LIGHTING SPECIAL RECOMMENDED CRITERIA


Grosvenor Hill, a spec offi ce development in Mayfair, with lighting by Hoare Lea


W


hat role do lighting criteria play in delivering lighting quality? Before any attempt can be made to answer this


question, it is necessary to defi ne these terms. Defi ning lighting criteria is easy. A


lighting criterion is some photometric or colorimetric quantity recommended as a basis for design. The Society of Light and Lighting (SLL) Code for Lighting is full of them. However, defi ning lighting quality is not


so easy. A number of different approaches have been suggested by the academic community: single-number photometric indices calibrated by subjective responses (Bean and Bell, 1992); the results of a holistic design process based on lighting patterns (Loe and Rowlands, 1996); lighting conditions that have desirable impacts on task performance, health and behaviour (Veitch and Newsham, 1998), through to lighting that enhances the ability to discriminate detail, colour, form, texture and surface fi nishes without discomfort (Cuttle 2008). Despite these attempts to focus, the most


universal defi nition remains the extent to which the installation meets the objectives and the constraints set by the client and the designer. The objectives can include enhancing the performance of relevant tasks, ensuring visual comfort, creating specifi c impressions and generating a desired pattern of behaviour, as well as minimising energy consumption and operating cost. The constraints are usually the budget,


the time available for completion of the work and, sometimes, restrictions on the design approach that can be used. To many people, defi ning lighting quality


in this way must be a disappointment. It is both mundane and obvious. It is not expressed in terms of photometric measures, but rather in terms of the impact lighting has on more distant outcomes. There are three arguments in favour of such an outcome-based defi nition of lighting quality, rather than any of the alternatives based directly on lighting variables. The fi rst is that lighting is usually designed and installed as a means to an end, not as an end in itself, so the extent to which the end is achieved becomes the


At the moment, good quality lighting most frequently occurs when a talented architect and a creative lighting designer work together – neither given to slavishly following numerical lighting criteria


www.cibsejournal.com


December 2012 CIBSE Journal 5


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20