For the purposes of this chapter, certain terms and words used
herein shall be interpreted as follows:
A.Â
The word "shall" denotes a mandatory requirement; the word "should"
denotes an advised or recommended provision that is desirable but
not mandatory.
B.Â
The word "includes" or "including" shall not limit the term to the
specific example but is intended to extend its meaning to all other
instances of like kind and character.
C.Â
Words used in the present tense include the future; words used in
the masculine gender include the feminine and neuter; the singular
number includes the plural and the plural the singular.
The meaning and applicability of words and terms in this chapter which are related to zoning, zoning districts, lots, lot usage, yards and the like shall be in accordance with Chapter 280, Zoning, of the Code.
The following lighting definitions are selected from the ANSI/IES
lighting definitions and the IES Lighting Handbook for ready reference
within the text of this chapter.
Glare that is so intense that, for an appreciable length
of time of time after it has been removed, no object can be seen.
The SI unit of luminous intensity. One candela is one lumen
per steradian (lm/sr).
Luminous intensity expressed in candelas.
The angle, measured up from nadir, between the vertical axis
and the first line of sight at which the bare source is not visible.
A luminaire light distribution is designated as "cutoff"
when the candlepower per 1,000 lamp lumens does not numerically exceed
25 (2.5%) at an angle of 90° above nadir (horizontal) and 100
(10%) at a vertical angle of 80° above nadir.
Glare resulting from high luminance or insufficiently shielded
light sources in the field of view.
The effect of stray light in the eye whereby visibility and
visual performance are reduced.
Glare that produces discomfort. It does not necessarily interfere
with visual performance or visibility.
A unit of illuminance. One footcandle is one lumen per square
foot.
The sensation produced by luminance within the visual field
that is sufficiently greater than the luminance to which the eyes
are adapted to cause annoyance, discomfort or loss in visual performance
or visibility.
The areal density of the luminous flux incident at a point
on a surface.
An alternative term for illuminance. Commonly used in a qualitative
or general sense to designate the act of illuminating or the state
of being illuminated.
A generic term for a man-made source of light.
Radiant energy that is capable of exciting the retina and
producing a visual sensation. The visible portion of the electromagnetic
spectrum extends from about 380 to 770 nanometers.
The ration of illuminance for a given area to the value that
would occur if lamps operated at their initial rated lumen output
and if no system variation or deprecation had occurred.
A subjective perception of undesirable illumination, including
the following examples:
The SI unit of luminous flux. Photometrically, it is the
luminous flux emitted within a unit solid angle (one steradian) by
a point source having a uniform luminous intensity of one candela.
A complete lighting unit consisting of one or more lamps
(light sources) together with the parts designed to control the light
distribution and other mechanical and electrical components.
The emitted or reflected light from a surface; relates directly
to perceived "brightness." The unit of luminance is the candela per
square meter (cd/m2).
Radiant flux (radiant power); the time rate of flow of radiant
energy evaluated in terms of a standardized visual response.
The luminous flux per unit solid angle in the direction in
question may be expressed in candelas or lumens per steradian (lm/sr).
The SI unit of illuminance. One lux is one lumen per square
meter (lm/m2).
The hours between the end of evening civil twilight and the
beginning of morning civil twilight. Civil twilight ends in the evening
when the center of the sun's disk is 6° below the horizon
and begins in the morning when the center of the sun's disk is
6° below the horizon.
Glare resulting from reflections of high luminance in polished
or glossy surfaces in the field of view.
Light shining beyond a facility that may annoy occupants
of the adjacent property.
