How can electric lighting contribute to human health and well-being?

Electric light in buildings may provide some health benefits; however, for most people these benefits are likely to be small. It is possible for electric lighting to cause health problems, if there is too little light or there is glare, but for the most part there is good guidance available and these problems can be avoided. The quality of the lit environment can have a psychological impact and this may in turn impact well-being. A starting point for this is perceived adequacy of illumination. Related lighting metrics are examined and a hypothetical explanation is suggested

Room lighting in the absence of a defined visual task and the impact of mean room surface exitance

With conditions for lighting design changing it is becoming important to consider what to do in rooms where there is no particular visual task. The current European standard for lighting in work places gives a number of requirements for room lighting, the most onerous being the requirement for cylindrical illuminance. Mean room surface exitance (MRSE) has been put forward as a metric that is a good predictor of perceived adequacy of illumination. The paper examines the consequences of adopting a proposed MRSE target of 100 lumens per square metre in two sizes of room with a variety of surface reflectances and lit by a regular array of light sources with a range of light distributions. The paper concludes that significant extra luminous flux will be required to meet the new MRSE target and that light distributions with a significant upward component will also be needed

Standards and Codes

CIBSE & SLL International Lighting Conferenc

Does pedestrian useful visual field change at night?

This paper reports an investigation into the shape and size of the useful visual field over which pedestrian visual gaze tends to fall during day and night and discusses the factors affecting useful visual field and the function of peripheral vision. A previous study by authors explored what people look at at night in the streets employing an eye tracking methodology. This study is secondary analysis of the data captured by the previous study. The study shows that street lighting affects and reduces useful visual field of pedestrians and provides guidelines to more effective distribution of light at night based on the optimum pedestrian useful field of view. Our finding emphasises the importance of illuminance on vertical surfaces and hence the for it to be considered when designing light for our streets

Familial polyposis of the colon

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Key Factors Dictating Excessive Lighting Energy Consumption in Schools: a Post-Occupancy Analysis

Good practice in lighting energy consumption in schools is regarded to be around 13 kWh/m2 per annum (CIBSE LG5, 2011). However, recent post-occupancy evaluations reveal lighting energy consumption in schools to be above 30kWh/m2 p.a., despite the use of energy efficient lamps, switching based on infrared presence/absence detection, and digital controls for daylight-linked dimming. To identify causes of excess energy consumption for lighting, this study undertook detailed post-occupancy field measurements of the lighting consumption of two recently-completed K schools – a small primary and a large secondary – equipped with digitally-addressable lighting interface (DALI) systems. Instrumentation of individual light fittings was carried out to obtain an accurate understanding of their switching and dimming characteristics. Results were compared with estimates of kilowatt hours per square metre per year (the Lighting Energy Numeric Indicator), calculated using the spreadsheet provided to support the European Standard that defines LENI, and against estimates of disaggregated whole-building energy consumption using the CIBSE energy assessment tool TM22. The post-occupancy evaluations uncovered excessive lighting consumption in classrooms and circulation area lighting, issues with DALI system installation and commissioning, and problems with the usability of lighting controls. Allied shortcomings included dysfunctional energy metering, lack of system fine-tuning after handover, and inaccuracies with as-built records. Methodological shortcomings were identified with the industry-standard methods of assessing lighting consumption. Recommendations are given on ways to mitigate excessive lighting energy consumption and to improve the predictive power of the current energy assessment methods

Assistive lighting for people with sight loss

This paper affirms the importance of lighting as a technology in the context of people with sight loss. Its importance lies in the ability of appropriate lighting interventions to support independent living and to reduce the likelihood of falls and accidents. The concept of “assistive lighting” is introduced with a set of tenets by which the merits of different lighting interventions can be considered. The tenets are derived from research on lighting and sight loss, including a thorough review of the literature; and consultation in the period from 2008 to 2010 with over 80 rehabilitation workers and occupational therapists in the United Kingdom. They affirm the need for lighting to be appropriate, sufficient, even, adjustable, sustainable and energy efficient, simple and adaptable. Examples of different lighting interventions are provided and these are considered in relation to the tenets. One of the key outcomes of the research was publication of a guide to good practice on lighting interventions for people with sight loss. Implications for Rehabilitation -Assistive lighting has important implications for rehabilitation in relation to people with sight loss. -Simple lighting interventions carry the potential for improving the independence and quality of life of people with sight loss and can reduce the risk of accidents. -The tenets by which options for lighting interventions can be considered can assist rehabilitation officers and occupational therapists in their work. -Lighting can be considered as a factor of increasing importance within the broader context of universal design