AREN 320 MIDTERM

Lighting design

The process of analyzing project needs and selecting light levels, sources, luminaires, layouts, and controls to meet visual, aesthetic, energy, and code goals.

Programming phase

The phase where the designer analyzes and understands the owner's needs and develops the building program, including spaces, activities, quantities, and special requirements.

Schematic design phase

The phase where design ideas are developed and refined to meet programming needs.

Design development phase

The phase where building systems begin to be developed and coordinated, including mechanical, electrical, plumbing, and structural systems.

Construction documentation phase

The phase where drawings, schedules, specifications, and other design documents are completed for bidding and construction.

Bidding phase

The phase where contractors prepare bids and the design team reviews bids for project coverage and reasonable totals.

Construction administration phase

The phase where the design team provides oversight during construction through meetings, RFIs, inspections, submittal reviews, and system setup.

LPD (Lighting Power Density)

A lighting power allowance or limit used in energy-code compliance, typically evaluated by whole-building or space-by-space methods.

IES

Illuminating Engineering Society.

Color Temperature / CCT

A numerical value describing the color appearance of light on a warm-to-cool spectrum; measured in kelvin (K).

Warm lighting

Lighting at approximately 3000 K and lower.

Cool lighting

Lighting at approximately 4000 K and above.

CRI (Color Rendering Index)

A measure of how naturally a light source renders object colors compared with a familiar reference such as incandescent light or daylight; 100 represents true color rendering.

Dimmability

The ability to operate a lamp at less than full intensity, often for energy savings or mood creation.

Efficacy

The energy efficiency of a light source, measured in lumens per watt (lm/W). Higher efficacy means more visible light per unit of power.

Lumen

A unit used to measure how much visible light is produced by a light source.

System efficacy

A performance metric describing the overall efficiency of a lighting system, used along with factors such as color temperature and optical distribution.

Operating temperature

The temperature conditions surrounding a lamp; some lamps are sensitive to or optimized for particular ambient temperatures.

Average Rated Life (ARL)

The average service life of a group of lamps.

Traditional lamp life

The total operating time at which 50% of a large group of lamps is expected to fail.

Lumen maintenance

A measure of a light source's ability to retain luminous flux and brightness as it ages.

L70

The point used to describe LED life when lumen output has decreased to 70% of its initial value.

Starting time

The time a light source needs to reach at least 60% of its total light output capacity.

Visual comfort

The level of satisfaction and well-being a person experiences in relation to the visual environment.

Glare

Excessive brightness that causes visual discomfort.

Light pollution

Human-made alteration of outdoor light levels from those that occur naturally.

Sky glow

Brightening of the night sky over inhabited areas.

Light trespass

Light falling where it is not intended or needed.

Clutter

Bright, confusing, and excessive groupings of light sources.

Wall grazing

An accent-lighting technique that positions light close to a wall to emphasize surface texture and details.

Wall washing

An accent-lighting technique that spreads relatively even light across a wall surface.

Brightness

The perceived amount of light; it affects visibility and can influence how a space feels.

Hue

The basic color appearance of light or an object.

Saturation

The intensity or purity of a color; higher saturation produces a stronger, more vivid color appearance.

Point source

A small apparent light source that tends to create dramatic highlights, sharp shadows, and higher contrast.

Linear source

An elongated light source, such as a tubular fluorescent lamp, that produces more diffuse light and softens shadows in one direction.

Area source

A large light-emitting surface that produces diffuse light, softer shadows, lower contrast, and generally greater visual comfort.

Light distribution

The way a luminaire directs light, commonly described by the percentage of light sent upward and downward.

Direct distribution

A distribution that directs essentially all light downward into the occupied area.

Semi-direct distribution

A distribution that sends most light downward with a smaller portion upward.

Direct/Indirect distribution

A distribution that sends substantial light both upward and downward.

Indirect distribution

A distribution that directs essentially all light upward so illumination reaches the space mainly by reflection.

Semi-indirect distribution

A distribution that sends most light upward with a smaller portion downward.

General-diffuse distribution

A distribution that spreads light broadly in many directions.

Ambient lighting

General lighting that provides overall, relatively even illumination throughout a room.

Task lighting

Lighting directed to a specific area to support a particular visual task.

Accent lighting

Lighting used to draw attention to an object, feature, artwork, or other point of interest.

Incandescent lamp

A lamp that produces light by heating a filament until it glows; much of its energy is lost as heat.

Fluorescent lamp

A lamp that produces light through fluorescence after an electric discharge excites material inside the lamp.

HID lamp

High-Intensity Discharge lamp; a discharge light source that produces high light output and is commonly used where large amounts of light are needed.

Halogen lamp

An improved incandescent lamp that uses a quartz envelope and halogen gas, allowing higher operating temperatures and a whiter/bluer light than standard incandescent.

LED

Light-Emitting Diode; a solid-state light source known for long life, high efficiency, and lack of mercury.

Light source

The technology that produces light by converting electrical energy to light, such as incandescent, fluorescent, HID, or LED.

Lamp

A replaceable light-producing component with a specific shape, size, and base that produces light.

Luminaire / fixture

A complete lighting assembly that includes the lamp or integrated LED plus optics, housing, electrical components, and mounting; it controls and directs light.

Integrated LED luminaire

A luminaire with a built-in LED light source that is generally not replaceable like a traditional lamp.

Omnidirectional lamp

A lamp that emits light in every direction.

A lamp

The standard or traditional arbitrary-shaped lamp.

B lamp

A blunt-tip or bullet-shaped decorative lamp commonly used in chandeliers and wall sconces.

CA lamp

A candle-flame-shaped decorative lamp commonly used in chandeliers and wall sconces.

C lamp

A cone-shaped lamp commonly used in night-lights and older-style decorative applications.

F lamp

A flame-shaped decorative lamp with a flame-like appearance.

G lamp

A globe-shaped lamp often used in decorative luminaires, theater marquees, and makeup-mirror lighting.

P / PS lamp

A pear-shaped lamp, commonly a higher-wattage incandescent lamp.

T lamp

A tubular lamp available in many light-source technologies, sizes, and wattages.

Directional lamp

A lamp with a built-in reflector, and sometimes a lens, that controls most of its light distribution.

R lamp

A reflector lamp with a simple built-in reflector, commonly available in spot or flood beam spreads.

PAR lamp

Parabolic Aluminized Reflector lamp; uses a parabolic reflector to produce parallel reflected rays and strong beam control.

MR lamp

Multi-reflector lamp; a directional lamp available with halogen, HID, or LED sources in many wattages and beam spreads.

AR lamp

Aluminum reflector lamp; uses a formed-aluminum reflector and a cap that blocks light from leaving directly through the face of the lamp.

Lamp size designation

In U.S. lamp codes, the number usually gives the lamp's widest diameter in eighths of an inch; for example, MR16 = 16/8 in = 2 in.

Lamp base

The connection portion of a lamp that must match the luminaire socket for proper physical and electrical compatibility.

Beam angle

The angle of the main beam measured to the points where intensity falls to 50% of center-beam intensity.

Field angle

The angle of the broader light spread measured to the points where intensity falls to 10% of center-beam intensity.

Spot beam

A relatively narrow beam angle that concentrates light on a smaller area.

Flood beam

A relatively wide beam angle that spreads light over a larger area.

NEMA lamp nomenclature

A standardized lamp naming format that can identify wattage, lamp shape, size, envelope, and beam information.

Daylighting

The practice of using natural light to illuminate indoor spaces while balancing artistic and scientific principles.

Top lighting

Daylighting introduced primarily from openings in the roof or high overhead; it is relatively unaffected by site orientation and adjacent buildings.

Skylight

Horizontal glazing or a roof aperture that admits direct solar and sky radiation.

Solar tube / sun tunnel / light tube / daylight pipe

A tubular daylighting device that captures exterior daylight and channels it into interior spaces.

Single clerestory

A high vertical window that provides both direct and indirect daylight; orientation can influence glare.

Sawtooth single clerestory

A roof daylighting configuration using a repeated sawtooth form and clerestory glazing to introduce daylight.

Monitor / double clerestory

A raised roof form with clerestory glazing on multiple sides that can provide abundant daylight.

Side lighting

Daylighting introduced through vertical openings in walls, such as windows.

Daylight Factor (DF)

A daylighting metric comparing indoor illuminance at a point with simultaneous outdoor illuminance, expressed as a percentage.

Sky component (SC)

The portion of daylight factor produced by light received directly from the sky.

Externally reflected component (ERC)

The portion of daylight factor produced by daylight reflected from exterior surfaces before entering the space.

Internally reflected component (IRC)

The portion of daylight factor produced by daylight reflected from interior room surfaces.

LRV (Light Reflectance Value)

A value describing how much visible light a surface reflects.

Daylight uniformity

The evenness of daylight distribution across a space or work plane.

Luminance

The brightness associated with light emitted from or reflected by a source or surface; in the lecture, described as source brightness.

Illuminance

Light landing on, or incident on, a surface.

Reflectance

The amount or fraction of light that bounces off a surface.

Lumen (lm)

The unit of total visible light output from a lamp in all directions.

Candela (cd)

The intensity of a light source in a particular direction.

Footlambert (fL)

An older Imperial unit used for surface luminance.

Candela per square meter (cd/m²)

The SI unit used to describe luminance.

Footcandle (fc)

The Imperial unit of illuminance, describing the density of light arriving on a surface.

Lux (lx)

The SI unit of illuminance.