Cooper Lighting McGraw-Edison PSL - Manual (Page 4)

The IES now recognizes that
lighting a parking garage is a
three-dimensional task and
therefore requires three-dimensional
illumination.
In recognition of the multitude of
visual tasks that need to be
accomplished in a parking garage,
the inclusion of vertical footcandles
is a critical element of quality
illumination in parking garage
environments.
Low mounting heights mean
a fixture must offer a wide
distribution along with excellent
glare control. In addition, a broad,
even coverage of light is even more
difficult to achieve because of the
limited mounting height (often less
than 7'), parking density of vehicles,
signage, shadows of columns and
vehicles, and difficulty in
maintaining surface reflectance
and cleanliness of parking garage
fixtures. With this in mind, the PSL
series garage luminaire has been
developed to provide excellent
vertical illumination, without
sacrificing good visibility for
vehicular and pedestrian traffic.
ies recommendations
The IES, in its recently revised metric for parking garages, RP20 ’98, has added an
important element in its consideration of designing lighting for parking garages—
vertical footcandles. It is now realized what the vertical footcandle does to the
visual environment. Classically, horizontal footcandles have been the only criteria
for the design of parking garages, whether at the horizontal floor plane of 30", 42"
or even 72" above the floor. However, the horizontal footcandle does not go far
enough in providing a comfortable environment for the multitude of visual tasks in
the parking garage.
There are three (3) main visual tasks involved:
1) Providing enough illumination for the driver of the car to safely negotiate the
garage while avoiding pedestrians.
2) Enabling pedestrians’ to visually identify their cars, as well as providing a
feeling of safety and security.
3) Containing light within the structure, so that no wasteful, glaring light is emitted
into the surrounding neighborhood (light trespass).
Max./Min.
Minimum Horizontal Minimum
Horizontal Uniformity Vertical
Lux fc Ratio Lux fc
Basic 10 1.0 10:1 5 0.5
Ramps
Day
20 2.0 10:1 10 1.0
Night 10 1.0 10:1 5 0.5
Entrance Areas
Day
500 50 250 25
Night 10 1.0 10:1 5 0.5
Stairways 20 2.0 10 1.0
NOTE: Consult IES RP20 for complete guidelines on parking garage lumination.
IES RECOMMENDATIONS
(Maintained Illumination for Parking Garages)
psl system—optics
PSL’S 3-D ILLUMINATION
IS PROVIDED BY
UNIQUELY SHAPED
OPTICS:
• Refractors become more efficient
when they have to deviate light
the least. The overall contour of
the refractor was designed to
minimize the depth of the prism,
which minimizes dirt
accumulation and maximizes
light transmission due to Snell’s
Law.
• The concave bottom was designed
to maximize fixture throw while
minimizing surface brightness.
The light that leaves this lower
surface is minimal directly from
the lamp, but becomes maximum
when used with glare guards for
the driver-side shielding.
• An uplight window has been
provided with the reflector system
for a uniform quantity of uplight
for ceiling and wall illumination.
PSL maximizes the uniform
spread of light across the ceiling,
reducing the visual cave effect of
a parking garage.
Single-Row Configuration Double-Row Configuration
The glass refractor has an asymmetric Type II distribution and is designed to throw light into the corners of a rectangular parking
bay. It can be used in single-row and double-row configurations. A quick-mounting bracket provides proper orientation for
fixture mounting to provide the correct optical distribution. One fixture can be used for both single- and double-row
installations.
30 °
60 °
90 °
30
°
180
°
1
2
0
°
1
5
0
°
60 °
30 °
CANDELA
270 °