Hea 01 - Visual comfort - BREEAM Knowledge Base

Control of glare from sunlight – ‘openness factor’ of blinds - KBCN1446

The ‘openness factor’ or ‘openness coefficient’ is the ratio between the area of openings and the total area of fabric. It is one of the factors in determining how much light will pass through the fabric of the blind. For example, opaque Venetian blinds or close weave fabric blinds may have an openness factor of blind of 1% or less. For further details, please refer to: BS EN 14501:2005 ‘Blinds and shutters — Thermal and visual comfort — Performance characteristics and classification’

06/10/2023 Updated to provide a relevant example to the definition.

Control of glare from sunlight – adjacent buildings - KBCN1248

It is acceptable to account for surrounding buildings, structures or other permanent environmental features when using simulation modelling to assess the risk of glare, provided this accounts for both direct sunlight and reflected glare from glazing or reflective surfaces.

This KBCN aligns with KBCN1211 from UKNC 2014

Control of glare from sunlight – blackout blinds - KBCN1246

Blackout blinds can be used to meet the glare control requirements. Where the criteria set an upper limit for transmittance value, but no lower limit, blackout blinds will meet this requirement.

This KBCN aligns with KBCN0447 from UKNC 2014

Control of glare from sunlight – hotel rooms - KBCN1087

The primary function attributed to hotel rooms is that of a bedroom and as such, lighting and resultant glare are not considered to be problematic for these spaces. The only exception to this is where designated additional office space is provided. In these circumstances it is the role of the assessor to determine if individual spaces should be determined as ‘relevant building areas’ in accordance with guidance provided. Glare control criteria apply to building areas where lighting and resultant glare could be problematic for users.

01 Nov 2023 - Applicability to BIU V6 Commercial confirmed
This KBCN aligns with KBCN0666 from UKNC 2014

Control of glare from sunlight – no relevant building areas - KBCN1086

If the scope of the assessment does not include any relevant building areas, as defined within the manual, the criteria for Control of glare from sunlight can be considered as met by default. Only spaces that fall within the definition of relevant areas and are within the assessment’s scope need to be assessed.

This KBCN aligns with KBCN0429 from UKNC 2014

Control of glare from sunlight – residential areas - KBCN1092

Control of glare from sunlight criteria apply to building areas where lighting and resultant glare could be problematic for users. In residential buildings this would include areas such as study bedrooms or facility management offices, where work or study will be carried out and where glare would hinder such activities. It does not apply to other residential areas.

This KBCN aligns with KBCN00040 from UKNC 2014

Control of glare from sunlight – roof lights - KBCN1091

Where roof lights are present, they must be considered when demonstrating that the glare control strategy provides adequate control/measures for minimising glare in that space. All sources of glare need to be considered when designing out the potential for disabling glare.

This KBCN aligns with KBCN0319 from UKNC 2014

Control of glare from sunlight – transmittance value - KBCN1089

Transmittance values should be based on those quoted for ‘visible' or 'optical' light transmittance.

23 Mar 2021 - Reference to the term 'optical' added, for clarity
This KBCN aligns with KBCN0709 of UKNC 2014

Control of glare from sunlight – types of glare - KBCN1043

Assessors should ensure that the design team has considered the possibility of glare from all sources, including direct sunlight, reflected sunlight and contrast glare.

Control of glare from sunlight – use of tinted windows - KBCN1090

Solar control or ‘tinted’ glazing could potentially support the attainment of this requirement. However, the assessor must be satisfied and provide evidence to demonstrate that the particular glazing type, when used on the assessed building for a given location, is meeting this overarching aim of preventing disabling glare. It should be noted that whilst certain types of glazing, such as low emissivity glazing, may be slightly tinted, they may not necessarily be effective in reducing disabling glare. For facades receiving direct sunlight, tinted windows alone are unlikely to be sufficient in the majority of situations.

This KBCN aligns with KBCN0862 from UKNC 2014

Control of glare from sunlight- no windows in relevant areas - KBCN1088

Where a ‘relevant area’ as defined in the manual does not include any windows, the glare control criteria can considered as met for this area. Note that the view out and daylight criteria would not be achieved in rooms with no windows. Where there are no windows in a room there would be no potential for disabling glare, so the aim of the credit would be achieved.

This KBCN aligns with KBCN0146 of UKNC 2014

Daylighting – speculative building - KBCN0269

Where the building is speculative and therefore the final layout is not defined (e.g. only an open plan shell is provided in each tenanted space), the required percentage of each open plan shell should meet the daylighting requirements. However, where it is possible to designate separable ancillary areas that would be required in the space (such as toilets or server room), these can be excluded from the calculation. For daylight calculations in speculative projects where the layout and colours are unknown, a realistic notional layout may be used.

Daylighting – ‘Internal association or atrium areas’ - KBCN1267

This term refers to areas intended to replace outdoor recreation spaces, typically found in prisons, but which may also be present in hospitals and residential accommodation for elderly people. The requirements relating to such spaces are, therefore, not generally applicable to other building types.

Daylighting – alternative route to compliance - KBCN1047

The alternative route was developed for rooms in Healthcare developments with multiple functions within the same space, and as such, having different daylight needs at various points within the room. For other building types, an assessor wishing to use the alternative route to compliance for daylighting should contact the BREEAM technical team with details and justification. The alternative route was applied to Healthcare building types specifically because these building types are likely to have spaces that have varying needs for daylight. For example, in a hospital ward, the areas where patient beds are located will benefit from good daylight, whereas this is of less importance for the nurses stations, which are used intermittently.

Daylighting – Changing rooms - KBCN1132

The daylighting criteria are not applicable to changing rooms.

Daylighting – communal kitchens (multi-residential) - KBCN0217

Communal kitchens should be assessed under 'Non-residential / Communal Occupied Spaces. Communal kitchens outside of self-contained dwelling units, for example a kitchen within a self-contained student flat shared between several students would be classed as a private kitchen for the purposes of this issue. However, if it was shared between rooms along a communal corridor it would be considered a communal kitchen, and assessed under 'Non-residential buildings - occupied spaces'.

Daylighting – requirements differing by area - KBCN0176

Where areas within a building have different daylighting requirements for the same credit, all relevant areas must meet the requirements to award the daylighting credit(s). The aim is to improve daylight conditions in all applicable area types of an assessed building.

Daylighting – retail cafe / dining areas - KBCN0968

Customer seating/dining areas in a cafe or restaurant should be considered as 'sales areas'. Sales counters, staff areas or food preparation areas, for example, should be assessed as 'Other occupied areas' in accordance with the definition of 'Occupied space'.. The requirements for 'Sales areas' are applied to transient spaces.

Daylighting – side-lit internal association and atrium areas - KBCN1198

In buildings where the design of internal associations or atriums areas means that the space cannot be top-lit and is instead side-lit, the Daylighting criteria can be applied as follows; Minimum values of average daylight factor: The internal association or atrium area space will need to achieve an average daylight factor of 3% across a minimum of 80% of the space and either a uniformity ratio of 0.3 or a minimum point daylight factor of 0.9%. Illuminance requirements: The internal association or atrium area space will need to achieve a minimum daylight illuminance of at least 90 lux for 2650 hours per year.

Daylighting – studio flats - KBCN0808

In the case of studio flats, the minimum area of compliance for the average daylight factor requirement is based on the combined area of kitchen, living room, bed and study area. Circulation areas do not need to be included in the calculation.

Daylighting – uniformity ratio applicability - KBCN0584

The uniformity ratio requirements apply to the percentage of the building’s relevant areas specified in the table. In the NC 2013 scheme, this is 80%.

Daylighting – Floor areas for average daylight calculations - KBCN1081

Where the room size is comparable and the function is the same, such as ‘kitchen’, the percentage rule needs to be applied to the total floor area. As the average daylight factor is a measure of daylight across the whole room, only whole rooms can be compliant. This is why we refer to rounding up the ‘80% of the floor area’ requirement to the rounded up number of compliant rooms. This rule applies to rooms of a similar size and function and the Daylight issue calculations methodology includes a simple example, where all the rooms are the same size. However, this rule can still be applied to rooms of different sizes. Spaces whose size is substantially larger should meet the average daylight factor requirement on their own. In these cases, the percentage requirement is still applicable to the floor area of the remaining rooms. Where a building contains different area types (as identified in tables 5.1, 5.3, 5.8 and 5.9), the 80% minimum floor area must be calculated by each separate area type. For example, a multi-residential building that contained kitchen areas and living room areas would need both of these areas to comply with the 80% minimum floor area requirement separately.

This KBCN aligns with KBCN0471 of UKNC 2014

EFSA daylight requirements for Schools - KBCN1272

For school buildings, it is acceptable to use the Education and Skills Funding Agency (EFSA) framework requirements as an alternative method of compliance with the 'Daylighting' criteria. In this case, evidence would be required to demonstrate that the requirements in the framework have been adhered to. At least 80% of all relevant room types (weighted by area) must meet the relevant criteria in the ESFA framework requirements.

Reworded to clarify that the 80% requirement still applies. 31/07/2019

External lighting – architectural façade lighting - KBCN0650

Architectural façade (or other decorative) lighting, which does not provide users with lighting to perform tasks outdoors, does not need to be included in the assessment of external lighting. This Issue seeks to ensure that lighting levels are appropriate for tasks which building users will be undertaking outdoors.

View out – alternative method of compliance for fixed workstations - KBCN1484

In relevant spaces that include fixed workstations* (such as a built-in cash registers or reception desks) an alternative method can be used. This is based on the number of compliant workstations. For instance, where the requirement is for 95% of the relevant area to comply, 95% of the fixed workstations must have a compliant view out, rounded up to the nearest workstation. Example A retail assessment has 35 built-in cash registers, 95% of which must comply with the view out criteria. 35 x 0.95 = 33.25, rounded up to 34. The requirement is met for this area if 34 registers comply with the criteria. Where an asset includes a mix of relevant areas; both fixed workstations and flexible areas, compliance for the whole assessment must be demonstrated for all areas, as appropriate, based on either area or number. *freestanding desks and other items of moveable furniture cannot be considered as fixed workstations, regardless of whether their locations are pre-determined.

View out – Calculating the glazing to wall ratio - KBCN1506

This should be calculated based on the glazed area of window, expressed as a percentage of the area of the external wall in which the window sits. Where the ceiling height of the room is unusually high, relative to the window height, the wall area can be calculated based on a standard ceiling height for the building type.

View out – eye level - KBCN0581

BREEAM defines an adequate view out as being at seated eye level (1.2 – 1.3m) within the relevant building areas. However, where occupants will not have the option to be seated, for example in some industrial operational areas where the work being undertaken requires occupants to remain standing, the height of the view out can be changed accordingly to suit the eye level of occupants. All other view out requirements have to be met and clear justification provided for changing the height/level of the view out. In some relevant building areas, occupants may not be sitting down to undertake tasks. Allowing the view out height requirements to be changed accordingly ensures building occupants gain maximum benefit from the view out.

View Out – First Aid Rooms - KBCN1104

The view out criteria do not apply to dedicated first aid or medical rooms in non-healthcare projects. BREEAM recognises the need for user privacy in such areas and that these are intermittently occupied.

View out – internal view within an atrium - KBCN1240

Where the criteria are otherwise met, an internal view across an unobstructed atrium void can be considered compliant. Internal views are generally not acceptable, however where it is physically impossible to obstruct the view with partitions, equipment or furniture, this can be accepted at the discretion of the assessor.

View out – no relevant areas - KBCN0876

If the scope of the assessment does not include any relevant building areas, as defined within the manual, the criteria for 'view out' can be considered as met by default. Only spaces that fall within the definition of relevant areas and are within the assessment's scope need to be assessed.

View out – percentage area - KBCN0166

For the view out credit, compliance must be demonstrated for the percentage of the floor area in each relevant building area, rather than the percentage of the total relevant building area in the building.

14/2/17 Wording amended to clarify that the percentage must be achieved for each 'relevant building area'.

View out – relevant areas - KBCN0268

The aim of the View Out criteria is to allow occupants to refocus their eyes from close work. Relevant areas are spaces where close work in a fixed position is carried out for sustained periods of time. The view out criteria are therefore not applicable to occupied areas such as meeting rooms, or other spaces where such close work is not being carried out. Where rooms contain areas of different functions, only relevant areas should be assessed. In this case a notional line can be drawn on the plans and calculations made based on these relevant areas only. However, spaces such circulation routes or other transient spaces within a relevant area can only be excluded if the route or area is clearly defined by the building layout. If this is arbitrary or based solely on a proposed furniture layout, it cannot be excluded. Features of the building layout which may be considered as dictating a function area would include, for example, the position of doors or fixed furniture such as a reception desk or canteen servery.

07-Oct-2022 Additional paragraph added to clarify how function areas must be defined. 
21-Sep-2022 General principle of 'relevant area' added, and applicability of KBCN extended to BIU V6 Commercial.

View out – rooms used for security or other critical functions - KBCN1040

The View out criteria are not applicable to rooms containing security or critical systems or sensitive material, such as CCTV monitoring rooms. Where it can be demonstrated that the presence of compliant windows would compromise a critical function of the space, the criteria can be considered not applicable.

View out – Shell only/Shell & Core - KBCN1354

Where it is not possible to confirm which areas of the building will contain workstations/benches or desks, then all areas of the building designed for and/or likely to be occupied by workstations/benches or desks must comply with the relevant criteria.

View out for commercial kitchens - KBCN1216

It is not necessary to provide a view out for commercial kitchens. This is because in such a space it is likely that kitchen staff will move around, doing various tasks. This makes the requirements for the view out to rest the eyes unnecessary.

Zoning and control – dimming - KBCN1018

Localised dimming controls installed in line with the criteria, along with a master on/off switch, can be considered as meeting the aim of the requirement for 'controls' in open plan offices. The aim is for occupants to have local control over their lighting and maintain comfortable lighting levels.

Zoning and control – exemplary level criteria - KBCN1545

The exemplary level criteria applies only to lighting zones in the asset where:

Zones will benefit from dimming control.
Dimming does not interfere with the function of the space.

Where lighting zones do not have dimming controls fitted, these must be clearly evidenced and justified.

Zoning and control – PIR in circulation spaces - KBCN0332

PIR controls can be deemed compliant in circulation spaces such as corridors. In this instance 'separate occupant controls' are not required. The requirement for user control is so that the building users can have direct control over their immediate work environment to ensure it is suitable for their personal needs. In circulation spaces, occupancy is transient and PIR control in these spaces is acceptable.

Zoning and occupant control – access to lighting controls - KBCN00032

The relevant areas for the criteria apply only to areas where users are expected to have control. For instance, this means that areas intended for the general public, or a shop floor would not be expected to have lighting controls. The general principle which applies to user access to general environmental controls (heating, cooling, ventilation) may also apply to access to lighting controls. See KBCN0170. However, the the exact approach may differ between the two types of systems and assessor judgement must be used to determine compliance. In all cases 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.

14-Dec-2022 - KBCN applicability updated to include BIU. Wording updated. Link to KBCN0170 created.

Zoning and occupant control – control via BMS - KBCN0703

Occupant control via a BMS is not normally considered a compliant BREEAM solution. Any solution that requires the action of a third party (eg facilities manager) is not considered under the control of the occupant. Solutions where all relevant building occupants have control via a user-interface via BMS may be considered compliant where the assessor is satisfied that the aim of the criteria are met. User-control must be available directly to the occupant.

01/08/2017 - KBCN applicability to Thermal comfort Issue removed.

Zoning and occupant control – PIR detection systems - KBCN0335

The aim of the Health & Wellbeing category is to recognise ways to benefit occupants through giving them control of their lighting environment. Without manual overrides, presence or absence detection lighting controls (such as PIR detection systems) are not compliant with the criteria. BREEAM recognises the energy efficiency benefits of detection systems in buildings through the Energy category. In some cases, the design team may have to prioritise one particular lighting strategy to the detriment of achieving a credit elsewhere.

28 04 2021 Wording amended to include absence detection systems.
18 09 2017 Wording amended to clarify the meaning.

Zoning and occupant control – whiteboards and display screens - KBCN1433

Whiteboards and display screens in dedicated teaching or presentation spaces require separate zoning and control for lighting, as specified in the criteria. Lighting around whiteboards and display screens which are typically found in general office areas, meeting rooms, or in other generic spaces do not require separate zoning and control to meet the criteria. In such cases, the assessor should provide justification. Whiteboards and display screens in dedicated teaching / presentation spaces are likely to be used frequently, and require appropriate zoning and control. An increasing number of offices and meeting rooms now include display screens - however separate zoning and control may not be appropriate.

Zoning and occupant controls – handheld remote controls - KBCN1243

Remote control light switches can be considered as compliant, on the basis that these are provided in sufficient numbers/locations to meet the aim of the criteria.

[KBCN withdrawn] ~ Daylighting – Education buildings - KBCN1031

This KBCN has been withdrawn and replaced with the more detailed KBCN1272.

KBCN withdrawn on 13/08/2019:

Where the requirements of Education and Skills Funding Agency Generic Design Brief, November 2017. Technical Annex 2E ‘Daylight and electric lighting’, have been demonstrably met, the BREEAM daylighting requirements can be deemed to have also been met. The two credits for daylighting can be awarded.

New Construction / UK / 2018 / 02 Health and Wellbeing /

Hea 01 - Visual comfort