1. Programming Inventorying Existing Spaces Establishing Design Goals

2. Measurement of light Candela (cd)(metric unit) Candlepower (Non-metric unit) The fundamental photometric quantity of luminous intensity The light output of an ordinary candle The luminous intensity, in a given direction (A solid angle), of a source that emits monochromatic radiation of frequency 540 x 10 12 Hz and that has a radiant intensity in that direction of 1/683 W/steridian Radiant Flux Radiant Power The transfer of Radiant Energy per unit of time Units of measurement (Rae, 2000)

3. Measurement of light Steradian - The solid angle For a sphere having a radius of one unit, a one-square-unit area on the sphere ’ s surface represents a solid angle of one steradian Luminous flux The radiant flux falling on a unit area of the sphere ’ s surface (steradian) from a source at the center of one candela Units of measurement (Rae, 2000)

4. Measurement of light Lumen (lm)  The unit of luminous flux (power)  The quantity of luminous flux falling on one square unit (steridian) the sphere ’ s surface is one lumen (lm)  The area of the sphere ’ s surface is 4  square units, so the luminous intensity of one candela(cd) produces a total luminous flux of 4  lumens (12.57 lumens) Units of measurement (Rae, 2000)

5. Measurement of light Illuminance The concentration of luminous flux falling on a surface Lux The illuminance on a sphere with a radius of 1 meter (m) (1 lm/m 2) ) Footcandle The illuminance on a sphere with a radius of 1 foot (ft) (1 lm/ft 2 ) Lux = FC x 10.76 FC = Lux/10.76 Units of measurement (Rae, 2000)

6. Measurement of light Luminance  The visual effect that luminance produces  The light entering the eye  Depends on Illuminance  The projected area on a plane perpendicular to the direction of view  Unit of measurement – cd/m 2 Units of measurement

7. Brightness Perception / Light distribution Distribution   Concentrated   Diffuse Direction   Downward Lighting   Has a restricted angular spread   Glare is prevented by spread and the eyebrow   Referred to as direct lighting   Upward Lighting   Usually indirect reflection from ceiling surface   Multi-directional   Lateral directioning is limited

8. Brightness Perception / Light distribution Concentrated Downward (Direct)   Narrow beam spread   Beam spread of 30 degree or less   Low ceiling - overlap of beam on floor surface is difficult Diffuse Downward (Direct)   Beam spreads of 80 to 120 degree   Most downlights offer this   Yield a low contrast setting

9. Brightness Perception / Light distribution Concentrated Upward (Indirect)   Ceiling becomes visually prominent   Ceiling becomes a secondary light source   In low ceiling situations areas of high luminance can cause glare   In high ceiling situations beam overlap may occur creating uniform lighting Diffuse Upward (Indirect)   Uniform ceiling luminance

10. Brightness Perception / Light distribution Multidirectional Diffuse (General Diffuse)   The upward indirect distribution will diffuse the downward distribution   May create a uniform, high-brightness interior Semi-direct and Semi-indirect - % Vertical Surface Illumination   May be a substitute for indirect ceiling lighting   Lightens shadow and reduces excessive contrast Direct / Indirect Often the ideal lighting arrangement

11. Subjective Impressions Spaciousness Uniform peripheral lighting – Wall lighting Intensity of room perimeter Uniformity of room perimeter Relaxation Non-uniform lighting Peripheral wall emphasis rather than overhead lighting Privacy or Intimacy Non-uniform lighting Tendency toward low light intensities in the immediate surroundings with higher brightness remote from the viewer peripheral emphasis is a reinforcing factor, not a decisive one

12. Subjective Impressions Pleasantness and Preference Non-uniform lighting systems from concentrated down lighting systems Peripheral wall emphasis - non uniform Gloom Conditions in which fine detail in the periphery are obscured High task luminance with low luminance on the peripheral surfaces Variation Increases stimulation and impressions of pleasantness Vary visual environment during the daily activities Ideal is a controllable variability of the lighting environment Finishes, textures, color variation

13. References Gordon, G. (2003). Interior lighting for designers (4th ed.). Hoboken: John Wiley & Sons. Rea, M. S. (2000). The IESNA lighting handbook: Reference and application (9th ed.) New York: IESNA. Steffy, G. (2002). Architectural lighting design (3rd ed.). New York: John Wiley & Sons. Michel, L. (1996). Light: The shape of space: Designing with space and light. New York: Van Nostrand Reinhold. West, J. L. (2001). Architectural Lighting Design. (personal lecture notes. Professor James West, Dean, Mississippi State University, College of Architecture Pile, J. F. (2003). Interior design (3rd ed.). New York: Prentiss Hall.

14. Inventorying Conditions of Existing Spaces Space Dimensions  Size of space impacts many lighting issues  Low ceilings – separation of fixtures may cause non- uniform lighting Narrow, low ceiling spaces offer the least efficient use of light Ceiling heights less than 9’ are unlikely candidates for ceiling-suspended indirect, semi-indirect, or direct/indirect lighting systems  Space measurements may afford quick Take-offs to ball- park budget issues (experience)

15. Inventorying Conditions of Existing Spaces Spatial form Generally, larger, moderate ceiling heights (10 to 12’) offer more efficient use of daylight and electric light Long, narrow spaces with low ceilings promote a sense of enclosure or confinement especially with no wall lighting Architectural element focus Lighting and color can help in the spatial perception of apparent size

16. Inventorying Conditions of Existing Spaces Space Activities  The variety of activities will affect the need for illuminance variation to match the activity requirements  Activities for the project may be different from the existing spaces  How spaces are to be used and what kinds of visual activities may be involved

17. Inventorying Conditions of Existing Spaces Visual Tasks  Survey and observe users regarding the kinds of tasks they typically perform and the duration of the tasks and the time of day  Size of tasks  This will help establish lighting criteria (goals) appropriate to address these tasks

18. Inventorying Conditions of Existing Spaces Occupants Ages  Occupants in newly designed spaces will usually have the same demographics  Lighting criteria should be developed based on these age groupings Scale of tasks will make a difference  60 year old eyes need twice as much light as 20 year-old eyes  Aging eyes are also more sensitive to glare – optical distribution, indirect versus direct  Increase in adaptation time  Decrease in visual acuity  Decrease in contrast sensitivity  Color distortion – yellowing of lens

19. Inventorying Conditions of Existing Spaces Furnishings  Lighting system efficiency is greatly influenced by furnishings  Shadows can result in complaints of dimness or too little light – a result of furniture size and configurations Ex: Work station partition height related to ceiling height. (less than 3’ difference)  Subjective impressions – feeling of confinement  Need to understand furniture in elevation

20. Inventorying Conditions of Existing Spaces Surface Finishes and Color  Surface finishes and color affect both the objective (quantitative) aspects of light and the subjective (qualitative) aspects of light  Reviewing the reflectance and the gloss of surfaces will help in understanding glare (or lack thereof) and degree of overall brightness impressions (or lack thereof)  Surface reflectances influence transient adaptation as users switch views among paper tasks, computer tasks, and background surfaces

21. Inventorying Conditions of Existing Spaces Existing Lighting  Existing lighting may be inadequate but the users have adapted  Illuminance measurements should be made on both horizontal and vertical surfaces  Record types of lamps and luminares used and their layout  Record daylight-admitting openings as well  Probably the most problematic lighting solution would be the users’ existing situation that is identified by the users as problematic – so, in order to improve you need knowledge of existing user criticisms.

22. Inventorying Conditions of Existing Spaces Owner’s Feedback and Expectations  What is the image the owner wants to promote  Are there quality expectations that the owner has seen or experienced in other facilities and wants to incorporate  What are the ego issues  Budget requirements  Decorative lighting may improve productivity – pleasant atmosphere.

23. (Steffy, 2008)

25. Establishing Lighting Design Goals Those attributes, both soft (subjective) and hard (objective) that the lighting system is designed to address Goals are not fixed but are the direction the design team is striving to meet.

26. Goal Change  Financial problems develop  Owners’ and users’ opinions change  There is a change in staff of the owner  Corporate takeover “Providing only enough light may, in fact, create occupant complaints and dissatisfaction and ultimately lead to a reduction in performance, less time spent in the offending environment, and an overall morale problem” ( Steffy, 2002, pg 43) Establishing Design Goals

27. Spatial Factors Visual environment pleasantness Lighting hardware scale and shape Lighting hardware spacing and relationships to architectural elements and other building systems Luminance patterns, intensities, and uniformities Spatial definition – Patterns that support the architecture, wall, ceiling, focus Spatial order – 3-D and 2-D – Sympathetic to the architecture Circulation – help to direct, intensity factor Flexibility – moveable Controls – functionality - energy use, load shedding, lamp life Acoustics – Ballasts and transformers noise impact HVAC – Lighting loads (cooling), positioning Ceiling systems – reflectance characteristics, trim, tegular, plenum Codes – egress, thermal protection, ADA, power limits Ordinances – Light trespass Sustainability – efficacy, lamp life, white light, recycling, embedded energy Establishing Design Goals

28. Psychological and Physiological Factors Sensory responses – color temperature/temperature sense Visual hierarchies and focal factors Signification, visual interest, distraction Visual attraction – perception, chromatic contrast Subjective impressions clarity, spaciousness, preference, relaxation, intimacy Daylighting – view, health, illuminance, sustainability Nightlighting Health – UV, Vitamin D, Circadian rhythm Establishing Design Goals

29. Task Factors Visual tasks – including facial recognition Illuminances – fc Luminances Disability glare, discomfort glare, reflected glare, veiling reflection Surface reflectances – spectral, spread, diffuse (guidelines) Surface transmittances – direct, spread, diffuse (guidelines) Establishing Design Goals

30. (Steffy, 2008)