22 August 2006
contribution. Using cut-off optics and low wattage lamps can minimize
light pollution. Shielded luminaires minimize the chance of light trespass
on a neighboring property or building.
Modeling of Faces or Objects: By providing vertical illuminance from
multiple directions, pedestrians' faces will be visible and accurately
Peripheral Detection: Detecting hazards near buildings relies heavily on
peripheral vision. Research shows that peripheral vision and detection
are enhanced under white light. White light (as opposed to more orange
light produced by high-pressure sodium) renders objects sharper and
provides excellent peripheral detection compared to high-pressure
Point(s) of Interest: Lighting should provide for wayfinding and indicate
points of interests, such as the building entry.
Reflected Glare: Polished surfaces can reflect a lamp image if luminaires
are not carefully located. Wet surfaces also often provide a surface that
has the potential for reflected glare. Select and locate luminaires to
minimize this as much as possible.
Shadows: Select and locate lighting to eliminate shadows near entries.
This increases an individual's sense of security.
Surface Characteristics: As noted under the reflected glare item, surface
characteristics and finishes affect the lighting design. Dark surfaces will
reflect little light and may appear dark even when illuminated. Polished
(rather than matte) surfaces may reflect a lamp image.
Vertical Illuminance: Vertical illuminance serves to light objects that may
be hazards as well as other pedestrians.
Target Horizontal Illuminance ( 10%): 50 lux (5 footcandles)
Building entrances may use one or all of the luminaire types and strategies outlined.
Lighting designs use these concepts to consistently designate a hierarchy of buildings
and entries to a single building in addition to providing egress lighting and wayfinding.
For example, the main entry to a building should be the brightest and may be the only
one with sign lighting. Secondary entrances may be designated with a wall sconce or
downlight only. White light, as produced by metal halide, fluorescent, and induction
lamps is two to thirty times more effective for nighttime visibility than high-pressure