09 Pollution

Achieving a reduction in noise levels where background levels are low - KBCN1692

Where existing background levels are low, such as during night-time, there is no dispensation or flexibility that can be applied in achieving the requirements. The aim of the issue is to reduce the potential impact of noise from the assessed building to local noise-sensitive buildings. Acoustic experts have confirmed that the requirements for the background noise levels are still appropriate where existing levels are low, including where a 5dB reduction is stated within the criteria.

District cooling – Used in combination with local cooling - KBCN1634

Where district cooling can be considered outside the scope of the assessment, either in accordance with the Methodology section of the technical manual or in line with KBCN0759, compliance must be based on calculating the DELC for all systems. However, where the district cooling system is exempt from assessment, as described above, this should be based on a GWP of zero for the district cooling system.

Flood Risk Assessment older than five years - KBCN1744

This sentence appears in the definition of 'Flood Risk Assessment': Where more than five years have passed since the FRA was carried out, evidence would be required to demonstrate that the basis of the FRA has not changed in that time. The requirement for evidence that the basis of the FRA has not changed where more than five years have passed is applicable only at Design Stage. It is not required at Post Construction Stage where a compliant FRA was undertaken at Design Stage and the development was carried out in accordance with that design.

GN38 Relating drainage reports to BREEAM UK NC - KBCN1564

Latest version: v2.0, November 2025 Guidance Note 38 (GN38) has been produced to help assist BREEAM Assessors relate the contents of drainage reports to the ‘Surface water run-off’ and ‘Minimising watercourse pollution’ criteria in Pol 03 for BREEAM UK New Construction 2018, V6/V6.1, and V7. The guidance note does not cover the criteria for ‘Flood resilience’. Completing the template is optional. It is an aid for demonstrating compliance and not a requirement. A separate template exists for BREEAM UK New Construction 2014 (see GN15). Download Guidance Note 38 View all Guidance Notes on BREEAM Projects (licensed assessors only)

27-Nov-2025 - Release of GN38 2.0

ILP Guidance Note 1 updated - KBCN1385

Pol 04 references the ILP Guidance notes for the reduction of obtrusive light 2011. This has now been updated to the ILP Guidance note 1 for the reduction of obtrusive light 2021. This is available for free from the ILP website. Requirements Table 2 of the guidance note classifies different lighting environments into Zones E0 to E4. Use this table to define which sets of requirements apply to the assessment. Tables 3-8 of the guidance note define the requirements for criterion 2. For cut-off type luminaires which (by design) block out light in obstructive directions, calculations are not required for meeting requirements relating to:

Vertical illuminance (Table 3), and
Luminous intensity (Table 4).

This update will be reflected in the future revisions of the relevant manuals.

02-Nov-2021 Applicability to all UK BREEAM schemes confirmed.
27-Sep-2023 Updated for ILP Guidance Note 1 2021. Requirements clarified. Scheme applicability updated.

No discharge for up to 5mm rainfall - KBCN0599

The criterion requires no run-off to leave the developed site into the local watercourse(s) for a storm event that results in rainfall depths up to 5mm. It is not acceptable to collect the rainfall within an attenuation tank and allow the runoff to be released from the site at a restricted rate. This simply slows the rate at which it is released to the watercourse(s). Compliance should be based upon zero runoff from the first 5mm rainfall for 80% of events during summer and 50% in winter. This is in line with the recommendations within Chapter 24.8 of The SuDs Manual (C753), CIRIA 2015. The 5mm rainfall event is considered one of the most common rainfall events and, therefore, a system should be designed to prevent this run-off leaving the site thus protecting a receiving watercourse from pollution. Where ground conditions prohibit the use of SuDs techniques to manage the rainfall onsite or it is not be possible for the first 5mm of rainfall to be prevented from leaving a site completely. An appropriately qualified professional must explain comprehensively why this criterion cannot be fully met and design a system to meet the intent of this criterion as far as possible. Where this can be justified and all other relevant criteria have been achieved, the credit can still be awarded.

16.08.2024 Clarification added on calculation requirements and text from KBCN1059 now included.

Prerequisite – Evidence requirements - KBCN1747

Confirmation of compliance with the standards or codes of practice required to meet the prerequisite should be provided by the relevant members of the project team, i.e. the system designer and/or the system installer, as appropriate.

This recognises the responsibilities of those designing and installing the system configuration. Evidence from the manufacturer is not required.

Scope of issue – clarification – fixed installations - KBCN1660

The scope of this issue covers noise from external building services (or 'fixed installations' as written in the manual) serving areas designed for human comfort. The noise impact assessment excludes:

Noise from process-related plant.
Noise from emergency or back-up plant which are not used during normal operation.

New Construction / UK / V6 /