Functional light and what about health? Norms and measurements

Healthy light DIN SPEC 67600: Biologically effective illumination, design guidelines DIN SPEC : Measurement using the eye, of the melanopic effect of light on humans: variables, formula symbols and actionspectrum

Biologically effective light can be healthy The following positive effects Stabilization of human circadian system Synchr. sleep-wake with 24 hour day-night Re-inforcement of amplitude of biol. clock Activation and improvement of concentration Facilitation and fostering of regeneration Improvement moods Strengthening immune system Note: to be applied to right time of the day!

Human circadian system Biological rhythm of about 1 day length, variations in body temperature hormone descretion rhythm of heart activity and rest Light can affect it and reset the timing of it

DIN SPEC 67600: Observations but not further considered here Light enters human not only via eyes (skin, hair roots) Production of Vit-D done by UV-B Focus in norm on Non-visual effects of light transmitted through the eyes Design guidelines for living spaces (extended stay) Statement: bio. effective light is not related to energy efficiency of visual light  keep separate Statement: better to use melanopic effects since normal vision is not considered (in biologic effects normal vision is included).

Melanopic effectiveness Minimum 250 lux as vertical illuminance on the eye At Tc = 8000 K (at eye) of a fluorescent TL Beware of reflections and filtering! Several hours of exposure a day Preferably in the morning Solid angle of light source is important < 0.1 sr no effect (20 deg view angle) > 0.1 sr and 0.1 sr and < 0.5 sr effect increases > 0.5 sr good effect (46 deg view angle) Coming from above or upper part of visual field

Office space 2.Dependent on visual task (EN ) (also lx_horiz)

Classroom i 2.Dependent on visual task (EN ). See example for school day.

Class- room ii (synchr biol. clock) (normal lesson) (test/concentration work) (calming after test) (activate after lunch)

DIN SPEC : a_mel_v = melanopic factor for visual radiation A: Determine melanopic effect of light with spectrum X_ λ B: Determine visual effect of light with spectrum X_ λ Divide A/B to get a_mel_v s_mel( λ )

Example a_mel_v

a_mel_v in practice Reference values: From 67600: 250 lux_vert for 8000K fluorescent TL a_mel_v = From 67600: 200 lux_vert for 3000K light a_mel_v = Given any lamp, once spectrum is determined we calculate the a_mel_v Compare to a_mel_v of 8000K Tl for which a recommendation exists, determine relation Then change 250lx_vert into lux for any lamp using relation

a_mel_v in practice ii a_mel_v_NOTEii/a_mel_v_8000KTL= 1.015/0.867=1.17 So needed 250/1.17= 214 lux_vert  simulate Dialux!

Pupil and transmission effects Correction factor based on Age: k_mel(A) k_mel(A)=k_mel,trans(A)*k_mel,pupil(A) Trans = transmission through eye medium Pupil = pupil size a_mel_v(A)=a_mel_v(32)*k_mel(A) k_trans values for 8000K TL: (25yr), (32yr), (50yr), (75yr), (90yr)

Spectral transmission effect

Pupil effect

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