The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 19th of October, 2007, at 12 noon.
Overview in PDF format (ISBN 978-951-22-8962-2) [8279 KB]
Dissertation is also available in print (ISBN 978-951-22-8961-5)
The main objectives of this work were to study which task illuminances industrial workers prefer and to find out if increasing the task illuminance from the levels given in the relevant Norms (CIE S 008/E-2001, EN 12464-1) can increase their productivity, and if so, what the possible reasons for the productivity increase when the lighting is changed are.
Six field studies were conducted in real industrial environments. The preferred illuminances of the industrial workers covered a wide range of values. However, most people tend to select levels higher than the minimums found in the norms and they prefer to be able to influence their task lighting.
The results from the productivity-related field studies show that increasing task illuminance above the minimum level given in norms can increase productivity even though the effect is influenced by the starting conditions, tasks and subjects. Productivity increases in the field tests were found between zero and 7.7 per cent. Additionally, two field studies where absenteeism was measured showed a decrease in absenteeism when the illuminance was increased. One study also showed that increasing the task illuminance can be achieved without increasing the energy consumption – the energy consumption can even be reduced. The results of this work encourage the building of industrial lighting installations where at least part of the task lighting has been provided by localised lighting. A change of the lighting can be achieved in several ways and an increase in productivity can take place via several mechanisms, such as visual performance, visual comfort, visual ambience, interpersonal relationships, biological clock, stimulation, job satisfaction, solving problems, the halo effect and/or change process. These mechanisms can be used to plan successful lighting renovations and changes.
This thesis consists of an overview and of the following 11 publications:
Keywords: lighting, productivity, preferred illuminances, case studies
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© 2007 Helsinki University of Technology