Review of spectral lighting simulation tools for non-image- forming effects of light

Light via our eyes influences visual performance, visual comfort and visual experience, but also affects several health related, non-image-forming (NIF) responses. New metrics have been developed to quantify the NIF effects of light. In order to incorporate these in lighting design practice, simulation tools are required that are able to process information about the spectral distribution of light sources and materials. However, most of the tools currently used for daylight and electric light simulations simplify the spectrum into RGB (Red, Green, Blue) colour values. This paper presents an overview of the currently used programs for simulating the NIF effects of light in building design and discusses the possibility of using existing spectral rendering software as an alternative. A review of literature shows that mostly Radiance or Radiance-based programs have been used so far, but new user-friendly tools could employ existing spectral rendering tools. As the NIF effects of light gain greater importance in lighting design, new simulation workflows are needed. This paper aims to support the development of future workflows by presenting the current state-of-the-art

The development of a method to measure circadian light on the eyes of elderly people with intellectual disability or dementia The development of a method to measure circadian light on the eyes of elderly people with intellectual disability or dementia

Disclaimer This document contains a student thesis (bachelor's or master's), as authored by a student at Eindhoven University of Technology. Student theses are made available in the TU/e repository upon obtaining the required degree. The grade received is not published on the document as presented in the repository. The required complexity or quality of research of student theses may vary by program, and the required minimum study period may vary in duration. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain Dit onderzoek toont grote afwijkingen bij een variërende hoek van inval (f 2 ) voor de pols gedragen instrumenten, veel verschillen in lineariteitsindex (f 3 ) tussen de zes instrumenten en vrij lage verschillen in temperatuurindices (f 6,T ). De plaats op het lichaam waar de lichtsensor geplaatst wordt is erg belangrijk. De grootste afwijking is gemeten bij de pols en beslaat 64% (de mediaan van alle afwijkingen gedurende de meetperiode) ten opzichte van de referentie locatie tussen de ogen in. Ieder instrument leverde praktische problemen en ieder instrument gaf ook tenminste één irritatie tijdens de vrije veldmetingen. Het overzicht dat in deze studie gemaakt is geeft de verschillen weer tussen alle geteste draagbare meetapparaten. Het is belangrijk om deze verschillen te zien, te weten en er ook de gevolgen van in te zien, zodat resultaten van de verschillende instrumenten niet zomaar vergeleken worden. De laatste jaren zijn er heel veel onderzoeken verricht waarbij verschillende meetinstrumenten zijn gebruikt. Conclusies uit deze studies worden nu als waar aangenomen, echter toont dit onderzoek aan dat er veel en uiteenlopende verschillen zijn tussen deze methodes en is het de vraag of alle voorafgaande conclusies wel als correct aangenomen mogen worden. De belangrijkste aanbeveling voor vervolgonderzoek is het meten van de f 1 ' index voor de instrumenten. Deze index is niet gemeten in dit onderzoek, maar zoals blijkt uit de voorafgaande literatuurstudie reageert de menselijke biologische klok op de aanwezigheid van circadiaan licht. Om ook daadwerkelijk iets te kunnen zeggen over het circadiane tijdsysteem van de mens is het belangrijk om circadiane straling te meten in plaats van visuele verlichtingssterkte. Daarom is het relevant om te weten welk meetinstrument in staat is om meerdere golflengtes te meten en om deze verschillende stralingen weer te geven in de data. J. van Duijnhoven iii III Summary This project is initiated prior to a new effect study which will be performed in Rotterdam at the Erasmus Medical Centre to investigate the possible effects of luminous radiation on different sleepwake rhythm disorders at elderly people suffering from intellectual disability (ID)

Personal lighting conditions of office workers: An exploratory field study

Light enables us to see and perceive our environment but it also initiates effects beyond vision, such as alertness. Literature describes that at least six factors are relevant for initiating effects beyond vision. The exact relationship between these factors and alertness is not yet fully understood. In the current field study, personal lighting conditions of 62 Dutch office workers (aged 49.7 ± 11.4 years) were continuously measured and simultaneously self-reported activities and locations during the day were gathered via diaries. Each office worker participated 10 working days in spring 2017. Personal lighting conditions were interpreted based on four of the six factors (light quantity, spectrum, timing, and duration of light exposure). Large individual differences were found for the daily luminous exposures, illuminances, correlated colour temperatures, and irradiances measured with the blue sensor area of the dosimeter. The average illuminance (over all participants and all days) over the course of the day peaked three times. The analysis of the duration of light exposure demonstrated that the participants were on average only exposed to an illuminance above 1000 lx for 72 minutes per day. The interpretation of personal lighting conditions based on the four factors provides essential information since all of these factors may be relevant for initiating effects beyond vision. The findings in the current paper give first in-depth insight in the possibilities to interpret personal lighting conditions of office workers

The importance of including position and viewing direction when measuring and assessing the lighting conditions of office workers

BACKGROUND: Light and alertness studies have applied different measurement methodologies to determine lighting conditions. However, it has been demonstrated that researchers rarely measure or describe the lighting conditions of their studies in sufficient detail to generalize conclusions or derive universal guidelines. OBJECTIVE: Part I of this paper summarizes the current measurement methodologies used in light and alertness studies to potentially identify methodological issues. Part II determines the differences in lighting conditions for different viewing directions within an office environment. METHODS: A literature review (part I) and both experimental studies and an observational study (part II) were undertaken in this study. RESULTS: Part I demonstrates that most light and alertness studies include photometric quantities; however, it is recommended that one should measure radiometric quantities as well. Further, the light measurements should be performed at the individual level. Part II demonstrates large differences in lighting conditions between viewing directions. For example, when looking toward the window, vertical illuminances were at least 12 times higher when compared to looking in the opposite direction. CONCLUSIONS: Our findings suggest that when analysing or designing an office environment, office workers’ positions and viewing direction should be included in the determination of personal lighting conditions

Simulations of non-image-forming effects of light in building design:A literature review

Light affects many aspects of human physiology, through the non-image-forming (NIF) pathway. To account for this pathway, lighting design simulation tools need to combine several luminous and temporal factors to predict how architectural and lighting design decisions affect eye-level light exposure. Based on a systematic literature review, containing 55 journal and conference papers, the state-of-the-art towards implementing lighting beyond vision in computer simulation workflows for building design is presented. The review shows that, while interest in simulating the NIF effects of light on people is increasing, there is not a common method to perform these simulations. Gaps were identified in the currently available simulation workflows in relation to metrics, software and approaches for predicting NIF effects of light in the context of the building design