LIGHTING GLOSSARY TERMS CONTINUED Low Bay
Mercury Vapor (MV) Lamp A high-intensity discharge lamp type that uses mercury as the primary light-producing element. Mercury vapor lamps produce light with a CCT from 3,000K to 7,000K. Mercury vapor lamps are less efficacious than other HID lamp types, typically producing only 30 to 65 LPW. Metal Halide Lamp (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. Networked Lighting Controls (NLC) Advanced lighting control systems that combine sensors, network interfaces, and controllers to effect lighting changes in luminaires, retrofit kits, or lamps. These systems integrate multiple control strate- gies such as occupancy sensing, daylight harvesting, high-end trim, and scheduling to provide enhanced energy savings, automation, and performance tracking. Occupancy Sensor A device that activates a fixture upon sensing the presence of a person in a space. 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. 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 is visible. Retrofit Upgrading a fixture by installing new lighting fixtures, parts, or equipment. Solid State Electronics that use semi-conductor chips and circuitry.
Standard Lighting Controls Devices including occupancy/vacancy, daylighting, or bi-level controls used as a single control strategy to adjust lighting systems to vary light level or turn on or off. Timer Device that turns lights on and off at pre-programmed times. Track Lighting Lighting system that utilizes multiple fixtures that 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.” 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.
Interior lighting where the roof trusses or ceiling height is approximately 25 feet or less above the floor. Common in warehouses, athletic facilities, and industrial settings. Low-Voltage Lighting Lighting system that operates on a system that supplies ≤50 volts to the lamps or light sources. Lumens Per Watt (LPW) The number of lumens produced by a light source for each watt of electrical power supplied to the light source. Also known as efficacy. Lumen Unit of total light output of a light source in all directions, expressed in lumens. Lumen Depreciation The decrease in lumen output of a light source over time. The decrease in lumen output that occurs as a lamp is operated, until failure. Also referred to as lamp lumen depreciation (LLD). Lumen Maintenance The ability of a lamp to retain its light output over time. Greater lumen maintenance means a lamp will remain brighter longer. The opposite of lumen maintenance is lumen depreciation, which represents the reduction of lumen output over time. Luminaire A complete lighting fixture consisting of lamp or lamps together with the socket and parts designed to distribute the light, to position and protect lights, and to connect the lights to their power supply. Luminaire Efficiency The ratio, expressed as a percentage, of the light output of a luminaire to the light output of the luminaire’s lamp(s) (percentage of the light generated by the light source that actually makes it out of the luminaire). Luminaire efficiency accounts for the optical and thermal effects that occur within the luminaire under standard test conditions. Luminaire-Level Lighting Controls The capability to have a networked occupancy sensor, ambient light sensor, and high-end trim installed for each luminaire/kit/lamp, and directly integrated or embedded into the form factor during the manufacturing process.
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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