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Hea 01 Visual comfort

Click here for an overview of Hea 01 Visual comfort.

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Assessment scope

  Fully fitted Simple building Shell and core Shell only
Applicable assessment criteria All All 4, 56, 910, and 14 4, 56, 910, and 14
Assessment type specific notes None None See ref 1.0 See ref 1.0
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ClosedSpecific notes

Assessment type specific
1.0

View out

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

Building type specific
2.0

Prison buildings

The criteria for zoning of lighting control are excluded for assessments of prison buildings.
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Assessment criteria

This issue is split into four parts:

ClosedOne credit - Control of glare from sunlight

1 Identify areas at risk of glare using a glare control assessment. The glare control assessment also justifies any areas deemed not at risk of glare.

2 Where risk has been identified within a relevant building area (Definitions), a glare control strategy is used to design out the potential for glare.

3 The glare control strategy does not increase energy consumption used for lighting. This is achieved by:

3.a: Maximising daylight levels in all weather, cloudy or sunny AND

3.b: Ensuring the use or location of shading does not conflict with the operation of lighting control systems.

ClosedUp to two credits - Daylighting (building type dependent)

4 Daylighting criteria have been met using either of the following options:

4.a: The relevant building areas meet good practice daylight factors and other criteria as outlined in Table 5.1 and Table 5.2 OR

4.b: The relevant building areas meet good practice average and minimum point daylight illuminance criteria as outlined in Table 5.3.

Additional alternative route for healthcare building types only:

4.c: The relevant building areas meet the median daylight factors and minimum daylight factors in Table 5.4 (see Methodology ).

Table 5.1 Minimum values of average daylight factor required

Building or area type Credits Average daylight factor required Minimum percentage area (m²) to comply Other requirements
Education buildings

Preschools, schools, further education

occupied spaces

2 2% 80% EITHER (a) OR {(b) and (c)} in Table 5.2

Higher education

occupied spaces

1 2% 60%
2 2% 80%
Healthcare buildings

Staff and public areas

1 2% 80%

EITHER (a) OR {(b) and (c)} in Table 5.2

Occupied patient’s areas (dayrooms, wards) and consulting rooms 2% 80%
Staff and public areas 2 2% 80% EITHER (a) OR {(b) and (c)} in Table 5.2
Occupied patient areas (dayrooms, wards) and consulting rooms 3% 80%
Multi-residential buildings

Kitchen

2 2% 80% EITHER (a) OR {(b) and (c)} in Table 5.2

Living rooms, dining rooms, studies (including home office)

2 % 80%

Non-residential or communal occupied spaces

2% 80%
Retail buildings
Sales areas 1 - 35% Point daylight factors of 2% or more
Other occupied areas 1 2% 80% EITHER (a) OR {(b) and (c)} in Table 5.2
Prison buildings
Cells and custody cells 2 1.5% 80% N/A
Internal association or atrium area 3% 80% EITHER a uniformity ratio of at least 0.7 OR a minimum point daylight factor of 2.1%
Patient care spaces 3% 80% EITHER (a) OR {(b) and (c)} in Table 5.2
Teaching, lecture and seminar spaces 2% 80% EITHER (a) OR {(b) and (c)} in Table 5.2
Office Buildings
All occupied spaces, unless indicated in Daylighting - relevant building areas 2 2% 80% EITHER (a) or {(b) and (c)} in Table 5.2
Crèche buildings
All occupied spaces, unless indicated in Daylighting - relevant building areas 2 2% 80% EITHER (a) or {(b) and (c)} in Table 5.2
Courts, Industrial and Other building types
All occupied spaces unless indicated in Daylighting - relevant building areas 1 2% 80% EITHER (a) or {(b) and (c)} in Table 5.2

Table 5.2 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 5.1. 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 5.1.

(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.

Table 5.5 gives maximum room depths in metres for different room widths and window head heights of side-lit rooms.

Table 5.3 Space type and illuminance requirements - both criteria (average illuminance and minimum point illuminance) should be met.

Area type Credits Minimum area to comply Average daylight illuminance (averaged over entire space) Minimum daylight illuminance at worst lit point
Education buildings

Preschools, schools, further education - occupied spaces

2 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 1 60%
OR Higher education - occupied spaces 2 80%
Healthcare buildings
Staff and public areas 1 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 80% At least 300 lux for 2000 hours per year or more At least 90 lux for 2000 hours per year or more
Staff and public areas 2 80% At least 300 lux for 2650 hours per year or more At least 90 lux for 2650 hours per year or more
Occupied patients areas (dayrooms, wards) and consulting rooms 80% At least 300 lux for 2650 hours per year or more At least 90 lux for 2650 hours per year or more
Multi-residential buildings

Kitchen

2 100% 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 offices)

At least 100 lux for 3450 hours per year or more At least 30 lux for 3450 hours per year or more

Non-residential or communal occupied spaces

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

1 35% At least 200 lux point daylight illuminances for 2650 hours per year or more

Other occupied areas

1 80% At least 200 lux for 2650 hours per year or more At least 60 lux for 2650 hours per year or more
Prison buildings
Cells and custody cells 2 80% At least 100 lux for 3150 hours per year or more N/A
Internal association or atrium 80% At least 300 lux for 2650 hours per year or more At least 210 lux for 2650 hours per year
Patient care spaces 80% At least 300 lux for 2650 hours per year or more At least 210 lux for 2650 hours per year or more
Teaching, lecture and seminar spaces 80% At least 300 lux for 2000 hours per year or more At least 90 lux for 2000 hours per year or more
Office buildings
All occupied spaces, unless indicated in Daylighting - relevant building areas 2 80% At least 300 lux for 2000 hours per year or more At least 90 lux for 2000 hours per year or more
Crèche buildings
All occupied spaces, unless indicated in Daylighting - relevant building areas 2 80% At least 300 lux for 2000 hours per year or more At least 90 lux for 2000 hours per year or more
Courts, Industrial and all Other building types
All occupied spaces, unless indicated in Daylighting - relevant building areas 1 80% At least 300 lux for 2000 hours per year or more At least 90 lux for 2000 hours per year or more

Table 5.4 Additional alternative route for healthcare building types only

         
Healthcare Buildings Credits Median daylight factor Minimum daylight factor Minimum area to comply
Staff and public areas 1 2% 0.6% 80%
Occupied patients areas (dayrooms, wards) and consulting rooms 2% 0.6%
Staff and public areas 2 2% 0.6% 80%
Occupied patients areas (dayrooms, wards) and consulting rooms 3% 0.9%

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 5.5 Reflectance for maximum room depths and window head heights

Reflectance (RB)

0.4 0.5 0.6
Room width (m) 3 10 3 10 3 10
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

ClosedOne credit - View out

5 95% of the floor area in 95% of spaces for each relevant building area provides an adequate view out (see Adequate view out).

6 In addition, the building type criteria in Table 5.6 are applicable to view out criteria.

Table 5.6 View out building-specific requirements.

Building type View out requirements
Prison buildings

Cells

An adequate view out from a normal standing or sitting position. The distance between each window and nearest external solid object (i.e. buildings, screens, walls or 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 or 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 5 and 6 for the relevant building areas PLUS the distance between the wall with the window or opening and nearest external solid object (e.g. buildings, screens, walls or fences) is 10m.

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

Internal lighting

7 Internal lighting in all relevant areas of the building is designed to provide illuminance (lux) levels and colouring rendering index in accordance with the SLL Code for Lighting 20121CIBSE.SLL Code for lighting. 2012. and any other relevant industry standard. Internal lighting should be appropriate to the tasks undertaken, accounting for building user concentration and comfort levels.

8 For areas where computer screens are regularly used, the lighting design complies with CIBSE Lighting Guide 72CIBSE. LG 7: Lighting Guide 07: Offices. 2015. sections 2.4, 2.13 to 2.15, 2.20, and 6.10 to 6.20. This gives recommendations highlighting:

8.a: Limits to the luminance of the luminaires to avoid screen reflections. (Manufacturers’ data for the luminaires should be sought to confirm this.)

8.b: Any area where a surface is used to reflect light in to a space, such as 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.

8.c: Recommendations for direct lighting, ceiling illuminance, and average wall illuminance.

External lighting

9 All external lighting located within the construction zone is specified in accordance with BS 5489-1:2013 Code for the practice for the design of road lighting. Lighting of roads and public amenity areas3BS 5489-1: 2013 Code of practice for the design of road lighting - Lighting of roads and public amenity areas BSI; 2013. and BS EN 12464-2:20144BS EN 12464-2:2014. Light and lighting. Lighting of work places - Outdoor work places. BSI; 2014. Light and lighting - Lighting of work places - Part 2: Outdoor work places. External lighting should provide illuminance levels that enable users to perform outdoor visual tasks efficiently and accurately, especially during the night.

10 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 criteria 78.c above. If no internal lighting is specified, the credit cannot be awarded.

Zoning and occupant control

11 Internal lighting is zoned to allow for occupant control. Zoning is in accordance with the criteria below for relevant areas present within the building:

11.a: In office areas, zones of no more than four workplaces

11.b: Workstations adjacent to windows or atria and other building areas separately zoned and controlled

11.c: Seminar and lecture rooms: zoned for presentation and audience areas

11.d: Library spaces: separate zoning of stacks, reading and counter areas

11.e: Teaching space or demonstration area

11.f: Whiteboard or display screen

11.g: Auditoria: zoning of seating areas, circulation space and lectern area

11.h: Dining, restaurant, café areas: separate zoning of servery and seating or dining areas

11.i: Retail: separate zoning of display and counter areas

11.j: Bar areas: separate zoning of bar and seating areas

11.k: Wards or bedded areas: zoned lighting control for individual bed spaces and control for staff over groups of bed spaces

11.l: Treatment areas, dayrooms, waiting areas: zoning of seating and activity areas and circulation space with controls accessible to staff.

12 Areas used for teaching, seminar or lecture purposes have lighting controls provided in accordance with CIBSE Lighting Guide 55CIBSE. LG 5: Lighting guide 05: Lighting for education. 2011. .

13 In addition, the building type criteria in Table 5.7 (where relevant).

Table 5.7 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 or leaving the teaching space. Manual lighting controls need only be provided for staff, not the children.
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):

  1. Judge's or magistrate's bench
  2. Dock
  3. Jury area
  4. Public seating area.

Lighting control of the zones in the above spaces, and the court as a whole, cater for the following settings:

  1. Full lighting (to allow cleaning etc.)
  2. Normal lighting (for court sessions)
  3. Dimmed (for the purpose of showing audio-visual evidence, but allowing enough light for note taking).
Small spaces (less than 40m²) Buildings consisting entirely of small rooms or spaces (less than 40m²) which do not require any subdivision of lighting zones or control will meet the zoning criteria by default.
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 or performance area would typically be expected to have lighting controls as follows:
  1. Full normal lighting (to allow for entry, exit, cleaning etc.)
  2. 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)
  3. All lighting off (for the projection of tone slides, colour slides, and for the purposes of visual demonstrations or performances)
  4. Separate localised lectern lighting.
Internal areas excluded from the lighting zone requirements

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).

ClosedExemplary level criteria

Exemplary level criteria - Daylighting

To achieve an exemplary performance credit for daylighting:

14 Daylighting criteria have been met using either of the following options:

14.a: Relevant building areas meet exemplary daylight factors and the relevant criteria in Table 5.8.

14.b: Relevant building areas meet exemplary average and minimum point daylight illuminance criteria in Table 5.9.

Exemplary level criteria - Internal and external lighting levels, zoning and control

To achieve an exemplary performance credit for Internal and external lighting levels, zoning and control:

15 Lighting in each zone can be manually dimmed by occupants down to 20% of the maximum light output using dimmer switches positioned in accessible locations. Dimming and control gear should avoid flicker and noise.

Table 5.8 Exemplary level values of average daylight factor required.

Area type Credits Average daylight factor required

Minimum area (m²) to comply

Other requirements
All building types The criteria outlined in Table 5.1 and Table 5.2 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 or 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 minimum point daylight factor of 2% must be achieved in the compliant areas. Assess total sales areas without rounding up to the nearest room.
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 5.9 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 (averaged over entire space) 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 dependent on whether you are assessing a multi-storey or single storey building.  
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Methodology

ClosedGlare control

Glare control assessment

A glare control assessment is used to determine the areas of the building that are at risk of glare, including a demonstration of the building areas not at risk. This can be achieved through a survey of or modelling of the relationship between sunlight and the building. Design studies can be used to demonstrate that glare cannot reach the eyes of building occupants, or the computer screens they are using, during occupied hours.

Where compliant shading measures are specified for all relevant building areas regardless of the risk of glare, a glare control assessment will not be necessary. The glare control strategy should demonstrate building design measures are specified for all relevant building areas, while also complying with criteria 33.b.

Assessing compliant forms of glare control

Control of glare from the sun is required in spaces with computer workstations such as offices, laboratories, study bedrooms, libraries, control rooms and reception desks. It is also required in spaces where people have to spend time in fixed locations such as classrooms, hospital wards, court rooms and factory production lines.

Compliant shading measures for meeting glare control criteria can include:

or a combination of the above.

Glare control must provide shading from both high level summer and low level winter sun. Design studies can be used to demonstrate the sunlight is prevented from reaching the eyes of building occupants, or the computer screens they are using, during occupied hours.

Curtains (where used without other forms of shading) do not meet the criteria for the glare control credit. This is because they do not provide sufficient control to optimise daylight in to the space. A such, the use of curtains to control glare is likely to cause occupants to rely more on artificial lighting.

Applicability of Glare control from sunlight

The ‘Control of glare from sunlight’ criteria are applicable to all spaces that meet the ‘Glare control: relevant building areas’ definition. This includes reception and atrium spaces where these spaces meet this definition. Where an atrium space does not meet the definition of ‘Glare control: relevant building areas’ it does not need to comply with the criteria. However, the risk of glare must be considered for any relevant building areas that connect off the atrium space. This is because sunlight could pass through the atrium causing discomfort for users of other relevant building areas that connect to the atrium space. Where this is the case, building design measures or the provision of shading will be required to enable glare to be controlled or eliminated.

ClosedDaylight issue calculations

Calculating the percentage of assessed area

The percentage of the total floor area of all relevant rooms must comply where the criteria specify that a percentage of floor area must have adequate daylight illuminance. For example, six relevant rooms each have a floor area of 150m² making a total relevant floor area of 900m²; 80% of this floor area must meet the criterion, so 720m² must comply. This is the equivalent to 4.8 rooms. The number of rooms must always be rounded up so, in this example, five rooms must comply to achieve the credit.

Using the point daylight factor to determine compliance for retail sales areas, the minimum percentage area is based on the total floor area being assessed. Individual 'rooms' or sub-areas do not need to meet the minimum thresholds. This allows for typical building form restrictions and layout configurations for these types of spaces.

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

External obstructions

In calculating minimum and average daylight factors and daylight illuminances, external obstructions should be taken into account to include future buildings that have received planning permission. For illuminance calculations, the reflectance of external obstructions should be taken as 0.2 unless on-site measurements of external reflectance have been made.

Dirt factors

Daylight calculations should include a maintenance factor for dirt on the windows, as given in BS 8206 Part 2, appendix A1.36BS8206-2:2008. Lighting for buildings. Code of practice for daylighting. Part 2 Appendix A1.3..

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 or transparent partitions (such as those using frosted glass).

Room depth criteria - rooms lit from two opposite sides or via rooflights

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.) The reflectance of the imaginary internal wall should be taken as 1.

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 2.11 (page 17) within CIBSE Lighting Guide 'LG10: Daylighting - a guide for designers' can be used to determine the uniformity ratio.

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.

View of sky calculation

To comply with the view of sky criterion (ref (b) in Table 5.2), 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.

ClosedAlternative route for healthcare buildings

This is intended for use where part of a space requires daylight and other parts may not. Examples could include ward areas opening off a central circulation spine, or seating areas leading off corridors. In these circumstances, it is possible to calculate the median daylight factor in the part of the space that does require daylight.

Further guidance is given in the definition of daylighting relevant building areas. Where the whole of a space requires daylight this route is not applicable.

For the calculation of median daylight factor a grid of points is set up in the area requiring daylight on the working plane. Daylight factor is calculated at each point. The median daylight factor is then the daylight factor exceeded at over 50% of the points in that area. The spacing of grid points should not be greater than that given in section 4.4 of BS EN 12464-1 Light and lighting - Lighting of work places- Part 1: Indoor work places7BSEN12464-1. Lighting and lighting- lighting for work places. Part 1: Indoor work places. 2011. . Table 5.10 gives the recommended number of grid points in each linear dimension. For example, a space 5m x 5m would have 8 x 8 = 64 grid.

In the calculations for the median daylight factor the areas within the space which are permanently occupied should be used; this may exclude areas close to the walls unless work stations, beds or seating areas are located there.

Table 5.10 Recommended number of grid points

Length of the area (m) Maximum distance between grid points (m) Minimum number of grid points
0.4 0.15 3
0.6 0.2 3
1 0.2 5
2 0.3 6
5 0.6 8
10 1 10
25 2 12
50 3 17
100 5 20

The median daylight factor in an area is the daylight factor exceeded over 50% of the working plane in that area.

ClosedAlternative route for school buildings

ClosedView out

Of all the spaces within relevant building areas, 95% of these spaces must comply with the criteria. For example, if a project had 20 spaces in a relevant building area, 19 of these spaces would need to demonstrate that, independently, 95% of their floor area was within 8m of an external wall that has a window or opening that provides an adequate view out.

ClosedInternal and external lighting levels, zoning and control

Occupancy or workstation layout

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 or 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.

Where occupancy or workstation layout is not known, lighting control can be zoned on the basis of 40m² grids, i.e. an assumption of 1 person or workspace per 10m².

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ClosedEvidence

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ClosedDefinitions

Accessible locations
An accessible location for dimming switches is a location that can be easily accessed by all of the building users in that zone. Alternatively, all building users could be given access to remote controls or computer software that controls the lighting.
Adequate view out
Where relevant building areas are within 8m of an external wall which has a window or permanent opening, and the window or opening is ≥20% of the surrounding wall area. Where the room depth is greater than 8m, the percentage of window or opening must instead be the same as, or greater than, the values in Table 1.0 BS8206: Part 2. The view out must be 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 or 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. In addition to this, an external view out can offer positive effects on health and wellbeing that cannot be offered by an internal view.
Average daylight factor
The average daylight factor is the average indoor illuminance (from daylight) on the working plane within a room. This is expressed as a percentage of the simultaneous outdoor illuminance on a horizontal plane under an unobstructed CIE Standard Overcast Sky8Commission Internationale de L’Eclairage (International Commission on Illumination). CIE Standard 011/E:2003 Spatial distribution of daylight - CIE standard overcast sky and clear sky. Vienna. CIE. 2003. .
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.
Construction zone
For the purpose of this BREEAM issue, the construction zone is defined as the site which is being developed for the BREEAM-assessed building. This includes the external site areas that fall within the scope of the new works.
Daylight factor
The daylight factor is defined as the ratio of the illuminance at a point on a given plane due to the light received directly or indirectly from a sky assumed or known luminance distribution, to the illuminance on a horizontal plane due to an unobstructed hemisphere of this sky, excluding the contribution of direct sunlight to both illuminances.
Daylighting - relevant building areas
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 or operational requirement.
Glare
The CIBSE SLL Code for Lighting (2012) defines glare as the condition of vision in which there is discomfort or a reduction in the ability to see details or objects, caused by an unsuitable distribution or range of luminance, or to extreme contrasts.
Glare control - relevant building areas
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 or 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.
Illuminance
The amount of light falling on a surface per unit area, measured in lux.
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. 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).
Lighting zoning
For rooms or spaces not listed within 11, 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.
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 expressed as a percentage based on the ratio of the daylight illuminance at a specific point on the working plane within a room compared with the illuminance on an outdoor unobstructed horizontal plane. An overcast sky is assumed by the ‘CIE (Commission Internationale de l’Eclairage) overcast sky’. For points on the working plane:
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).
Separate zoning control
Light switches or controls for a particular area or zone of the building that can be accessed and operated by the individuals 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 or opening is located, including the area of the window or 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 and 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.
View out - relevant building areas
BREEAM defines relevant building areas requiring a view out to include areas of the building where:
  1. There are or will be workstations or benches or desks for building users.
  2. Close work will be undertaken or visual aids will be used.
Excluded areas for each of these might include:
  1. Nurse bases where they are located centrally in a ward or patient area in order to enable patient observation.
  2. Courts 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 or 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.
  6. Isolated work station for intermittent, short term work, e.g. work station within a server room.
Working plane
CIBSE LG109CIBSE. LG 10: Daylighting- a guide for designers. 2014. 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.
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ClosedAdditional information

Internal and external lighting levels, zoning and control

Relevant industry standards for lighting design

For preschools, schools and sixth form colleges, the following can be considered a relevant industry standard for lighting design:

For care homes housing people with dementia the following standard can be used instead of the SLL Code for Lighting:

For multi-residential buildings, CIBSE SLL LG911CIBSE. LG 9: Lighting Guide 09: Lighting for Communal Residential Buildings. 2013. can be considered as a relevant standard in addition to, or instead of SLL Code for Lighting 2012

Illuminance levels specified in the SLL Code for Lighting, 2012 align with BS EN 12464-112BSEN12464-1:2011. Light and lighting. Lighting for work places. Indoor work places. 2011. .

BREEAM has not attempted to list all appropriate industry standards. Any recognised collaborative industry or sector best practice standard or guidance that sets levels appropriate to the tasks undertaken, accounting for building user concentration and comfort levels, can be considered an appropriate industry standard for the purposes of this BREEAM issue.

BREEAM New Construction 2018
Reference: SD5078 – Issue: 3.0
Issue Date: 31/07/2019
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