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  1. Light
  2. Electric light glare control

Electric light glare control

Features>Light>55. Electric light glare control

55. Electric light glare control

Non-diffuse bright indoor lights create uneven levels of brightness in the visual field. The resulting glare can cause visual fatigue and discomfort.

This feature sets limits on glare based on measures of luminous intensity, or luminance per area of light source. This quantity, often given in cd/m² or foot-lamberts, can be measured directly or calculated from lighting specification sheets with sufficient detail. Light fixtures of greater luminous intensity require a greater shielding angle to reduce the likelihood of creating direct glare for occupants.

Part 1: Working and Learning Area Surface Reflectivity

The following Light Reflectance Values (LRV) are met:

a.80 Ceilings have an average LRV of 0.8 (80%) or more for at least 80% of surface area in regularly occupied spaces.
b.80 Walls have an average LRV of 0.7 (70%) or more for at least 50% of surface area directly visible from regularly occupied spaces.
c. Furniture systems have an LRV of 0.5 (50%) or more for 50% of visible surface area within regularly occupied spaces.
Part 2: Lamp Shielding in Sport Centers

The following requirements are met:

a. All lights in the field or arena are shielded such that the sources not in direct line of sight of spectators within 30 m [100 ft].
Skeletal
Muscular
Nervous

Applicability Matrix

Core & Shell Tenant Improvement New Construction
Part 1: Working and Learning Area Surface Reflectivity - O O
Part 2: Lamp Shielding in Sport Centers - - -
Commercial Kitchen Schools Multifamily Residential Restaurant Retail
Part 1: Working and Learning Area Surface Reflectivity O O - - -
Part 2: Lamp Shielding in Sport Centers - - - - -

Verification Methods Matrix

Letters of Assurance Annotated Documents On-Site Checks
PART 1 (Design)
Working and Learning Area Surface Reflectivity 		Architect

79

licht.de. licht.wissen 04: Office Lighting: Motivating and Efficient. Frankfurt; 2014: 35.
55.1.b

Office Lighting: Motivating and Efficient notes that to avoid glare caused by bright light sources, lamps should be shielded. The minimum shielding angle for lamp luminance of 20,000 - 50,000 cd/m² is 15°.
55.1.c

Office Lighting: Motivating and Efficient notes that to avoid glare caused by bright light sources, lamps should be shielded. The minimum shielding angle for lamp luminance of 50,000 - 500,000 cd/m² is 20°.
55.1.d

Office Lighting: Motivating and Efficient notes that to avoid glare caused by bright light sources, lamps should be shielded. The minimum shielding angle for lamp luminance of 500,000 cd/m² and above is 30°.
174

American National Standards Institute and Illuminating Engineering Society of North America. American National Standard Practice for Office Lighting. New York, NY: Illuminating Engineering Society of North America; 2012. RP-1-12.
55.2.a

ANSI/IES American National Standard Practice for Office Lighting (RP-1-12) notes that luminaires at angles higher than 53° above horizontal may cause discomfort, and that such luminaires should be less than 8,000 cd/m².
Features>Light>55. Electric light glare control