HomeMy WebLinkAboutLDS TEMPLE - PDP - PDP120029 - SUBMITTAL DOCUMENTS - ROUND 2 - PHOTOMETRIC PLANFORT COLLINS TEMPLE
Statue and Spire
lighting study
January
2013
The Church of Jesus Christ of Latter Day Saints
PAGE 1
Introduction
It is intended that 4 small LED fixtures with tightly controlled beam spreads be placed at the lower corners
of the spire hidden from view to illuminate the religious monument that sits atop the spire. The purpose of
this subtle lighting effect is very important to the occupant’s religious expression, and is consistant with
similar religious projects done in the past
The goal of this study is to show that the lights being used to light the monument will have limited impact
on the surrounding area. All other lights in the surrounding area are full cut-off light fixtures. This being
the only lights on the site that will not fit this classification it is important that it is demonstrated they are of
religious significance and will enhance the building significantly while not presenting negative
environmental effects to the night sky.
PAGE 2
Visual Study of spill light
Using a tightily conctrolled 9 Degree beam spread it will be possible to direct light to the areas where light
is desired while reducing the amount of spill light. The following elevations shows that the tight 9 degree
beam spreads of the Angel Moroni lights will fall on the statue with very limited light going beyond.
Figure 1: Spill Light Elevation study
PAGE 3
Photometric Calculations of Spill Light
Figure 2: Pseudo Rendering - Less than 1 fc Spill Light @ 150 ft
Figure 3: Pseudo Rendering – 3 fc Spill Light @ 50 ft.
PAGE 4
Comparison: Fort Collins Temple and other Temples
Figure 4: Comparison - Ft. Lauderdale, Florida Temple Pseudo Rendering – 9 fc spill light @ 150 ft.
In this Comparison in Ft. Lauderdale, Florida the illuminace of spill light at 150 ft. is comparable to the
spill light at 50 ft. in our proposed design. It should be noted that this translates to 1/9th the amount of spill
light. Ft. Lauderdale, Florida Temple was also considered a Dark sky compliant project.
PAGE 5
Figure 5: Brigham City, Utah Temple – Pseudo
Rendering
Figure 7: Brigham City, Utah Temple - Rendering
The Brigham City, Utah temple is worth comparing to the Fort Collins Temple. Located close
geographically to Fort Collins in a bordering state, both temples are in mountain towns located within
neighborhood s. This temple has traditional façade lighting as is seen in all temples. This includes
multiple floodlights washing the entire façade surface with light, as well as multiple high intensity spot
lights toward the spire. Lighting the spire is four, high lumen output, 250 watt ‘Color Kinetics Powercore
Reach’ LED fixtures giving an illuminance level of approximately 20 fc. This is comparably brighter than
the proposed Fort Collins illuminance level of 12 fc.
Figure 6: Brigham City, Utah Temple - Night Photo
PAGE 6
Figure 8: Salt Lake City, Utah - Night Photo
The Salt Lake City, Utah Temple is the example most referenced when discussing lights used on or near
the façade of the temple buildings. The Salt Lake temple is a highly illuminated structure with the intent of
standing out against the surrounding area. The lighting ads a level of context, accentuating the large
granite structure. The lighting concept of multiple floodlights washing the entire façade surface with light
is suitable to its surroundings and fits in well with neighboring buildings. Seasonally this is accentuated
more by the Christmas lights at Temple Square.
Historic Temple Square is in the heart of Downtown Salt Lake City and is one of Utah's number one
tourist attractions. Many people show their fondness for this Temple by traveling from all over the world
to salt lake city to visit and view it. It is visited by 3 – 5 Million people per year.i In comparison this is more
people than visit the Grand Canyon, or Yellowstone National Park. Visitation is at its highest level during
the winter months, when visitors come specifically to look at the lights of the temple and surrounding
Temple square.
PAGE 7
Comparison: Specifications of Temple Statue lights and light typically used
Fort Collins Statue Lighting
Typical LDS Temple Statue
Lighting
Luminaire Description
Bega small 9 degree spot:
Compact LED spotlight with a
26 Watt power output.
Color Kinetics Powercore
Reach LED
Proximity of fixture to surface being
light
37’ 8” 150 ft. – 200 ft.
Beam Spread
Very narrow 9 deg. beam
spotlight
Very narrow 5 deg. beam
spotlight
Wattages 26 Watts 250 Watts
Lumens 1238 Lumens 10,950 Lumens
Illuminance: The total luminous flux
incident on a surface, per unit area.
Measured in lux (lx) or lumens per
square meter
12 fc (129.1 lux) 20 fc (215.3 lux)
Luminance: The measure of
the luminous intensity per unit area
of light travelling in a given direction.
Measured in candela per square
meter (cd/m2)
( )
( )
As seen by a viewer looking
at the illuminated object.ii
( )
As seen by a viewer looking
at the illuminated object.ii
Beam diameter at surface 5.7 ft. 15.2 ft.
Spill Light Minimal Average
Figure 10: Bega small 9 degree spot Figure 9: Color Kinetics Powercore Reach
PAGE 8
Comparison: Specifications of Temple Statue lights and surrounding area
lights
Angel Moroni Statue
Lighting
Fort Collins Street Lighting
Luminaire Description
Bega small 9 degree spot:
Compact LED spotlight with a
26 Watt power output.
Streetlight fixture,
70 W high pressure sodium
IES type III
Holophane - PTU
100HP12BG3bt
Beam Spread
Very narrow 9 deg. beam
spotlight
Wattages 26 Watts x 4 70 Watts
Lumens 1238 Lumens x 4 = 4952 8000 Lumens
Illuminance: The total luminous flux
incident on a surface, per unit area.
Measured in lux (lx) or lumens per
square meter
12 fc (129.1 lux) 2.5 fc (26.9 lux)
Luminance: The measure of
the luminous intensity per unit area
of light travelling in a given direction.
Measured in candela per square
meter (cd/m2)
( )
( )
As seen by a viewer looking
at the illuminated object.ii
12, 000 cd/m2
As seen by a viewer under
the light sourceiii
Luminance ratio between lights 1 : 738 (Proposed light: Street light)
Color Temperature 3000k 2200k
Color Rendering Index 80 22
PAGE 9
Analysis
Luminance
Comparing Luminance of a flood light on an object is of considerable difference to the light emitted from a
street light. In a sense it is like comparing apples and oranges.
Luminance: the quantitative expression for the amount of light reflected by a surface in a
specific direction. A more familiar word is “brightness”, although this term must, strictly
speaking, be reserved to describe the subjective impression of luminance on the eye.
A light source will always look brighter than an object with light on it.
Color Rendering Index
Color Rendering Index (CRI): method of categorizing light sources as to how effectively
they illuminate colors as compared to daylight. Rated from 1- 100, with 100 being light
that is similar to daylight
The high pressure sodium lamps being suggested have a CRI of 22. This means that they are very poor
in rendering differences in color. High pressure sodium lamps have the worst CRI of all light sources
available on the market today.
Light sources with a CRI between 80-100 tend to be considered acceptable sources of quality light. The
lights being proposed fit within this category.
Dark Sky Compliance
Dark Sky compliance requires the use of ‘Full-Cut Off’ light fixtures. The easiest way to verify if a fixture is
dark sky compliant or not to look to see if it includes a lens. Any fixture with a lens will reflect some light
toward the sky, and is therefore not dark sky compliant. Fort Collins Street lights are not Dark Sky
Compliant.
The 4 small flood lights being proposed for this project, though are not specifically dark sky compliant, will
have a very limited impact on the night sky. From any one vantage point the effects of only two of these
lights will be seen.
i http://en.wikipedia.org/wiki/Temple_Square
ii Calculated based on Illuminance
iii Chrest, Anthony P. Parking Structures: Planning, Design, Construction, Maintenance, and Repair