(a) "Cut-off angle (of a lumenaire)." The angle, measured up from the nadir, between the vertical axis and the first line of sight at which the bare source is not visible (Ref. Figure 1).
(b) "Full cut-off" or "fully-shielded lumenaire." A lumenaire constructed or shielded in such a manner that all light emitted by the lumenaire, either directly from the lamp or indirectly from the lumenaire, is projected below the horizontal plane through the lumenaire's lowest light emitting part as certified by the manufacturer (Ref. Figure 2).
(c) "Direct light." Light emitted directly from the lamp, off the reflector or reflector diffuser, or through the refractor or diffuser lens, of a lumenaire.
(d) "Glare." Light emitting from a lumenaire with an intensity great enough to cause annoyance, discomfort, or loss of visual performance and visibility.
(e) "Light trespass." The unwanted shining of direct light produced by a lumenaire beyond the boundaries of the property, which it is located. Light that is of an intrusive and objectionable nature (Ref. Figure 3).
(f) "Foot candle." Unit of illumenance equal to one lumen per square foot or 10.76 Lux.
(g) "Lux." The ANSI (American National Standard Institute) unit of illuminance. One lux is one lumen per square meter.
Foot Candle | Lumen | Lux |
1 | 1 per sq. ft. | 10.76 |
0.09 | 1 per sq. meter | 1 |
(h) "Maximum mean average lux." The maximum average lux level on a surface based upon the average lumen output of a lamp over its life. Average lumen output over the life of the lamp is typically about 75% of new lamp lumen output.
(i) "Flood" or "spot light." Any light fixture or lamp that incorporates a reflector or a refractor to concentrate the light output into a directed beam in a particular direction.
(j) "Temporary outdoor lighting." Lighting that is applied temporarily for construction, safety, seasonal events, or public events.
(k) "High intensity discharge lighting (HID)." An arc light that relies upon a gas plasma to emit light rather than a filament.
(Ord. 16-01. Passed 6-25-01.)