Defining the Zone of Biological Darkness: A Novel Area-Based Circadian Daylight Metric for Building Design and Evaluation

Transcription

1 Defining the Zone of Biological Darkness: A el Area-Based Circadian Daylight Metric for Building Design and Evaluation DIVA DAY 2016 Toronto Kyle Konis, Ph.D, AIA School of Architecture University of Southern California

2 The Nomadic Laboratory Lab Field Greater precision and control Less control, greater level of reality

3 O.M.G.

4 Optimizing the Daylight Ecosystem in Buildings: A workshop on Circadian Lighting, il 21-22, 2015 Mandate light levels for circadian stimulation (0.1CS minimum and 0.3 CS for morning daylight in selected areas) for all new projects and renovations Organizers Kevin Kampschroer, GSA Judith Heerwagen, GSA k Rea, LRC ~20 Invited Participants From Carnegie Mellon Rensselaer, LRC ZGF Architects SERA Architects Property MGMT firms Manufacturers Other government agencies

5 History of Lighting Research

6 Health Impacts Lack of sufficient exposure of the retina to bright light can disrupt the circadian system Disruption has been associated with a host of maladies including: sleep disorders, fatigue, performance problems, hormone and metabolic disorders

7 Emerging Opportunities

8

9 Daylighting Design Performance Criteria for Alzheimer Care Facilities Towards Evidence-based Practices for Improved Health

10 ?

11 History of Lighting Research

12 Well... Critique Well Building Standard Not strictly a daylighting metric No references/citations to underlying science (why?) Only requires 75% of occupied area to comply 4-hour/day metric discounts need to assess bright light stimulus for AM circadian resetting (6:00 10:00AM) Many latitudes / climates would never comply (if daylight) Problematic when view direction is flexible or unknown

13 Body Clock Must Be Synchronized With Environment Average period is ~24.2h Larks (23.6h) vs. Owls (25.0h) Entrainment to 24h period requires daily resetting Light is the most powerful time cue for resetting

14 Timing Adjusting the circadian pacemaker is like pushing a child on a swing the effect depends on the timing of the push Adapted from Rajaratnam & Arendt, 2001

15 Delay wakeup / sleep onset Timing Exposure at night Adapted from Rajaratnam & Arendt, 2001

16 Timing Advance wakeup (and sleep onset) Exposure in AM... Adapted from Rajaratnam & Arendt, 2001

17 NOTE: Circadian resetting period is critical That period is 6:00 to 10:00 AM Perhaps exclude the 6:00 7:00 AM hour depending on program.

18 NOTE: Cumulative occurrence masks spatial and temporal occurrence of BD zones

19 Intensity Table: Circadian stimulus effect from various common light sources (lux) Not all lux are created equal Circadian system takes longer to respond than visual system According to Rea et al. model. Lucas has another model Models are becoming more complex as knowledge grows

20 Field-based Measurement / Verification Procedures

21 Spectral power (W/m^2) Biological Darkness % stimulus 27 lux C (l) V (l) Measured SPD C (l) V (l) Wavelength (nm)

22 Spectral power (W/m^2) Daylight Example % stimulus 262 lux C (l) V (l) Measured SPD C (l) V (l) Wavelength (nm)

23 Evaluating Real Spaces

24 52% N 42% 67% 5 E 53% Note: real daylit spaces are almost always a combination of daylight and electrical lighting

25 15% 46% N 55% 15 E 29%

26

27 From Horiz. To Vertical Sensors

28

29 Test case, portable school classroom Located in SF climate We do regular old annual hourly CBDM, but Lux * EML.coef = EML Note that the simulations actually have 4 windows...

30 EML Coefficient Derived from Weighting of Direct and Diff. Sky Illuminance (EPW) (Better than nothing, but M. Inanici has a better method.) Lux * EML.coef = EML San Francisco EPW file

31 Explain what the daily Circadian Stimulus (CS) criteria is... If >= 250 EML = 1 else = 0 7:00 8:00 AM, ch 20, San Francisco

32 A grid point location can be scored based on all, or subset of vectors If >= 250 EML = 1 else = 0 8:00 9:00 AM, ch 20, San Francisco

33 Locations that exceed the EML threshold for all 3 hours are scored as Circadian Effective If >= 250 EML = 1 else = 0 9:00 10:00 AM, ch 20, San Francisco

34 PROBLEMS HERE!!! Daily CE Area Simple interpretation of daily spatial outcomes... What is this? 40% Annual Mean CE Area

35 There is a need to assess personalized exposure over time (How much time?)

36 This is for one grid point location, (using the all-vectors approach)... Daily Compliance Outcomes (gr id point 203) CS 0 Need an indicator for the frequency of CE 47.9% of Year (Stimulus[7 10AM] >= 250 EML) Stimulus is present for only 47% of year, but stimulus is available over ~9 months

37 Circadian Frequency CS of 7days 100% 6 of 7 85% 5 of 7 71% 4 of 7 57% 3 of 7 43% 2 of 7 29% 1 of 7 14% 0

38 Here is what happens if you require regular daily stimulus over the past 6 days to score the analysis day as [1] Daily Compliance Outcomes (gr id point 203) % of Trailing 7 Days When CE Criteria Was Met CE.freq (0 100%) 6-day trailing mean 100% 47.9% of Year (Stimulus[7 10AM] >= 250 EML) 7.7% of Year (CE.freq. >= 100%) Stimulus is present for 47% of year, but stimulus is daily for only 7.7% of year

39 Now relax the CE.freq requirement to CE achieved for at least 6 of past 7 days Daily Compliance Outcomes (gr id point 203) % of Trailing 7 Days When CE Criteria Was Met 85% 47.9% of Year (Stimulus[7 10AM] >= 250 EML) 24.7% of Year (CE.freq. >= 85%) Annual performance outcome for point 203

40 Now relax CE.freq to 5 of past 7 days (i.e. >70%) Daily Compliance Outcomes (gr id point 203) % of Trailing 7 Days When CE Criteria Was Met This red circle is the CE.freq acceptability threshold Good 70% 47.9% of Year (Stimulus[7 10AM] >= 250 EML) 40.5% of Year (CE.freq. >= 70%)

41 . And on and on (e.g. 4 of 7) Daily Compliance Outcomes (gr id point 203) % of Trailing 7 Days When CE Criteria Was Met 57% 47.9% of Year (Stimulus[7 10AM] >= 250 EML) 55.1% of Year (CE.freq. >= 57%)

42 ?

43 7 Days per week 6 Days per week 5 Days per week 4 Days per week 3 Days per week 2 Days per week 1 Day per week 0

44 Good Enough? 7 Days per week 6 Days per week 5 Days per week 4 Days per week 3 Days per week 2 Days per week 1 Day per week 0 (Remember this is assessed per grid point location)

45 So how do we annualize it? Building Geometry + Climate 280 Grid points, 365 days per year

46 7 CE Area (CE.freq >= 7d/wk) Daily Variation in CE Area for San Francisco Climate (7:00 10:00 AM period) CE Area (CE.freq >= 6d/wk) 6/7 5/7 4/7 CE Area (CE.freq >= 5d/wk) CE Area (CE.freq >= 4d/wk) We can report mean annual CE area 20.5% 29.9% 38.1% 3/7 2/7 1/7 CE Area (CE.freq >= 3d/wk) CE Area (CE.freq >= 2d/wk) CE Area (CE.freq >= 1d/wk) 45.5% 50.4% 53.7% 56.2%

47 Daily Variation in CE Area for Helsinki Climate (7:00 10:00 AM period) CE Area (CE.freq >= 7d/wk) CE Area (CE.freq >= 6d/wk) CE Area (CE.freq >= 5d/wk) CE Area (CE.freq >= 4d/wk) 18.9% 23.3% 26.6% 29% CE Area (CE.freq >= 3d/wk) CE Area (CE.freq >= 2d/wk) CE Area (CE.freq >= 1d/wk) 31.2% 33.4% 35.7%

48 So how do we spatialize it? 280 Grid points, 365 days per year

49 SF Climate

50 Flattened (Stacked) Outcomes % 100% 80% 80% 60% 60% 40% 40% 20% 20% San Francisco Helsinki

51 So how do we spatialize AND annualize it?

52 We have to specific a minimum acceptable CE.freq... CS achieved Good Enough? 7 Days per week 6 Days per week 5 Days per week 4 Days per week 3 Days per week 2 Days per week 1 Day per week 0 (Remember this is assessed per grid point location)

53 Daily Variation in CE Area for San Francisco Climate (7:00 10:00 AM period) CE Area (CE.freq >= 7d/wk) CE Area (CE.freq >= 6d/wk) CE Area (CE.freq >= 5d/wk) CE Area (CE.freq >= 4d/wk) 20.5% 29.9% 38.1% 45.5% CE Area (CE.freq >= 3d/wk) CE Area (CE.freq >= 2d/wk) CE Area (CE.freq >= 1d/wk) 50.4% 53.7% 56.2% For each grid point location, quantify the percentage of the year where the CE.freq is >= 5 d/wk

54 SF Climate Circadian Resetting Period (7:00 10:00AM) (Best vector approach) Annual mean CE area is 38%

55 SF Climate Circadian Resetting Period (7:00 10:00AM) (Fixed vector approach)

56 Conclusions There are no static zones Dynamic nature of zones can be identified and seasonal patterns can be assessed While the CE zone can be mapped, the boundaries are probably only applicable over short intervals (e.g. month) Annual scores can be used to make relative comparisons between designs for the same site / climate Parameters such as daily CE criteria (EML thresh. and N exposure hours) can be easily adjusted Even with limited scientific information, we can make a judgment that locations with greater CE.freq will be more beneficial for human circadian entrainment See paper in peer-review (Building and Environment) Konis, K. Defining the Zone of Biological Darkness: A el Area-Based Circadian Daylight Metric for Building Design and Evaluation

57 THANK YOU Kyle Konis, USC