Crestron electronic GLPS-HSW, IPAC-GL1 Commercial Lighting Design Guide, Appendix E, Doc 4775A

Commercial Lighting Design Guide Appendix E

resultant light distribution produced by this shape provides reduced glare, better light control, and is considered to have greater aesthetic appeal

PARACUBE: A metallic coated plastic louver made up of small squares. Often used to replace the lens in an installed troffer to enhance its appearance. The paracube is visually comfortable, but the luminaire efficiency is lowered. Also used in rooms with computer screens because of their glare-reducing qualities

PHOTOCELL: A light sensing device used to control luminaires and dimmers in response to detected light levels

PHOTOMETRIC REPORT: A photometric report is a set of printed data describing the light distribution, efficiency, and zonal lumen output of a luminaire. This report is generated from laboratory testing

POWER FACTOR: The ratio of the AC Volts x Amps through a device to the AC wattage of the device. A device such as a ballast that measures 120 Volts, 1 Amp, and 60 Watts has a power factor of 50% (Volts x Amps

=120 VA, therefore 60 Watts/120 VA = 0.5). Some utilities charge customers for low power factor systems

PREHEAT: A type of ballast/lamp circuit that uses a separate starter to heat up a fluorescent lamp before high voltage is applied to start the lamp

Q

QUAD-TUBE LAMP: A compact fluorescent lamp with a double twin tube configuration

R

RADIO FREQUENCY INTERFERENCE (RFI): Interference to the radio frequency band caused by other high frequency equipment or devices in the immediate area. Fluorescent lighting systems generate RFI

RAPID START (RS): The most popular fluorescent lamp/ballast combination used today. This ballast quickly and efficiently preheats lamp cathodes to start the lamp. Uses a "bi-pin" base

ROOM CAVITY RATIO (RCR): A ratio of room dimensions used to quantify how light will interact with room surfaces. A factor used in illuminance calculations

REFLECTANCE: The ratio of light reflected from a surface to the light incident on the surface. Reflectances are often used for lighting calculations. The reflectance of a dark carpet is around 20%, and a clean white wall is roughly 50% to 60%

REFLECTOR: The part of a light fixture that shrouds the lamps and redirects some light emitted from the lamp

REFRACTOR: A device used to redirect the light output from a source, primarily by bending the waves of light.

RECESSED: The term used to describe the doorframe of a troffer where the lens or louver lies above the surface of the ceiling.

REGULATION: The ability of a ballast to hold constant (or nearly constant) the output watts (light output) during fluctuations in the voltage feeding of the ballast. Normally specified as +/- percent change in output compared to +/- percent change in input.

RELAY: A device that switches an electrical load on or off based on small

changes in current or voltage. Examples: low voltage relay and solid state relay

RETROFIT: Refers to upgrading a fixture, room, or building by installing new parts or equipment

REVERSE PHASE DIMMING: Rather than attempting to restrict the amplitude of the current flowing through a lamp, as in other forms of dimming, reverse phase control works by switching off the end part of each cycle of the alternating current supply

S

SELF-LUMINOUS EXIT SIGN: An illumination technology using phosphor- coated glass tubes filled with radioactive tritium gas. The exit sign uses no electricity and thus does not need to be hardwired

SEMI-SPECULAR: Term describing the light reflection characteristics of a material. Some light is reflected directionally, with some amount of scatter

SHIELDING ANGLE: The angle measured from the ceiling plane to the line of sight where the bare lamp in a luminaire becomes visible. Higher shielding angles reduce direct glare. It is the complementary angle of the cutoff angle. (See: CUTOFF ANGLE)

SPACING CRITERION: A maximum distance that interior fixtures may be spaced that ensures uniform illumination on the work plane. The luminaire height above the work plane multiplied by the spacing criterion equals the center-to-center luminaire spacing

SPECULAR: Mirrored or polished surface. The angle of reflection is equal to the angle of incidence. This word describes the finish of the material used in some louvers and reflectors

STARTER: A device used with a ballast to start (preheat) fluorescent lamps

STROBOSCOPIC EFFECT: Condition where rotating machinery or other rapidly moving objects appear to be standing still due to the alternating current supplied to light sources. Sometimes called "strobe effect."

T

T12 LAMP: Industry standard for a fluorescent lamp that is 12 one- eighths, one inch in diameter. Other sizes are T10 and T8 lamps

TANDEM WIRING: A wiring option in which a single ballast is shared by two or more luminaires. This reduces labor, materials, and energy costs. Also called "master-slave" wiring.

THERMAL FACTOR: A factor used in lighting calculations that compensates for the change in light output of a fluorescent lamp due to a change in bulb wall temperature. It is applied when the lamp-ballast combination under consideration is different from that used in the photometric tests.

THREE-WIRE ANALOG POWER DIMMING: Three-wire control is a line- voltage phase-control dimming method. Along with Hot and Neutral, the dimming signal is communicated via a third wire called Dimmed Hot. All three wires are rated Class 1 and can be run within the same conduit.

TRIGGER START: Type of ballast commonly used with 15-watt and 20- watt straight fluorescent lamps

TROFFER: The term used to refer to a recessed fluorescent light fixture (combination of trough and coffer)

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