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.

Lighting, Productivity and Preferred Illuminances – Field Studies in the Industrial Environment

Henri Juslén

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:

  1. Juslén HT, Tenner AD. (2005) Mechanisms involved in enhancing human performance by changing the lighting in the industrial workplace. International Journal of Industrial Ergonomics. 35, 843-855. © 2005 Elsevier Science. By permission.
  2. Juslén HT, Wouters MCHM, Tenner AD. (2005) Preferred task-lighting levels in an industrial work area without daylight. Lighting Research & Technology. 37, 3, 219-233. © 2005 SAGE Publications. By permission.
  3. Juslén HT, Wouters MCHM, Tenner AD. (2007) The influence of controllable task-lighting on productivity: a field study in a factory. Applied Ergonomics. 38, 39-44. © 2007 Elsevier Science. By permission.
  4. Juslén HT. (2005) The influence of the preset level to the preferred illuminances in the industrial environment. Proceedings of the 10th European Lighting Conference Lux Europa 2005, Berlin, Germany, 463. © 2005 by author.
  5. Juslén H. (2006) Influence of the colour temperature of the preferred lighting level in an industrial work area devoid of daylight. Ingineria Iluminatului. 8, 18, 25-36. © 2006 Technical University of Cluj-Napoca, Lighting Engineering Center. By permission.
  6. Juslén HT, Tenner AD. (2007) The use of task lighting in an industrial work area provided with daylight. Journal of Light & Visual Environment. 31, 1, 25-31. © 2007 Illuminating Engineering Institute of Japan (IEIJ). By permission.
  7. Juslén HT, Wouters MCHM, Tenner AD. (2007) Lighting level and productivity: a field study in the electronics industry. Ergonomics. 50, 4, 615-624.
  8. Juslén H, Fassian M. (2005) Lighting and productivity – Night shift field study in the industrial environment. Light & Engineering. 13, 2, 59-62. © 2005 Znack Publishing House. By permission.
  9. Juslén H, Verbossen J, Wouters M. (2007) Appreciation of localised task lighting in shift work – A field study in the food industry. International Journal of Industrial Ergonomics. 37, 433-443. © 2007 Elsevier Science. By permission.
  10. Juslén H, Kremer E. (2005) Localised lighting for efficient use of energy and better performance – Field Study in the factory. Proceedings of CIE Midterm Meeting and International Lighting Congress, León, Spain, 2005. © 2005 by authors.
  11. Juslén H. (2006) Lighting and productivity in the industrial working place. Proceedings of the Fifteenth International Symposium Lighting Engineering 2006. Lighting of Work Places. Lighting Engineering Society of Slovenia, Bled, Slovenia, 53-62. © 2006 by author.

Keywords: lighting, productivity, preferred illuminances, case studies

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© 2007 Helsinki University of Technology

Last update 2011-05-26