HomeMy WebLinkAbout01-27-20 City Commission Packet Materials - SP3. City Street Lighting Evaluation with NWECommission Memorandum
REPORT TO: Honorable Mayor and City Commission
FROM: Kellen Gamradt, Engineer II
Shawn Kohtz, City Engineer
SUBJECT: City Street Lighting Evaluation and Joint Presentation with
Northwestern Energy
MEETING DATE: January 27th, 2020
AGENDA ITEM TYPE: Special Presentation
BACKGROUND:
In 2017, the City adopted a new street lighting design standard, created by Clanton & Associates,
which exclusively specifies light emitting diode (LED) light sources for all newly installed street
lights. Prior to adopting this standard, the City specified high pressure sodium (HPS) light
sources which were the industry standard at the time.
LED lights provide substantial cost savings in comparison to HPS through decreased energy
usage and increased lifespan. LED light sources also emit much higher quality light, which
results in safer streets for all users. The City was proactive by adopting this new standard during
a time when the LED industry was relatively new and rapidly changing. Adoption of an LED
street lighting standard was driven by the City’s sustainability program to reduce energy output
of the lights and reduce fossil fuel emissions associated with frequent lamp replacement
associated with HPS lights. However, as LED lights were installed around the city, there were
concerns over the intensity of these new lights and light intrusion into residential areas.
The City Commission recognized these issues at the April 1, 2019 Commission Meeting, and a
strategic plan priority was created to evaluate the City’s new street lighting standard and lights
installed since that standard was implemented in 2017. Upon receiving direction from the
Commission, Clanton & Associates was selected through the City’s professional services
procurement process to perform an onsite evaluation of City street lights, prepare an LED street
lighting evaluation report, recommend updates to our street lighting design standards, and
coordinate with Northwestern Energy on their upcoming LED retrofit project in Bozeman.
364
Street Lighting Evaluation
In late October, Clanton & Associates performed street lighting measurements at twelve sites
located throughout the City. Clanton evaluated nine locations with recently installed City owned
LED street lights, two locations with high pressure sodium lights, and one location where
Northwestern Energy retrofitted an existing HPS light to LED. The sites were primarily selected
based on where light intrusion complaints have been received. The results of this study are
included in the attached Street Lighting Evaluation Report. In summary, Clanton found some
LED light installations were not meeting the 2017 standard, resulting in light intrusion and high
light density on some streets. After reviewing the results of this report, the engineering team
researched lighting designs from these projects and reached out to the lighting professionals who
completed the designs. The lighting study produced three primary considerations:
1. Recent Advancements in Lighting Technology
National lighting standards have lagged behind LED technology in the lighting industry and even
today, those standards are based on high pressure sodium (HPS) lights. An important distinction
between HPS lights and LED lights is what’s referred to as color temperature. HPS lights
typically have a color temperature range between 1900 – 2100 Kelvin which corresponds to a
very warm, orange colored light. Alternatively, LED lights typically have color temperatures in
the 2700 – 5000 Kelvin range which corresponds to a white light (ranging from “warm white”
(2700K – 3000K) to “cool white” (4000K – 5000K) with more blue spectrum light) similar to
moonlight. The human eye has adapted over time to be much more sensitive to higher color
temperatures during night conditions and therefore, LED lights are perceived to be much brighter
at the same lumen output. As a result, national standards that were developed based on HPS
lights result in the perception of over-lighted streets when LED lights are used. The LED
industry has recently began to shift toward lower color temperature lights. In 2016 the lowest
color temperature commercially available was 4,000 Kelvin and just weeks before the 2017 City
lighting standard was adopted, 3,000 Kelvin color temperature lights became available. The
City’s 2017 design standards were updated to require 3,000 Kelvin color temperature lights with
lighting criteria consistent with the national Illuminating Engineering Standards (IES).
Generally speaking, higher color temperature equates to better visibility and more energy
efficiency, while lower color temperature equates to a more comfortable, less glaring light.
Because LED technology is quickly advancing to produce more efficient and better performing
light fixtures, it is important to reevaluate the City’s design standards.
2. Lack of Clarity in Design Standards
Through conversations with our design professionals and Clanton, it became apparent that some
elements of the City street light standards were susceptible to differences of interpretation by
design professionals. The current standards give lighting guidelines based on the amount of
pedestrian conflict on the street (higher pedestrian conflict streets require higher intensity
365
lighting). The current standards do not give clear guidance on what qualifies as “medium” vs
“low” pedestrian conflict which resulted in instances of overly conservative lighting designs.
City standards also set lighting criteria based on street classification. For example, an arterial
street has higher lighting requirements than a local street. The intent of the standard is to provide
additional street lighting for high volume traffic conditions on arterial and collector streets
relative to local streets. However, residential land use is increasingly observed adjacent to
arterial and collector streets. Our current standards did not sufficiently account for residential
land use adjacent to higher volume streets and subsequently, the street lights installed on some
arterial and collector streets appear overly bright and have instances of light intrusion on
residential properties. This was a common theme in areas of light intrusion, where higher
capacity streets receive higher lighting requirements, which are in conflict with adjacent
residential uses.
3. Using Old Design Standards
Some light installations were designed using the City’s old design standards, even though they
were installed recently. Baxter Lane between Davis Lane and North 19th Avenue was designed
in 2015; however, due to complications with securing right-of-way and other design delays, the
project was not constructed until 2019. The lights on this section of Baxter were designed based
on the pre-2017 design standards, and at the time of construction, it was decided not to incur a
costly change order to redesign these lights when new 2017 standards went into effect. This
resulted in an LED light design and installation, based on an HPS standard.
Proposed Recommendations
As part of the street lighting evaluation, Clanton provided recommendations to correct existing
light trespass issues. These recommendations include light dimming and light shielding. A
majority of the issues uncovered during our evaluation can be solved by either dimming or
shielding the light. These options are relatively easy and inexpensive to accomplish and can be
handled internally by the City Streets Division. Light dimming involves adjusting a set screw on
the individual light fixture with a flathead screwdriver (or similar tool) which effectively lowers
the wattage supplied to the light and reduces the amount of light emitted from the fixture, similar
to a dimmer switch on a residential light fixture. Light shielding involves fabricating or ordering
a piece of sheet metal that can be attached to the light head and limits the direction that the
emitted light can travel. Our streets department installs light shields on City owned lights, where
shields have been determined to be necessary, and the cost is generally less than $100 per
installation.
Street Lighting Design Standards Update
366
The next step in our process was to evaluate and modify the 2017 City street light design
standards in order to reduce unwanted light intrusion to the extent feasible while still maintaining
safe levels of light on City streets, to clarify the specifications for design professionals, and to
update street light standards to account for recent LED technology changes. Clanton and
Associates drafted updates to the 2017 design standards to address the issues observed during the
street light evaluation. A draft copy of the proposed revisions are included as an attachment to
this memorandum; a brief summary of these changes are described below:
Pedestrian activity levels are clarified by linking them to adjacent land use
Lighting distributions are clarified based on street width
The luminance criteria is reduced 33% from the current national IES standards
House side shields are required in residential areas
On-board manual dimming capability is required on all lights
Designers are required to provide lighting calculations
A light trespass limitation of 0.2 cd/m2 is now required 5 feet behind right-of-way
The backlight-uplight-glare (BUG) rating has been modified to reduce the potential
for light intrusion A submittal review checklist has been created to verify lighting
designs prior to engineering approval
City staff will finalize and arrange for adoption of updated standards through the City’s standard
procedure to modify the Bozeman Design Standards and Specifications Policy outlined in
Resolution Number 1611.
As mentioned previously, LED technology is rapidly changing and becoming more efficient.
This creates problems when drafting design standards or designing lighting projects that may not
be constructed until several years after adoption of a new standard. During the onsite lighting
evaluation, we found locations where lighting designs met all standard requirements for wattage,
lumen output, and spacing; however, the street lights still resulted in higher roadway luminance
than was required. In the proposed design standards update, we’ve mitigated against this issue
by eliminating hard requirements for spacing and wattage, and instead focused on roadway
luminance. This change prioritizes the amount of light reaching the street (luminance) and
allows for flexibility as LED technology advances.
Coordination with Northwestern Energy
Northwestern Energy is currently preparing to begin an LED retrofit project in Bozeman. Out of
the 3,300 light fixtures in the City, Northwestern Energy owns approximately 1,400 of the street
lights, and a vast majority of these lights are high pressure sodium. The City owns and maintains
approximately 768 street lights, Montana Department of Transportation owns and maintains
approximately 64 street lights and ownership is currently not identified for approximately 1100
street lights. In the spring of 2020, Northwestern Energy will begin the process of retrofitting
their lights to energy efficient LED fixtures. Northwestern Energy has already completed a
retrofit project throughout the City of Billings and started to retrofit street lights in Helena. In
367
Bozeman, the retrofits will primarily be 3,000 Kelvin color temperature lights; however, in
highly sensitive residential areas, 2,700 Kelvin fixtures will be used.
In order to take full advantage of the professional expertise of the City’s street light consultant,
the City held a meeting on January 7th with Northwestern Energy and Clanton & Associates to
discuss the upcoming retrofit project, to share information about LED street lights, and to
collaborate based on results of the City’s street light study. The City has also invited
Northwestern Energy to this special presentation to the City Commission to discuss the retrofit
project in more detail and inform the public about what we can expect this coming spring.
Conclusions
In conclusion, street lighting is a rapidly evolving industry that requires updates to design
standards to ensure expectations are in step with new LED technologies. The proposed standards
update is consistent with the City’s needs to balance sufficient light levels for safety on public
streets while also limiting light intrusion to residential areas to the extent possible. In order to
address light intrusion issues from recently installed LED light installations, City Streets
Division Staff will respond within existing maintenance budget limits to make modifications to
problematic street lights in the current fiscal year and new budget will be proposed in the next
several months to address any remaining unfunded street light modifications in fiscal year 2021
as recommended by Clanton & Associates.
LED street lights provide substantial cost savings through increased energy efficiency and longer
lifespans relative to the high pressure sodium lights installed using the pre-2017 City standard.
In fact, it is becoming more and more difficult to obtain high pressure sodium lamps due to the
advantages of LED lights. High pressure sodium lamps are being phased out of the industry
such that they will soon be unavailable for replacements. As reviewed during this study, LED
lights provide more visible light to City streets at night, resulting in lower light density
requirements to sufficiently light streets.
Lastly, City staff have worked with Northwestern Energy to coordinate findings of the City’s
street light study and updates to City standards with the Northwestern Energy retrofit project.
Attachments: Street Lighting Evaluation Report, Proposed Design Standards Update
Report compiled on: 01/16/2020
368
Bozeman Street Lighting Evaluation November 2019
1
Bozeman Street Lighting Evaluation
Bozeman, Montana
October 23rd, 2019
369
Bozeman Street Lighting Evaluation November 2019
Project Summary
Site Evaluation Summary
The City of Bozeman, Montana requested Clanton and Associate do a street lighting
evaluation at 12 different sites throughout the City to gain an understanding of how the new
“Standard Specifications for Lighting Materials and Installation” was being implemented and
to evaluate how the lighting meets criteria throughout the City. The City provided Clanton
with survey locations that consist of arterial, collector and local roads in mostly residential
areas. On October 23rd
, 2019, Clanton and Associates evaluated the following sites:
Clanton and Associates photographed each site during the day and night and took the
following measurements after dark: roadway luminance (the amount of light reflected from a
surface that the eye perceives, expressed in units of candela per square meter [cd/m2
]),
sidewalk illuminance (the amount of light reaching a surface, expressed in units of
footcandles [fc]), luminaire spacing, luminaire mounting height, and color temperature. The
City of Bozeman provided Clanton with luminaire submittals for sites that were documented,
and with this information Clanton was able to determine some of the following information:
lumen package, distribution, BUG rating, and wattage. With the information provided by the
City and the measurements that were taken at each site, Clanton determined which
characteristics of each lighting installation met the Specification and which did not. This
report summarizes each site and compares lighting characteristics and measured values to
criteria set forth in the “Standard Specifications for Lighting Materials and Installation”
document.
For each site, Clanton provides recommendations for improving the lighting, and strategies to
help avoid similar mistakes in the future. When designing with LED luminaires in Bozeman,
Clanton recommends reducing the current criteria by 33% to account for the perceived
brightness from white LEDs. This reduction will preserve the visibility and safety at each site
while also reducing over lighting and glare.
7. Westmoreland & Vermeer
8. Laurel @ Debour
9. 10th @ Villard
10. Arthur @ Grand
11. 11th @ Graf
12. Blackwood @ 19th
1. Baster @ Ferguson
2. Baxter @ the Post Office
3. Ryun Sun @ Sickle
4. Oak @ Windrow
5. Durston @ Laurel
6. Arnhem Way
370
Bozeman Street Lighting Evaluation November 2019
3
Street Classifications
371
Bozeman Street Lighting Evaluation November 2019
Evaluated Sites Map
372
Bozeman Street Lighting Evaluation November 2019
Criteria Acutal Criteria Acutal Criteria Acutal Criteria Acutal Criteria Acutal
Baxter @ Ferguson Minor Arterial/Collector Poor: Site Is Far Too Bright 0.6
cd/m^2
1.56
cd/m^2
11,500 -
11,800 16,181 135 145 300-400 220 3,000 3,000
Baxter @ the Post
Office Minor Arterial Moderate: Site Is Slightly Too Bright
0.6
cd/m^2
1.38
cd/m^2
11,500 -
11,800 NA 135 137 300-400 325 3,000 4,000
Ryun Sun @ Sickle Local Moderate: Luminaire Needs To Be Rotated 0.3
cd/m^2
0.35
cd/m^2
5,000 -
5,300
7,000 -
8,000 65 75 400-600 NA 3,000 3,651
Oak @ Windrow Principal Arterial Moderate: Site Is Slightly Too Bright 0.9
cd/m^2
1.11
cd/m^2
21,700 -
22,000 27000 270 207 200-250 260 3,000 2,928
Dusrton @ Laurel Minor Arterial Poor: Luminaires Are Not Focused On Roadway And
Are Very Glaring
0.6
cd/m^2
0.39
cd/m^2
11,500 -
11,800 19,245 135 188 300-400 240 3,000 3,700
Arnhem Way Local Moderate: Light Is Too Glaring. However, Pedestrian
Lights Are Nice In Neighborhoods
0.3
cd/m^2
0.63
cd/m^2
5,000 -
5,300 1944 65 34 400-600 NA 3,000 4,751
Westmoreland &
Vermeer Local Excellent: Lighting Is Great For Residential Intersection
0.3
cd/m^2
0.30
cd/m^2
5,000 -
5,300 5,770 65 66 400-600 NA 3,000 3,661
Laurel @ Debour Collector Excellent: Lighting Is Comfortable And Appropriate For
Collector Street
0.4
cd/m^2
0.22
cd/M62
Bozeman Street Lighting Evaluation November 2019
Site : Baxter @ Ferguson
Principal Arterial Residential
1
Summary –
There was too much light at this site resulting in glare, light trespass, and wasted energy.
Bad:
• Site was extremely over lighted - over 2.5times the roadway criteria, and twice the sidewalk criteria.
• Luminaire lumens were significantly higher than criteria as well as a higher than approved glare rating.
• Higher glare rating and over lighting resulted in extremely high light trespass values.
Good:
• Part number has "Field Adjustable Wattage Selector" allowing light levels to be reduced in the field.
• Luminaire spacing was adequate for single sided arrangement when using appropriate lumen package
and distribution.
• Mounting height is appropriate.
Recommendations:
• Significantly dim lighting to 40% of current output.
• Add front light shield.
• Replace luminaires with less wattage Type 2S Luminaires.
• Removal of every other light in along Baxter. Verify that uniformity would still be acceptable with a
field test.
Light Trespass Example
Criteria Actual
Roadway Luminance: 0.6 cd/m^2 1.56 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.572 fc
Luminaire Lumens: 11,500-11,800 16,181
Luminaire Wattage: 135 145
Luminaire CCT: 3000 3000
Luminaire Spacing: 300-400 220'*
Luminaire Mounting Height: 30-35 30-35
Luminaire BUG Rating: B3-U0-G2 B3-U0-G3
Luminaire Part Number:
*Luminaires were in a single sided arrangement
Measurement Summary
Minor Arterial - Low Pedestrian Conflict
RFL-145W64LED3K-G2-R3M-FAWS
374
Bozeman Street Lighting Evaluation November 2019
Site : Baxter @ the Post Office
Minor Arterial Residential/Commercial
2
Summary –
This site is slightly over lighted, with too much light on the roadway, but appropriate
amounts of light on the sidewalk.
Bad:
• Site is over lighted - over 2 times the roadway criteria.
• Luminaire is 4000K which does not meet criteria.
• There was slightly too much light trespass onto neighboring residents.
Good:
• Sidewalk illuminance met criteria.
• Luminaire spacing was adequate as well as correct mounting height.
• Luminaire had "Field Adjustable Wattage Selector" to allow for adjustments to be made.
Recommendations:
• Dim the luminaires to approximately 50% of current output.
Criteria Actual
Roadway Luminance: 0.6 cd/m^2 1.38 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.338 fc
Luminaire Lumens: 11,500-11,800 NA
Luminaire Wattage: 135 137
Luminaire CCT: 3000 4,000
Luminaire Spacing: 300-400 325'*
Luminaire Mounting Height: 30-35 30-35
Luminaire BUG Rating: B3-U0-G2 NA
Luminaire Part Number:
*Luminaires were in a single sided arrangement
Measurement Summary
Minor Arterial - Low Pedestrian Conflict
NA
Roadway Slightly Over Lighted
375
Bozeman Street Lighting Evaluation November 2019
Site : Ryun Sun @ Sickle
Local Residential
3
Summary –
The lighting is appropriate for this site, but the luminaire is aimed the wrong way.
Bad:
• The Luminaire is aimed the wrong way. Distribution should parallel Ryun Sun.
• Luminaire lumens exceeds criteria. When luminaire is rotated, it could be dimmed and still
sufficiently light the roadway.
• CCT exceeds criteria.
Good:
• Roadway luminance is slightly above criteria, but will most likely exceed criteria if luminaire is
reoriented.
• Intersection only lighting is appropriate for this area.
Recommendations:
• Rotate the luminaire so it is aligned with the primary street in the area and dim luminaire to 75% of
current output if site become over lighted.
Luminaire Aimed The Wrong Way
Criteria Actual
Roadway Luminance: 0.3 cd/m^2 0.35 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.868 fc
Luminaire Lumens: 5,000-5,300 7000-8000
Luminaire Wattage: 65 75
Luminaire CCT: 3000 3,651
Luminaire Spacing: 400-600 NA
Luminaire Mounting Height: 25-30 25
Luminaire BUG Rating: B2-U0-G1 NA
Luminaire Part Number:
Measurement Summary
Local - Low Pedestrian Conflict
ELA BELL22-CR21A-P3048K-MOD25
376
Bozeman Street Lighting Evaluation November 2019
Criteria Actual
Roadway Luminance: 0.9 cd/m^2 1.11 cd/m^2
Sidewalk Illuminance: 0.5 fc 0.916 fc
Luminaire Lumens: 21,700-22,000 27,000
Luminaire Wattage: 270 207
Luminaire CCT: 3000 2928
Luminaire Spacing: 200-250 260
Luminaire Mounting Height: 35-40 30-35
Luminaire BUG Rating: B3-U0-G3 NA
Luminaire Part Number:
Measurement Summary
Principal Arterial - Medium Pedestrian Conflict
RFL 215W96LEDK-T
Site : Oak @ Windrow
Principal Arterial Residential
4
Summary –
The site was slightly over lighted, but felt comfortable at this location.
Bad:
• Luminaire lumens exceed the specification.
• Roadway luminance slightly exceeds criteria, however this amount of excess is standard for new
installations.
• Sidewalk illuminance exceeds criteria.
• There was spill light onto adjacent properties, but it was not as noticeable because there are not any
residents yet. This could be more of an issue in the future.
Good:
• Color temperature is correct
• Site feels comfortable and crosswalks are well lighted.
Recommendations:
• Dim luminaires to 80% of current output.
Intersections Are Well Lighting, But Slightly Too Much
Light On Roadway
377
Bozeman Street Lighting Evaluation November 2019
Criteria Actual
Roadway Luminance: 0.6 cd/m^2 0.39 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.34 fc
Luminaire Lumens: 11,500-11,800 19,245
Luminaire Wattage: 135 188
Luminaire CCT: 3000 3,700
Luminaire Spacing: 300-400 240
Luminaire Mounting Height: 30-35 38
Luminaire BUG Rating: B3-U0-G2 B3-U0-G4
Luminaire Part Number: AR-3P-70-80L-4K-240-CC
Measurement Summary
Principal Arterial - Low Pedestrian Conflict
Site : Durston @ Laurel
Minor Arterial Residential
5
Summary –
Site lights are extremely glaring and cause significant light trespass. Shielding interrupts
distribution resulting in high contrast.
Bad:
• Lights are extremely glaring and are too bright for this site.
• House side shields create dramatic shadowing on road resulting in the roadway not meeting criteria.
• Extreme light trespass on the property line behind the luminaires.
• There is too much light at this site, and it is poorly distributed resulting in the site not meeting
criteria and wasted energy.
Good:
• Front light shield blocks light trespass onto residents across the road.
Recommendations:
• Replace luminaires with a lower wattage Type 2S distribution. Run calculations to ensure there is no
light trespass, and if necessary use backlight or front light shielding.
Luminaire Shielding Results In Dark Spots On
Roadway
378
Bozeman Street Lighting Evaluation November 2019
Criteria Actual
Roadway Luminance: 0.3 cd/m^2 0.63 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.879 fc
Luminaire Lumens: 5,000-5,300 1944
Luminaire Wattage: 65 34
Luminaire CCT: 3000 4,751
Luminaire Spacing: 400-600 NA
Luminaire Mounting Height: 25-30 8
Luminaire BUG Rating: B2-U0-G1 B1-U0-G1
Luminaire Part Number:
Measurement Summary
Local - Low Pedestrian Conflict
PWY-EDG-3M-P8-02-D-24-BZ-F
Site : Arnhem Way
Local Residential
6
Summary –
This luminaire is extremely glaring when mounted at this height. The effect of creating pools
of light for wayfinding is appropriate for residential neighborhoods.
Bad:
• Luminaire is very glaring at this height and needs better shielding. Luminaire causes discomfort when
close to it.
• Color temperature far exceeds the spec.
Good:
• Lighting creates pools of light to aid in wayfinding.
Recommendations:
• Replace luminaires and do not use this luminaire mounted at this height.
• Pedestrian height luminaires (12’-15’) in residential areas create a nice effect and are often preferred
by residents. Clanton recommends continuing this style of lighting, but using a full cutoff, well
shielded luminaire mounted at an appropriate height.
Light Is Very Glaring When Near It
379
Bozeman Street Lighting Evaluation November 2019
Site : Westmoreland & Vermeer
Local / Residential
7
Criteria Actual
Roadway Luminance: 0.3 cd/m^2 0.3 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.24 fc
Luminaire Lumens: 5,000-5,300 5,770
Luminaire Wattage: 65 66
Luminaire CCT: 3000 3,661
Luminaire Spacing: 400-600 NA
Luminaire Mounting Height: 25-30 25
Luminaire BUG Rating: B2-U0-G1 B2-U0-G2*
Luminaire Part Number:
*Has houseside shield
Measurement Summary
Local - Low Pedestrian Conflict
SAR-1SA-3-E35-60L-4K-DB-A-32
Summary –
This site is a very well lighted intersection in a residential neighborhood and should be an
example for the rest of the city.
Bad:
• A HSS shield is needed at this site to be comfortable. Future lights should have less lumen output
to meet the spec, which should reduce the need for a house side shield.
Good:
• Site meets roadway and sidewalk criteria.
• HSS provides great backlight control without dramatic shadows on the roadway
Recommendations:
• This is a good site and should be an example for the rest of the city.
• When designing local residential streets in the future, a luminaire with less lumen output and
Type 2S distribution should reduce the need for any shielding.
Intersection Is Sufficiently And Appropriately Lighted
380
Bozeman Street Lighting Evaluation November 2019
Criteria Actual
Roadway Luminance: 0.4 cd/m^2 0.22 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.1 fc
Luminaire Lumens: 8,300-8,600 10,613
Luminaire Wattage: 100 95
Luminaire CCT: 3000 3,661
Luminaire Spacing: 250-300 NA
Luminaire Mounting Height: 25-30 35
Luminaire BUG Rating: B3-U0-G2 B3-U0-G3*
Luminaire Part Number:
*Has houseside shield
Measurement Summary
Collector - Low Pedestrian Conflict
AR-1A-3P-35-80L-4K-240-CC-HUNTER
Site : Laurel @ Debour
Collector Residential
8
Summary –
This is a well lighted collector street which felt comfortable when driving and walking along it.
Bad:
• CCT exceeds criteria.
• Luminaire lumens exceed criteria, but HSS controls light.
• Sidewalks are dark due to harsh cut off caused by shielding.
• BUG rating exceeds criteria without HSS.
Good:
• The street lighting is very comfortable and is appropriate for a residential collector street.
Recommendations:
• Reduce the lumens to meet the specification and use a Type 2S distribution to better focus light on the
street without the need for shielding. This distribution will also provide light onto the sidewalk without
excessive light trespass.
• This is an appropriate light level for collector streets and felt comfortable while driving the street.
Roadway Is Sufficiently And Appropriately Lighted
381
Bozeman Street Lighting Evaluation November 2019
Site : 10th & Villard
Local Residential
9
Summary –
The LED upgrade at this site has good backlight control, but also has too much front light
and is illuminating housing across the road.
Bad:
• LED has too much front light and is shining directly on houses across the street.
• Th HPS lights on this road are cycling on/off.
• Roadway luminance exceeds criteria.
Good:
• Backlight control on LED light is great!
Recommendations:
• This LED appears to be a Type 3. Clanton recommends using a Type 2S with les wattage on narrow
residential roads to reduce light trespass.
• Residential streets do not need to be continuously lighted. Consider only lighting intersections and
possibly mid block.
Criteria Actual
Roadway Luminance: 0.3 cd/m^2 0.49 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.24 fc
Luminaire Lumens: 5,000-5,300 NA
Luminaire Wattage: 65 NA
Luminaire CCT: 3000 2926
Luminaire Spacing: 400-600 270
Luminaire Mounting Height: 25-30 35
Luminaire BUG Rating: B2-U0-G1 NA
Luminaire Part Number: NA
Measurement Summary
Local - Low Pedestrian Conflict
Front Light Is Illuminating Houses Across The Road
382
Bozeman Street Lighting Evaluation November 2019
Site : Arthur @ Grand
Local Residential
10
Summary –
This Intersection is illuminated with HPS light and is over lighted, resulting in light trespass.
Bad:
• Roadway luminance exceeds criteria.
• HPS luminaires lack control of light resulting in spill light and light trespass.
Good:
• Sidewalk is well lighted.
• Mounting height is appropriate.
Recommendations:
• When upgrading to LED, run calculations to determine best lighting strategy. Intersections of this size
may only need one luminaire to be sufficiently illuminated.
• Type 3 distributions are often best for intersection lighting but calculations should be run to confirm
this.
Criteria Actual
Roadway Luminance: 0.3 cd/m^2 0.85 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.31 fc
Luminaire Lumens: 5,000-5,300 NA
Luminaire Wattage: 65 NA
Luminaire CCT: 3000 1,847
Luminaire Spacing: 400-600 NA
Luminaire Mounting Height: 25-30 25
Luminaire BUG Rating: B2-U0-G1 NA
Luminaire Part Number: NA
Measurement Summary
Local - Low Pedestrian Conflict
HPS Lights Lack Control Resulting In Spill Light
383
Bozeman Street Lighting Evaluation November 2019
Site : 11th & Graf
Collector Residential/Open Space
11
Criteria Actual
Roadway Luminance: 0.4 cd/m^2 0.71 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.39 fc
Luminaire Lumens: 8,300-8,600 7168
Luminaire Wattage: 100 72
Luminaire CCT: 3000 3635
Luminaire Spacing: 250-300 225'
Luminaire Mounting Height: 25-30 35
Luminaire BUG Rating: B3-U0-G2 B1-U0-G2
Luminaire Part Number:
RFM-72W32LED3K-T-R3S-UNIV-DMG-
RCD-PH9-GN6TX
Measurement Summary
Collector - Low Pedestrian Conflict
Summary –
The lights at this site meet the spec, but the luminance is above criteria and there is too
much spill light onto private property.
Bad:
• Roadway luminance exceeds the criteria.
• CCT is above the spec.
• Front light is obtrusively shining onto private property and will most like be an issue is residents are
building along this road.
• Luminaires are spaced too closely together.
Good:
• Although luminaire lumens and wattage meet the spec, the site is over lighted.
Recommendations:
• Dim lights to approximately 40% of current output.
• Add front light shield to reduce spill light onto adjacent properties.
Front Light Is Excessive and Spilling Onto Private
Property
384
Bozeman Street Lighting Evaluation November 2019
Criteria Actual
Roadway Luminance: 0.4 cd/m^2 0.28 cd/m^2
Sidewalk Illuminance: 0.3 fc 0.5 fc
Luminaire Lumens: 8,300-8,600 NA
Luminaire Wattage: 100 NA
Luminaire CCT: 3000 1816
Luminaire Spacing: 250-300 210*
Luminaire Mounting Height: 25-30 25-30
Luminaire BUG Rating: B3-U0-G2 NA
Luminaire Part Number: NA
*Luminaires were in a single sided arrangement
Measurement Summary
Collector - Low Pedestrian Conflict
Site : 19th and Blackwood
Collector Residential
12
Summary –
This site is lighted with HPS lights, but is comfortable and light levels are appropriate. Light
could be controlled better to reduce spill light.
Bad:
• The HPS luminaires lack control of light resulting in spill light onto residents.
• HPS lights do not meet the spec.
Good:
• Light levels are appropriate for this street and lighting is comfortable while driving and walking.
Recommendations:
• Install house side shield to reduce light trespass onto residents.
• Replace with 2700K or 3000K LED and light to 0.2cd/m^2 (?)
Light Trespass Example
385
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Table of Contents
Section I. General ....................................................................................................... 3
Section II. Definitions ............................................................................................... 3
Section III. Scope of Work. ....................................................................................... 4
A. General .............................................................................................................................. 4
Section IV. Control of Work ...................................................................................... 4
A. General .............................................................................................................................. 4
B. Deviation Request .............................................................................................................. 5
Section V. Utility Clearances ................................................................................... 5
A. Overhead Powerline Clearances ....................................................................................... 5
B. Below-grade Utility Clearances .......................................................................................... 5
Section VI. Conduit .................................................................................................... 5
A. Plastic Conduit - PVC ......................................................................................................... 5
B. Plastic Conduit – HDPE ..................................................................................................... 6
C. Steel Conduit ...................................................................................................................... 6
D. Conduit Installation ............................................................................................................. 6
Section VII. Pull Boxes / Splice Boxes ...................................................................... 7
A. General .............................................................................................................................. 7
B. Pull Box / Splice Box Installation ........................................................................................ 7
Section VIII. Concrete Foundations ........................................................................ 8
A. Light Standard Foundations ............................................................................................... 8
B. Concrete Foundation Pads ................................................................................................ 8
C. Concrete Fill for Pedestal Type Cabinets ........................................................................... 8
Section IX. Wiring ...................................................................................................... 8
A. General .............................................................................................................................. 8
Section X. Bonding and Grounding ........................................................................ 9
A. General .............................................................................................................................. 9
Section XI. Lighting Control Centers and Metered Pedestals ............................... 9
A. General .............................................................................................................................. 9
B. Installation .......................................................................................................................... 9
Section XII. Lighting Design Criteria ....................................................................... 10
A. General .............................................................................. Error! Bookmark not defined.
B. Correlated Color Temperature (CCT) ................................ Error! Bookmark not defined.
All luminaires shall have a Correlated Color Temperature (CCT) of 2700K - 3000K (+/- 275K).
.................................................................................................. Error! Bookmark not defined.
C. Non-Signalized Intersection ............................................................................................. 11
D. Signalized Intersections ..................................................... Error! Bookmark not defined.
E. Intersections of Pathways and Streets ............................................................................. 12
F. Continuous Lighting on Streets ........................................................................................ 14
G. Design Considerations. ................................................................................................ 16
H. Pedestrian Lighting. ......................................................................................................... 18
386
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
I. Pathway Lighting. ............................................................................................................. 18
Section XIII. Streetlight Luminaires ...................................................................... 19
A. General ............................................................................................................................ 19
B. Installation ........................................................................................................................ 20
C. Approved Manufacturers – Cobrahead Style [Refer to Figure 10 – Typical Streetlight
Standard Detail] ....................................................................................................................... 20
D. Approved Manufacturers – Bell Style [Refer to Figure 10 – Typical Streetlight Standard
Detail] ...................................................................................................................................... 20
Section XIV. Pedestrian Luminaires ...................................................................... 20
A. General ............................................................................................................................ 20
B. Installation ........................................................................................................................ 21
C. Approved Products – Traditional Post-top Style [Refer to Figure 11 – Typical Post-Top
Pedestrian Light Standard Detail] ............................................................................................ 21
D. Approved Products – Bell Style [Refer to Figure 12 – Typical Arm-Mount Pedestrian Light
Standard Detail] ....................................................................................................................... 21
Section XV. Pathway Luminaires ......................................................................... 21
A. General ............................................................................................................................ 21
B. Installation ........................................................................................................................ 22
C. Approved Products ........................................................................................................... 22
Section XVI. Poles. ................................................................................................. 22
A. General ............................................................................................................................ 22
B. Installation ........................................................................................................................ 24
Section XVII. Pole bases ......................................................................................... 24
A. General ............................................................................................................................ 24
B. Breakaway Bolt Couplings. .............................................................................................. 24
C. Frangible Transformer Base. ........................................................................................... 24
D. Non-Breakaway Anchor Base. ......................................................................................... 24
Section XVIII. Submittal Requirements ................................................................... 25
A. General ............................................................................................................................ 25
387
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Section I. General
These specifications for the provision of lighting installations are intended to provide a set of
minimum standards that shall be followed for street lighting, pedestrian lighting and pathway
lighting installations within the City of Bozeman public right-of-way or property. These standards,
plans, and any special provisions shall apply to all materials supplied, methods, and procedures
of work to be followed, and other general minimum requirements that shall be complied with
before work is accepted by the City of Bozeman.
The City of Bozeman has adopted the following as part of these standard specifications:
A Standard Specifications for Road and Bridge Construction (latest edition), Montana
Department of Transportation, and all amendments and revisions pertaining thereto.
B Manual on Uniform Traffic Control Devices (latest edition), Federal Highway
Administration.
C NFPA 70 - National Electrical Code (latest edition)
D NESC - National Electrical Safety Code
The standard specifications outlined in this document are revisions and amendments to the
Montana Department of Transportation Standard Specifications for Road and Bridge
Construction. In situations where there is a conflict or question of interpretation, these
specifications and any special provisions shall prevail.
These specifications, the plans, any special provisions, and all supplemental documents are
essential parts of a contract and a requirement occurring in one is as binding as though occurring
in all. They are intended to be complementary and to describe and provide for the complete work.
In case of a discrepancy, figured dimensions shall govern over scaled dimensions; plans shall
govern over standard specifications; and special provisions shall govern over plans and standard
specifications.
Section II. Definitions
Development Review Committee (DRC) evaluates all proposals subject to the provisions of
Chapter 38, the Unified Development Code within the Bozeman Municipal Code. The DRC is
charged with reviewing items related to public health and safety.
Low Pedestrian Conflict occurs when adjacent to residential, rural or industrial land uses with
very low volumes of nighttime pedestrian usage. These can occur in any of the cited street
classifications but are typically suburban streets with single family dwellings, multi-family
residential developments, and rural or semi-rural areas.
Medium Pedestrian Conflict occurs when adjacent to commercial and institutional land uses
where a moderate numbers of pedestrians utilize the streets at night. Typical are downtown
office areas, blocks with libraries, schools, churches, shopping centers, restaurants, parks, and
streets with transit lines.
Pathway lighting is provided to light trails and pathways that are not adjacent to streets.
Pathway lighting assemblies are typically 36 inches to 48 inches. The distribution of the light is
388
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
directed towards the trail or pathway.
Pedestrian lighting is provided to light the sidewalk (attached or detached) along arterial,
collector, local streets, public plazas, trails or other pedestrian areas. Pedestrian lighting
assemblies are typically between 12 feet to 15 feet. The distribution of the light is directed
towards the sidewalk.
Special Improvement Lighting District (SILD) an improvement district embracing street or
streets or public highway therein or portions thereof and property adjacent thereto or property
which may be declared by said council to be benefitted by the improvement to be made for the
purpose of lighting such street or streets or public highway. All or any portion of the cost of
installing and maintaining such lighting system is required to be paid by the owners of the
property embraced within the boundaries of such districts.
Street lighting is provided for arterial, collector, and local streets where pedestrians and cyclists
are generally present. The primary purpose of street lighting is to help the motorist identify
obstacles, provide adequate visibility of pedestrians and cyclists, and assist in visual search
tasks, both on and adjacent to the street. Street lighting assemblies are typically between 25
feet and 40 feet. The distribution of the light is directed towards the street.
Section III. Scope of Work.
A. General
The design engineer shall consider the need for street lighting, pedestrian lighting and pathway
lighting, as specified in Section XII Lighting Criteria, in the development plans for any new or
reconstructed roadways. The guidelines and specifications outlined here shall be applicable to
lighting located within the City’s Right of Way.
All street, pedestrian and pathway lighting shall be operated and maintained through the
creation of a new SILD, through the annexation to an existing SILD or through some other
equivalent means approved by the City of Bozeman. The application to create or annex to an
existing SILD shall be submitted to the City within two months of preliminary approval of the
development. The approval to create or annex to an SILD shall be granted prior to final plat for a
subdivision or Occupancy if a final plat is not required.
Street lighting shall be installed per 38.39.030 B, BMC (in regards to completion time for
improvements).
Individual yard lights on private property shall not be used for street lighting.
Section IV. Control of Work
A. General
Record drawings shall be provided to the City for all new and re-constructed lighting systems that
are to be maintained by the City. Cut sheets of all equipment shall be provided with the record
drawings.
For lighting projects in new subdivisions, record drawings shall be provided and a final
inspection done before building permits will be approved.
Contractor is required to submit record drawings and equipment cut sheets for any electrical
389
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
work that alters an existing lighting system, prior to receiving full payment for project work.
B. Deviation Request
Deviations may be granted by the City Engineer. Appeals to denials of deviation requests shall
be to the Director of Public Works. Refer to Section 38.35.050 for additional information.
Section V. Utility Clearances
A. Overhead Powerline Clearances
Light standard assembly locations must comply with National Electrical Safety Code (NESC)
Rules regarding clearance requirements between phase conductor and streetlight and between
primary conductor and streetlight.
Light standard assembly locations must comply with the Occupational Safety and Health
Administration (OSHA) 1926.1408 minimum clearance distances to overhead power lines.
The City will not accept work that does not meet these clearance requirements or requires a
qualified worker to maintain the lighting system.
B. Below-grade Utility Clearances
Light standard foundations shall be located to maintain a minimum horizontal clearance of 10 feet
from the edge of foundation to the edge of any water line, sewer line, storm drain line or gas line.
When paralleling water, sewer, storm and gas lines with lighting conduit, a 10-foot horizontal
separation is preferred. Where 10 foot separation is impractical, a minimum of 5-foot horizontal
separation will be allowed.
Section VI. Conduit
A. Plastic Conduit - PVC
All PVC conduits located under roadways, driveways, and other vehicular access areas shall be
schedule 80 type EPC-80-PVC.
Conduits under non-vehicular locations may be schedule 40 type EPC-40-PVC.
PVC conduit shall be manufactured of high-impact PVC, and shall conform to industry standards
and commercial standard CS-207-60 and NEMA TC 2.
When bending PVC conduit, a water bending process may be used. This shall consist of a water
filled steel pipe 4' long, heated to the temperature that will render the PVC conduit pliable in 30
seconds after insertion in the pipe. The conduit may then be bent to the desired angle and held
in an appropriate jig for a cooling period.
The Contractor may use other methods of bending PVC conduit if the preceding method is found
unsuitable due to climatic conditions, but only after demonstrating the proposed method to the
Engineer and receiving his approval.
Bends in PVC conduit shall be made and conform to all appropriate sections of the National
Electric Code or local codes governing bending radius, and the number of bends allowed as
applicable for rigid conduit.
390
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Conduit bends, except factory bends, shall have a radius of not less than six times the inside
diameter of the conduit.
B. Plastic Conduit – HDPE
All HDPE conduit shall be factory lubricated, low friction, high-density conduit constructed of virgin
high density conduit constructed of virgin high-density polyethylene resin. Conduit shall be
capable of being coiled on reels in continuous lengths, transported, stored outdoors, and
subsequently uncoiled for installation, without affecting its properties or performance.
Bored electrical conduit shall be HDPE and installed using trenchless technology of either jacked
conduit or directional boring.
C. Steel Conduit
Steel conduit for exterior, surface mounted, above grade installations shall be Galvanized Rigid
Conduit (GRC). Polyvinyl Chloride coated Galvanized Rigid Conduit (PVC coated GRC) may be
used for below grade installations, encased in concrete and above grade where exposure to water
is imminent.
GRC conduit shall comply with ANSI C80.1 and UL 6.
PVC coated GRC shall comply with NEMA RN 1. Coating thickness shall be a minimum of 0.040
inch (1mm), both inside and out.
D. Conduit Installation
All conduit direct buried in contact with earth shall be PVC, HDPE or PVC coated GRC. PVC
conduit Installation through foundations (other than light standard foundations) shall have
transition to GRC or PVC coated GRC prior to exposure above foundation.
Underground conduit shall have the following minimum diameter (ID) trade size conduit, unless
otherwise approved by the Engineer.
1. Conduit Sleeves Under Roadways: 3 inch minimum
2. Conduit in Typical Trench: 2 inch minimum
3. Conduit from Pull Box / Splice Box to Foundation: 1 inch minimum
4. Conduit to Pathway Luminaires: 3/4 inch minimum
Conduits shall be placed two feet from back of curb.
All existing conduits shall be cleaned with a mandrel or cylindrical wire brush and all conduits
(existing or new) shall be blown out with compressed air, before conductors or signal facilities are
installed. All conduits shall contain a nylon or polyester pull tape of at least 1250 lbs strength with
footage marking tape. In occurrences that require complete intersection rewiring or new
construction, a 12 AWG tracer wire shall be installed across every conduit leg, and conduit plugs
shall be installed in all conduits. Pull rope with footage tape, tracer wire, and conduit plugs shall
be included in the price of electrical conduit.
When conduit is specified to be installed under existing pavement by directional line boring, the
boring pits shall be kept a minimum of 2 feet clear of the edge of pavement whenever possible.
Conduit installed under pavement, sidewalk, dirt, sod or any condition other than under an existing
391
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
roadway shall be installed with not less than 24 inches of cover to the top of the conduit. Under
existing roadway, conduit shall be installed with not less than 30 inches of cover to the top of the
conduit. Conduit installed under railroad tracks shall be installed not be less than 42 inches
below the bottom of the tie to the top of the conduit. [Refer to Figure 1 – Typical Conduit Burial
Standard Detail].
Section VII. Pull Boxes / Splice Boxes
A. General
All pull / splice boxes and covers must be made of polymer concrete with fiberglass
reinforcement with a traffic rating of TIER 22.
Pull / splice boxes shall be labeled "ELECTRIC" on pull / splice boxes containing electrical power
or “LIGHTING” on all pull / splice boxes containing street lighting conductors. The labeling must
be cast into the cover and not a separate independent tag. [Refer to Figure 2 – Typical In-Grade
Pull Box / Splice Box Dimensions Standard Detail]
B. Pull Box / Splice Box Installation
When pull / splice boxes are located behind sidewalk or in non-pavement areas, they shall be
surrounded by a 12 inch wide collar of class B concrete 6 inches deep. [Refer to Figure 3 – Typical
In-Grade Composite Pull Box / Splice Box Detail]
Maximum distance between pull / splice boxes is 200 feet for street and pedestrian lights, and
100 feet for pathway lights.
Street crossings for conduit runs need to have a pull / splice box at each side of the street crossing.
Pull / splice boxes are to be installed at each street corner where conduit takes a 90 degree bend
around the corner of the block.
Provide a Type 1 or Type 2 pull / splice box by each streetlight or pedestrian light with smaller 1.5
inch diameter conduit allowed going into light base from pull / splice box.
For pathway lights, conduit may be routed in and out of the foundation, with a minimum conduit
size of 1 inch. Pull / splice boxes for pathway lights shall be placed at 90-degree bends around a
corner, and at the minimum spacing listed above.
Box size shall be determined by the diameter of the Largest Trade Size Conduit (LTSC) installed
in the box. For conductors 6 AWG or smaller, the box shall be sized (6) six times LTSC in width
or length dimension. For conductors 4 AWG and larger, the box shall be sized (8) eight ties LTSC
in width or length dimension.
For future expansion, empty conduit, with nylon or polyester tape pull tape of at least 1250 lbs
strength with footage marking tape, shall terminate in a pull / splice box. Stub spare conduit(s)
out of the box and cap below grade at 2 feet from the box, in the direction of future expansion.
Label conduit stub out(s) in pull / splice box “for future expansion to the direction of expansion”.
392
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Wire connections in pull / splice boxes should use water-proof, insulated multi-tap connectors, by
Burndy, or Ilsco, or equivalent.
Section VIII. Concrete Foundations
A. Light Standard Foundations
In locations where the roadway is not curbed, and/or in dirt, the top of the foundation shall be six
inches above the grade of the edge of the pavement or as directed by the Engineer. The top of
the foundation shall be finished smooth and have a 3/4 inch chamfered edge. [Refer to Figures
4, 5 and 6 – Typical Light Standard Foundation Electrical Details]
Where caisson foundations are located in the sidewalk, the caisson foundation shall be installed
to 6 inch under finished curb or sidewalk grade or as directed by the Engineer. [Refer to Figure 4
– Typical Light Standard Foundation Electrical Details ]
Where foundations are to be installed in dirt, landscaped areas, or any other situation where the
top of the caisson is not being installed with an existing sidewalk or concrete improvement, the
contractor shall use sono-tube on the top section of the caisson for finished appearance.
A structural engineer licensed in the state of Montana shall determine the foundation size (depth
and diameter) and concrete reinforcement for the specific light standard configuration.
B. Concrete Foundation Pads
All lighting control center cabinets that are to be installed in concrete, shall have either, an
approved anchor bolt template with bolts installed before concrete pour, or upon approval of the
Engineer, be installed using approved concrete drop in style anchors. All lighting control center
cabinets installed in areas other than concrete, shall be installed to their marked grade on a
concrete foundation pad with 24” depth, sized to fit cabinet dimensions with 3 inch minimum to 6
inch maximum offset of concrete on all sides of the enclosure. Provide 3 foot x 3 foot step pad
with a maximum slope of 1:24. [Refer to Figures 7a, 7b, 8 and 9 – Typical Lighting Control Center
Standard Details]
C. Concrete Fill for Pedestal Type Cabinets
All pedestal type cabinets mounted on galvanized strut-channel supports shall have concrete filled
post holes with a minimum depth of 36-inches and minimum diameter of 9-inches. [Refer to Figure
8 – Typical Lighting Control Center Pedestal Standard Detail ]
Section IX. Wiring
A. General
All wiring shall be copper conductors installed in conduit to meet the National Electric Code.
Minimum size current carrying conductor for exterior installations shall be #10 AWG copper.
Furnish conductors of solid or stranded copper of the gauge shown in the contract.
393
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Insulation for conductors must be Type THW, XHHW, XHHW-2, USE, RHH, RHW, THWN, and
THWN-2. All insulation must be designed for 600 volts and meet NEC requirements.
Metal Clad cable (MC) or Armored Cable (AC) shall not be allowed in exterior applications.
Exterior lighting shall be powered at 120/240V-1PH-3W unless otherwise noted on the plans.
Wiring color code shall be as follows:
Line 1 = Black
Line 2 = Red
Neutral = White
Ground = Green
Section X. Bonding and Grounding
A. General
All PVC or PVC coated GRC conduits from a metered power source shall have a raceway ground
conductor installed with the current carrying conductors, sized to the NEC. Ground conductor
shall have the size increased to match current carrying conductor size increase for voltage drop
purposes.
All light standard foundations for streetlights and pedestrian lights shall have a 5/8 inch diameter
x 8 foot long, copper clad driven ground rod installed in the pull / splice box next to the light
standard. Top of rod shall be a minimum of 4 inches below grade. Exothermic weld or
underground rated lug connect a #6 AWG soft drawn bare copper conductor from rod through 1/2
inch trade size conduit in the foundation to the lug on the pole in the back of the hand hole.
Pathway lights shall have the system grounding conductor bonded to the grounding lug inside
each bollard.
All grounding electrodes shall be bonded together per the NEC.
Section XI. Lighting Control Centers and Metered Pedestals
A. General
All street lighting systems shall be metered separately from other uses, with the exception of
streetlights installed in conjunction with traffic signal poles.
Lighting control centers and metered pedestals shall be located away from intersection corners,
behind the sidewalk, outside of the sight triangle and within the public right of way or easement.
B. Installation
Electric services shall use NEMA Type 3R cabinets with hinged, lockable covers and 3/8” holes
for a padlock.
Services shall be equipped with 3-way switches for hand-off-auto (HOA) operation. Wire photocell
on/off control in the auto position.
Lighting control centers shall house electrically held lighting contactors that are 12-pole with 30
394
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
amp contacts rated at 600V, and 120V coils.
Street lighting circuits shall be automatically controlled with turn lock mounting delayed response
photo cells. Lighting control centers shall have a 120V twist-lock receptacle type photoelectric cell
with matching receptacle base attached to the assembly with heavy duty galvanized c-channel
structure using 1 inch galvanized rigid conduit, mounted 8 feet above grade. Orient window of
photocell to face north. Photocell to operate the lighting contactors for on/off control when HOA
is in the auto position.
Meters shall be installed a minimum of 4 feet and maximum of 5 feet above grade to the center of
the meter.
395
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Section XII. Lighting Design Criteria
This section describes the luminaire selection and lighting layout for each street classification.
Designers are required to submit the following to the City of Bozeman for all street lighting
projects:
Calculation summary (more information can be found in Section XII.D)
Luminaire Submittal Form (found in Appendix A)
A. Lighting Controls
All street and pedestrian lights installed shall have on board dimmers to allow for dimming in the
field after luminaires have been installed. Onboard dimmers will allow for city officials to be able
to dim lights when residents are offended following new installations.
All streetlights shall have and ANSI 7-Pin receptacle to be compatible with future wireless control
systems.
B. Intersections and Crosswalks
The same luminaires are to be used throughout the intersection. When an intersection is between
two different street classifications, the higher street classification target criteria is used throughout
the entire intersection. The recommended streetlight layout for an intersection is also dependent
on whether the street classification calls for continuous or non-continuous lighting.
All traffic signal mounted streetlights shall meet the lighting requirements listed below. The
intersection design should ensure that the crosswalks are sufficiently lighted to light the vertical
surface (body) of pedestrians in the crosswalk. This may require that additional streetlights be
located before the intersection as shown in the Figures below.
Mid-block crossings and denoted crosswalks shall always be lighted. Crosswalks can be denoted
by striping, signage, flashing beacons, etc. Crosswalks are important parts of the streetscape and
an appropriate lighting design will improve the visibility of pedestrians in the crosswalk. The
lighting should be installed between the vehicle and the crosswalk (ie: half to one pole height
before the crosswalk) to ensure that the body of the pedestrian is adequately lighted. If streetlights
are installed above or immediately adjacent to the crosswalk, only the top of the pedestrian’s head
will be lighted making it difficult for motorists to see the pedestrian. Crosswalks and mid-block
crossings shall be lighted to the Vertical Illuminance requirements in the table below. See Section
XX for instructions on how to set up a calculation for crosswalks and mid-block crossings.
Figure X: Streetlight Located Before Crosswalk Figure X: Streetlight Placement with Respect to Crosswalk
396
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Table X: Intersection Target Horizontal & Vertical Criteria
Signalized, large intersections
This intersection type applies to:
Arterial/Arterial
Arterial/Collector
For a signalized intersection, with
continuous lighting, the typical streetlight
arrangement is interrupted by placing a
streetlight half to one pole height in front of
the crosswalk. This is called out as “1/2 to
1 pole height before crosswalk”. See the
Crosswalk section for more information.
Additional streetlights should be located
on signal poles if additional lighting is
needed to meet the intersection criteria.
Figure X: Signalized, Large Intersection
Functional
Classification Adjacent Land Use
Average
Horizontal
Illuminance
(Fc)
Uniformity
Ratio
(Fcavg/Fc
min)
Average
Vertical
Illuminance
(Fc)
Luminaire
Mounting
Height
(feet)
Recommended
Mast Arm
Length (ft)
Distribution Max BUG
Rating
Commercial / Institutional 2.4 6 1.0 35-40 10 Type 2 or 3 3-0-3
Residential / Industrial / Rural 1.7 6 0.8 30-35 10 Type 2 or 3 2-0-2
Commercial / Institutional 2.0 6 1.0 35-40 10 Type 2 or 3 2-0-2
Residential / Industrial / Rural 1.4 6 0.7 30-35 10 Type 2 or 3 2-0-2
Commercial / Institutional 1.9 6 0.8 35-40 10 Type 2 or 3 2-0-2
Residential / Industrial / Rural 1.2 6 0.6 30-35 10 Type 2 or 3 2-0-2
Commercial / Institutional 1.7 8 0.8 30-35 6 Type 2 or 3 2-0-2
Residential / Industrial / Rural 1.1 8 0.5 30-35 6 Type 2 or 3 1-0-2
Commercial / Institutional 1.5 8 0.7 30-35 6 Type 2 or 3 1-0-2
Residential / Industrial / Rural 0.9 8 0.5 30-35 6 Type 2 or 3 1-0-2
Commercial / Institutional 1.3 10 0.6 25-30 6 Type 2 or 3 1-0-1
Residential / Industrial / Rural 0.7 10 0.5 25-30 6 Type 2 or 3 1-0-1
Commercial / Institutional
Residential / Industrial / Rural
Arterial /
Arterial1
Arterial /
Collector1
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Non-signalized, large intersection
This intersection type applies to:
Arterial/Collector
Arterial/Local
Collector/Collector
The larger street sections should be
continuously lighted through the
intersection. The typical streetlight
arrangement is carried through the
intersection. The streetlights should be
located half to one pole height before the
crosswalk, if it exists.
The smaller cross street should have at
least one light located before the stop bar.
Signalized, small intersection
This intersection type applies to:
Arterial/Local
Collector/Collector
Streetlights should be located half to one
pole height before the crosswalk. This will
light the people within the crosswalk. An
additional streetlight located along the
cross street should be included to better
illuminate the crosswalk if necessary.
Additional streetlights should be located on
signal poles if additional lighting is needed
to meet the intersection criteria.
Non-signalized, small intersection
This intersection type applies to:
Collector/Local
Local/Local
At least one luminaire is to be placed at
each intersection.
Figure X: Non-Signalized, Large Intersection
Figure X: Signalized, Small Intersection
Figure X: Non-Signalized, Small Intersection
398
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Mid-Block Crosswalks
A streetlight shall be located one half to 1 mounting height in front of the crosswalk on both sides
of the street for all mid-block crossings.
Figure X: Streetlight Placement with Respect to Mid-Block Crossing
Figure X: Mid-Block Crossing
399
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
C. Continuous Lighting on Streets
Provide continuous lighting for all arterial, collector, and local streets as specified in Table X.
Lighting criteria varies for each street classification based on adjacent land use. Due to a higher
pedestrian activity, streets located adjacent to commercial and institutional properties will have a
higher lighting criteria. Commercial and institutional properties include churches, schools, retail
areas, and restaurants. Streets located adjacent to residential, industrial, and rural properties, as
well as office parks have a lower lighting criteria due to lower pedestrian activity. The lighting
criteria and adjacent land use shall be evaluated on a block-by-block basis. Therefore, if a project
is traveling through a residential area and passes by a school, the block that the school is on will
have a higher criteria than the rest of the project. A house-side shield is highly recommended on
all installations and may be needed to meet the required maximum BUG Rating. All streetlights
shall have a U0 uplight rating, unless an external house side shield is being used. When an
external shield is in use, light can be reflected upwards, therefore, when a shield is necessary to
reduce light trespass, a U2 uplight rating is acceptable. Internal house side shields can maintain
a U0 uplight rating and are preferred. All roadway calculations where a house-side shield is
intended on being used shall be calculated with an .ies file that includes the shielding.
Designers should strive to meet the luminaire spacing that will provide the highest quality street
lighting possible, but this is not always feasible. It is necessary to integrate lighting locations to
coordinate with other improvements:
Clearance from driveways (10 feet commercial and 5 feet residential).
Clearance from fire hydrants (5 feet).
Trees (centered in between trees or 10 feet from the tree trunk).
Place poles and luminaires near property lines wherever practical and avoid locations in front of
doorways, windows, and lines of egress. A staggered luminaire arrangement is preferred but is
not always feasible. Single sided arrangements should only be used when necessary.
Table X: New Construction Lighting Design Guidance.
Functional
Classification
Adjacent Land
Use
Average
Luminance
(cd/m2
)
Uniformity
Ratio
(Lavg/Lmin
)
Luminaire
Mounting
Height (ft)
Arrangement Lumen
Output Range Distribution
Max
CCT
Max BUG
Rating
Staggered 11,000 - 14,000 Type 2 or 3 3,000 B2-U0-G2
Single Sided
Staggered 7,000 - 10,000 Type 2 3,000 B1-U0-G2
Single Sided 7,000 - 12,000 Type 2 3,000 B1-U0-G2
Staggered 7,000 - 10,000 Type 2 3,000 B2-U0-G2
Single Sided 7,000 - 12,000 Type 2 3,000 B2-U0-G2
Staggered 3,500 - 5,500 Type 2 2,700 B1-U0-G2
Single Sided 5,000 - 7,500 Type 2 2,700 B1-U0-G2
Staggered 3,500 - 5,000 Type 2 3,000 B1-U0-G1
Single Sided 4,000 - 6,000 Type 2 3,000 B1-U0-G1
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
All new installations and retrofits of streetlights shall conform to the standards set forth in Table
X, based on street classification, adjacent land use, and luminaire arrangement.
D. Calculations
Lighting calculations are required for all street lighting projects for the City of Bozeman.
Calculations shall be done in AGi32, DIALux, Visual, or comparable software, and include the
following calculation grids:
Roadway Luminance
o A calculation grid is required for every lane of traffic and shall be oriented in the
direction of travel spaced 10’ OC along each lane, with two points across each
lane.
o Every section of roadway where criteria changes requires a separate calculation
grid.
Intersection Illuminance
o Intersection calculations shall be done using horizontal illuminance grids that
include the whole intersection, as well as all crosswalks associated with the
intersections. Calculation points shall be placed in a 5’x5’ grid.
Sidewalk Illuminance
o Horizontal sidewalk illuminance grids shall be placed on all sidewalks, spaced
every 5’-10’ OC along the sidewalk with two points across the sidewalk.
Light Trespass Illuminance
o Light trespass grids shall be located 5’ past the edge of ROW, into private property.
Light trespass grids shall be placed 5’ AFF, oriented toward the street with
calculation points every 5’-10’ OC.
o Light trespass calculation grids shall be separated based on adjacent land use. If
the project goes from a residential area to a commercial area, a separate light
trespass calculation grid will be required for each section of the project.
o If a structure is within 5’ from the property line, light trespass grid to be placed on
the structure, 5’ AFF.
o Light trespass values shall not exceed the following:
Residential properties: 0.1Fc Maximum.
If this criteria is not feasible with proper shielding and distribution, a
variance may be considered to allow up to 0.2Fc Maximum light
trespass in residential areas. Designer will be required to submit a
narrative describing the efforts to control light trespass to the City
Engineer.
Commercial and mixed-use residential properties: 0.3Fc Maximum
Crosswalk Vertical Illuminance
o Vertical illuminance grids shall be placed in all crosswalks at 5’ AFF, and oriented
according to Figure X. Calculation points shall be located along the center line of
each crosswalk, placed every 5’ OC.
Designers shall submit to the City a calculation summary table for each calculation grid and
401
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
include the average illuminance or luminance, maximum illuminance or luminance, minimum
illuminance or luminance, and Avg:Min ratio. Calculated values may vary from criteria by no more
than 10% above or below.
Calculations shall not include a light loss factor (LFF).
Figure X: Intersection Calculation Grid Setup
Figure X: Roadway, Sidewalk, and Light Trespass Calculation Grid Setup
Figure X: Horizontal Intersection Illuminance Grid Figure X: Vertical Intersection Illuminance Grid
Figure X: Calculation Grids for Roadway Luminance, Sidewalk Illuminance, and Light Trespass
402
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
E. Design Considerations.
In addition to spacing requirements outlined in Table 1, the following layout criteria shall be used:
When a streetlight location falls near an unlit intersection, the light shall be located at
the intersection;
Streetlights shall be located at property lines to the greatest extent possible, but not in
conflict with other utility service providers;
All proposed local streets within the proposed subdivision, having a curve of 300 feet
or longer in length, shall have a streetlight in the middle of the horizontal curve or as
required by the City Engineer;
A streetlight shall be placed at the terminal ends of center median islands having trees
and/or other fixed objects not having a breakaway design for speeds of 25 miles per hour
or greater;
Additional streetlights may be required by the DRC when potential traffic hazards are
identified during plan review; and
Street and pedestrian lighting arrangements with poles aligned on opposite sides of the
street, rather than staggered are allowed.
Mounting heights shall be measured from the grade of the street at the edge of the travelled
way and shall comply with the requirements of Table X.
F. Pedestrian Lighting.
Pedestrian lighting is defined as luminaires mounted between 12ft and 15ft and shall be installed
at 60 feet to 105 feet on center, as appropriate to coordinate with landscape and hardscape
features. Two pedestrian lights shall be installed on opposite sides of the street at all intersections
of pathways and local streets located within the proposed development or along existing streets
or roads abutting the development, unless the pathway intersects the street at a lighted
intersection. Pedestrian lights shall have a lumen output range of 2,000 – 3,500 lumens, and a
maximum B.U.G. rating of B2-U1-G1. Pedestrian lights in special districts, including those along
Main Street and Wilson Ave, will require special approval from a City Engineer. Spacing of
pedestrian lights shall be determined by meeting the illuminance requirements outlined in Table
X.
Table X. Pedestrian Lighting Guidance.
Adjacent Land Use Average Horizontal Illuminance
for Pedestrian Walkways in
Maintained Footcandles
Illuminance Uniformity
Ratio (avg/min)
Commercial or Institutional 0.5 4.0
Residential, Industrial or Rural 0.3 6.0
Source: Roadway Lighting (RP-8), Illuminating Engineering Society of North America.
G. Pathway Lighting.
Pathway lights shall be installed along pathways through parks and other pathways that are
detached from the street. All pathway lights shall comply with City of Bozeman specifications.
Pathway lights shall have a height range of 40 - 48 inches, a lumen output range of 500 - 1,000
lumens, and a maximum wattage of 25 Watts.
403
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Section XIII. Streetlight Luminaires
A. General
All luminaires shall be light emitting diode (LED).
Color temperature 3000K maximum, per ANSI C78.377-2011 standard.
All luminaires shall be equipped with a surge suppression device with a minimum
immunity level of 10kV.
All luminaires shall have a field adjustable dimming system to allow for onsite dimming
once installed.
Shielding: All luminaires shall have standard house-side shielding options. Front-side
shielding may also be required to control light trespass across the street. Front-side
shields may be custom, but manufacturer standard shielding is preferred.
New light installations will be evaluated by the City of Bozeman during the required 2-
year warranty period immediately following project acceptance. The City may require
the developer to modify light installations through shielding or dimming to get the
desired light distribution.
The contractor may be required to provide house side light shields to the City of
Bozeman for each new luminaire as a condition of project acceptance.
All luminaires shall have a minimum ingress protection (IP) rating of IP66, and shall be
UL/ETL listed for wet locations.
All luminaires shall be equipped with a 0-10V or DALI dimming driver, capable of
receiving input line voltage 120V-277V. Driver shall comply with Federal
Communication Commission (FCC) 47 Code of Federal Regulations (CFR) part 15
non-consumer radio frequency interference (RFI) and/or electromagnetic interference
(EMI) standards. Minimum power factor (PF) shall be no less than 0.9 at full input
power. Maximum total harmonic distortion (THD) shall be no greater than 20 percent
at full input power.
A minimum 10 year warranty is required for all parts, materials, and shipping required
to repair or replace luminaire.
All luminaires are to be equipped with an ANSI C136.41 7-pin receptacle. Shorting
caps are to be installed on each luminaire.
Luminaires are to have a Type II distribution. Type III distribution allowed on Principal
Arterials and Large Signalized Intersections.
Access to all internal parts requiring replacement shall not require tools (i.e., “tool-less
entry”).
Luminaire shall be tested in accordance with IES LM79 and TM21 certifying
photometric performance and rated life, respectively. LM79 (performance) and TM21
(predicted life) testing shall both be for the same luminaire’s operating drive current as
specified.
Luminaires shall have a minimum L70 live of 100,000 hours based on IES TM21
testing.
Luminaire system efficacy shall be no less than 80 lumens per input watt.
Luminaire shall have an external label per ANSI C136.15 and internal label per ANSI
C136.22.
Luminaires shall be equipped with internal leveling bubble.
Breakaway connections using sheer bolts must have a skirt to protect the bolts.
Luminaires shall be powder coat finished black or powder coat finished to match pole,
unless installed on a local street, then either dark brown or hunter green.
Luminaire distribution shall be equal or less than the Illuminating Engineering Society
of North America’s (IES) TM 15-11 Backlight, Uplight, and Glare (BUG) ratings as
404
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
specified in Table X.
B. Installation
Luminaires shall be mounted in accordance with the manufacturer’s specifications.
Plumb or level all elements, symmetrically arrange, and securely assemble. Conceal all
conductors in the poles and assembly.
Luminaires shall have an adjustable slipfitter-type mounting system for the installation on 1.25
inch (1.66 inch o.d.) to 2 inch (2.375 inch o.d.) outside diameter pipe tenons. Slipfitter shall consist
of a two-piece clamp and four 9/16 inch hex bolts. Slipfitter shall allow for a vertical tilt adjustment
of +/- 5 percent in order to mount plumb for a U0 rating.
C. Approved Manufacturers – Cobrahead Style [Refer to Figure 10 – Typical
Street Light Standard Detail]
GE Evolve LED Cobrahead
Cree XSP (only to be used with a House-Side Shield and distribution Type II Long)
Lumec Roadfocus
D. Approved Manufacturers – Bell Style [Refer to Figure 10 – Typical Streetlight
Standard Detail]
Lumec Domus
Architectural Area Lighting Universe
Or Pre-Approved Equal
Section XIV. Pedestrian Luminaires
A. General
All luminaires shall be light emitting diode (LED).
Color temperature maximum 3000K, per ANSI C78.377-2011 standard.
All luminaires shall be equipped with a surge suppression device with a minimum
immunity level of 10kV.
All luminaires shall be equipped with a 0-10V dimming driver, capable of receiving input
line voltage 120V-277V. Driver shall comply with Federal Communication Commission
(FCC) 47 Code of Federal Regulations (CFR) part 15 non-consumer radio frequency
interference (RFI) and/or electromagnetic interference (EMI) standards. Minimum
power factor (PF) shall be no less than 0.9 at full input power. Maximum total harmonic
distortion (THD) shall be no greater than 20 percent at full input power.
A minimum 10 year warranty is required for all parts, materials, and shipping required
to repair or replace luminaire.
All luminaires are to be equipped with an ANSI C136.41 7-pin receptacle. Shorting
caps are to be installed on each luminaire.
Luminaires are to have either a Type III or Type V distribution. Type V distributions will
be considered for special use through DRC review.
Access to all internal parts requiring replacement shall not require tools (i.e., “tool-less
entry”).
Luminaire shall be tested in accordance with IES LM79 and TM21 certifying
405
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
photometric performance and rated life, respectively. LM79 (performance) and TM21
(predicted life) testing shall both be for the same luminaire’s operating drive current as
specified.
Internal house-side shield must be available.
Luminaire system efficacy shall be no less than 60 lumens per input watt.
Luminaire shall have an external label per ANSI C136.15 and internal label per ANSI
C136.22.
Luminaires shall be powder coat finished black or powder coat finished to match pole,
unless installed on local street, then either dark brown or hunter green.
Luminaire distribution shall be equal or less than the Illuminating Engineering Society
of North America’s (IES) TM 15-11 Backlight, Uplight, and Glare (BUG) rating of B2
U1 G1
For applications approved for Type V distribution, the Backlight rating shall not
apply.
B. Installation
Luminaires shall be mounted in accordance with the manufacturer’s specifications.
Plumb or level all elements, symmetrically arrange, and securely assemble. Conceal all
conductors in the poles and assembly.
C. Approved Products – Traditional Post-top Style [Refer to Figure 11 – Typical
Post-Top Pedestrian Light Standard Detail]
Sternberg Euro
Architectural Area Lighting Providence
Or approved equal
D. Approved Products – Bell Style [Refer to Figure 12 – Typical Arm-Mount
Pedestrian Light Standard Detail]
Lumec Domus
Architectural Area Lighting Universe
Or approved equal
Section XV. Pathway Luminaires
A. General
All luminaires shall be light emitting diode (LED).
Color temperature maximum 3000K, per ANSI C78.377-2011 standard, +/- 275K.
All luminaires shall be equipped with a surge suppression device with a minimum
immunity level of 10kV.
All luminaires shall be equipped with a 0-10V dimming or DALI driver, capable of
receiving input line voltage 120V-277V. Driver shall comply with Federal
Communication Commission (FCC) 47 Code of Federal Regulations (CFR) part 15
non-consumer radio frequency interference (RFI) and/or electromagnetic interference
(EMI) standards. Minimum power factor (PF) shall be 0.9 at full input power. Maximum
total harmonic distortion (THD) shall be 20 percent at full input power.
A minimum 10 year warranty is required for all parts, materials, and shipping required
to repair or replace luminaire.
All luminaires are to be equipped with an ANSI C136.41 7-pin receptacle. For
406
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
luminaires that are not supplied with integral 7-pin receptacles, provide the 7-pin
receptacle in pole cap on the top of the pole. Shorting caps are to be installed on each
luminaire.
Luminaires are to have either a Type III or Type V distribution. Type V distributions will
be considered for special use through DRC review.
Luminaire shall be tested in accordance with IES LM79 and TM21 certifying
photometric performance and rated life, respectively. LM79 (performance) and TM21
(predicted life) testing shall both be for the same luminaire’s operating drive current as
specified.
Luminaire system efficacy shall be no less than 30 lumens per input watt.
Luminaires shall be powder coat finished black.
Vandal proof. Not flat heads, rounded heads.
Concrete base, no direct burial
Luminaire distribution shall be equal or less than the Illuminating Engineering Society
of North America’s (IES) TM 15-11 Backlight, Uplight, and Glare (BUG) ratings as
follows:
B2 U1 G1
For applications approved for Type V distribution, the Backlight rating shall not
apply.
B. Installation
Luminaires shall be mounted in accordance with the manufacturer’s specifications.
Plumb or level all elements, symmetrically arrange, and securely assemble. Conceal all
conductors in the assembly. [Refer to Figure 13 – Typical Pathway Light Standard Detail]
C. Approved Products
Lithonia Lighting KBR8 LED Bollard
Lithonia Lighting D-Series LED Bollard
Or approved equal
Section XVI. Poles.
A. General
Unless specifically approved by the City Commission, the use of “Montana Angle”, “Budget
Angle”, or similar style streetlight poles is prohibited.
All poles, mast arms, and luminaires for streetlights and signal poles shall be round, tapered
steel with galvanized and painted finish.
Poles for pedestrian lights shall be round, non-tapered steel, with optional decorative fluting, and
galvanized and painted finish.
Unless a variance is granted, all future ARTERIAL AND COLLECTOR street and signal light
poles shall be “Hunter Green” (RAL#6005) or similar in color, excepting that all future street and
signal light poles in the Downtown Business District and North 7th Avenue TIF District shall be
black, and further excepting that entryway streets into Montana State University (i.e. S. 8th
Avenue, College Street, Kagy Boulevard, and S. 11th Avenue) may be dark Bobcat Blue.
407
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
The height of streetlight poles shall be determined based upon the lumen output and
application. Refer to
408
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Lighting Design Criteria.
Streetlight luminaires shall have a mast arm of 6 feet for local and collector streets, or 10 feet for
principal and minor arterials.
All streetlight poles shall be installed on a concrete foundation with the appropriate base for
the application. [Refer to Figure 9 – Typical Streetlight Standard Details]
All poles, foundations, and breakaway bases shall meet the criteria set forth in the AASHTO
publication Standard Specifications for Structural Supports for Highway Signs, Luminaires, and
Traffic Signals.
B. Installation
Streetlight poles shall be placed typically at five feet from back of curb.
Streetlight standards, pedestrian light standards and pathway lights shall have an access panel
and cover near base for access to wiring, fusible, in-line, water tight, breakaway connectors on
wiring in pole hand hole area such as Bussman type water tight fuse holders. [Refer to Figures
14, 15 and 16 – Typical Pole Base Standard Details]
Section XVII. Pole bases
A. General
Unless otherwise protected, a breakaway base should be provided for all streetlight standards
within the clear zone along rural and high-speed urban highways, except where located within 1.5
times pole height from a bus stop. Non-breakaway bases shall be used for all pedestrian lights
and pathway lights.
B. Breakaway Bolt Couplings.
Breakaway bolt couplings are aluminum connectors or sleeves that are designed to shear when
the pole is hit. The bottom of the coupling is threaded onto the foundation anchor bolts, and the
light standard is attached to the top of the coupling. Four couplings are used with each light
standard. Where breakaway supports are required, use the breakaway bolt coupling unless it will
not function with the approved light standard. [Refer to Figure 14 – Typical Breakaway Bolt
Coupling Standard Details]
C. Frangible Transformer Base.
The frangible transformer base consists of a cast aluminum apron between the concrete
foundation and the base of the pole. It is designed to deform and breakaway when hit by a vehicle
bumper. Use the frangible transfer base where a breakaway base is justified but breakaway bolt
couplings cannot be used. [Refer to Figure 15 – Typical Frangible Transformer Base Detail]
D. Non-Breakaway Anchor Base.
A non-breakaway anchor base consists primarily of a metal plate that is welded to the bottom of
the light standard. The plate allows the light standard to be bolted directly to the foundation without
an intermediate breakaway device. It does not meet AASHTO breakaway base criteria. [Refer to
Figure 16 – Typical Non-Breakaway Pole Base Detail]
409
City of Bozeman
Standard Specifications for Lighting Materials and Installation
Draft Revision January, 2020
Section XVIII. Submittal Requirements
A. General
Plan sheets showing pole locations, conduit locations, pull / splice box locations, and
meter locations are required.
For Street Lighting submittals, provide luminaire cutsheets showing compliance with
Table 1. New Construction Lighting Design Guidance and Section XIII. Streetlight
Luminaires,
For Pedestrian Lighting submittals, provide a Photometric Plan for new installations
showing compliance with Table 3. Pedestrian Lighting Guidance. Also provide luminaire
cutsheets showing compliance with Section XIV. Pedestrian Luminaires.
For Pathway Lighting submittals, provide luminaire cutsheets showing compliance with
Section XII.J. Lighting Design Criteria – Pathway Lighting, and Section XV. Pathway
Luminaires.
Details of point of service, lighting control center, electrical one-line diagrams, pole
foundations, poles, and luminaires are required.
Prior to construction, submit shop drawings (cut sheets) for all material and equipment.
Lighting calculations showing roadway luminance, intersection illuminance, sidewalk
illuminance, and light trespass.
410
Staggered 2,500 - 4,000 Type 2 2,700 B1-U0-G1
Single Sided 3,500 - 4,500 Type 2 2,700 B1-U0-G1
Local -
Continous
Commercial /
Institutional
0.3 10 25-30 Single Sided 3,500 - 4,500 Type 2 3,000 B1-U0-G1
Local Residential /
Industrial / Rural
NA 10 25-30 Single Sided 2,500 -4,000 Type 2 2,700 B0-U0-G1
* At time of publication, all Principal Arterial Streets except for Conttonwood Road are owned and maintained by MDT.
Residential /
Industrial / Rural
Commercial /
Institutional
25-30
25-30
0.3
0.5
10
10
0.6
Commercial /
Institutional
6
6
0.4 30-35
Residential /
Industrial / Rural 8
* A U2 BUG rating is acceptable when using a house side shield.
Principal
Arterial
Minor Arterial
Collector
Not Recommended
0.9 30-35
Commercial /
Institutional
0.6 30-35
Residential /
Industrial / Rural
30-35
5
400
Arterial /
Local1
Collector /
Collector2
Collector /
Local2
Local / Local
<30mph
Local / Local
>30mph
* A U2 BUG rating is acceptable when using a house side shield?
1. Arterial mid block crossing shall follow the arterial/arterial intersection criteria.
NA
NA
2. Collector mid block crossing shall follow the collector/collector intersection criteria.
397
8,300 -
8,600 10,613 100 95 250-300 NA 3,000 3,661
10th @ Villard Local
Moderate : LED Backlight Control Is Great, Front Light
Is Very Glaring
0.3
cd/m^2
0.49
cd/m^2
5,000 -
5,300 NA 65 NA 400-600 270 3,000 2,926
Arthur @ Grand Local Moderate: HPS Lighting Is Comfortable, But There Is
Too Much Spill Light
0.3
cd/m^2
0.85
cd/m^2
5,000 -
5,300 NA 65 NA 400-600 NA 3,000 1,847
11th @ Graf Collector
Moderate: Site Is Too Bright And Front Light Needs To
Be Better Controlled
0.4
cd/m^2
0.71
cd/m^2
8,300 -
8,600 7168 100 72 250-300 225 3,000 3,635
19th & Blackwood Collector
Acceptable: HPS Lights Provide Appropriate And
Comfortable Light, But There Is Too Much Spill Light
0.4
cd/m^2
0.28
cd/M62
8,300 -
8,600 NA 100 NA 250-300 210 3,000 1,816
Luminaire Luminaire CCT
Spacing
Luminaire
SiteLumens # Site Name Street Classification Existing Lighting
Luminaire
Wattage
Roadway
Luminance
1
12
11
10
2
3
5
6
7
8
9
4
373