Light Concept Flashcards
How many adults have chronic sleep disorders?
50-70 million
what 6 health risks are sleep deprivation linked to?
diabetes obesity depression heart attack hypertension stroke
Rods facilitate what type of vision?
peripheral and dim lighting
Cones facilitate what type of vision?
daytime and color
What are ipRGCs and what type of vision?
Intrinsically Photosensitive Retinal Ganglion Cells
sluggish, non-image forming, see light over long-term, used in circadian system
What is our internal clock called that synchronizes physiology over 24-hr cycle?
circadian rhythm
What are external cues called, including light, that align physiology to solar day?
Zeitgebers - keeps body clock synchronized - circadian photo entrainment
Light exposure in the late night/early morning (4-6am) leads to ____.
phase advance - shifting our rhythms forward
Light exposure in the late afternoon/early night (4-6pm) shifts our rhythms ____.
backward - phase delay
How many features in Light, and what’s the last precondition?
11 features in Light, 53-63
4 preconditions 53-56
What are the last precondition feature #s for the first 4 concepts?
12 for air, 34 for water, 45 for nutrion, 56 for light
53 - Visual Lighting Design
Ambient light levels of ____ lux is sufficient - but the requirement is at least ___ lux measured ___ above floor.
300 lux
215 lux 30” above floor
If light is below 300 lux, then task lights providing ___ to ___ lux need to be provided at work stations
300-500 lux
Ambient light system needs to be zoned in independently controlled banks no larger than ____ Sf or ___% of open floor area
500 SF or 20% of floor area
53 - Visual Lighting part 2, Brightness
A narrative is provided that describes how light will be balanced between ___ and ___.
adjacent and non-adjacent spaces in the same room such as
main rooms and ancillary spaces
desk surface and computer screen
across a ceiling
54 - Circadian Lighting Design
What is EML and what is the desired level?
___ EML at ___% of workstations measured ___ft above floor for ___hrs/day all year
Equivalent Mealnopic Lux - a measurement of biological effect of light on humans
250 EML at 75% stations, 4’ above floor, 4 hrs/day
- Electric Light Glare - lamp shielding reqs:
a) less than 20,000 cd/m2 = ____
b) 20k =
c) 50k =
d) 500k =
a) under 20k = no shielding
b) 20k = 15 degrees
c) 50k = 20 degrees
d) 500k + = 30 degrees
What is the luminance limit for bare bulbs?
less than 8,000 cd/m2
56 - Solar Glare Control (windows)
what are the two unique glazing options for windows higher than 7ft above floor?
- interior light shelves
- film of micro-mirrors
both reflect light toward the ceiling
57 - optional - Low-glare workstation design (screen angle)
computer screens at desks located within ___ft of windows should be oriented ____ degrees perpendicular to winow plane
15 ft
20 degrees
58 - optional - Color Quality (all electric light bulbs)
meet a Color Render Index (CRI) Ra (R1-R8) of ____ or higher.
80 Ra
What is Color Rendering Index R9 and what’s the requirement?
warmer hues - R9 of 50+
59 - Surface Design (reflective quality)
what are the Light Relfectance Value (LRV) limits for:
Ceilings, wall, furniture?
Ceilings - LRV 0.8 for 80% of surface
Walls - LRV 0.7 for 50%
Furniture - LRV 0.5 for 50%
If you want to promote alertness and activity in a workspace, should you pick a surface with a high or low LRV?
Higher LRVs mean they reflect more light
60 - optional - Auto shading and dimming
All windows larger than ___ have light sensor triggered shades
6 ft2
60 - shading/dimming part 2
fixtures are auto dimmed to ___% or less when the zone is unoccupied, and will ____in response to daylight
20%
dim continuously
61 - right to light (window/sunlight)
___% of ALL regularly occupied area is within ___ft of windows
75%, 25’
61 - right to light, part 2, workstations
____% of workstations are within ____ft of an atrium/window
75% workstations within 25’ of window
9% within 41’
62 - Daylight Modeling (correct exposure to sunlight)
what describes the minimum levels?
Minimum - Spacial Daylight Autonomy - (sDA300, 50%)
meaning 55% of space receives 300 lux 50% of operating hours annualy
62 - Daylight Modeling (correct exposure to sunlight)
and what describes the maximum levels?
Maximum - Annual Sunlight Exposure - (ASE1000,250)
meaning 10% of space receives 1000 lux for 250 hours annualy
63 - Daylight Fenestration - window sizes, glass opacity
part 1 - proper window- wall ratio
20-60% (greater than 40% glass requires external shading)
How much of window area should be at least 7’ from floor (daylight glass)?
40-60%
All glazing located above 7’ should have a visible transmittance (VT) of ____% or more
60%
All glazing located below 7’ should have a visible transmittance (VT) of ____% or more
50%
63, part 3 - uniform color - colored glass window transmittance used for daylighting should not vary more than a factor of ___.
2
