Crestron electronic manual Crestron Residential Lighting Design Guide

Crestron Residential Lighting Design Guide Appendix D

L

LAMP CURRENT CREST FACTOR (LCCF): The peak lamp current divided by the RMS (average) lamp current. Lamp manufacturers require <1.7 for best lamp life. An LCCF of 1.414 is a perfect sine wave

LAMP LUMEN DEPRECIATION FACTOR (LLDF): A factor that represents the reduction of lumen output over time. The factor is commonly used as a multiplier to the initial lumen rating in illumination calculations, which compensates for the lumen depreciation. The LLD factor is a dimensionless value between 0 and 1

LAY-IN-TROFFER: A fluorescent fixture; usually a 2' x 4' fixture that sets or "lays" into a specific ceiling grid

LED: Abbreviation for light emitting diode. An illumination technology used for exit signs. Consumes low wattage and has a rated life of greater than 80 years

LENS: Transparent or translucent medium that alters the directional characteristics of light passing through it. Usually made of glass or acrylic

LIGHT LOSS FACTOR (LLF): Factors that allow for a lighting system's operation at less than initial conditions. These factors are used to calculate maintained light levels. LLFs are divided into two categories, recoverable and non-recoverable. Examples are lamp lumen depreciation and luminaire surface depreciation

LIFE-CYCLE COST: The total costs associated with purchasing, operating, and maintaining a system over the life of that system

LOUVER: Grid type of optical assembly used to control light distribution from a fixture. Can range from small-cell plastic to the large-cell anodized aluminum louvers used in parabolic fluorescent fixtures

LOW POWER FACTOR: Essentially, an uncorrected ballast power factor of less than 0.9 (SEE NPF)

LOW-PRESSURE SODIUM: A low-pressure discharge lamp in which light is produced by radiation from sodium vapor. Considered a monochromatic light source (most colors are rendered as gray)

LOW-VOLTAGE LAMP: A lamp (typically compact halogen) that provides both intensity and good color rendition. Lamp operates at 12V and requires the use of a transformer. Common lamps are MR11, MR16, and PAR36

LOW-VOLTAGE SWITCH: A relay (magnetically-operated switch) that allows local and remote control of lights, including centralized time clock or computer control

LUMEN: A unit of light flow, or luminous flux. The lumen rating of a lamp is a measure of the total light output of the lamp

LUMINAIRE: A complete lighting unit consisting of a lamp or lamps, along with the parts designed to distribute the light, hold the lamps, and connect the lamps to a power source. Also called a fixture

LUMINAIRE EFFICIENCY: The ratio of total lumen output of a luminaire and the lumen output of the lamps, expressed as a percentage. For example, if two luminaires use the same lamps, more light will be emitted from the fixture with the higher efficiency.

LUMINANCE: A photometric term that quantifies brightness of a light source or of an illuminated surface that reflects light. It is expressed as footlamberts (English units) or candelas per square meter (Metric units)

LUX (LX): The metric unit of measure for illuminance of a surface. One lux is equal to one lumen per square meter. One lux equals 0.093 footcandles

M

MAINTAINED ILLUMINANCE: Refers to light levels of a space at other than initial or rated conditions. This term considers light loss factors such as lamp lumen depreciation, luminaire dirt depreciation, and room surface dirt depreciation

MAGNETIC LOW-VOLTAGE (MLV): Magnetic low-voltage lighting uses a magnetic (core and coil technology) transformer to convert line voltage (120 VAC) to low voltage (typically 12 VAC). This lower voltage is then used to power an incandescent low-voltage lamp. Recessed lights are most often magnetic low-voltage. Magnetic low-voltage lights tend to be larger and heavier than electronic low-voltage

MERCURY VAPOR LAMP: A type of high intensity discharge (HID) lamp in which most of the light is produced by radiation from mercury vapor. Emits a blue-green cast of light. Available in clear and phosphor-coated lamps

METAL HALIDE: A type of high intensity discharge (HID) lamp in which most of the light is produced by radiation of metal halide and mercury vapors in the arc tube. Available in clear and phosphor-coated lamps

MR-16: A low-voltage quartz reflector lamp, only 2" in diameter. Typically the lamp and reflector is one unit, which directs a sharp, precise beam of light

N

NADIR: A reference direction directly below a luminaire, or "straight down" (0 degree angle

NEMA: Abbreviation for National Electrical Manufacturers Association

NEON/COLD CATHODE: Highly inductive boost transformer for neon/cold cathode lighting

NIST: Abbreviation for National Institute of Standards and Technology

NPF (NORMAL POWER FACTOR): A ballast/lamp combination in which no components (e.g., capacitors) have been added to correct the power factor, making it normal (essentially low, typically 0.5 or 50%)

O

OCCUPANCY SENSOR: Control device that turns lights off after the space becomes unoccupied. May be ultrasonic, infrared or other type

OPTICS: A term referring to the components of a light fixture (such as reflectors, refractors, lenses, louvers) or to the light emitting or light- controlling performance of a fixture

P

PAR LAMP: A parabolic aluminized reflector lamp. An incandescent, metal halide, or compact fluorescent lamp used to redirect light from the source using a parabolic reflector. Lamps are available with flood or spot distributions

PAR 36: A PAR lamp that is 36 one-eighths of an inch in diameter with a parabolic shaped reflector (SEE PAR LAMP)

PARABOLIC LUMINAIRE: A popular type of fluorescent fixture that has a louver composed of aluminum baffles curved in a parabolic shape. The

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