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ESTABLISH DESIGN CRITERIA

ILLUMINANCE GUIDELINES

The illuminances for different tasks are shown in the table below [1, 2]:

Tasks	Discussion	Typical Application Examples	Horizontal Illuminance for Typical Task	Horizontal Illuminance for Casual or Transient Tasks or Users Under 40	Horizontal Illuminance for Critical Task or Users At or Over 55	Vertical Illuminance
Exterior/ Low Activity	Casual passage, low-activity pedestrian zones, low activity parking	Ceremonial publicways, park walkways, typical sidewalks, small commerical parking zones, local roadways, small-town college campus	0.4 fc (4 lx) on grade	0.3 fc (3 lx) on grade	0.6 fc (6 lx) on grade	1/2 of horizontal illuminance at face height for normal situations or full-level at face height in critical situations
Exterior/ High Activity	Pedestrian zones, parking	Community plazas, town squares/ city centers, busy sidewalks, large commerical parking zones, major roadways, large of city university campus	0.8 fc (8 lx) on grade	0.6 fc (6 lx) on grade	1.2 fc (12 lx) on grade	1/2 of horizontal illuminance at face height for normal situations or full-level at face height in critical situations
Exterior/ Interior	Destination/ arrival zones where vehicles and pedestrians interact; Interior areas of casual passgae	Dropoffs (small-town commuter stations, apartments), building entries, car lots, service stations, clubs, historic and/ or elegant interiors' circulation	1.6 fc (16 lx) on grade or floor	1.2 fc (12 lx) on grade or floor	2.4 fc (24 lx) on grade or floor	exterior: 1/4th of horizontal illuminance at face height for normal situations or 1/2 of horizontal illuminance at face height in critical situations interior: 1/2 of horizontal illuminance at face height for social situations and less for computer-intensive tasks
Exterior/ Interior	Key destination/ arrival zones with much vehicular and pedestrian traffic interface; interior areas of passgae, leisure, respite and/ or where tasks are internally lighted	Porte cocheres (hotels, malls), Dropoffs (metro commuter stations, malls) and building entries, atria, ceremonial public spaces, lobbies, vestibules, concourses, interior passages (stairs/ ramps/ horizontal circulation), historic and/ or elegant interiors, restaurants and bars, rotundas, computer-intensive spaces (CAD, call centers, drug design)	3.2 fc (32 lx) on task surfaces	2.4 fc (24 lx) on task surfaces	5.0 fc (50 lx) on task surfaces	full-level vertical illuminance at face height for grooming, 1/4th of horizontal illuminance at face height for social situations
Interior	Areas of deliberate and necessary passage and/ or of conversatinal activity and/ or of limited casual reading	Atria, dining rooms, elevators, lobbies, vestibules, restrooms, concourses, interior passages (vertical/ horizontal circulation), rotundas	7.5 fc (75 lx) on task surfaces	5.0 fc (50 lx) on task surfaces	10 fc (100 lx) on task surfaces	full-level vertical illuminance at face height for grooming, 1/4th of horizontal illuminance at face height for social situations
Working spaces where simple visual tasks are performed	Areas of casual and/ or recreational reading or where periodic paper task performance is required and/ or extensive screen use occurs	Restrooms, residential master bathrooms, copyrooms, casual reading, religious naves, dining rooms/ multipurpose meeting rooms, library stacks (K-12 youth, vertical at 30" AFF), lounges, reception areas, waiting areas, fitness centers, ceremonial offices, computer-intensive offices	15 fc (150 lx) on task surfaces	10 fc (100 lx) on task surfaces	20 fc (200 lx) on task surfaces	full-level vertical illuminance at face height for grooming, 1/2 of horizontal illuminance at 30" AFF for library stacks, 1/4th of horizontal illuminance at face height for social situations and less for computer-intensive tasks
Performance of visual tasks of high contrast or large size	Areas of prolonged discourse and/ or where visual work is typically easy to read, or where hard-to-read paperwork is intermittent	Committee rooms, hearing rooms, intermittent reading, conference rooms, meeting rooms, classrooms, videoconferencing, hair-styling studios (on faces), library stacks, offices — computer/ paper tasks mixed	30 fc (300 lx) on task surfaces	20 fc (200 lx) on task surfaces	100 fc (1000 lx) on task surfaces	1/ 2 to full-level vertical illuminance at face height for teleconferencing (camera dependent) , full-level vertical illuminance at face height for hair styling, 1/2 of horizontal illuminance at 30" AFF for library stacks
Performance of visual tasks of medium contrast or small size	Areas of prolonged assessment of consistently difficult to read documents or detailed 3-dimensional tasks	Accounting ledgers (hardcopy), bank tellers' stations, commercial research laboratories, hair-styling studios (on tops of heads), blueprints or hardcopy drawings, intermediate and high school science labs, detailed/ laborious/ critical visual tasks	75 fc (750 lx) on task surfaces	50 fc (500 lx) on task surfaces	100 fc (1000 lx) on task surfaces

Note:
a. Targets are intended to apply to the plane of interest on which the task is located.
b. For dark pavement or dark surfaces and/ or where users' ages are 40 to 55 years, consider increasing base illuminance targets by 50%.
c. Calculations within 10% of target values are considered acceptable. Field results within 20% of acceptable values are considered acceptable.

References

1. Gary Steffy, Architectural Lighting Design, 3rd ed. (New York: John Wiley & Sons, Inc., 2008), 146-147.
2. Mark S. Rea, ed., The IESNA Lighting Handbook: Reference and Application, Ninth Edition. (New York: Illuminating Engineering Society of North America, 2000), 10-13.