This article will example how BREEAM ratings can be affected by timber specification, focusing on the Mat 03 BREEAM area.
BREEAM is the world’s largest and most well-known means of measuring the sustainability of buildings. As of the time of writing, BREEAM have registered 2.3 million buildings globally.
BREEAM stands for Building Research Establishment Environmental Assessment Method. The Building Research Establishment (BRE) was a former UK government laboratory that is now a registered charity. All profits made by BRE are channelled into further research to meet their aims of promoting greater building sustainability and safety. In fact, BRE was instrumental in developing the bouncing bomb used in the Dambusters raid in WW2 thanks to their scientific research into the structure of buildings.
BRE established the Environmental Assessment Method is 1990. Since then, there has been numerous developments and changes, but the basic premise remains that BREEAM regulates buildings according to their sustainability.
Not every building obtains a BREEAM rating – there is also an unclassified section for buildings with a percentage score of less than 30%. In addition to ratings, BREEAM also have established minimum standards so unclassified buildings that fail to meet the minimum standards criteria do not get a BREEAM rating.
BREEAM calculations are incredibly complex and detailed. The actual rating is carried out by independent licensed assessors who will assess the building against the appropriate BREEAM scheme document. The scheme document refers to what kind of building it is, for example a new commercial building or residential redevelopment.
Essentially, there are two parts to a BREEAM assessment – the main part judges the building across a set of 9 environmental categories plus a tenth category focusing on innovation. Each category has a given number of credits available. Available credits vary per category depending on the perceived importance of the category, which is shown in the category weighting section.
|Environmental Category||Credits Available||Category Weighting||Category Score (%)|
|Management||22||0.12||% of Credits achieved |
|Health & Wellbeing||10||0.15|
|Land Use & Ecology||10||0.10|
|Total: Aggregate of all Category %’s|
For example, say the aggregate score was 47% then the building would have a BREEAM Good rating.
To achieve a desired rating, most credits can be traded – for example noncompliance in one category can be offset through exceeded compliance in another. However, to ensure that this flexibility does not result in environmental malpractice, BREEAM set minimum performance standards for specified subcategories across a range of key areas. These minimum standards vary according to the rating and form the second part of a BREEAM assessment.
For example, the minimum standards for a BREEAM Very Good rating would look like this:
|Minimum Standards||Relevant Category||Achieved Yes/No|
|Man 01: Sustainable Procurement||Management||Y|
|Hea 01: Visual Comfort||Health & Wellbeing||Y|
|Hea 04: Water Quality||Health & Wellbeing||Y|
|Ene 02: Energy Monitoring||Energy||Y|
|Wat 01: Water Consumption||Water||Y|
|Wat 02: Water Monitoring||Water||Y|
|Mat 03: Responsible Sourcing||Materials||Y|
|LE 03: Mitigating Ecological Impact||Land Use & Ecology||Y|
In total, BREEAM looks at 49 different subcategories. Each subcategory is given a different code for example Health & Wellbeing subcategory 01 is called Hea 01 and concerns visual comfort. Hea 01 can score up to 3 credits plus 1 additional innovation credit, which then feeds into the overall Health & Wellbeing category total in Part 1 of the assessment.
To sum up, the minimum standards are part of the overall assessment rather than a separate assessment. The minimum standards simply pick out the most pertinent subcategories to maintain the integrity of BREEAM ratings.
Considering the methodology described above, the means to improving the BREEAM rating of a building is by increasing the number of credits achieved.
The category relevant to timber specification is the Materials category, and the subcategory is Mat 03, Responsible sourcing of materials which is often abbreviated to RSM.
There are 3 Credits available for Mat 03 BREEAM. Obviously, Mat 03 does not only concern timber – it concerns all material used in building construction such as concrete, steel, plasterboard etc. However, timber does have a relatively high profile within the assessment framework due to concerns over deforestation.
Each material is given a Responsible Sourcing Certification Scheme (RSCS) point score which is a fundamental element of the overall Mat 03 credit score. To achieve any credits whatsoever, the material must be covered by an RSCS certification scheme recognised by BREEAM, such as FSC.
We will go through, step by step, how a BREEAM assessor would decide how many of the 3 Mat 03 credits a building would achieve, particularly looking at timber used in external furniture.
The prerequisite for any timber used on a project is that it is sourced in accordance with the UK Government’s Timber Procurement Policy. With regards to timber imported from outside the UK, this would require that the timber must be compliant with UKTR regulations. This is a minimum standard and without it the Mat 03 score will not be valid, but it will not have any effect on the number of credits that are achieved. Please note that if the timber in question is not UKTR compliant but FSC/PEFC certified, then it would meet this requirement as FSC and PEFC are recognised under the UK Government’s Timber Procurement Policy. However, a UKTR certificate or UK Forestry Commission felling license will only be of use in meeting the minimum requirements – it cannot be used as a substitute for an RSCS Certification and to gain subsequent credits.
There are 2 ways of gaining the 3 Mat 03 BREEAM credits. The main method is named Responsible Sourcing of Materials (RSM), which offers the potential for awarding all 3 credits if the materials used are all exemplary. However, if you fail to achieve all 3 RSM credits on offer, a secondary way to achieve 1 credit is through demonstrating that all materials are sourced in accordance with a documented Sustainable Procurement Plan. The plan covers all the aspects of procurement and quality checks. For timber, it is useful to know that this considers where the timber is sourced from – locally sourced timber will carry a premium. The following stages of this step-by-step process will consider how the RSM score is calculated, rather than the Sustainable Procurement Plan.
Establish the RSCS score. As mentioned above, establishing the average RSCS score for timber used in external furniture in fundamental to the RSM score. If the timber is intended to be used as internal structural components, you would have to do a separate calculation, as separate calculations are needed for each location/use. RSCS scores go from 1 to 10 and scores are based on the certification’s scope and rigour. The table below shows how the BREEAM recognised timber certification programs are scored:
|RSCS Certification||Version of Certification||Weighting Score to be used in RSM Calculation|
|SFI||SFI Certified Chain of Custody||5|
Just a note on these schemes – the scores reflect what we found when reviewing forestry certifications in our blog here. Briefly, FSC is the most rigorous, followed by PEFC. SFI is little known for external furniture purposes.
This is where the RSM score will be calculated. There are two ways of doing this, depending on if detailed information regarding material quantities is known. For the purposes of this blog, it is unnecessary to explain the methodology of each method.
However, for both methods you can use the BREEAM calculator tool which will calculate the % of available RSCS points achieved for each location/use category and take into account how much of the material in question is used. For example, on a skyscraper the overall score would be far more heavily impacted by glass and steel scores rather than the external timber score.
For the timber, say the maximum number of RSCS points available is 10 and the RSCS score of the materials used is 5, then the % of RSCS points achieved is 50%. The calculator tool will consider all materials used on a project and calculate an overall score, not just external furniture.
Once the percentage score is determined, you can find out how many credits that % score would give you using the table below:
|BREEAM Credits||% Score|
For example, a 30% overall score would give you 2 Credits for the Mat 03 subcategory.
The most influential method to increase the number of credits you can achieve through timber sourcing is to consider timber certification. If the timber is only UKTR compliant, this will limit the number of credits achieved in the Mat 03 BREEAM section.
The most well rewarded certification for timber is FSC 100% Certified. Therefore, if all external timber is FSC 100% Certified, depending on the RSCS of other materials used on a project such as Concrete and Steel, this could increase your percentage score so you could gain an additional credit. In turn, this could move the project from a Good rating to Very Good. It should be noted that this one change will only comprise a tiny percentage of the overall BREEAM assessment, but a series of small changes like this will add up and make a difference.
The second method to achieve more credits is to use timber that has been sourced locally wherever possible. This may involve using a UK grown Class 2 hardwood such as Oak rather than a Class 2 tropical hardwood. Doing this would improve the chances of being awarded the credit for demonstrating a Sustainable Procurement Plan if the building has not achieved all 3 RSM credits. Although it will not have as big of an impact as using FSC 100% timber, it may still be worthwhile to do.
Also bear in mind that the location of where the timber was sourced from will have no impact if a Sustainable Procurement Plan is not submitted or all 3 credits have been awarded as part of the RSM assessment.
In conclusion, timber and the wider Mat 03 subcategory does have a relatively big impact on the overall BREEAM rating. Granted, the impact of changes may still seem small, but it is useful to be aware that there is a clear path for timber choices to affect BREEAM scores.