Feature Article - October 2004
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Let There Be Lighting

How to illuminate the world inside and outside your facility

By Kyle Ryan


BALLAST: The device that regulates electricity in fluorescent and discharge lamps

BULB: The protective glass sphere of a lamp. The light source is located within the lamp's bulb.

FIXTURE: A luminaire. A complete lighting unit consisting of a lamp together with other parts such as the socket, reflector and lens designed to locate, orient and control electrically and optically a light-producing device

FOOT CANDLE (FC): The total intensity of light that falls upon one square foot surface placed one foot away from a source of light that equals one candle power. In the metric system, it's called lux.

GLARE: Any luminous source that is in sharp contrast to the area around it

HID: Short for "high intensity discharge," the most common type of sports lighting. High-pressure sodium and metal halide are its most popular types.

ILLUMINANCE: The density of light uniformly incident upon a surface. Measured and calculated in foot-candles (fc) or lux

LAMP: A generic term for a man-made source of light, including the light source, bulb and base, specified by ANSI codes. Characteristics of a lamp that a designer must consider include efficacy, bulb type, maximum overall length, light center length, base type, operating position, lumen maintenance, lumen output, anticipated life, color rendering index, color temperature, restrike time, spectral distribution, mortality, etc.

LIGHT SOURCE: A source of visible electromagnetic radiation. Typical light sources used in sports lighting include high intensity discharge sources (metal halide, high-pressure sodium) and sometimes incandescent or fluorescent. Other light sources include mercury vapor and light emitting diodes.

LIGHT SPILL: Illuminance falling beyond the boundary of the playing field

LUMEN: A measuring unit for the flow of light

LUMINANCE (ALSO KNOWN AS PHOTOMETRIC BRIGHTNESS): The concentration of light reflected in a given direction per unit area. Measured and calculated in cd/m2

SKY GLOW: Light that's cast upward that obscures the view of the nighttime sky

Some definitions provided by Bill Whitman, a lighting designer for DMD & Associates in Seattle.