Hea 01 Visual comfort

Number of credits available	Minimum standards	Applicability
Up to 7 (building type dependent)	No	Part 1	Part 2	Part 3	Part 4
		Yes	No	Yes	Yes

Aim

To encourage and recognise projects that maximise opportunities for good daylighting, artificial lighting and occupant controls at the design stage to ensure best practice in visual performance and comfort for building occupants.

Assessment criteria

This issue is split into four parts:

• Glare control (1 credit)
• Daylighting (up to 3 credits)
• View out (up to 2 credits)
• Internal and external lighting (1 credit)

The following is required to demonstrate compliance:

One credit - Glare control

1. The potential for disabling glare has been designed out of all relevant building areas using a glare control strategy, either through building form and layout and/or building design measures (see compliance note CN7).
2. The glare control strategy avoids increasing lighting energy consumption, by ensuring that:
1. The glare control system is designed to maximise daylight levels under all conditions while avoiding disabling glare in the workplace or other sensitive areas. The system should not inhibit daylight from entering the space under cloudy conditions, or when sunlight is not on the façade: AND
2. The use or location of shading does not conflict with the operation of lighting control systems.

Up to three credits - Daylighting

3. Up to three credits are awarded on a sliding scale depending on the percentage of relevant building areas that comply with one of the following daylighting criteria:
4. 1. The relevant building areas meet good practice daylight factor(s) and other criterion as outlined in Table 12 and Table 13 OR
   2. The relevant building areas meet good practice average and minimum point daylight illuminance criteria as outlined in Table 14 .
4. Two credits where daylighting provision, averaged over all relevant spaces, has improved after refurbishment or fit-out by 30% or more and there is a minimum glazing to floor area ratio of either:
   1. 5% glass to floor area ratio for side windows; OR
   2. 2.5% glass to floor area ratio for roof lights;

5. One credit where daylighting provision, averaged over all relevant spaces, has improved after refurbishment or fit-out by 15% or more and there is a minimum glazing to floor area ratio of either:
   1. 5% glass to floor area ratio for side windows; OR
   2. 2.5% glass to floor area ratio for roof lights

Note: The improvement in daylighting provision is calculated using the BREEAM Hea 01 Calculator tool based upon either the increase in glazing area, transmittance, illuminance or percentage daylight factor. Please refer to the Methodology section for calculation procedures.

Table 12 Minimum values of average daylight factor required

Building/area type	Average daylight factor required	Minimum area ( m2 ) to comply			Other requirements
		1 Credit	2 Credits	3 Credits
Education buildings
Pre-schools, schools, further education- occupied spaces	2%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13
Higher education- occupied spaces	2%	30%	45%	60%
Healthcare buildings
Staff and public areas	2%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13
Occupied patients' areas (dayrooms, wards) and consulting rooms	3%	40%	60%	80%
Multi-residential buildings
Kitchen	2%	40%	60%	80%	EITHER (a) OR (c) in Table 13
Living rooms, dining rooms, studies (including home office)	2 %	40%	60%	80%
Non-residential or communal occupied spaces	2%	40%	60%	80%
Retail buildings
Sales areas	-	17.5%	25%	35%	Point daylight factors of 2% or more
Other occupied areas	2%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13
Courts, Industrial, Office, Prison buildings and all Other building types
Cells and custody cells	1.5%	40%	60%	80%	N/A
Internal association or atrium area (prison buildings only)	3%	40%	60%	80%	EITHER a uniformity ratio of at least 0.7 OR a minimum point daylight factor of 2.1%
Patient care spaces	3%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13
Teaching, lecture and seminar spaces	2%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13
All occupied spaces, unless indicated in Relevant definitions	2%	40%	60%	80%	EITHER (a) OR {(b) and (c)} in Table 13

Table 13 Daylighting uniformity criteria

Ref	Criteria
(a)	A uniformity ratio of at least 0.3 or a minimum point daylight factor of at least 0.3 times the relevant average daylight factor value in Table 12 . Spaces with glazed roofs, such as atria, must achieve a uniformity ratio of at least 0.7 or a minimum point daylight factor of at least 0.7 times the relevant average daylight factor value in Table 12 .
(b)	At least 80% of the room has a view of sky from desk or table top height (0.85m in multi-residential buildings, 0.7m in other buildings).
(c)	The room depth criterion d/w +d/HW < 2/(1-RB) is satisfied. Where: d = room depth w = room width HW = window head height from floor level RB = average reflectance of surfaces in the rear half of the room Note: Table 19 gives maximum room depths in metres for different room widths and window head heights of side-lit rooms .

Table 14 Space type and illuminance requirements - both criteria (average illuminance and minimum point illuminance) should be met.

Area type	Minimum area to comply			Average daylight illuminance (averaged over entire space)	Minimum daylight illuminance at worst lit point
	1 credit	2 credits	3 credits
Education buildings
Pre-schools, schools, further education - occupied spaces	40%	60%	80%	At least 300 lux for 2000 hours per year or more	At least 90 lux for 2000 hours per year or more
Higher education - occupied spaces	30%	45%	60%
Healthcare buildings
Staff and public areas	40%	60%	80%	At least 300 lux for 2000 hours per year or more	At least 90 lux for 2000 hours per year or more
Occupied patients' areas (dayrooms, wards) and consulting rooms	40%	60%	80%	At least 300 lux for 2650 hours per year or more	At least 90 lux for 2000 hours per year or more
Multi-residential buildings
Kitchens	50%	75%	100%	At least 100 lux for 3450 hours per year or more	At least 30 lux for 3450 hours per year or more
Living rooms, dining rooms, studies (including home office)				At least 100 lux for 3450 hours per year or more	At least 30 lux for 3450 hours per year or more
Non-residential/communal occupied spaces	40%	60%	80%	At least 200 lux for 2650 hours per year or more	At least 60 lux for 2650 hours per year or more
Retail buildings
Sales areas	17.5%	25%	35%	At least 200 lux point daylight illuminances for 2650 hours per year or more
Other occupied areas	40%	60%	80%	At least 200 lux for 2650 hours per year or more	At least 60 lux for 2650 hours per year or more
Courts, Industrial, Office, Prison buildings and all Other building types
Cells and custody cells	40%	60%	80%	At least 100 lux for 3150 hours per year or more	N/A
Internal association/atrium area	40%	60%	80%	At least 300 lux for 2650 hours per year or more	At least 210 lux for 2650 hours per year or more
Patient care spaces	40%	60%	80%
Teaching, lecture and seminar spaces	40%	60%	80%	At least 300 lux for 2000 hours per year or more	At least 90 lux for 2000 hours per year or more
All occupied spaces, unless indicated in Relevant definitions	40%	60%	80%	At least 300 lux for 2000 hours per year or more	At least 90 lux for 2000 hours per year or more

Up to two credits - View out

6. Two credits where 95% or one credit where 80% of the floor area in each relevant building area is within 7m of a wall which has a window or permanent opening that provides an adequate view out.
7. The window/opening must be ≥ 20% of the surrounding wall area (refer to Relevant definitions in the Additional information section). Where the room depth is greater than 7m, compliance is only possible where the percentage of window/opening is the same as, or greater than, the values in Table 1.0 of BS 8206 1BS 8206-2:2008 Lighting for buildings Code of practice for daylighting.
8. In addition, the building type criteria in Table 15 are applicable to view out criteria.

Table 15 View out building specific requirements

Building type	View out requirements
Prison buildings	Cells An adequate view out from a normal standing or sitting position and the distance between each window and nearest external solid object (i.e. buildings, screens, walls/fences) is ≥ 10m. Where existing features prevent compliance with this criteria in less than 20% of the cells within the building, the credit can still be awarded. Patient occupied spaces See Healthcare requirements for these spaces.
Multi-residential buildings	Self-contained flats - living rooms Sheltered housing - communal lounges, individual bedrooms and bedsits All positions within relevant areas are to be within 5m of a wall which has a window or permanent opening providing an adequate view out. The window/opening must be ≥ 20% of the surrounding wall area.
Healthcare buildings with inpatient areas (one additional credit)	Patient occupied spaces, e.g. wards and dayrooms As criteria 4 and 5 for the relevant building areas PLUS the distance between the wall with the window/opening and nearest external solid object (e.g. buildings, screens, walls/fences) is ≥ 10m.

One credit - Internal and external lighting levels, zoning and control

Internal lighting

9. All internal fluorescent and compact fluorescent lamps are fitted with high frequency ballasts.
10. Internal lighting in all relevant areas of the building is designed to provide an illuminance (lux) level appropriate to the tasks undertaken, accounting for building user concentration and comfort levels. This can be demonstrated through a lighting design strategy that provides illuminance levels in accordance with the SLL Code for Lighting 2012 and any other relevant industry standard.
11. For areas where computer screens are regularly used, the lighting design complies with CIBSE Lighting Guide 7 2CIBSE LG 7:Lighting Guide 07: Offices, 2015 sections 2.4, 2.20 and 6.10 to 6.20. This gives recommendations highlighting:
    1. Limits to the luminance of the luminaires to avoid screen reflections. (Manufacturers’ data for the luminaires should be sought to confirm this.)
    2. For uplighting, the recommendations refer to the luminance of the lit ceiling rather than the luminaire; a design team calculation is usually required to demonstrate this.
    3. Recommendations for direct lighting, ceiling illuminance, and average wall illuminance.

External lighting

12. All external lighting located within the refurbishment or fit-out zone is designed to provide illuminance levels that enable users to perform outdoor visual tasks efficiently and accurately, especially during the night. To demonstrate this, external lighting provided is specified in accordance with BS 5489-1:2013 Lighting of roads and public amenity areas3BS 5489-1:2013 Lighting of roads and public amenity areas, Code of Practice for the design of road lighting, BSI, 2013 and BS EN 12464-2:2014 Light and lighting - Lighting of work places - Part 2: Outdoor work places.

Zoning and occupant control

13. Internal lighting is zoned to allow for occupant control (see Relevant definitions) in accordance with the criteria below for relevant areas present within the building:
    1. In office areas, zones of no more than four workplaces
    2. Workstations adjacent to windows/atria and other building areas separately zoned and controlled
    3. Seminar and lecture rooms: zoned for presentation and audience areas
    4. Library spaces: separate zoning of stacks, reading and counter areas
    5. Teaching space or demonstration area
    6. Whiteboard or display screen
    7. Auditoria: zoning of seating areas, circulation space and lectern area
    8. Dining, restaurant, café areas: separate zoning of servery and seating/dining areas
    9. Retail: separate zoning of display and counter areas
    10. Bar areas: separate zoning of bar and seating areas
    11. Wards or bedded areas: zoned lighting control for individual bed spaces and control for staff over groups of bed spaces
    12. Treatment areas, dayrooms, waiting areas: zoning of seating and activity areas and circulation space with controls accessible to staff.

    Note: the criteria for zoning of lighting control are excluded for assessments of prison buildings.

14. Areas used for teaching, seminar or lecture purposes have lighting controls provided in accordance with CIBSE Lighting Guide 5 4SLL LIGHTING GUIDE 5: Lecture, teaching and conference rooms, 1991
15. In addition the building type criteria in Table 16 (where relevant) are met;

Table 16 Internal and external lighting building specific requirements

Building type	Internal and external lighting requirements
Education buildings	Manual lighting controls are easily accessible for the teacher while teaching and on entering/leaving the teaching space.
Prison buildings	Cells Lit to a maintained illuminance of 200 lux at table top level. In addition there must be the facility (using, for example, dimming, step switching or separate task and general lighting) for the occupant of the cell to select a lower level of general lighting if required. Exercise yards Lit to a maintained illuminance of at least 10 lux. However, if such spaces are, or will be, used as sports facilities they must be lit to a maintained illuminance of 100 lux.
Court buildings	Separate zoning is also provided for the following areas (as a minimum): Judge’s/magistrate’s bench Dock Jury area Public seating area. Lighting control of the zones in the above spaces, and the courtroom as a whole, cater for the following settings: Full lighting (to allow cleaning etc.) Normal lighting (for court sessions) Dimmed (for the purpose of showing audio-visual evidence, but allowing enough light for note taking).

Area type	Credits	Average daylight factor required	Minimum area ( m2 ) to comply	Other requirements
All building types	The criteria outlined in Table 18 concerning uniformity ratio (a), view of sky (b) or room depth criterion (c) are met where they are used to demonstrate compliance.
All building types (excluding retail – see below)
Functions as identified in the standard criteria (multi-storey buildings)	1	3%	80%	Where used, a minimum point daylight factor of 1.2% OR 2.1% for spaces with glazed roofs, such as atria
Functions as identified in the standard criteria (single storey buildings)		4%	80%	Where used, a minimum point daylight factor of 1.6% OR 2.8% for spaces with glazed roofs, such as atria
Prisons and court cells		2%	80%	N/A
Prison internal association/atrium area		5%	80%	A uniformity ratio of at least 0.7 or a minimum point daylight factor of 3.5%
Retail
Sales areas	1	N/A	50%	A point daylight factor of 2%
Common areas and offices (multi-storey buildings)		3%	80%	Where used, a minimum point daylight factor of 1.2% OR 2.1% for spaces with glazed roofs, such as atria
Common areas and offices (single storey buildings)		4%	80%	Where used, a minimum point daylight factor of 1.6% OR 2.8% for spaces with glazed roofs, such as atria

Table 18 Exemplary level illuminance value requirements - both criteria (average illuminance and minimum point illuminance) should be met.

Area type	Credits	Minimum area to comply	Average daylight illuminance	Minimum daylight illuminance at worst lit point
All building types (excluding retail – see below)
Multi-storey buildings Occupied spaces (unless indicated below)	1	80%	At least 300 lux for 2650 hours per year or more	At least 90 lux for 2650 hours per year or more
Single storey buildings Occupied spaces (unless indicated below)		80%	At least 300 lux for 3000 hours per year or more	At least 120 lux for 3000 hours per year or more; or in spaces with glazed roofs (such as atria), at least 210 lux for 3000 hours per year or more
Prisons and courts buildings Cells and custody cells		80%	At least 100 lux for 3450 hours per year or more	N/A
Prison buildings Internal association or atrium areas		80%	At least 300 lux for 3250 hours per year or more	At least 210 lux for 3250 hours per year or more
Retail
Retail buildings Sales areas	1	50%	At least 300 lux point daylight illuminances for 2000 hours per year or more
Retail buildings Other occupied areas		80%	Select relevant criteria above for occupied spaces dependant on whether a multi-storey or single storey building is being assessed.

Checklists and tables

Reflectance for maximum room depths and window head heights

The table below gives maximum room depths in metres for different room widths and window head heights of side-lit rooms.

Table 19 Reflectance for maximum room depths and window head heights

	Reflectance (RB)
	0.4		0.5		0.6
Room width (m)	3.0	10.0	3.0	10.0	3.0	10.0
Window head height (m)
2.5	4.5	6.7	5.4	8.0	6.8	10.0
3.0	5.0	7.7	6.0	9.2	7.5	11.5
3.5	5.4	8.6	6.5	10.4	8.1	13.0

Compliance notes

Ref	Terms	Description
Applicable assessment criteria
CN1	Part 1: Fabric and Structure	Criteria 3 - 8 and 16 are applicable.
CN2	Part 2: Core Services	This issue is not applicable.
CN3	Part 3: Local Services	Criteria 9 - 15 are applicable. Note: where no external lighting is specified, criterion 13 is filtered out from the assessment.
CN4	Part 4: Interior Design	Criteria 1 - 8 and 16 are applicable Note: It is recognised that fit-out projects will have limited influence over fabric measures that can increase daylighting. Criteria 1 - 5 are applicable in order to assess the impact of changes to internal layout on daylighting and view out (e.g. location of partitions, use of glare control film on glazing etc.) to recognise fit-out projects that optimise the percentage of spaces that benefit from daylighting and view(s) out.
Simple buildings
CN5	Applicable assessment criteria	All criteria relevant to the building type and function apply.
General
CN6	Historic buildings; lighting zoning and controls	In some cases (e.g. grade 1 or grade 2* listed buildings) an explicit requirement from the relevant conservation authority (e.g. local authority conservation officer) may require the retention of existing listed lighting features which prevents zoning of lighting in accordance with criterion 13. In such cases, evidence should be provided from the conservation officer and measures should be considered to ensure that adequate control is provided for existing retained lighting zones and measures adopted for the provision of task lighting as relevant for the function type and as is feasible within the constraints as applied by the conservation officer.
Glare control
CN7	Compliant forms of glare control - curtains as glare control	Compliant shading measures for meeting glare control criteria include: Building integrated measures (e.g. low eaves) Occupant controlled devices such as blinds (where transmittance value is < 0.1 (10%) for visible light). Blackout blinds can be used as all relevant criteria are met. Bioclimatic design External shading or brise soleil. Glare control must provide shading from both high level summer and low level winter sun. Where using fixed systems, design studies can be used to demonstrate that sunlight is prevented from reaching building occupants during occupied hours. Curtains (where used without other forms of shading) do not meet the criteria for the glare control criteria, as they do not provide sufficient control to optimise daylight into the space. Furthermore, the use of curtains to control glare is likely to cause occupants to rely more on artificial lighting. The only exception to this rule is in healthcare buildings in patient occupied spaces, treatment rooms and other high infection risk areas where the use of blinds is not recommended due to known risks relating to infection control.
Daylighting
CN8	Percentage of assessed area See criterion 5.	Where the criteria specify that a percentage of floor area must be adequately illuminated by daylight, this refers to the percentage of the total floor area of all the rooms that must be assessed, i.e. the compliant area. At 80% of the assessed floor area must meet the criterion. See the following calculation: a. Total are of all applicable rooms (see definitions for daylighting) b. Total area of rooms comply with the criteria b/a x 100 = % floor area that complies If for example, a development has six rooms that must be assessed, each 150 m2 (total area 900 m2 ) then 720 m2 must comply with the criterion; this is equal to 4.8 rooms. The number of rooms that must comply must always be rounded up; therefore in this example, five rooms must have an average daylight factor of 2% or more (plus meet the other criteria) in order to achieve the credit(s).
CN9	External obstructions	In calculating minimum and average daylight factors and daylight illuminances, external obstructions should be taken into account. For illuminance calculations, the reflectance of external obstructions should be taken as 0.2 unless on-site measurements of external reflectance have been made.
CN10	Dirt factors when calculating daylight	Daylight calculations should include a maintenance factor for dirt on the windows, as given in British Standard Code of Practice for daylighting, BS 8206 Part 2, appendix A1.3.
CN11	Borrowed light	For areas where borrowed light is used to demonstrate compliance with daylighting criteria, calculations or results from appropriate lighting design software must be provided to demonstrate that such areas meet the BREEAM criteria (if the light from these sources is required in order for the room to comply). Examples of borrowed light include: light shelves, clerestory glazing, sun pipes or internal translucent/transparent partitions (such as those using frosted glass).
CN12	Room depth criterion - rooms lit from two opposite sides	For rooms lit by windows on two opposite sides, the maximum room depth that can be satisfactorily illuminated by daylight is twice the limiting room depth (d) (measured from window wall to window wall; CIBSE Lighting Guide LG10 5CIBSE Lighting Guide LG10 Daylighting and window design, 1999.. The reflectance of the imaginary internal wall should be taken as 1.
CN13	Uniformity with rooflights	The room depth criteria cannot be used where the lighting strategy relies on rooflights. In such areas either appropriate software has to be used to calculate the uniformity ratio or, in the case of a regular array of rooflights across the whole of the space, figure 2.36 (page 37) within CIBSE Lighting Guide LG10 can be used to determine the uniformity ratio.
CN14	Daylighting - uniformity ratio calculation	The uniformity ratio calculation, minimum point daylight factor and minimum daylight illuminance can exclude areas within 0.5m of walls. Areas within 0.5m are not regarded as part of the working plane for this purpose, although they are included in the average daylight factor and average daylight illuminance calculations.
CN15	View of sky requirement See criterion 3.	To comply with the view of sky criteria (ref (b)) in Table 13 , at least 80% of the room that complies with the average daylight factor requirement must receive direct light from the sky, i.e. it is permissible for up to 20% of the room not to meet the view of sky requirement and still achieve a compliant room.
Internal and external lighting levels/zoning and control
CN16	Relevant industry standard for lighting design	Pre-schools, schools and sixth form colleges: Building Bulletin 90: ‘Lighting Design for Schools’ 6Building Bulletin 90: ‘Lighting Design for Schools’ Please note that for care homes housing people with dementia the following standard can be used instead of the SLL Code for Lighting: Design Lighting for People with Dementia, University of Stirling, Stirling, 2013 7Pollock R, McNair D, McGuire B and Cunningham C, Design Lighting for People with Dementia, Dementia Services Development Centre, University of Stirling, Stirling, 2013. Please note that the illuminance levels specified in the SLL Code for Lighting, 2012 align with BS EN 12464-1 8BS EN 12464-1:2014 Light and lighting. Lighting of work places. Indoor work places, 2003.
CN17	Occupancy/ workstation layout unknown	Where occupancy or workstation layout is not known, lighting control can be zoned on the basis of 40 m2 grids, i.e. an assumption of 1 person/workspace per 10 m2 .
CN18	Small spaces	Buildings consisting entirely of small rooms/spaces (less than 40 m2 ) which do not require any subdivision of lighting zones/control will meet the zoning criteria by default.
CN19	Zones of four workspaces	The limit of four workspaces is indicative of the required standard but is not a fixed requirement. Where there is justification for this to be increased to fit with the adopted lighting strategy, this may be accepted provided that the assessor is satisfied that the aim of this criterion is upheld, i.e. that there is suitable zoning/control of lighting to enable a reasonable degree of occupant control over lighting in their personal work area. The relevant design team member, e.g. lighting consultant, should set out how this is to be achieved in such an instance.
CN20	Lighting zoning and control - auditoria spaces	The controls specified will depend on the size and use of the space, but a typical auditorium or lecture theatre with stepped seating and a formal lectern/demonstration/performance area would typically be expected to have lighting controls as follows: Full normal lighting (to allow for entry/exit, cleaning etc.) Demonstration area lighting off and audience area lighting reduced to a low level (for the purpose of line slide projection, but allowing enough light for the audience to take notes) All lighting off (for the projection of tone slides, colour slides, and for the purposes of visual demonstrations/performances) Separate localised lectern lighting.
Building type specific
CN21	Education - Education Funding Agency (EFA) requirements	For Education buildings, where the EFA daylighting requirements have been achieved, for all relevant rooms within the building (in accordance with Priority School Building Programme (PSBP) Authority Draft, Facilities Output Specification: Generic Design Brief by the Education Funding Agency, June 2013 9Priority School Building Programme PSBP Authority Draft, Facilities Output Specification: Generic Design Brief by the Education Funding Agency, June 2013), it can be assumed that the BREEAM daylighting requirements have also been met and therefore the two credits available for daylighting can be awarded by default. In this instance, evidence would need to be provided to demonstrate that the EFA requirements have been achieved.
CN22	Education (pre-schools) and acute Special Educational Needs (SEN) controls for children	Where child care and/or acute SEN spaces are included within the scope of the assessment, controls should be provided for the teacher/member of staff, i.e. it is not a necessity for the controls to be accessible to the children. Where nursery spaces are included within the scope of the assessment, controls should be provided for the member of staff, not the nursery school children.

Methodology

Calculation procedures

In order to demonstrate compliance with criteria 3-5 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:

1. If window area has increased but all other aspects remain the same, Pi = ((increase in glass area)/(original glass area)) x100%.
2. 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.):

1. Calculate the average daylight factor (ADF) in the space ‘before’ and ‘after’. Pi =( (ADF after – ADF before)/ ADF before) x100%.
2. 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%.

Evidence

Criteria	Interim design stage	Final post construction stage
All	One or more of the appropriate evidence types listed in The BREEAM evidential requirements section can be used to demonstrate compliance with these criteria.
3 - 6	Daylighting calculations	Refer to generic evidence requirement above

Additional information

Relevant definitions

Adequate view out

BREEAM defines an adequate view out as a view of a landscape or buildings (rather than just the sky) at seated eye level (1.2 – 1.3m) within the relevant building areas and should ideally be through an external window. A view into an internal courtyard or atrium will comply provided the distance from the opening to the back wall of the courtyard/atrium is at least 10m (therefore allowing enough distance for the eyes to refocus). The view cannot be an internal view across the room, as this is likely to become obstructed by partitions, filing cabinets etc.

Average daylight factor

The average daylight factor is the average indoor illuminance (from daylight) on the working plane within a room, expressed as a percentage of the simultaneous outdoor illuminance on a horizontal plane under an unobstructed CIE Standard Overcast Sky.

Clinical areas

Areas of the building in which medical functions are carried out that require specific restricted environmental conditions such as humidity, daylighting, temperature, etc. (e.g. X-ray, operating department, delivery room, etc.).

Computer simulation

Software tools that can be used to model more complex room geometries for daylighting.

Refurbishment or Fit-out zone

For the purpose of this BREEAM issue the Refurbishment or Fit-out zone is defined as the area of the building undergoing refurbishment or fit-out for the BREEAM-assessed building, and the external site areas that fall within the scope of the new works.

Illuminance

The amount of light falling on a surface per unit area, measured in lux.

Occupied space

A room or space within the assessed building that is likely to be occupied for 30 minutes or more by a building user. Please note there is a specific, unrelated, definition of 'unoccupied' with reference to acoustic testing and measurement and this should not be confused with the definition used here.

Patient areas

Areas of the building used mainly by inpatients (e.g. wards, dayrooms, etc.).

Point daylight factor

A point daylight factor is the ratio between the illuminance (from daylight) at a specific point on the working plane within a room, expressed as a percentage of the illuminance received on an outdoor unobstructed horizontal plane. This is based on an assumed overcast sky, approximated by the ‘CIE (Commission Internationale de l’Eclairage) overcast sky’.
The minimum point daylight factor is the lowest value of the daylight factor on the working plane at a point that is not within 0.5m of a wall. Similarly the minimum illuminance is calculated at the worst lit point on the working plane that is not within 0.5m of a wall. These points will usually be close to a rear corner of the room. Computer simulations are the most appropriate tools to allow for point daylight factors and illuminances to be calculated.

Public areas

Within a Healthcare building type, this includes areas of the building designed for public use where no medical functions are carried out (e.g. reception, retail unit, waiting areas).

Relevant building areas:

Daylighting

For the purpose of BREEAM this is defined as areas within the building where good daylighting is considered to be of benefit to the building users (typically those areas occupied continuously for 30 minutes or more). This includes the following (where occupied continuously for 30 minutes or more) specifically stated because they are often omitted;

1. Sports hall exercise spaces
2. Laboratory areas unless the type of research that will be carried out requires strictly controlled environmental conditions, such as the exclusion of natural light at all times.
3. Self-contained flats
4. Kitchen and catering areas
5. General communal areas
6. Small offices (including those within multi-residential buildings)
7. Meeting rooms (including those within multi-residential buildings)
8. Leisure areas
9. Any area that may involve close up work.

However, this excludes the following (where present):

1. Media, arts production, SEN sensory spaces, x-ray rooms and other areas requiring strictly controlled acoustic or lighting conditions
2. Clinical areas with controlled environmental conditions, e.g. operating theatres, delivery rooms or pathology. However, BREEAM strongly advises that the benefits from daylighting and view out are seriously considered when designing areas of critical and intensive care in Healthcare buildings.
3. Holding areas and custody cells where security issues conflict with the BREEAM daylighting requirements
4. Custody cells in courts, where privacy is a functional/operational requirement.

Glare control

For glare control include areas of the building where lighting and resultant glare could be problematic for users, e.g. those areas that have been designed to contain/use workstations, projector screens etc. and sports halls. Spaces in the categories described above, for which daylight and view out are excluded, should not be assessed against the glare control criteria.

View out

BREEAM defines relevant building areas requiring a view out to include areas of the building where:

1. There are or will be workstations/benches or desks for building users.
2. Close work will be undertaken or visual aids will be used.
3. A view out is deemed to be of benefit to the building occupants, e.g. in spaces where occupants are likely to spend a significant amount of time.

Excluded areas for each of these might include:

1. Nurse bases where they are located centrally in a ward/patient area in order to enable patient observation.
2. Courtrooms and interview rooms where compliance is not possible due to security or privacy criteria.
3. Prison staff areas containing workstations that for security or observational purposes must be located centrally within the building.
4. Any clinical areas where the control of environmental/operational conditions prevents such spaces from providing a view out.
5. Conference rooms, lecture theatres, sports halls, acute SEN and also any spaces where the exclusion or limitation of natural light is a functional requirement e.g. laboratories, media spaces, etc.

Internal and external lighting

Where no external light fittings are specified (either separate from or mounted on the external building façade or roof), the criteria relating to external lighting do not apply and the credit can be awarded on the basis of compliance with the internal lighting criteria. The following internal areas are excluded from the lighting zone requirements:

1. Media and arts production spaces
2. Sports facilities (exercise spaces only, including hydrotherapy and physiotherapy areas).

Note: Architectural facade (or other decorative) lighting which is not designed to provide users with lighting to perform tasks outdoors does not need to be included in the assessment of external lighting.

Lighting zoning

For rooms or spaces not listed within criterion 14, the assessor can exercise an element of judgement when determining whether the specification is appropriate for the space given its end use, and the aim and criteria of this BREEAM issue.

Separate zoning control

Light switches or controls for a particular area/zone of the building that can be accessed and operated by the individual(s) occupying that area or zone. Such controls will be located within, or within the vicinity of, the zone or area they control.

Staff areas

Areas of the building used mainly by staff (e.g. offices, meeting rooms, staff rooms) and medical areas where patients are admitted but that do not require restricted environmental conditions (e.g. consulting rooms, physiotherapy, etc.).

Surrounding wall area

Surrounding wall area refers to the area (in m² ) of the internal wall on which the window/opening is located, including the area of the window/opening itself.

Uniformity

The uniformity is the ratio between the minimum illuminance (from daylight) on the working plane within a room (or minimum daylight factor) and the average illuminance (from daylight) on the same working plane (or average daylight factor).

View of sky/no-sky line

Areas of the working plane have a view of sky when they receive direct light from the sky, i.e. when the sky can be seen from working plane height. The no-sky line divides those areas of the working plane, which can receive direct skylight, from those that cannot.

Working plane

CIBSE LG10 defines the working plane as the horizontal, vertical or inclined plane in which a visual task lies. The working plane is normally taken as 0.7m above the floor for offices and 0.85m for industry.

Other information

None.