LIGHTING GLOSSARY TERMS
A Lamp Standard incandescent lamp shape, typically with an omnidirectional distribution of light. Average Rated Life An average rating, in hours, indicating end of useful life. For most lamps, this indicates when 50% of a large group of lamps will have failed, when operated at nominal lamp voltage and current. For LED, this would be the point at which the light system has depreciated to an unacceptable level and needs to be replaced, often when it has dropped to 70% of initial light output. Ballast An electrical control device that initiates the light arc in fluorescent and HID lights with high starting voltage and regulates the
Consortium for Energy Efficiency (CEE) CEE is the U.S. and Canadian consortium of gas and electric efficiency program administrators. CEE works together to accelerate the development and availability of energy-efficient products and services for lasting public benefit. Continuous Dimming
Downlights Light fixtures that direct all of the light in a downward direction. Most often are completely recessed into the ceiling, circular, or square shaped, and less than 12" in diameter. Efficacy The amount of light produced per watt of electricity (lumens/watt). It is the rate at which a light source is able to convert electrical power (watts) into light (lumens), expressed in terms of lumens per watt (LPW). For example, a 10-watt lamp producing 800 lumens has an efficacy of 80 lumens per watt. ENERGY STAR A U.S. Environmental Protection Agency (EPA) voluntary program that helps businesses and individuals save money and protect our climate through superior energy efficiency. Flood Floodlights create a widespread distribution of light for illuminating a wall, sign, or large object or building. A floodlight should be well shielded with an accessory louver or shield to avoid stray light and glare. Fluorescent Lamps Lamps that operate by creating an electric arc inside a gas-filled tube. The color of the light is determined by the type of phosphor coating used in the lamp. Fluorescent Troffers Recessed fluorescent fixtures for 2-foot and 4-foot lamps, generally in modular sizes (2'x4', 1'x4', 2'x2'); commonly used in commercial spaces. Flushmount A type of light fixture that mounts directly to a junction box, typically in the ceiling. Footcandle The unit of measure for the density of light as it reaches a surface. One footcandle is equal to one lumen per square foot. G Lamp Globe-shaped light bulb, generally for exposed use. General Lighting Also known as ambient lighting, general lighting provides an area with overall, non-specific illumination. Glare Lighting that causes discomfort and impairs good visibility. Halogen Lamp An incandescent lamp that uses a halogen fill gas. Halogen lamps have higher-rated efficacies and longer lives than standard incandescent A-lamps.
Control of a light source’s intensity to practically any value within a given operating range.
Correlated Color Temperature (CCT) A measure of the color appearance of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2700K) and have a red-yellowish tone; daylight has a high color temperature (approximately 5000K) and appears bluish (fluorescent Cool White
operation of the lamp. Ballast Factor (BF)
The ratio of the light output of a fluorescent lamp or lamps operated on a ballast to the light output of the lamp(s) operated on a standard (reference) ballast. BF depends on both the ballast and the lamp type; a single ballast can have several ballast factors depending on lamp type. Rated Lamp Lumens x BF = Net Lumen output for the system. Also referred to as relative light output. Typically grouped into Low (≤ 0.85), Normal (> 0.85 to ≤ 1.0) and High (≥ 1.01) light output categories. Bi-Level Control Device that controls light source intensity at two discrete levels in addition to off. Bollards Lights mounted on short, heavy piers, or posts. They are used mostly for larger residences and campus settings. Bulged Reflector Lamp (BR Lamp) Flood style lamp with wide, diffuse beam. Often used in downlights for general lighting. Canopy Lighting Recessed or surface-mounted lighting on the underside of a covered drive through, covered walkway, or covered gasoline pumping station. Color Rendering Index (CRI) A rating index commonly used to represent how well a light source renders the colors of objects that it illuminates. The maximum value of 100 indicates that the colors of objects can be expected to be seen as they would appear under an incandescent or natural daylight. Sources with CRI values less than 50 are generally regarded as rendering colors poorly.
is rated at 4100K). Cove Lighting
Light built into a cove, a shelf, or ledge at the upper part of a wall, to illuminate the ceiling and upper wall area. Daylight Sensor A device that senses the amount of daylight in a room and adjusts the electric lighting accordingly. Decorative Lamps General service lamps available in a variety of wattages and shapes. Decorative bulbs include flame, teardrop, globe, and candelabra shapes. Typically available in incandescent, CFL, and LED. DesignLights Consortium® (DLC) The DLC is a project of Northeast Energy Efficiency Partnerships (NEEP), a regional nonprofit whose mission is to serve the Northeast and mid-Atlantic regions to accelerate energy efficiency in the building sector through public policy, program strategies, and education. Visit designlights.org . Diffuser Light control device that spreads light by scattering it. Dimmer Control that varies the output of the light source by reducing the voltage or current to the lamp. Directional Lamps Lamp type that typically integrates a reflector to distribute light forward away from the lamp. Typically used to direct light toward an object or display. Includes flood and spot lamps with a variety of beam patterns (includes PAR, R, BR, MR, and AR types).
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