A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Circadian metric – Computation of circadian stimulus using illuminance, correlated colour temperature and colour rendering index
Abstract The circadian rhythm is influenced by light and other non-visual responses in humans. Recent researches have shown that the visual quantity illuminance is not appropriate for evaluating non-visual effects. Metrics such as the circadian stimulus have been developed to address this issue. One of the limitations with circadian metrics is that the determination requires a spectroradiometer instead of the standard illuminance meters. In this article, a simple circadian stimulus calculation model for white light sources is presented. The model is determined with the parameters illuminance, correlated colour temperature CCT and colour rendering index R a. The accuracy and reliability of the model is high and is based on 7641 spectra with 19 illuminance levels, which are generated using a heuristic optimisation procedure. In addition, the model has been internally validated with the method repeated-split-data and has an error deviation of 0.058 for CCT > 3710 K and 0.045 for CCT ≤ 3710 K at 99% confidence interval in the circadian stimulus CS range between 0.2 and 0.5. Since the quantities illuminance, correlated temperature and colour rendering index are common in practice, this model enables non-visual planning of illumination installations by lighting designers or lighting design tools. Furthermore, it allows retrospective analysis of past non-visual research results in scientific studies, where illuminance and correlated colour temperature were provided.
Highlights A simplified circadian stimulus (CS) calculation model for white light sources. Circadian lighting design with illuminance, colour temperature and colour rendering index. The model enables a reanalysis of past research works on non-visual light effects. The error deviation of the model is smaller than 0.058 (99% confidence interval).
Circadian metric – Computation of circadian stimulus using illuminance, correlated colour temperature and colour rendering index
Abstract The circadian rhythm is influenced by light and other non-visual responses in humans. Recent researches have shown that the visual quantity illuminance is not appropriate for evaluating non-visual effects. Metrics such as the circadian stimulus have been developed to address this issue. One of the limitations with circadian metrics is that the determination requires a spectroradiometer instead of the standard illuminance meters. In this article, a simple circadian stimulus calculation model for white light sources is presented. The model is determined with the parameters illuminance, correlated colour temperature CCT and colour rendering index R a. The accuracy and reliability of the model is high and is based on 7641 spectra with 19 illuminance levels, which are generated using a heuristic optimisation procedure. In addition, the model has been internally validated with the method repeated-split-data and has an error deviation of 0.058 for CCT > 3710 K and 0.045 for CCT ≤ 3710 K at 99% confidence interval in the circadian stimulus CS range between 0.2 and 0.5. Since the quantities illuminance, correlated temperature and colour rendering index are common in practice, this model enables non-visual planning of illumination installations by lighting designers or lighting design tools. Furthermore, it allows retrospective analysis of past non-visual research results in scientific studies, where illuminance and correlated colour temperature were provided.
Highlights A simplified circadian stimulus (CS) calculation model for white light sources. Circadian lighting design with illuminance, colour temperature and colour rendering index. The model enables a reanalysis of past research works on non-visual light effects. The error deviation of the model is smaller than 0.058 (99% confidence interval).
Circadian metric – Computation of circadian stimulus using illuminance, correlated colour temperature and colour rendering index
Truong, William (author) / Zandi, Babak (author) / Dr.-Ing. Trinh, Vinh Quang (author) / Dr.-Ing. habil. Khanh, Tran Quoc (author)
Building and Environment ; 184
2020-07-16
Article (Journal)
Electronic Resource
English
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