Common Lighting Terms

ANSI –  American National Standards Institute.The coordinator of standards (including lighting) on a national level.

Average Rated Life-  How long it takes to for a lamp to burn out.  Indicating when 50% of a large group of lamps have burned out and 50% still shine. Also referred to as half-life.

Ballast- A device which provides the necessary starting voltage and appropriate current to a fluorescent or  HID  luminaire.

Ballast Factor-  is the measured ability of a particular ballast to produce light from the lamp it powers. Calculated as the difference between the expected performance of a lamp with a commercial ballast versus the measured performance of that lamp with a reference ballast.

Base- The portion of the lamp that provides a means of connecting the lamp to the socket.

Compact Fluorescent (CF) - The generic name for a  family of single ended fluorescent lamps of folded or bridge tube design with high color rendering and long life.

Color Rendering Index (CRI)-  The ability of a light source to accurately render an object’s color in comparison with a natural light source. Measured on a scale of 1 -100 with 100 being the ideal(natural light).

Efficacy-  A measure used to compare light output to energy consumption,   expressed in lumens per watt.

Foot Candle (FC)- one lumen uniformly distributed over one square foot of surface

Fluorescent Lamps- A low pressure mercury electric-discharge lamp in which a phosphor transforms energy into light.

Halogen-  A gas-filled tungsten incandescent lamp containing a certain proportion of halogen

High-Intensity Discharge (HID)- A general term for mercury vapor, metal  halide and high pressure sodium lamps. HID lamps contain compact are tubes which enclose various gases operating at relatively high pressures and temperatures

Incandescence- Light emission by a heated filament or coil.

Incandescent Lamp- A lamp in which light is produced by the passage of an electric current through a wire.

Initial Lumens-  The lumen output of a new lamp as measured after it has been powered on for a standard length of time.

Instant Start – A type of ballast designed to start fluorescent lamps as soon as the power is applied. Most T8 fluorescent lamps are  operated on electronic instant-start ballasts.

Kelvin Temperature- A numerical scale used to describe the color of light. Light with a lower Kelvin rating will have a more yellow tint, while light with a higher kelvin rating will have a bluer tint.

Kilowatt-  1000 Watts.

Kilowatt Per Hour-  1000 Watts used continuously for one hour.

Lamp — a man-made light source ( aka light bulb)

Lamp Disposal-  Refers to the proper recycling of lamps containing mercury or other hazardous materials.

Lumen depreciation-  The decrease in lumen output of a light source over time; every lamp type has a unique lumen depreciation curve (sometimes called a lumen maintenance curve) depicting the pattern of decreasing light output.

Lumens – A unit of luminous flux; overall light output; quantity of light

Luminaire- A complete lighting unit which contains a lamp, housing, ballast, sockets and any other necessary components.

Metal Halide Lamp- A HID Lamp in which the light is produced by the radiation from mercury together with halides of metal(such as sodium and scandium)

Mercury Vapor Lamp- A HID Lamp in which the light is product by the radiation from mercury.

Preheat- A fluorescent system in which requires starters. This system requires several seconds of heating from the time the circuit is turned on to the time the lamp produces light.

Starter- A device used in conjunction with a ballast for the purpose of starting a lamp.

Rapid Start- A method of starting a lamp typically associated with magnetic ballasts; where a low filament voltage is applied to preheat the cathodes.

T5 —  5/8″ diameter fluorescent lamps.

T8 — 1″ diameter fluorescent lamps.

T12 — 1  1/2″ diameter fluorescent lamps.

Troffer- A recessed luminaire shaped like an inverted trough used to enclose and reflect fluorescent lamps.

Volt -The standard unit of measure for electrical potential.

Watt- A unit of power consumption.

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