The SLL Code for Lighting establishes the fundamentals required by lighting designers and anyone responsible for the application of light and lighting within the built environment.

The 2022 update reflects the rapid development in lighting technologies and research. Advances in LED lighting technology over the last decade have seen it become the dominant light source. Amongst other developments, this has led to extensive lighting research around the non-visual effects of LED light, and the potential for artificial lighting to disrupt and/or support human circadian rhythms.

It is understood that lighting conditions can affect visual performance, and in some cases, cause visual discomfort. The dominance of LED lighting has contributed to discussions relating to lighting metrics, colour rendering, and the spectral content of LED light sources. The possibility that exposure to light can have significant effects on human health and function beyond the obvious visual effect implies another basis for lighting recommendations. However, more knowledge is required before non-visual effects can be applied with confidence, particularly about the effects on healthy people exposed to light by day.

Lighting is vital in the modern world, enabling 24-hour society to exist. It is used for many different purposes, from enabling people to work accurately and safely, to visually enhancing our environment and improving accessibility and security.

The new edition of the Code considers the cost of lighting in relation to the health and wellbeing of an occupant and the environment. The recommendations included in the Code aim to strike a balance between the benefits and the costs. The basis of energy-efficient lighting is to provide the right amount of light, in the right place, at the right time, with the right lighting equipment.

Split over twenty chapters, the Code covers definitions for the various units of measurement and the interrelationships between them; calculation methodologies for a range of applications; photometric data; colour metrics; and maintenance factors for LED light sources and luminaires.

Most lighting calculations are carried out using software tools based on the fundamental calculations that are listed within the Code for Lighting. The Code specifies the quantitative lighting requirements for a wide range of applications, along with guidance on how these might be achieved. By understanding these fundamentals, the designer, engineer, or facilities manager is equipped with the information they might need to verify automated calculations.

The Code sits alongside the SLL Lighting Handbook, which is more aligned to project-based lighting design, technology, and applications.


Project manager and editor-in-chief:

  • Sophie Parry, CEng MIET FSLL, head of Akademie, Trilux UK

Chapter authors and principal contributors:

  • Allan Howard, BEng (Hons) FLIP FSLL, group technical director (lighting), WSP
  • Peter Raynham, CEng MSc MCIBSE FILP FSLL, professor of the lit environment, Institute for Environmental Design and Engineering, UCL
  • Sophie Parry (as above)
  • Peter Thorns, CEng BSc (Hons) FCIBSE FSLL, head of strategic lighting applications, Zumtobel Group Lighting
  • Ruth Kelly-Waskett, PhD CEng MCIBSE FSLL, senior associate, Hoare Lea, SLL past president

Contributors and reviewers

  • Steve Fotios, PhD CEng MEI MILP FSLL, professor of lighting and visual perception, University of Sheffield
  • Nigel Monaghan, FSLL, senior lighting consultant, Luminous Solutions
  • Peter Raynham (as above)
  • Peter Thorns (as above)
  • Technical secretary, SLL technical and publications committee
  • John Fitzpatrick


  • Ken Butcher, CIBSE Publications

For more information about the SLL Code for Lighting, visit

For more information about the Society of Light and Lighting (SLL), visit

information extracted from CIBSE website, read more here

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