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
dim lighting
green-blue
Cones facilitate what type of vision?
daytime
color
green-yellow
What are ipRGCs and what type of vision?
Intrinsically Photosensitive Retinal Ganglion Cells
see light over long-term
used in circadian system
teal blue
What are external cues called, including light, that align physiology to solar day?
Zeitgebers
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
53 - Visual Lighting Design Ambient light levels of ____ lux is sufficient, as measured at __ inches above the floor.
215 lux
30 inches
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 2 of 4 of the following will be considered:
brightness contrasts adjacent and non-adjacent spaces
brightness contrasts main rooms and ancillary spaces
brightness contrasts in the same room such as desk surface and computer screen
how brightness is distributed on the 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: (4 levesl)
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 - 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 - Color Quality (all electric light bulbs) To accurately oirtrat colors, all electric lights should meet the following (2):
R1-R8 is 80 Ra or higher
Color Rendering Index R9 of 50 or higher
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 - 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 (2 standards)
75% workstations within 25’ of window
95% within 41’
