B1 Comfort

2030s weather files - KBCN000006

The Exeter University Prometheus project contains future weather files which cover the 2030s. These can be found here: https://emps.exeter.ac.uk/engineering/research/cee/research/prometheus/downloads/

13 09 2017 Hyperlink to Prometheus project updated. Applicability to BREEAM International schemes removed - (see  KBCN0732)

Accreditation – sampling and testing laboratories - KBCN1337

Analysis / testing laboratory NC 2016 or newer: Where an organisation used for the analysis of indoor air or emissions from building products is not accredited to ISO/IEC 17025, the organisation must be accredited, either by a national accreditation body, or by a member of any one of the following accreditation groups: European Cooperation for Accreditation International Accreditation Forum International Laboratory Accreditation Cooperation The accreditation must specifically cover the analysis of indoor air or emissions from building products. Other schemes: Accreditation to ISO/IEC 17025 is not required in the criteria. However, this KBCN has been applied to encourage a consistent approach towards accreditation. Accreditation by a national or internationally recognised organisation helps to ensure rigorous, consistent and reliable testing results. Sampling organisation If another organisation carries out sampling on behalf of the analysis / testing laboratory, this organisation does not need to be accredited to the above. However, they must provide a brief report justifying:

The sampling methodology used.
Appropriate environmental conditions during the sampling.
The number and location of samples taken.

This report is provided to the BREEAM assessor and submitted as supporting evidence for this issue.

31-Oct-2022 Wording clarified. Scheme applicability updated.
10-Oct-2022 Title amended for clarity. Scheme applicability updated.
24-May-2022 Updated to differentiate between sampling and analysis requirements. 
07-May-2021 Added clarification regarding alternative qualifications. 
10-May-2021 Updated scheme applicability.

Assessing overheating risk in homes – TM59 - KBCN0892

CIBSE TM59 can be used to demonstrate compliance with the requirements in HQM's Temperature issue, where CIBSE Guide A and CIBSE TM52 are referred to in the Temperature issue. This is to recognise the most up to date methodology relating to the assessment of homes, which builds on and refers to relevant parts of standards referred to in the Temperature issue.

Calculating average plan depth for HQM Temperature Tool - KBCN0891

The average plan depth is calculated by measuring, for each room, the distance from the window nearest to the centre of the room. Then calculate the total distance for all rooms and divide this by the number of rooms. The following should also be taken into account:

If the room is a straightforward parallelogram, the ‘centre’ of the room can be considered the midpoint between a line perpendicular to the midpoint of the external wall with the window and the opposite wall.
If the room is more complicated, a point marked visually (by eye) is acceptable where the plans are provided as evidence.
Alternatively, the centroid of the floor plan polygon can be calculated mathematically if the calculations are also submitted.
Only the window nearest to the centre is considered, for each wall.
Roof lights should not considered.

There is an element of discretion in terms of calculating this and common sense should be applied to ensure that room depth is being calculated correctly, keeping in mind that this aspect is about determining the rooms ability to circulate air as part of managing high temperatures. Generally speaking, the average plan depth only becomes an issue for homes with relatively deep rooms and it does not tend to be a problem in the majority of cases, for the purposes of the HQM temperature tool. The HQM temperature outputs help to determine homes that are less likely to be at risk of overheating in summer months. It is not a design tool and efforts should be applied to reduce risk wherever possible (e.g. appropriate use of ventilation and thermal modelling).

Communal ventilation system - KBCN1388

A communal ventilation system is acceptable as long as it meets the requirements in the HQM manual. In terms of maintenance, if it is not possible for the home occupants to carry out system maintenance themselves due to the type of system installed we would need a statement from the professional designing the system stating this. Instead, any specified ventilation system requiring maintenance must be designed to allow building services engineers to easily complete the work in a safe manner in accordance with manufacturer’s instructions and any other safety regulations, to prevent systems becoming redundant or being unable to function to their designed intention.

Compliant test body – alternative compliance route using a Suitably Qualified Acoustician - KBCN1412

Where acoustic testing and measurement has not been performed by an organisation or individual that meets the definition of a compliant test body, compliance with this requirement can still be demonstrated where a Suitably Qualified Acoustician has reviewed the relevant test report(s). The test report must: a) Be countersigned or authorised by a Suitably Qualified Acoustician b) Include a clear statement that the acoustic testing and measurements have been carried out in accordance with the BREEAM or HQM testing requirements AND c) Include evidence that the verifier meets the definition for a Suitably Qualified Acoustician within the relevant BREEAM or HQM technical manual

Emissions from products – Guidance Note 22 (GN22) - KBCN0719

Latest version: v2.8, January 2024 Within the Health and Wellbeing category of several BREEAM schemes, credits are awarded for specifying materials that minimise emissions from building products of formaldehyde and volatile organic compounds (VOCs). The criteria involve meeting emission level performance requirements in accordance with compliant performance and testing standards. Guidance Note 22 (GN22) lists schemes that show equivalent or better performance than the current BREEAM and HQM criteria, and therefore can be used to demonstrate compliance with the criteria. This document should be read in conjunction with the relevant assessment issue guidance provided in the appropriate BREEAM or HQM technical manual. The guidance note contains two tables:

Table 1 is for use with BREEAM schemes that were first released before December 2015.
Table 2 is for use with BREEAM (and HQM) schemes that were first released from December 2015 onwards (post-November 2015).

Download Guidance Note 22 View all Guidance Notes on BREEAM Projects (licensed assessors only)

01-Feb-2024 - Updated for release of GN22 2.8
31-Jan-2023 - Updated for release of GN22 2.7 
10-Oct-2022 - This KBCN merged with KBCN0646. Title amended to align with standard KBCN naming format for clarity and consistency. Made applicable to UK and International NC V6.
25-Jan-2019 - Link to Guidance Note updated
12-Mar-2018 - Link to Guidance Note updated

Emissions from products – installations manufactured off-site - KBCN0137

Internal finishes to installations manufactured off-site such as elevators need to be assessed for the emissions from products criteria. The specification of internal finishes (regardless of whether they are installed on site or in the factory) will impact on VOC emissions. By specifying low VOC finishes, design teams will be encouraging manufacturers to consider the environmental impacts of their products.

10-Oct-2022 - Title amended to align with standard KBCN naming format for clarity and consistency. Made applicable to UK and International NC V6.

Emissions from products – scope of assessment - KBCN0212

General This issue covers any product installed or applied inside the inner surface of the building’s infiltration, vapour or waterproof membrane. Where this membrane is not present, it applies to the inside of the building envelope’s interior-facing thermal insulation layer. Only products that are installed or applied in parts of the building where their emissions are likely to affect indoor air quality need to be assessed. Paints and coatings Any decorative paints and varnishes that occupants are exposed to should be assessed. This is likely to include paints and coatings applied to walls, ceilings, floors, doors, etc. Whole products A finish applied to a product in the factory is assessed as a whole product, and not separately as a paint or coating. For instance, a wood panel has a finish applied in the factory. The whole panel, including all the elements that make up that panel, would need to comply with the requirements set for wood panel products in this issue. The finished product as a whole must meet the performance requirements / emission limits set in the manual.

11-Oct-2022 - Title amended for clarity and consistency. Content merged with KBCN0871.
10-Oct-2022 - Wording simplified. Scheme applicability updated.
16-Jun-2017 - Title and general principle amended to extend the applicability of the KBCN to all finishes. Paints specified for specialist applications covered in KBCN0872.

Post-construction measurement- TVOC concentration using BS ISO 16000-6: 2021 VOCs in air by active sampling - KBCN1642

Where BS ISO 16000-6: 2021 VOCs in air by active sampling is used, the TVOC concentration measurement can be performed over a 40-60 minute period.

Robust Details – 01 Sound insulation between homes - KBCN1517

Due to HQM credit entitlements being unavailable for Robust Details wall and floor types, this route can no longer be used to demonstrate compliance with crit. 1

Sampling formaldehyde and TVOCs - KBCN0834

The requirement for three sampling tubes per parameter per room is based on guidance in Annex D of ISO 16000-2, covering the dependence of the confidence interval for the determination of formaldehyde in indoor air. Where deemed appropriate by the accredited organisation performing the sampling work, it is acceptable for one sampling tube to be used in each room for each of the formaldehyde and TVOC measurements (i.e. two per room if both parameters are being measured).

Sound Insulation between rooms - KBCN1114

Testing between rooms cannot be carried out in–situ for the purposes of HQM. Software calculations are not acceptable either. Lab testing must be carried out as required by Part E of the building regulations (which also does not allow in-situ testing or software calculations).

Sound Insulation testing for Cupboards - KBCN1299

A cupboard (even built in) does not constitute a room and does not need to be assessed for the 'Sound insulation levels for internal walls and floors' credits as it is not permanent (part of the home's fabric) and also non-habitable.

Sound testing between rooms - KBCN1303

Only lab tests carried out in accordance with Part E of the building regulations are accepted as evidence to show compliance with the requirements sound insulation between rooms ( 02 Sound insulation levels for internal walls and floors - HQM ONE). In-situ testing and software calculations are not acceptable ways of showing compliance.

Suitably Qualified Acoustician – Associate membership of the Institute of Acoustics - KBCN00064

Associate membership of the Institute of Acoustics (IOA) can be considered to demonstrate that the individual is a member of an appropriate professional body. This supersedes previous guidance on this matter, which has been updated following confirmation from the IOA that ‘Associate members’ are bound by the same Members’ Code of Conduct as ‘Full members’.

06/06/2022 - BRE stance on this has been revised - Title also updated for clarity
13/01/2020 Wording clarified and confirmed applicability to Issue Pol 05

06/01/2020 Clarification that this applies to BREEAM UK NC2018

Thermal model sampling - KBCN1015

Thermal modelling, in accordance with CIBSE AM11, does not need to be carried out for each individual home, where the thermal modeller uses their professional judgement to ensure that an appropriate sampling approach is adopted, in line with section 3.1 of CIBSE TM59 and the following considerations:

All house types are adequately sampled
The homes and situations most at risk of overheating are modelled (i.e. the worst case scenarios)
There is no risk of overheating in the homes not modelled

The modeller needs to provide evidence and justifications that demonstrate how the samples have been determined, with their justifications, in line with the above. A house type should include homes that are identical in specification, design and location (end/ mid-terrace, ground or mid/ top floor).

Ventilation air intakes CIBSE TM21 compliance - KBCN0669

As TM21 largely contains general guidance, rather that strict rules, it is expected that the designer or services engineer would be familiar with the requirements within TM21 and be able to determine which sections are relevant for the development in question. The main areas to consider in relation to TM21 are: • Provision of filtration • Positioning inlets to minimise impacts of traffic pollution • Positioning inlets to minimise impacts of other local sources of pollution • Positioning inlets to minimise recirculation from ventilation exhausts Confirmation is required that each of these items (and anything else the designer/engineer deems relevant) has been considered in determining the location of air intakes. Suitable evidence may for example be in the form of a short report with diagrams indicating the proposed location of intakes, with respect to sources of pollution and with reference to the relevant parts of TM21.

Ventilation controls - KBCN0932

To meet the requirements of crit 9, CO₂ levels (monitored via sensors in bed and living rooms) can be used as a proxy for occupancy levels within a home. The increase in ventilation rates above the minimum set out in Approved Document F should be proportional to the rise in occupancy above that set out in Approved Document F. Relative humidity sensors can be used to trigger a 'boost' mode in wet rooms.

Ventilation rates criteria for MVHR - KBCN0924

The ventilation rates provided in Approved Document F 2010 are explicitly stated as being the ‘minimum’. 25% as a boost should be factored in as a matter of good design. If systems are so critically sized that an increase of 25% requires larger MVHRs, and larger ducts then this suggests there was no flexibility in the original design/sizing and AD-F was deemed to be the target ventilation rate. Correct sizing of systems is especially critical for flats where we have the worst problems of under ventilation and where making changes retrospectively may be costly. MVHRs should not be operating above 50% fan speed in background mode, so the ability to achieve boost should always be present, regardless of dwelling type.

[KBCN withdrawn] ~ Erratum – Table 1 in GN22 v2.5 - KBCN1436

Table 1 in V2.5 of GN22 has two footnote symbols missing: • Product Type column – Paints and varnishes should read Paints and varnishes* • Product Type column – Wood panels should read Wood panels^

10-Oct-2022 KBCN withdrawn as GN22 has been re-issued with fixes.

[KBCN withdrawn] ~ GN22 – Scheme version applicability - KBCN0646

Table 1 is for the use of any version of a scheme where the first version was released pre-December 2015, and table 2 is for the use of any version of a scheme where the first version was released post-November 2015.

10-Oct-2022 This KBCN has been merged with KBCN0719. KBCN withdrawn.

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