LIGHTING GLOSSARY TERMS CONTINUED
Metal Halide (MH) Lamp A high-intensity discharge lamp type that uses mercury and several halide additives as light-producing elements. MH lamps have better color properties than other HID lamp types because the different additives produce more visible wavelengths, resulting in a more complete spectrum. MH lamps are available with CCTs from 2,300K to 5,400K and with CRI values from 60 to 93. Efficacies of MH lamps typically range from 75 to 125 LPW. Multi-Facet Reflector Lamp (MR Lamp) Multi-facet reflector lamp, of which the most popular is MR16. Occupancy Sensor A device that activates a fixture upon sensing the presence of a person in a space. Parabolic Aluminized Reflector Lamp (PAR Lamp) Incandescent PAR lamps are constructed of hard glass with a separate back reflector. Also available in CMH and LED. LED PAR lamps typically have a similar overall shape and beam angle of light, but do not actually use the parabolic reflector. Photocell Light-sensitive device used to operate fixtures according to available daylight. They are used to integrate an electric lighting system with a daylighting system so lights operate only when daylighting is insufficient and turn outdoor or security lights on and off at dusk and dawn. Programmed Start A method of starting fluorescent lamps, associated with electronic ballasts, where low voltage is applied to the cathode to pre-heat prior to lamp ignition. Recommended for use with occupancy sensors. Rated Lamp Life See: Average Rated Life Recessed Fixture A fixture mounted in the ceiling. With downlights, only the aperture and trim are visible from below. With fluorescent troffers and luminous ceilings, only the light shield
Re-Strike Refers to the restarting of a previously operating HID lamp shortly after turn off. Typically requires a minimum of 4–15 minutes to restart after turn off. Retrofit Upgrading a fixture by installing new lighting fixtures, parts, or equipment. Semi-Specular A reflective but somewhat diffuse surface. Soffit In architecture, the underside of an overhead component. Often used to describe an exterior element under the roofline. Solid State Electronics that use semi-conductor chips and circuitry. Specular A highly polished or mirrored surface. Spot Lamp Reflectorized lamp with a narrow
TRT vX.X Acronym for DLC’s Technical Requirements Table followed by version number. U Lamp Linear, double-ended fluorescent lamp, usually T8 or T12, bent into a “U” shape. UL Underwriters Laboratory. An independent organization whose responsibilities include rigorous testing of electrical products. Watt A unit of electrical power.
light distribution. Task Lighting
Lighting directed to a specific area or surface that provides illumination for visual tasks, such as reading, writing, wiring, or grinding. Thermal Characteristics The manner in which a luminaire manages heat, either dissipating heat or retaining it. Timer Device that turns lights on and off at pre-programmed times. Track Lighting Lighting system that utilizes multiple fixtures which operate off a track or strip mounted to the wall or ceiling. May be low voltage or line voltage. Trim The edge or visible part of a recessed downlight. The finishing section of the exterior of a recessed fixture. Troffer Recessed fluorescent fixture for use in a suspended ceiling; derived from the words “trough” and “coffer.”
is visible. R Lamp
Reflector lamp whose interior is coated with a reflecting material so as to direct the light forward. Relamping A project where the existing lighting fixtures are cleaned and new lamps installed.
SOURCES Terms defined in the Glossary were referenced from the following sources: products.gecurrent.com/sites/products. currentbyge.com/files/documents/document_ file/35311-GE-Retail-Lighting-101-eBook.pdf focusonenergy.com lightsearch.com/resources
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