HEA 01 - Visual Comfort - BREEAM Knowledge Base

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 – calculation procedures - KBCN1339

For all spaces in the building where daylight provision is relevant (these are defined in the defintions for the relevant building areas), calculate the area weighted percentage improvement in daylight (Σ A_i P_i) / (Σ A_i ). Here A_i is the floor area of space i and P_i is the percentage increase in daylight in it. The Σ operator means to sum over all the relevant spaces. In order to demonstrate compliance with criteria 4 and 5 for an improvement in existing daylighting, for each space, the percentage increase in daylight (Pi) is calculated in one of the following ways: Where only the window area or glass transmission will increase:

If window area has increased but all other aspects remain the same, Pi = ((increase in glass area)/(original glass area)) x100%.
If glass transmission has increased but all other aspects remain the same, Pi = ((increase in glass transmission)/(original glass transmission)) x100%.

Where many aspects will change (e.g. room size, a combination of reflectance and window size etc.):

Calculate the average daylight factor (ADF) in the space ‘before’ and ‘after’. Pi =( (ADF after – ADF before)/ ADF before) x100%.
Calculate the average illuminance in the space that is exceeded for 2000 hours per year. Pi =( (Average illuminance after – Average illuminance before)/ Average illuminance before) x100%.

This will be amended in the next version of the manual.

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 – Floor areas for average daylight calculations - KBCN0471

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 compliance note ‘percentage of assessed area’ 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. For example, where 80% of ‘teaching, lecture and seminar spaces’ need to comply with the average daylight factor, if we have a large lecture theatre of 200m² and 3 seminar spaces of 30m² each, the requirements for 80% would mean 232m² of the floor area need to comply. This would require the lecture theatre and two seminar spaces to comply. Where a building contains different area types, the 80% minimum floor area must be calculated by each separate building area type as defined in the table listing the average daylight factors required. For example, a multi-residential building that contains kitchen areas and living room areas, would need each one of these areas to comply with the 80% minimum floor area requirement separately. In schemes where dwellings are assessed separately, this is likely to result in 100% of the relevant dwelling areas complying. This is because in a typical house with one kitchen and one living room, an 80% requirement for the kitchen and an 80% requirement for the living room, would mean the whole kitchen and the whole living room need to comply (since only whole rooms can be compliant).

08/01/2021

Clarifications and example added.

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 – studio flats - KBCN0866

In the case of studio flats, where there are no separating walls between occupied spaces, 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. The required daylight factor for the open-plan space (subject to percentage requirement) should be based on the highest daylight factor required for any of the spaces. It is impractical to separate the open-plan space and assess the daylight according to notional lines. In order to maintain robustness, the highest daylight factor should be applied throughout.

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 uniformity criteria – Multi-residential/Residential institutions - KBCN1129

The view of sky criteria (Table 11 (b)) are applicable to Multi-residential/Residential institutions where the room depth criterion (Table 11 (c)) is used.

Other requirements for Multi-residential/Residential institutions in the Daylighting table should read 'Either (a) OR [(b) and (c)]'

11/02/2019  

Removed applicability to 2018 as this has been corrected in the latest version of the manual

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.

External lighting – High frequency ballasts - KBCN0278

The requirement for all fluorescent and compact fluorescent lamps to be fitted with high frequency ballasts does not apply to external lighting.

Glare control – adjacent buildings - KBCN1211

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.

Glare control – blackout blinds - KBCN0447

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.

Glare Control – no relevant areas - KBCN0429

If the scope of the assessment does not include any relevant building areas, as defined within the manual, the criteria for Glare Control 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.

22/06/17 Wording clarified

16/06/17 KBCN amended to exclude content of KBCN0146.

Glare control – no windows in relevant areas - KBCN0146

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.

Glare control – residential institution and multi-residential bedrooms - KBCN0666

Assuming that occupants are generally elsewhere during daylight hours, lighting and resultant glare are not considered to be problematic for bedrooms in residential institution and multi-residential assessments. The only exception to this is where designated additional office working 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.

Glare control – transmittance value - KBCN0709

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

10 Mar 2021 Reference to 'optical transmittance' added for clarity

Glare control – use of tinted windows - KBCN0862

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.

Glare control for roof lights - KBCN0319

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.

Glare control in Part 1 assessments - KBCN0100

Although the current technical manual indicates that forms of glare control are applicable to Part1 assessments, this has been reviewed and the BREEAM Projects template now allows the credit to be filtered out for such projects. This is in line with the NC 2014 scheme and takes account of 'occupant controlled devices' not being within scope.

28.5.21 Issue 2.0 of the UK RFO technical manual has been updated to address this.  International RFO 2016 technical manual to be updated accordingly in next reissue.

Glare control in residential areas - KBCN00040

Glare control criteria apply to building 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.

Internal lighting levels where computer screens are used - KBCN0283

For areas where computer screens are regularly used projects can specify 300 lux, as referenced in CIBSE Lighting Guide 7, rather than the levels prescribed in the standard EN 12464:2011.

07/12/2021 Applicability to BIU V6 Commercial confirmed.

Pods or privacy booths used as workstations – Impact on view out - KBCN1697

Provided the space or room itself is compliant based on a more traditional furniture arrangement, the enclosure of workstations in booths or pods can be disregarded when considering compliance with the ‘View out’ criteria.

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 – Corrections to Table - KBCN1136

The values for distance from window to workplace in the View out Table are incorrect. The Table should read as follows:

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 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 – 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.

17 09 2024 Updated to apply to BIU Part 1 - Lighting Controls
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.

Refurbishment and Fit Out / International / 2015 / 02 - Health and Wellbeing /

HEA 01 - Visual Comfort