§ 42-76. Definitions.

The following words, terms and phrases, when used in this article, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:

Ambient noise means the all-encompassing noise associated with a given environment, being usually a composite of sounds from many sources.

A-weighted sound level means the sound pressure level in decibels as measured on a sound level meter using the A-weighting network. The level so read is designated dBA.

Decibel (dB) means a unit for describing the amplitude of sound, equal to 20 times the logarithm to the base ten of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micronewtons per square meter.

Direct light means light emitted directly from the lamp, off the reflector or reflector diffuser, or through the refractor or diffuser lens, of a luminaire.

Emergency work means any work performed for the purpose of preventing or alleviating the physical trauma or property damage threatened or caused by an existing or imminent peril.

Fixture means the assembly that houses the lamp or lamps and can include all or some of the following parts: a housing, a mounting bracket or pole socket, a lamp holder, a ballast, a reflector or mirror, and/or a refractor or lens.

Flood or spotlight means any light fixture or lamp that incorporates a reflector or refractor to concentrate the light output onto a directed beam in a particular direction.

Footcandle (fc) means a unit of illuminance. One fc is equal to one lumen per square foot. 0.1 fc is roughly equivalent to a 150 watt reflectorized incandescent floodlight at a distance of 100 feet.

Full cut-off means less than 0.5 fc from a luminaire illuminating an adjacent property when measured on a vertical and horizontal plane at the property line.

Glare means any light emitting from a luminaire with an intensity great enough to reduce a viewer's ability to see and in extreme cases causing momentary reduction in sight.

Illuminance means a measurement of direct light on an illuminated surface. Horizontal illuminance is the illuminance on a horizontal surface, and vertical illuminance is the illuminance on a vertical surface. Illuminance is expressed in footcandles.

Lamp means the component of a luminaire that produces the actual light.

Light trespass means the shining of light produced by a luminaire beyond the boundaries of the property on which it is located and/or intended to shine in an amount greater than full cut-off.

Lumen means a measurement of light output. One lumen is equal to the amount of light emitted by one candle that falls on one square foot of surface located one foot away from the candle.

Luminaire means a complete lighting system, and includes a lamp or lamps and a fixture.

Microbar means a unit of pressure commonly used in acoustics and is equal to one dyne per square centimeter.

RMS sound pressure means the square root of the time averaged square of the sound pressure, denoted PRMS.

Sound level means the weighted sound pressure level obtained by the use of a sound level meter and frequency weighting network, such as A, B or C as specified in American National Standards Institute specifications for sound level meters (ANSI S1.4-1983). If the frequency weighting employed is not indicated, the A-weighting shall apply.

Sound level meter means an instrument including a microphone, an amplifier, an output meter, and frequency weighting networks for the measurement of noise and sound levels in a specific manner.

Sound pressure means the instantaneous difference between the actual pressure and the average or barometric pressure at a given point in space, as provided by sound energy.

Sound pressure level means 20 times the logarithm to the base ten of the ratio of the RMS sound pressure level to the reference of 20 micronewtons per square meter.

(Ord. No. 2008-21, § 1, 8-19-08)