GSSG - Light

Question 1

Light enters the eye and hits ___ on the retina: ___, ___ and ___.

Answer 1

-photoreceptors
-rods, cones and intrinsically photosensitive retinal
ganglion cells (ipRGCs)

Question 2

___ facilitate peripheral vision and vision in dim lighting conditions, with peak sensitivity to ____.

Answer 2

Rods

green-blue light (498 nm).

Question 3

___ facilitate daytime vision and color perception, and the peak sensitivity for the sensation of brightness with this system occurs at___.

Answer 3

Cones

green-yellow light (555 nm)

Question 4

The ___ are critical to the circadian system, sending information to various parts of the brain to trigger
reactions downstream in the body. These cells demonstrate peak sensitivity to ___.

Answer 4

ipRGCs

teal-blue light (≈480 nm).

Question 5

The ___ the main mammalian 24-hour circadian clock then acts as an oscillator to clocks in peripheral tissues and organs.

Answer 5

Suprachiasmatic nucleuis

Question 6

___ are the external cues that align physiological functions to the solar cycle. Light is the most important of these cues, keeping the body’s internal clocks synchronized in a process known as ___

Answer 6

Zeitgebers

Circadian photoentrainment

Question 7

___ radiation at smaller wavelengths and___ at larger wavelengths

Answer 7

ultraviolet radiation

infrared

Question 8

Light exposure in the late night/early morning will shift our rhythms ____ ___, whereas exposure in the late afternoon/early night will shift our rhythms___.

Answer 8

Forward (phase advance)

Back (phase delay)

Question 9

Chronic sleep deprivation are associated with increased risk of certain morbidities, including ___, ___,
___, ___, ___ and ___.

Answer 9

• Diabetes, obesity,

- Depression, heart attack, hypertension and stroke.

Question 10

In general, WELL advocates for lighting that are closer to the daylight light temperature color spectrum ___-____during daytime hours.

Answer 10

5000K-6500K

Question 11

Light intensity for visual acuity is measured in___, which is a measure of the way the eye responds to light weighted to the response of the ___—the main photoreceptors for daytime vision, located on the retina of the human eye.

Answer 11

• Lux (or foot candles)

- Cone cells

Question 12

VISUAL ACUITY FOR FOCUS

The following requirements are met at workstations or desks:

Answer 12

• The ambient lighting system is able to maintain an average light intensity of 215 lux or more, measured on the horizontal work plane measured at 30” A.F.F. The lights may be dimmed in the presence of daylight, but they are able to independently achieve these levels.
• The ambient lighting system is zoned in independently controlled banks no larger than 500 ft² or 20% of open floor area of the room (whichever is larger).
• If average ambient light is below 300 lux, task lights providing 300 to 500 lux at the work surface are available upon request.

Question 13

BRIGHTNESS MANAGEMENT STRATEGIES
Provide a narrative that describes strategies for maintaining luminance balance in spaces, which takes into consideration at least two of the following:

Answer 13

• Maximum brightness contrasts between main rooms and ancillary spaces, such as corridors and stairwells, if present.
• Maximum brightness contrasts between task surfaces and immediately adjacent surfaces, including adjacent visual display terminal screens.
• Brightness contrasts between task surfaces and remote, non-adjacent surfaces in the same room.
• The way brightness is distributed across ceilings in a given room

Question 14

Ambient light levels of ___ are sufficient for most tasks.

Answer 14

300 lux

Question 15

Feature 54: Circadian Lighting Design promotes lighting environments for ___. The biological effects of light on humans can be measured in ___, a proposed alternate metric that is weighted to the___ instead of to the cones, which is the case with traditional lux.

Answer 15

• Circadian health
• Equivalent Melanopic Lux (EML)
• ipRGCs

Question 16

MELANOPIC LIGHT INTENSITY FOR WORK AREAS

Light models or light calculations demonstrate that at least one of the following requirements is met:

Answer 16

• At 75% or more of workstations, at least 200 equivalent melanopic lux is present. This light level may incorporate daylight, and is present for at least the hours between 9:00 AM and 1:00 PM for every day of the year
• For all workstations, electric lights provide maintained illuminance on the vertical plane facing forward (to simulate the view of the occupant) of 150 equivalent melanopic lux or greater.

Question 17

Through___, lights of high frequency and intensity promote ___, while the lack of this stimulus signals the body to reduce energy expenditure and prepare for ___.

Answer 17

ipRGCs
alertness
rest

Question 18

EML=____ x____

Answer 18

visual lux

melanopic rate

Question 19

LUMINAIRE (LAMP) SHIELDING
The following shielding angles (⍺ = 90 - cutoff angle) must be observed for lamps in regularly occupied spaces with luminance values in the ranges specified:

Answer 19

• Less than 20,000 cd/m² (including reflected sources) no shielding required
  b. 20,000 to 50,000 cd/m². ⍺15°
  c. 50,000 to 500,000 cd/m². ⍺20°
  d. 500,000 cd/m² and above. ⍺30°

Question 20

GLARE MINIMIZATION

At workstations, desks and other seating areas, one of the following requirements is met:

Answer 20

• Luminaires more than 53° above the center of view (degrees above horizontal) have luminances less than 8,000 cd/m²
• Workstations achieve a UGR of 19 (or less) (19=moderate glare control)

Question 21

VIEW WINDOW SHADING
At least ONE of the following is present for all glazing less than 7 ft above the floor in regularly occupied
spaces (excluding lobbies):

Answer 21

• Interior window shading or blinds that are controllable by the occupants or set to automatically prevent glare.
• External shading systems that are set to prevent glare.
• Variable opacity glazing, such as electrochromic glass, which can reduce transmissivity by 90% or more.

Question 22

DAYLIGHT MANAGEMENT
At least ONE of the following is required for all glazing greater than 7 ft above the floor in regularly occupied spaces (excluding lobbies)

Answer 22

• Interior window shading or blinds that are controllable by the occupants or set to automatically prevent glare.
• External shading systems that are set to prevent glare.
• Interior light shelves to reflect sunlight toward the ceiling.
• A film of micro-mirrors on the window that reflects sunlight toward the ceiling.
• Variable opacity glazing, such as electrochromic glass, which can reduce transmissivity by 90% or more.

Question 23

GLARE AVOIDANCE

The following requirements are met:

Answer 23

• To minimize glare caused by incoming sunlight, all computer screens at desks located within 15 ft of view windows can be oriented within a 20° angle perpendicular to the plane of the nearest window.
• Overhead luminaires are not aimed directly at computer screens.

Question 24

COLOR RENDERING INDEX
To accurately portray colors in the space and enhance occupant comfort, all electric lights (except decorative
fixtures, emergency lights and other special-purpose lighting) meet the following conditions:

Answer 24

• Color Rendering Index Ra (CRI, average of R1 through R8) of 80 or higher.
• Color Rendering Index R9 of 50 or higher.

Question 25

WORKING AND LEARNING AREA SURFACE REFLECTIVITY | The following Light Reflectance Values (LRV) are met:

Answer 25

- Ceilings have an average LRV of 0.8 (80%) or more for at least 80% of surface area in regularly occupied spaces. - Vertical surfaces have an average LRV of 0.7 (70%) or more for at least 50% of surface area directly visible from regularly occupied spaces. - Furniture systems have an average LRV of 0.5 (50%) or more for 50% of surface area directly visible from regularly occupied spaces.

Question 26

AUTOMATED SUNLIGHT CONTROL | All windows larger than 6 ft² have the following:

Answer 26

Shading devices that automatically engage when light sensors indicate that sunlight could contribute to glare at workstations and other seating areas.

Question 27

RESPONSIVE LIGHT CONTROL | The following requirements are met in all major workspace areas:

Answer 27

- All lighting except decorative fixtures is programmed using occupancy sensors to automatically dim to 20% or less (or switch off) when the zone is unoccupied. - All lighting except decorative fixtures has the capacity and is programmed to dim continuously in response to daylight.

Question 28

LEASE DEPTH | The following requirement is met:

Answer 28

-75% of the area of all regularly occupied spaces is within 25 ft of view windows.

Question 29

WINDOW ACCESS | The following conditions are met:

Answer 29

- 75% of all workstations are within 25 ft of an atrium or a window with views to the exterior. - 95% of all workstations are within 41 ft of an atrium or a window with views to the exterior

Question 30

HEALTHY SUNLIGHT EXPOSURE | Lighting simulations demonstrate that the following conditions are expected:

Answer 30

- Spatial daylight autonomy (sDA300,50%) is achieved for at least 55% of regularly occupied space. In other words, at least 55% of the space receives at least 300 lux of sunlight for at least 50% of operating hours each year. - Annual sunlight exposure (ASE1000,250) is achieved for no more than 10% of regularly occupied space. In other words, no more than 10% of the area can receive more than 1,000 lux for 250 hours each year.

Question 31

WINDOW SIZES FOR WORKING AND LEARNING SPACES | The following conditions are met on façades along regularly occupied spaces:

Answer 31

- Window-wall ratio as measured on external elevations is between 20% and 60%. Percentages greater than 40% require external shading or adjustable opacity glazing to control unwanted heat gain and glare. - Between 40% and 60% of window area is at least 7 ft above the floor.

Question 32

WINDOW TRANSMITTANCE IN WORKING AND LEARNING AREAS The following visible transmittance (VT) conditions are met for all non-decorative glazing:

Answer 32

- All glazing (excluding skylights) located higher than 7 ft from the floor has VT of 60% or more. - All glazing located 7 ft or lower from the floor has VT of 50% or more.

Question 33

UNIFORM COLOR TRANSMITTANCE | All windows used for daylighting meet the following requirement:

Answer 33

-The visible light transmittance of wavelengths between 400 and 650 nm does not vary by more than a factor of 2.