Hea 03 - Thermal Comfort - BREEAM Knowledge Base

Air-conditioned spaces - KBCN00035

Air-conditioned spaces are assessed to ensure appropriate thermal comfort levels are achieved. Cooling capacity should be sufficient to comply with the requirements of CIBSE Guide A, however providing sufficient space to install additional capacity to meet the requirements at a later date in line with projected climate change scenarios is also acceptable. In addition, if it can be demonstrated that the air-conditioning system can achieve the thermal comfort criteria in accordance with CIBSE Guide A, Table 1.5, thermal modelling does not need to be carried out. The “time out of range” (TOR) metric should be reported as 0%.

Approach to thermal model when using BMS - KBCN0169

Where there are smart systems such as BMS in place, modelling must consider normal operating conditions, with the heating and cooling system in operation regardless of the control strategy. In order for the design team to size the heating/cooling plant, they will carry out modelling to calculate the heat/cold loss throughout the year. Results of these calculations must be submitted, with the heating/cooling plant specification which would demonstrate that the building has been designed to ensure internal winter/summer temperatures will not drop below an acceptable level, and that in effect the winter TOR is zero.

14 Apr 2023 Applicability to UK NC2018 and UK/Int V6 confirmed

Assessing industrial spaces – exemptions - KBCN0734

The thermal comfort criteria do not apply to the operational or storage areas typically found in industrial assets or other similar asset types. The criteria is still be applied to the other parts of the asset as appropriate. Operational and storage areas often have function-related thermal requirements determined by operational or storage needs. These functional requirements override the needs of any occupants.

17-Jan-2024 - Scheme applicability updated.
03-Nov-2020 - Issue 2.0 of UK RFO technical manual updated with new CN detailing the above.

Assessing thermal comfort in residential buildings - KBCN1408

CIBSE TM59 can be used to demonstrate compliance with the thermal comfort requirements for residential buildings, instead of ISO 7730:2005. This is to recognise the most up to date methodology relating to the assessment of homes.

Definition of concourse - KBCN0386

A concourse is an open area within or in front of a public building which is used primarily for circulation, short term waiting, or incidental interaction, analogous to the concourse of a train station. It should not be considered occupied space.

Natural ventilation – use of CIBSE TM52 - KBCN0935

For a naturally ventilated building, it is acceptable for the thermal comfort limits and calculation methodology in CIBSE TM52: The Limits of Thermal Comfort: Avoiding Overheating in European Buildings to be used in place of ISO 7730:2005. BREEAM recognises that adaptive comfort models can provide more appropriate thermal comfort limits for naturally ventilated buildings.

Occupant control – BMS and degree of control - KBCN0175

A Building Management System controlled set point with local override controls limited to a set range would satisfy the occupant control requirement so long as the temperature range available to building users is confirmed as appropriate for the building type and user profile.

Occupant control – spaces requiring user controls - KBCN0170

This guidance is intended to clarify the types of area for which user controls are required or would be considered beneficial. Zoning is required in all areas of the asset where specified in the assessment criteria. Please refer to the specific requirements of the applicable BREEAM standard to interpret this guidance appropriately. User controls required Spaces where users are expected to have independent control over their environment.

Owned spaces: small rooms for a few people. For instance, cellular offices, owned spaces in residential assets.
Temporarily owned spaces: where occupants expect to operate the environmental controls while they are there. For instance, meeting rooms and hotel bedrooms.
Shared spaces. For instance, multi-occupied areas such as open-plan offices or workshops.

User controls not required Spaces where users are not expected to have independent control over their environment.

Managed spaces: where environmental control is expected to be centrally managed. For instance, atria, circulation areas, concourses, entrance halls, function halls, restaurants, libraries, and shops.
Occasionally visited spaces. For instance, storerooms, bookstacks in libraries, aisles of warehouses, toilets.

14-Dec-2022 - KBCN applicability updated to include BIU. Wording clarified, and amended for compatibility with BIU criteria.

Reporting PPD and PMV Figures - KBCN0867

The PMV (Predicted Mean Vote) and PPD (Predicted Percentage Dissatisfied) values need to be entered into the scoring & reporting tool for data recording purposes. The thermal modelling specialist should be able to provide values for both the PMV and PPD for the asset. The values to report are the observed range of values for PMV and PPD:

Across all occupied areas and,
Across all expected occupied hours.

If the software or calculation method used does not generate these PMV / PPD metrics, they do not have to be provided. [accordion] [accordion_block title="Example"] An asset has the following thermal comfort ranges across its occupied spaces:

PMV ranges from -0.3 to +0.2. Enter '-0.3 to +0.2' into the relevant field.
PPD ranges from 3% to 10%. Enter '3% to 10%' into the relevant field.

[/accordion_block] [/accordion]

15.09.22 Wording and example clarified.

Thermal comfort – Changing rooms - KBCN1133

Whilst thermal comfort in changing rooms may be considered as significant, such spaces are, generally, outside the scope of this Issue, as they would not fall within the definition of an 'occupied space'.

17/06/2019 - This supersedes the advice previously provided in this KBCN, which was published in error on 13/06/2018

New Construction / International / 2013 / 02 - Health and Wellbeing /

Hea 03 - Thermal Comfort