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SLL Code for Lighting (2012)
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SLL Code for Lighting (2012)

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A new edition of the SLL Code for Lighting is due to be published on 28th November 2022. Please note that this page is for the 2012 edition.

For many years, the IES Code for Lighting was the de facto standard for lighting provision in the United Kingdom. However, in 2002, the Committee for European Standardisation (CEN) took on the task of providing lighting recommendations, and, since then the British Standards Institution has adopted the CEN recommendations for use in the United Kingdom. As a result, there are now a range of British Standards that specify the quantitative lighting requirements for a wide range of applications. Consequently, the role of the SLL Code for Lighting has shifted from being the only source for quantitative lighting recommendations to being a guide on how to interpret the British Standard recommendations and how to implement them in practice.

This edition of the SLL Code for Lighting takes the changes in lighting guidance a step further by a process of separation and concentration. The separation involves moving the details of vision, lighting technology and lighting applications into another publication, the SLL Lighting Handbook. The concentration occurs because this SLL Code for Lighting provides information on three fundamental matters of relevance to lighting practice. These matters are:

  • A summary of what is known about the effects of lighting on task performance, behaviour, safety, perception and health as well as its financial and environmental costs.
  • A compendium of all the lighting recommendations relevant to the United Kingdom with suggestions as to how these should be interpreted. This compendium covers recommendations for both interior and exterior lighting in normal conditions.
  • A detailed description of all the calculations required for quantitative lighting design. While it is a fact that, today, most lighting calculations are done using software that simply implements the fundamental calculations described here, without knowledge of these calculations, it is diffi cult to assess the meaning and merit of the results produced by software.

First published in 1936, the Code for Lighting was published in printed form until 1994. In 2002 the Code was published as a CD for the first time and the following editions in 2004, 2006 and 2009 were produced purely in CD format. This 2012 edition reverts back to hard copy (and as a pdf), complimented by the SLL Lighting Handbook.

Please note, this Guide is currently under review.


Chapter 1: The balance of lighting

1.1 Lighting quality

1.2 The place of lighting in the modern world

1.3 An overview of the effects of light on human performance

1.4 Lighting and visual task performance

1.4.1 Visual performance

1.4.2 Visual search

1.4.3 Mesopic conditions

1.4.4 A discrepancy

1.4.5 Improving visual performance

1.5 Lighting and behaviour

1.5.1 Attracting attention

1.5.2 Directing movement

1.5.3 Communication

1.6 Lighting and safety

1.6.1 Emergency escape lighting

1.6.2 Road lighting

1.6.3 Lighting and crime

1.7 Lighting and perception

1.7.1 Brightness

1.7.2 Form

1.7.3 Higher order perceptions

1.8 Lighting and health

1.8.1 Eyestrain

1.8.2 Non-visual effects

1.8.3 Tissue damage by optical radiation

1.9 Lighting costs

1.9.1 Financial costs

1.9.2 Electricity consumption

1.9.3 Chemical pollution

1.9.4 Light pollution

1.10 The future

Chapter 2: Indoor workplaces

2.1 Lighting design criteria

2.1.1 Luminous environment

2.1.2 Luminance distribution

2.1.3 Illuminance

2.1.4 Illuminance grid

2.1.5 Glare

2.1.6 Lighting in the interior space

2.1.7 Colour aspects

2.1.8 Flicker and stroboscopic effects

2.1.9 Lighting of work stations with display screen equipment (DSE)

2.1.10 Maintenance factor

2.1.11 Energy efficiency requirements

2.1.12 Additional benefits of daylight

2.1.13 Variability of light

2.2 Schedule of lighting requirements

2.2.1 Composition of the tables

2.2.2 Schedule of interior areas, tasks and activities

2.2.3 Verification procedures

Chapter 3: Outdoor workplaces

3.1 Lighting design criteria

3.1.1 Luminous environment

3.1.2 Luminance distribution

3.1.3 Illuminance

3.1.4 Glare

3.1.5 Obtrusive light

3.1.6 Directional lighting

3.1.7 Colour aspects

3.1.8 Flicker and stroboscopic effects

3.1.9 Maintenance factor (MF)

3.1.10 Energy considerations

3.1.11 Sustainability

3.1.12 Emergency lighting

3.2 Schedule of lighting requirements

3.2.1 Composition of Tables 3.5 to 3.19

3.2.2 Schedule of areas, tasks and activities

3.2.3 Lighting requirements for areas, tasks and activities

3.2.4 Lighting requirements for safety and security

3.3 Verification procedures

3.3.1 Illuminance

3.3.2 Glare rating

3.3.3 Colour Rendering Index

3.3.4 Obtrusive light

Chapter 4: Road lighting

4.1 Classification of roads

4.1.1 Traffic routes

4.1.2 Subsidiary roads

4.1.3 Conflict areas

4.2 Lighting classes

4.2.1 ME classes

4.2.2 S classes

4.2.3 CE classes

4.2.4 G classes

Chapter 5: Daylight

5.1 Daylight and health

5.1.1 Regulation of the circadian system

5.1.2 Mood

5.1.3 Seasonal affective disorder (SAD)

5.1.4 Ultraviolet (UV) radiation

5.2 Windows and view

5.2.1 Analysis of view

5.2.2 Size and proportion of windows

5.3 Daylight and room brightness

5.3.1 Sunlight

5.3.2 Skylight

5.3.3 Contrast between the interior and the view outside

5.4 Daylight for task lighting

5.4.1 Glare

5.4.2 Specular reflection

5.5 Electric lighting used in conjunction with daylight

5.5.1 Balance of daylight and electric light

5.5.2 Modelling

5.5.3 Contrast between exterior and interior

5.5.4 Colour appearance of lamps

5.5.5 Changes of lighting at dusk

5.6 Sunlight shading

Chapter 6: Energy

6.1 Simple guidance for energy efficient lighting

6.1.1 The right amount of light

6.1.2 Light in the right place

6.1.3 Light at the right time

6.1.4 The right lighting equipment

6.2 Energy regulations and standards

6.2.1 Building regulations

6.2.2 Dwellings

6.2.3 Non-domestic buildings

6.2.4 BS EN 15193

6.2.5 Schemes to support energy efficient lighting

Chapter 7: Construction (Design and Management) Regulations

7.1 Introduction

7.2 General management duties

7.2.1 Duties of clients

7.2.2 Duties of designers

7.2.3 Duties of contractors

7.3 Additional duties if the project is notifiable

7.3.1 Additional duties of the client

7.3.2 Additional duties of designers

7.3.3 Additional duties of contractors

7.3.4 Duties of the CDM co-ordinator

7.3.5 Duties of the principal contractor

7.4 Duties relating to health and safety on construction sites

7.4.1 Electricity distribution

7.4.2 Emergency routes and exits

7.4.3 Lighting

Chapter 8: Basic energy and light

8.1 Properties of electromagnetic waves

8.2 Evaluating energy as light

Chapter 9: Luminous flux, intensity, illuminance, luminance and their interrelationships

9.1 Definitions of the units

9.1.1 Flux

9.1.2 Intensity

9.1.3 Illuminance

9.1.4 Luminance

9.2 Interrelationships between the units

9.2.1 Flux and intensity

9.2.2 Intensity and illuminance

Chapter 10: Direct lighting

10.1 Illuminance from point sources

10.1.1 Planar illuminance

10.1.2 Cylindrical illuminance

10.1.3 Semi-cylindrical illuminance

10.1.4 Spherical illuminance

10.1.5 Hemispherical illuminance

10.2 Non-point sources

10.2.1 Line source calculations

10.2.2 Area sources

10.2.3 Recursive source subdivision

Chapter 11: Indirect lighting

11.1 Introduction

11.2 Sumpner’s method

11.2.1 Checking the results of lighting calculation software

11.3 Transfer factors

11.3.1 Basis of calculation

11.3.2 Calculation of form factors

11.3.3 The three surface case

11.3.4 The four surface case

11.3.5 Derivation of transfer factors

Chapter 12: Photometric datasheets

12.1 Photometric measurement

12.1.1 The C-γ system

12.1.2 The B-β system

12.1.3 Relationships between the two angular co-ordinate systems

12.1.4 Photometric centre

12.2 Elements of a datasheet

12.2.1 Normalised intensity table

12.2.2 Intensity diagram

12.2.3 Light output ratios

12.2.4 Spacing to height ratio (SHR)

12.2.5 Utilisation factor (UF) tables

12.2.6 Shielding angle

12.2.7 Normalised luminance table

12.2.8 Unified glare rating (UGR) table

12.2.9 Luminaire maintenance factor (LMF)

12.2.10 Spacing tables (emergency lighting)

12.3 Calculations for datasheets

12.3.1 Flux calculations

12.3.2 Calculation of spacing to height ratio

12.3.3 Calculation of utilisation factors

12.3.4 Calculation of normalised luminance tables

12.3.5 Calculation of UGR tables

Chapter 13: Indoor lighting calculations

13.1 Introduction

13.2 The illumination vector

13.3 Cubic illuminance

13.4 Derived values

Chapter: 14 Outdoor lighting calculations

14.1 Calculation of intensity towards a point

14.1.1 Calculation of C and c

14.1.2 Finding the intensity value I

14.2 The reflective properties of road surfaces

14.3 Calculation of illuminance and luminance

14.4 Calculation of glare

14.5 Calculations in other outdoor areas

Chapter 15: Measurement of lighting installations and interpreting the results

15.1 Light measuring equipment

15.1.1 Illuminance meters

15.1.2 Luminance meters

15.2 Field measurements

15.2.1 Operating conditions

15.2.2 Grids and illuminance measurement

15.2.3 Averages and uniformities

15.2.4 Measurement of road luminance

15.2.5 Other measures of spatial illuminance

Chapter 16: Colour

16.1 Introduction

16.2 Colour properties of light sources

16.2.1 Colour appearance in the CIE chromaticity (1931) diagram

16.2.2 CIE UCS (1976) diagram

16.2.3 Colour temperature

16.2.4 Colour rendering

16.2.5 Colour rendering index (CRI)

16.2.6 Colour quality scale (CQS)

16.3 Colour properties of surfaces

16.3.1 Munsell system

16.3.2 Natural Colour System (NCS)

16.3.3 DIN system

16.3.4 BS 5252

16.3.5 RAL design system

16.3.6 CIE L*a*b*

Chapter 17: Daylight calculations

17.1 Average daylight factor

17.2 Calculation of the sun position

Chapter 18: Predicting maintenance factor

18.1 Determination of maintenance factor

18.1.1 Indoor lighting

18.1.2 Outdoor lighting

18.2 Lamp lumen maintenance factor and survival factor

18.3 Luminaire maintenance factor (LMF) – indoor

18.4 Luminaire maintenance factor (LMF) – outdoor

18.5 Room surface maintenance factor (RSMF)

18.6 Ingress protection (IP) classes

Chapter 19: Glossary

Chapter 20: Bibliography

20.1 Standards

20.2 Guidance

20.3 References


CORRECTIONS (to be incorporated in text in due course)

June 2012: On page 90, Table 3.2:

a) Column 4, 'Upward light', in row 3, delete '%' and

b) in list of definitions following table: for 'ULR', delete phrase ', and given in %'


Principal author: Peter Raynham

Contributors: Peter Boyce; John Fitzpatrick

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