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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1191/1365782806lrt161oaLighting Research and Technology, 38, 3, pp. 191-223, 2006-09-01 Lighting quality and office work: two field simulation experiments Boyce, P. R.; Veitch, J. A.; Newsham, G. R.; Jones, C.; Heerwagen, J.; Myer, M.; Hunter, C. M. A version of this document is published in / Une version de ce document se trouve dans : Lighting Research and Technology, v. 38, no. 3, Sept. 2006, pp. 191-223 Lighting Research &Technology , v. 38(3) (2006) AbstractThis paper describes two experiments concerning the effects of variations in lighting quality on office worker performance, health, and well-being. Experiment 1 had four experimental conditions: a regular array of fully direct recessed parabolic luminaires; direct / indirect luminaires with no control; direct / indirect luminaires with a switchable desk lamp; and, workstation-specific direct / indirect luminaires with control over the direct portion. Experiment 2 contrasted two conditions with no individual lighting control: a regular array of recessed prismatic lensed luminaires, and suspended direct / indirect luminaires. Participants considered the direct / indirect systems to be comfortable than the direct-only systems, with a further increase in comfort associated with individual control in Experiment 1. There were no simple main effects of lighting quality on the performance of any task, although the expected changes in performance associated with task visibility, practice, and fatigue were found. Interactions between lighting quality and time suggested that having a degree of individual control of lighting tended to maintain motivation and vigilance over the day.

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1177/1477153507086279Lighting Research and Technology, 40, 2, pp. 133-151, 2008-06-01 Lighting appraisal, well-being, and performance in open-plan offices: a linked mechanisms approach Veitch, J. A.; Newsham, G. R.; Boyce, P. R.; Jones, C. C. The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42 Please cite as: Veitch, J. A., Newsham, G. R., Boyce, P. R., & Jones, C. C. (2008). Lighting appraisal, well-being, and performance in open-plan offices: A linked mechanisms approach. Lighting Research and Technology, 40(2) AbstractIn two experiments in a simulated office space, temporary office personnel worked under one of six lighting conditions for a day. A previous paper reported the results of statistical tests for lighting conditions effects on perceptions, feelings, and task performance. This paper reports mediated regression analyses testing the linked mechanisms by which lighting conditions affect health, well-being, and task performance. Combined results from the two statistical approaches show that people who perceived their office lighting as being of higher quality rated the space as more attractive, reported more pleasant mood, and showed greater well-being at the end of the day. Direct-indirect lighting and personal control were favoured. Lighting conditions that improved visibility also improved task performance.

Lighting has been shown to be an effective tool in the fight against crime, but too often the tool has been a sledgehammer. The four field studies described in this paper set out to answer two questions: 'How much light is needed to provide a perception of safety at night in urban and suburban areas?' and 'How important is light spectrum to that tion?' The first two field studies examined people's perceptions of the quality of the lighting for security on streets in New York City and Albany, New York. The third measured people's perceptions of safety when walking alone in urban and suburban parking lots, by day and night. The fourth measured perceptions of safety in a parking lot lit by high-pressure sodium and metal halide lamps. Taken together, these studies indicate that an average horizontal illuminance on a parking lot surface or street sidewalk of about 30 Ix provides enough light to ensure that perceptions of safety are close to what they are in daylight. The light spectrum is a minor factor relative to illuminance.

A feature of many national lighting standards is the recommendation that lamps with high correlated colour temperatures should not be used at low illuminances. The technical justification for this advice is limited so two experiments have been conducted to explore its validity. In the first experiment, fifteen observers carried out colour discrimination tasks and assessed the lighting of a small room lit to different illuminances using lamps with good colour rendering properties but with different correlated colour temperatures. The room decor was achromatic but natural colour, in the form of fruit and flowers, was introduced as another variable. In the second experiment, ten observers carried out colour discrimination tasks and made assessments of the lighting of the same room lit to 225 lx, but decorated with blue or pink walls and lit by lamps with good colour rendering properties but different correlated colour temperatures. Again, natural colour, in the form of fruit and flowers, was introduced as another variable. Analyses of the assessments of the lighting of the room showed that one major factor determining the impression given by the lighting was the illuminance. Increasing the illuminance made the lighting of the room appear more pleasant, more comfortable, clearer, more stimulating, brighter, more colourful, more natural, more friendly, more warm, more uniform, less hazy, less oppressive, less dim and less hostile. The correlated colour temperature of the lamps used had virtually no effect on the observer's impression of the lighting of the room. The other major factor influencing the impression of the lighting of the room was the presence of natural colour. Introducing natural colour, in the form of fruit and flowers, enhances the positive impressions created by the lighting, particularly at the higher illuminances. This enhancement occurs regardless of the correlated colour temperature of the lamps being used. It can be concluded that the advice limiting the use of high correlated colour temperature lamps in rooms lit to low illuminances is unnnecesarily restrictive. The results obtained suggest that provided the occupants are fully adapted to the lighting the correlated colour temperature of the lamp has little effect on people's impressions of the lighting of the room.

The paper reports two experiments concerned with the balance between illuminance and lamp colour properties for equal satisfaction with visual appearance. The first demonstrates the existence of this balance over a wide range of interior colourfulnesses. An explanation, based on the influence of lamp type and illuminance on the saturation of colours in an interior is proposed, which suggests that Colour Discrimination Index should be a better predictor of the magnitude of the balance than Colour Rendering Index. To test this suggestion the second experiment was designed, using both coloured and achromatic interiors. The results for the coloured interior support the earlier study and lead to the conclusion that Colour Discrimination Index is a better predictor. The results for the achromatic interior are of a different nature.

The effects of light on health can be divided into three sections. The first is that of light as radiation. Exposure to the ultraviolet, visible, and infrared radiation produced by light sources can damage both the eye and skin, through both thermal and photochemical mechanisms. Such damage is rare for indoor lighting installations designed for vision but can occur in some situations. The second is light operating through the visual system. Lighting enables us to see but lighting conditions that cause visual discomfort are likely to lead to eyestrain. Anyone who frequently experiences eyestrain is not enjoying the best of health. The lighting conditions that cause visual discomfort in buildings are well known and easily avoided. The third is light operating through the circadian system. This is known to influence sleep patterns and believed to be linked to the development of breast cancer among night shift workers. There is still much to learn about the impact of light on human health but what is known is enough to ensure that the topic requires the attention of all those concerned with the lighting of buildings.