programming inventorying existing spaces establishing design goals

Programming

Inventorying Existing SpacesEstablishing Design Goals

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 1012 Hz and that has a radiant intensity in that direction of 1/683 W/steridian

Radiant FluxRadiant PowerThe transfer of Radiant Energy per unit of time

Units of measurement

(Rae, 2000)

Measurement of light

Steradian - The solid angleFor 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 fluxThe radiant flux falling on a unit area of the sphere’s surface (steradian) from a source at the center of one candela


(Rae, 2000)


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)


(Rae, 2000)


IlluminanceThe concentration of luminous flux falling on a surface

LuxThe illuminance on a sphere with a radius of 1 meter (m) (1 lm/m2))

FootcandleThe illuminance on a sphere with

a radius of 1 foot (ft) (1 lm/ft2)

Lux = FC x 10.76FC = Lux/10.76


(Rae, 2000)


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/m2


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


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


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


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

Subjective Impressions Spaciousness

Uniform peripheral lighting – Wall lightingIntensity of room perimeterUniformity of room perimeter

RelaxationNon-uniform lighting

Peripheral wall emphasis rather than overhead lighting

Privacy or IntimacyNon-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

Subjective Impressions

Pleasantness and Preference

Non-uniform lighting systems from concentrated down lighting systemsPeripheral wall emphasis - non uniform

Gloom

Conditions in which fine detail in the periphery are obscuredHigh task luminance with low luminance on the peripheral surfaces

VariationIncreases stimulation and impressions of pleasantnessVary visual environment during the daily activitiesIdeal is a controllable variability of the lighting environmentFinishes, textures, color variation

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 ArchitecturePile, J. F. (2003). Interior design (3rd ed.). New York: Prentiss Hall.

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)


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


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


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


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


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


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


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.


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.

(Steffy, 2008)

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.

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

Spatial Factors

Visual environment pleasantnessLighting hardware scale and shapeLighting hardware spacing and relationships to architectural

elements and other building systemsLuminance patterns, intensities, and uniformities

Spatial definition – Patterns that support the architecture, wall, ceiling, focusSpatial order – 3-D and 2-D – Sympathetic to the architectureCirculation – help to direct, intensity factorFlexibility – moveableControls – functionality - energy use, load shedding, lamp lifeAcoustics – Ballasts and transformers noise impactHVAC – Lighting loads (cooling), positioningCeiling systems – reflectance characteristics, trim, tegular, plenumCodes – egress, thermal protection, ADA, power limitsOrdinances – Light trespassSustainability – efficacy, lamp life, white light, recycling, embedded

energy


Psychological and Physiological Factors

Sensory responses – color temperature/temperature senseVisual hierarchies and focal factors

Signification, visual interest, distractionVisual attraction – perception, chromatic contrastSubjective impressions

clarity, spaciousness, preference, relaxation, intimacyDaylighting – view, health, illuminance, sustainabilityNightlightingHealth – UV, Vitamin D, Circadian rhythm


Task Factors

Visual tasks – including facial recognitionIlluminances – fc Luminances

Disability glare, discomfort glare, reflected glare, veiling reflectionSurface reflectances – spectral, spread, diffuse (guidelines)Surface transmittances – direct, spread, diffuse (guidelines)


(Steffy, 2008)

programming inventorying existing spaces establishing design goals

Documents

measurement of light

units of measurement

measurement of light

measurement of light

indirect ceiling lighting

light output

unit of luminous flux

steradian luminous flux