DAYLIGHT MODELLING
Aperture-Based Daylight Modelling: a new direction for daylight planning Paul Bennett talks to daylight modelling pioneer John Mardaljevic about his latest work and its potential to provide a more reliable basis for sunlight/daylight planning than currently used methods. Professor John Mardaljevic BSc PhD, Professor of Building Daylight Modelling, School of Architecture, Building and Civil Engineering, Loughborough University
Since pioneering what is now widely known as Climate-Based Daylight Modelling (CBDM), John Mardaljevic, Professor of Building Daylight Modelling School of Architecture, Building and Civil Engineering at Loughborough University, has remained at the forefront of research and academic studies in this complex and increasingly widely-referenced field. In 2013 the UK Education Funding Agency (EFA) made CBDM a mandatory requirement for the evaluation of designs submitted for the Priority Schools Building Programme (PSBP). School designs submitted to the PSBP must achieve certain ‘target’ criteria for the useful daylight illuminance metric (proposed by John in 2005). This is believed to be the first major upgrade to mandatory daylight requirements since the introduction of the daylight factor more than half a century ago and CBDM remains the predominant basis for research and, increasingly, industry practice worldwide. Since 2018 the requirement was extended to all school buildings funded by the EFA.
14
Jan/Feb 2020
Differences of opinion... In January 2019, in his role of Chair at a meeting of the CIBSE Daylight Group (Chartered Institution of Building Services Engineers), John attended a presentation by UK/EU practitioners in London introducing EN 17037, the first Europe-wide standard to deal exclusively with the design for, and provision of, daylight in buildings. There were stark differences of opinion regarding the daylight part - a small minority were in favour of a national annex essentially keeping BS8206. The majority however favoured the 17037 methodology for daylight, which was reflected in a revised, ‘light touch’ national annex. In contrast, there was little discussion of the parts of the standard relating to sunlight and planning, perhaps because there was little that was substantively different to what had gone before. However, as a consequence of serving on the panel, John had formed misgivings about the various schema for sunlight and daylight planning, both in the EU standard and guidelines such as BR 209. The rationale for these
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