Calculating a building's BREEAM rating
A BREEAM Assessor must determine the BREEAM rating using the appropriate assessment tools and calculators. An indication of performance against the BREEAM scheme can also be determined using a BREEAM Pre-Assessment Estimator, which is available on BREEAM Projects. Any pre-assessment estimate should be informed by a licensed BREEAM Assessor who understands the full details of the process.
The process of determining a BREEAM rating is outlined below and an example calculation included in Table 6.
- Firstly, the scope of the project being assessed needs to be determined, i.e. Shell only or Shell and Core. The appropriate BREEAM assessment tool or calculator then adjusts the scoring and weightings to reflect the categories and individual credits assessed.
- The BREEAM Assessor will then determine for each of BREEAM's nine environmental sections (as applicable) the number of 'credits' awarded. This must be determined by the BREEAM Assessor in accordance with the criteria of each assessment issue (as detailed in the technical sections of this document).
- The percentage of 'credits' achieved is then calculated for each section.
- The percentage of 'credits' achieved in each section is then multiplied by the corresponding section weighting. This gives the overall environmental section score.
- The section scores are then added together to give the overall BREEAM score.
- The overall score is then compared to the BREEAM rating benchmark levels and, provided all minimum standards have been met, the relevant BREEAM rating is achieved.
- An additional 1% can be added to the final BREEAM score for each 'innovation credit' achieved (up to a maximum of 10% and with the total BREEAM score capped at 100%).
Table 6: Example BREEAM score and rating calculation
| BREEAM section | Credits achieved | Credits available | Credits achieved, % | Section weighting (fully fitted) | Section score |
|---|---|---|---|---|---|
| Management | 10 | 20 | 50.00% | 0.12 | 6.00% |
| Health and wellbeing | 17 | 21 | 80.95% | 0.14 | 11.33% |
| Hazards | 1 | 1 | 100.00% | 0.01 | 1.00% |
| Energy | 16 | 32 | 50.00% | 0.19 | 9.50% |
| Transport | 5 | 11 | 45.45% | 0.08 | 3.63% |
| Water | 5 | 9 | 55.56% | 0.06 | 3.33% |
| Materials | 10 | 14 | 71.43% | 0.125 | 8.92% |
| Waste | 3 | 13 | 23.07% | 0.075 | 1.73% |
| Land use and ecology | 5 | 5 | 100.00% | 0.10 | 10.00% |
| Pollution | 9 | 12 | 75.00% | 0.10 | 7.44% |
| Innovation | 2 | 10 | 20.00% | 0.10 | 2.00% |
| Final BREEAM score | 64.88% | ||||
| BREEAM rating | VERY GOOD | ||||
Table 7: Minimum standards for a BREEAM Very Good rating
| Minimum standards for BREEAM 'Very Good' rating | Achieved? |
|---|---|
| Man 03 Responsible construction practices | Y |
| Hea 01 Visual comfort | Y |
| Hea 02 Indoor air quality | Y |
| Hea 09 Water quality | Y |
| Ene 01 Reduction of energy use and carbon emissions | N/A |
| Wat 01 Water consumption | Y |
| Wat 02 Water monitoring | Y |
| Mat 03 Responsible sourcing of construction products | Y |
Producing case studies for BREEAM ‘Outstanding’ rated buildings
Projects certified to the BREEAM ‘Outstanding’ rating should act as exemplars for the industry. If they are to do this, case studies of these projects are needed so that other project teams and clients can refer to them.
Prior to Final Certification, the design team and client for BREEAM ‘Outstanding’ rated projects are asked to provide either a case study of the building or information to allow BRE Global to produce a case study. This information will be requested at the final Post-construction stage and should be provided with the BREEAM Assessor’s Final Certification Report.
BRE Global will publish the case study on the BREEAM website, Green Book Live website and in other BRE and BREEAM-related publications.