is apportioned to that assessment).
Elements that are only in a given assessment (e.g. internal partitions, internal finishes etc): 100% of the impact is allocated to the assessment they are in.

Life cycle environmental impact of curtain walling - KBCN0178

Curtain walling performs two functions – the provision of windows and the provision of external walls. Specifications performing the same function are grouped together in the Green Guide to Specification. This means that curtain walling needs to be modelled as two separate building elements (external walls and windows). The overall performance of the curtain wall will combine the ratings for the two parts according to their areas. It will depend on the curtain walling system selected, the choice of internal lining and the relevant proportion of glazed and opaque elements.

For the opaque area of the external wall (Area A in the figure below):
1. Select the relevant generic specification from the Green Guide (element category – External walls / Curtain walling, then either aluminium or timber framed and the internal skin specification) and note the rating and element number. If your specification is different from all of the generics, please submit a request for a bespoke rating.
2. Enter the rating into the BREEAM Materials calculator with the area for the opaque section of the curtain wall (Area A).
For the glazed (window-like) area of the curtain wall (Area B):
1. Select the relevant specification from the Commercial window element category of the Green Guide. There are two specifications: Aluminium curtain walling system (Element no: 831500016) and Laminated timber curtain walling system (Element no: 831500015)
2. Enter the rating into the BREEAM Materials calculator with the area for the glazed (window-like) section of the curtain wall (Area B).

The BREEAM Materials calculator will calculate the overall performance for the curtain walling system. It will also calculate the performance of the building elements and the overall number of credits to be awarded.

Mat 01 / Mat 03 calculator not big enough - KBCN0647

If a project has more specifications than there is rows available in the tool you can group specifications that have the same green guide rating/responsible sourcing level with each of the specifications with the same rating listed in the same row. The proportion that they contribute to the overall area is also combined. For example where a project has 30 different upper floor specifications, if 10 upper floor specifications are A+, 10 are A, 5 are B and 5 are C then you would only need to use 4 lines.

Mat 01 Calculator Option 1 – verified LCA tools - KBCN0237

Before an LCA tool can be recognised by BREEAM, the tool developer must submit evidence to BRE to verify the tool’s points scored in the Mat 01 Calculator. The LCA tool is then given its own tab in the calculator, which confirms the maximum score the tool can achieve, if used to its fullest extent. Items coloured green within the calculator are locked because they do not change when using the LCA tool. The items in blue should be edited by the design team to confirm the extent the tool has been used on the project. For RFO schemes, the assessment parts must also be selected. Items listed as ‘N’ in column W ‘Included in assessment?’ cannot be changed to a ‘Y’, as the LCA tool cannot be used for this element. For example internal doors cannot be assessed by the Green Guide. An element listed as ‘Y’ can be changed to a ‘N’ if the LCA tool has not been used for the element in the assessment. Column S confirms if the assessed building includes the element and should be included. For example if there are no stairs in the assessment, then this element is removed from the calculation by saying ‘N’ to cell S15 (in the green guide calculator).

12/01/2017 Reference to LCA approved tools updated.

Multiple buildings on the same site - KBCN0559

The areas of hard landscaping and boundary protection that need to be assessed on a site that contains several developments/buildings depends on the scope of works and scope of the assessment(s) being undertaken. Essentially, the areas that need to be assessed are all the areas of hard landscaping (as defined within the relevant definitions of the credit issue) and boundary protection within the construction zone (again defined within the relevant definitions) that are within the scope of works of the building under assessment. Therefore, if all buildings on one site are being assessed in one BREEAM assessment, then the hard landscaping and boundary protection related to all of these building's scope of works will need to be assessed. If there are several buildings with individual assessments and their own defined scope of works, then the hard landscaping and boundary protection applicable to the scope of works of each individual building will be assessed for each associated assessment. The assessment is concerned with the hard landscaping and boundary protection associated to the project under assessment, i.e. the areas under the control of the project under assessment.

Option 1 scoring based on robustness and extent of LCA - KBCN0674

For Option 1, BRE Global verifies the LCA tool's score within the Mat 01 calculator based on the rigour of the life cycle assessment tool and the extent it is used on the assessment. For this reason, as opposed to the UK New Construction schemes, the performance/scoring of building elements is not to be taken into consideration and Green Guide ratings for building elements are not linked to the scoring of the Mat 01 tool and credits achieved. Please see KBCN0237 for further details on using the calculator with verified LCA tools.

Playground or other specialist surfaces - KBCN0694

Where the hard landscaping surface is specified to meet safety related performance (e.g. non-slip or soft surfaces for playgrounds) or particular performance related requirements (e.g. specialist sports performance surfaces such as astro-turf, netball courts and running tracks), then these surfaces can be omitted from the assessment. The standard specification of surfaces for multi-use areas (e.g. cement, tarmac, asphalt) must still be assessed.

Recycled materials in hard landscaping - KBCN0975

When recycled material is to be used for hard landscaping, the Green Guide rating will depend on whether the material comes from the same site or from another location. Typically, on-site recycled material is treated with very little impact, or ignored, as there is little or no energy/material input in putting it in place. When recycled material is brought in from elsewhere, transport, as well as any processing the material has gone through to make it fit for purpose, will be taken into account. If the assessor is in doubt, they need to submit a landscaping proforma along with any supporting documentation on the materials and their use and BRE will provide a rating and/or guidance.

Scope of hard landscaping - KBCN0634

For the purpose of assessment, hard landscaping includes (but is not limited to) parking areas (including manoeuvring areas, lanes, roads within the parking area), pedestrian walkways, paths, patios. The definition excludes basement parking, access or approach roads and designated vehicle manoeuvring areas, balconies, roof terraces,specialist sports areas (running tracks, netball areas etc.) and retaining walls.

New Construction / International / 2013 / 06 - Materials /

Mat 01 - Life Cycle Impacts