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  2. Circadian lighting design

Circadian lighting design

Features>Light>54. Circadian lighting design

54. Circadian lighting design

Exposure to light regulates the circadian rhythm, which determines sleep and wake cycles. To promote alertness and activity, the human circadian cycle is most sensitive to lights of high frequency and intensity. Conversely, lights of low frequency and intensity signal the circadian rhythm to decrease energy and prepare for rest.

This feature aims to provide lighting conditions that reinforce the natural patterns of the human circadian cycle. The Equivalent Melanopic Lux (EML) is a measurement of light's effects on the circadian cycle. EML can be used to determine how interior lighting conditions may be optimized to support the circadian function. See Appendices L1 and L2 for more information on how to calculate the EML of individual lamps and larger spaces.

Part 1: Melanopic Light Intensity in Work Areas

Light models (which may incorporate daylight) show that the following conditions are met for at least 4 hours per day for every day of the year:

a) At least 250 equivalent melanopic lux is present within at least 75% of workstations, on the vertical plane facing forward 1.2 m [4 ft] above finished floor (to simulate the view of the occupant).
Part 2: Melanopic Light Intensity in Living Environments

In all bedrooms, bathrooms, and rooms with windows, one or more fixtures provide the following:

a) 250 or more equivalent melanopic lux as measured facing the wall in the center of the room 1.2 m [4 ft] above the floor. The lights may be dimmed in the presence of daylight, but are able to independently achieve these levels.
b) Evening lights provide not more than 50 equivalent melanopic lux (to the extent allowable by code) as measured 0.76 m [30 inches] above finished floor.
Part 3: Melanopic Light Intensity in Breakrooms

Workplaces with where employees spend most of their time in spaces with light levels limited by work type (such as restaurant servers or hospital ward workers) have break rooms which meet the following requirement:

a) Lights provide a maintained average of at least 500 equivalent melanopic lux as measured on the vertical plane facing forward at desks 1.2 m [4 ft] above finished floor. The lights may be dimmed in the presence of daylight, but are able to independently achieve these levels.
Endocrine
Digestive
Lymphatic
Nervous
Muscular
Immune
Cardiovascular

Applicability Matrix

Core & Shell New Construction WELL Interiors
Part 1: Melanopic Light Intensity in Work Areas - P P
Part 2: Melanopic Light Intensity in Living Environments - - -
Part 3: Melanopic Light Intensity in Breakrooms - - -
Commercial Kitchen Education Multifamily Residential Retail
Part 1: Melanopic Light Intensity in Work Areas - P - -
Part 2: Melanopic Light Intensity in Living Environments - - O -
Part 3: Melanopic Light Intensity in Breakrooms O - - O

Verification Methods Matrix

Letters of Assurance Annotated Documents On-Site Checks
PART 1 (Design)
Melanopic Light Intensity in Work Areas 		Architect Spot Measurement
PART 2 (Performance)
Melanopic Light Intensity in Living Environments 		Performance Test
PART 3 (Performance)
Melanopic Light Intensity in Breakrooms 		Performance Test
Features>Light>54. Circadian lighting design