Ireland's only dedicated building services engineering journal
Ireland's only dedicated building services engineering journal

SLL Code on Lighting — 2012 Edition Now Available

Dr Kevin Kelly, DIT and Vice-President, SLL with Peter Raynham and Stephen Donohoe, DIT.

The new edition is significantly different to the 2009 edition in a number of ways. First of all the format has changed – instead of the CD format of old the 2012 version has been produced as a book. However, it is also available as a PDF download from the CIBSE Knowledge Portal (https://

The content of the Code is also significantly different and these changes were introduced for two reasons. Firstly, the SLL Handbook, which was introduced in 2009, carries a lot of material about lighting equipment and lighting design. Consequently, there was no point repeating that material in the Code.

The second major source of change was the introduction of the new CEN standard on workplace lighting (EN 12464-1:2011 Light and Lighting – Lighting of Work Places Part 1: Indoor Work Places). The recommendations in the new standard have changed in a number of ways:

– Each task now has its own uniformity requirement;

– There is now a requirement for a background illuminance in areas up to 3.5 m away from the task being performed;

– There is a requirement for illuminance on the walls and ceiling although the levels are below that recommended by the SLL;

– There is a requirement to provide a certain amount of semi-cylindrical illuminance in all spaces to make it possible for people to see each other’s faces.

A key point made more explicit in the new edition of the Code relating to requirements for indoor workplaces is that the lighting should be on the stated visual tasks. This has in fact been the case since the 2002 edition, and the term “working plane” has not been used in the Code since 1994. The latest edition of the Code takes this one step further. In the section on indoor workplaces it advises that it is wasteful of energy to light the whole space when a particular task is carried out over a relatively small area.

As well as the section on indoor workplaces, the Code also provides recommendations on “outdoor workplaces” road lighting. Thus it provides, in a single book, the performance requirement for the vast majority of lighting applications. These sections are supported by all of the necessary background information so that all the parameters discussed can be evaluated from first principals. The topics covered include:

– Basic energy and light;
– Luminous flux, intensity, illuminance, luminance and their interrelationships;
– Direct lighting;
– Indirect lighting;
– Photometric datasheets;
– Indoor lighting calculations;
– Outdoor lighting calculations;
– Measurement of lighting installations and interpreting the results;
– Colour;
– Daylight calculations;
– Predicting maintenance factor.

Given the ever-increasing pressure on lighting design to reduce the amount of energy used, there is a specific section on energy. This looks at building regulations, the CEN standard EN 15193 on lighting energy consumption, and some of the voluntary schemes such as BREAM. It also provides advice on how to provide
energy efficient lighting based on the formula of providing the right amount of light, at the right place, for the right time, using the right lighting equipment.

The Code also contains a glossary where all of the lighting terms that are used are defined. This section is based on EN 12665:2011 Light and Lighting – Basic terms and criteria for specifying lighting requirements.

To sum up, the SLL Code is a must-have reference book for anyone involved in the design of lighting. It has been written so that it complements the SLL Handbook and together the two books provide the information necessary to carry out the design of virtually all lighting schemes. 

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