NC-v4 SSc6: Light pollution reduction

  • To BUG or not to BUG

    This credit offers two major compliance options.

    Depending on your site lighting plan, this credit can be easier to achieve with the calculation method, which allows light trespass to the center of the street under certain conditions. Technologies to reduce light pollution and achieve this compliance option include full cutoffA full cutoff luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir or straight down) and at all angles greater than 90 degrees from straight down. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire. luminaries, low-reflectance surfaces, and low-angle spotlights.

    The other option is to pursue the BUG Rating method. BUG is a prescriptive rating method based on the assessment of backlight, uplight, and glare for site lighting fixtures. BUG tested lights are available for purchase or can be calculated. While the market needs to catch up a bit here, it’s very likely that a wider selection of fixtures will be available as time goes on.

    What’s New in LEED v4

    • This credit includes a new compliance option based on the BUG rating method.
    • The EA Prerequisite Minimum Energy Performance now contains lighting power density requirements, and the interior lighting requirements.
    • Only vertical illuminance calculations must be included in the photometric information. Only worst-case vertical plane and not all site lighting require point-by-point output calculation documentation.
    • Sports field lighting (including Schools projects) is not exempt from the credit requirements. 

    FAQs

    Is existing lighting required to be included in the calculations? What are the exceptions?

    Yes, existing lighting within the LEED project boundary should be included to show compliance. Some exterior lighting is exempt from the requirements, provided that it is controlled separately from the nonexempt lighting. See the LEED Reference Guide for details. 

    Does athletic field lighting need to be included in this credit?

    Yes, athletic field lighting should be included in this credit and meet all requirements.

  • SS Credit 6: Light pollution reduction

    Intent

    To increase night sky access, improve nighttime visibility, and reduce the consequences of development for wildlife and people.

    Requirements

    Meet uplight and light trespass requirements, using either the backlight-uplight-glare (BUG) method (Option 1) or the calculation method (Option 2). Projects may use different options for uplight and light trespass.

    Meet these requirements for all exterior luminaires located inside the project boundary (except those listed under “Exemptions”), based on the following:

    • the photometric characteristics of each luminaire when mounted in the same orientation and tilt as specified in the project design; and
    • the lighting zone of the project property (at the time construction begins). Classify the project under one lighting zone using the lighting zones definitions provided in the Illuminating Engineering Society and International Dark Sky Association (IES/IDA) Model Lighting Ordinance (MLO) User Guide.

    Additionally, meet the internally illuminated signage requirement.

    Uplight
    Option 1. BUG rating method

    Do not exceed the following luminaire uplight ratings, based on the specific light source installed in the luminaire, as defined in IES TM-15-11, Addendum A.

    Table 1. maximum uplight ratings for luminaires

    MLO lighting zone Luminaire uplight rating
    LZ0 U0
    LZ1 U1
    LZ2 U2
    LZ3 U3
    LZ4 U4



    OR
    Option 2. calculation method

    Do not exceed the following percentages of total lumens emitted above horizontal.

    Table 2. maximum percentage of total lumens emitted above horizontal, by lighting zone

    MLO lighting zone Maximum allowed percentage of total luminaire lumens emitted above horizontal
    LZ0 0%
    LZ1 0%
    LZ2 1.5%
    LZ3 3%
    LZ4 6%



    AND
    Light trespass
    Option 1. BUG rating method

    Do not exceed the following luminaire backlight and glare ratings (based on the specific light source installed in the luminaire), as defined in IES TM-15-11, Addendum A, based on the mounting location and distance from the lighting boundary.

    Table 3. maximum backlight and glare ratings

      MLO lighting zone
    Luminaire mounting LZ0 LZ1 LZ2 LZ3 LZ4
      Allowed backlight ratings
    > 2 mounting heights from lighting boundary B1 B3 B4 B5 B5
    1 to 2 mounting heights from lighting boundary and properly oriented B1 B2 B3 B4 B4
    0.5 to 1 mounting height to lighting boundary and properly oriented B0 B1 B2 B3 B3
    < 0.5 mounting height to lighting boundary and properly oriented B0 B0 B0 B1 B2
      Allowed glare ratings
    Building-mounted > 2 mounting heights from any lighting boundary G0 G1 G2 G3 G4
    Building-mounted 1–2 mounting heights from any lighting boundary G0 G0 G1 G1 G2
    Building-mounted 0.5 to 1 mounting heights from any lighting boundary G0 G0 G0 G1 G1
    Building-mounted < 0.5 mounting heights from any lighting boundary G0 G0 G0 G0 G1
    All other luminaires G0 G1 G2 G3 G4



    The lighting boundary is located at the property lines of the property, or properties, that the LEED project occupies. The lighting boundary can be modified under the following conditions:

    • When the property line abuts a public area that includes, but is not limited to, a walkway, bikeway, plaza, or parking lot, the lighting boundary may be moved to 5 feet (1.5 meters) beyond the property line.
    • When the property line abuts a public street, alley, or transit corridor, the lighting boundary may be moved to the center line of that street, alley, or corridor.
    • When there are additional properties owned by the same entity that are contiguous to the property, or properties, that the LEED project is within and have the same or higher MLO lighting zone designation as the LEED project, the lighting boundary may be expanded to include those properties.

    Orient all luminaires less than two mounting heights from the lighting boundary such that the backlight points toward the nearest lighting boundary line. Building-mounted luminaires with the backlight oriented toward the building are exempt from the backlight rating requirement.

    OR
    Option 2. calculation method

    Do not exceed the following vertical illuminances at the lighting boundary (use the definition of lighting boundary in Option 1). Calculation points may be no more than 5 feet (1.5 meters) apart. Vertical illuminances must be calculated on vertical planes running parallel to the lighting boundary, with the normal to each plane oriented toward the property and perpendicular to the lighting boundary, extending from grade level to 33 feet (10 meters) above the height of the highest luminaire.

    Table 4. maximum vertical illuminance at lighting boundary, by lighting zone

    MLO lighting zone Vertical illuminance
    LZ0 0.05 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. (0.5 luxMeasurement of lumens per square meter.)
    LZ1 0.05 fc (0.5 lux)
    LZ2 0.10 fc (1 lux)
    LZ3 0.20 fc (2 lux)
    LZ4 0.60 fc (6 lux)



    AND

    Internally illuminated exterior signage

    Do not exceed a luminance of 200 cd/m2 (nits) during nighttime hours and 2000 cd/m2 (nits) during daytime hours.

    Exemptions from uplight and light trespass requirements

    The following exterior lighting is exempt from the requirements, provided it is controlled separately from the nonexempt lighting:

    • specialized signal, directional, and marker lighting for transportation;
    • lighting that is used solely for façade and landscape lighting in MLO lighting zones 3 and 4, and is automatically turned off from midnight until 6 a.m.;
    • lighting for theatrical purposes for stage, film, and video performances;
    • government-mandated roadway lighting;
    • hospital emergency departments, including associated helipads;
    • lighting for the national flag in MLO lighting zones 2, 3, or 4; and
    • internally illuminated signage.

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

Documentation Using BUG Ratings

Here's a sample photometric report for a lighting product that shows what you're looking for when gathering BUG ratings. Also shown is a sample site plan showing how to include BUG ratings in making a credit-compliant plan.

Calculation Method

This perspective provides an example for documenting this credit using the calculation method, and annotations provide step-by-step tips.

Step by Step Calculations

These instructions from LEEDuser Expert Bill Swanson walk you through calculations and documentation for both Light Pollution Reduction options.

88 Comments

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Rita Haberman Brightworks
Jun 27 2017
LEEDuser Member
401 Thumbs Up

Garage lighting

This may be a silly question, but are fixtures attached to the garage considered building-mounted? The garage is separate from our LEED project but within the site boundary. Just wanting to see if my G3 fixture will meet the requirement for "all other luminaires" of if it has to be 2 mounting heights from the boundary. Thanks!

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Edgar Arevalo
Jun 14 2017
Guest
62 Thumbs Up

Zero Lot Line Property

Project Location: United States

The building that is going for LEED certification is on a zero lot line property.
There are no landscapes or anything else, just the building immediately surrounded by public sidewalks and a public park. It is safe to assume the property line and project boundary will the be the same and meet at the perimeter of the building itself. Can I still adjust the lighting boundary based on being adjacent to a public walkway on one side (which would be 5 feet away from property line) and adjacent public streets on the other three sides (which would be at the center line of the street)?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 15 2017 LEEDuser Expert 24296 Thumbs Up

The lighting boundary can still be adjusted like any other project. Just like you described.

That 5' extra on the public walkway won't be very helpful to you.

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Edgar Arevalo Jun 16 2017 Guest 62 Thumbs Up

Won't be helpful in what way?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 16 2017 LEEDuser Expert 24296 Thumbs Up

Just my experience. If I add usable light to a walkway, it's very difficult to prevent the light from going past that 5' boundary line.

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Jill Dalglish, PE Senior Engineer Dalglish Daylighting
May 24 2017
LEEDuser Expert
6658 Thumbs Up

Above ground-floor horizontal exterior spaces (plaza, roof)

Project Location: United States

Forgive me if this was covered elsewhere but I couldn't find it. We have a building with a 4th floor plaza that will have landscaping and landscape lighting that will be inside the lighting boundary.

Does the landscape lighting on the 4th floor plaza need to meet uplight and/or the trespass requirements?

Can I use the BUG method for compliance? If so, what do I consider as the "mounting height" - the actual height from the street to the fixture (so, 50' +) or the height from the 4th floor plaza?

Thanks!

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 08 2017 LEEDuser Expert 24296 Thumbs Up

Any lighting outside of the building envelope needs to comply.

Landscape lighting is listed as exempt as long as it is controlled appropriately.
"lighting that is used solely for façade and landscape lighting in MLO lighting zones 3 and 4, and is automatically turned off from midnight until 6 a.m."

If there are lights in the plaza that are not exempt, and are not shielded by solid building materials, I would use the mounting height from the street to the fixture. Can someone looking out of a neighboring building get glare from the light?

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Bill Swanson PE, LEED AP Integrated Architecture
May 17 2017
LEEDuser Expert
24296 Thumbs Up

Project vs Lighting boundary

There appears to still be confusion on the differences between the Project Boundary and the Lighting Boundary.

The Project boundary is the same as shown in every other credit. All lighting within the project boundary must show compliance with this credit's requirements.

The Lighting boundary often has a lot of overlap with the project boundary. But they are separate. The Lighting boundary can be moved out at roadways or to the entire campus. The lighting boundary exists for a single purpose. As a line to measure spill light at.

People who should know better are confusing the terms. Both the LEED Reviewer and now GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). want "ALL" lights within the lighting boundary to show compliance. For a campus project, this is problematic and against official LEED Interpretations.

Created on October 1, 2012
LEED Interpretation
ID# 10236

"If the LEED project boundary is smaller than the property line, projects can use the lighting boundary to meet the light trespass requirements of this credit. Buildings that are part of campuses or shared properties can use the "campus boundary", i.e. the campus property line, to comply with the light trespass requirements of this credit. All LEED projects attempting SSc8 should continue to meet all exterior requirements (LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space., uplight, trespass) based all of the exterior luminaries within the LEED project boundary. The lighting boundary is only for the purposes of the trespass calculation, based on the light emitted by the luminaires within the LEED project boundary. Project teams should take note that the LEED project boundary must be appropriately defined and comply with Minimum Program Requirement (MPR) #3- "Must be a reasonable site boundary"."

GBCI Case 01680820

"We recommend that you revise your documentation such as to account for ALL luminaries contained within the lightning boundary established for your project, or to revise the lighting zone accordingly, and to provide proper justification for the same."

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April Wang
Feb 18 2017
Guest
17 Thumbs Up

Trespass Calculation Method

Hello all,

In this project in Taiwan (I cannot find the country selection below), there are no available IES files nor BUG ratings for the exterior luminaires; therefore, I am pursuing the credit using the Calculation Method. I would appreciate any assistance for clarification of the following.

For Uplight, I will need to obtain information of total lumen1. A lumen is a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of 1 candle intensity. 2. A measurement of light output. and total lumen above horizontal for each luminaire, and satisfying the maximum percentage requirement for all luminaries.

For Trespass, I need to conduct vertical illuminance simulation using software such as Visual (as mentioned from previous posts) to satisfy the fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. requirements. I am a little stuck as to the input of the lighting information. The examples I've seen directly imports IES files which makes running the vertical illuminance fairly straight forwards. When I don't have such files, how do I go about obtaining and importing the photometric data of the luminaire. Do these luminaires need to be tested locally with photometric data and if so, which specific outputs are needed for inputting in the software.

Thank you very much.

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Max Pierson Principal, Minuscule Lighting Design Feb 18 2017 Guest 3 Thumbs Up

I would check with the manufacturer, they may have unpiblished photometry (IES or Eulumdat is the other common format). You can ask for an LM-79 report, which will contain the same information. Personally speaking, if a site lighting manufacturer didn't have an LM-79 and LM-80 reports available I would run away fast, it means they have not verified the performance in any meaningful way.
Note that you can comply with this credit using the V4 credit language even on 2009 projects, and this is usually the easier path.

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April Wang Feb 19 2017 Guest 17 Thumbs Up

Hi Max,

Thanks for your response. The LM-79 and LM-80 will be able to give me information on the BUG rating? Or do you mean to use it for the Calculation Method? I see sample LM-79 reports will show Total Uplight Lumens which I believe to be useful for the calculation of the Uplight Requirement. However, can I satisfy the Calculation Method for Trespass requirement with parameters from the LM-79 reports?

Thank you.

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Bill Swanson PE, LEED AP, Integrated Architecture Feb 20 2017 LEEDuser Expert 24296 Thumbs Up

Ignoring LEED for the moment, what information are you using to locate and size the lighting for this site? How do you know there aren't dark spots between the lights? Is there any computer modeling done or is this just estimated with past experience?

Any attempt to do the calculation method to show compliance with LEED will need a computer model for the Trespass requirement.

The IES file format is admittedly North American based. I don't know what format is common in Taiwan. But most large lighting companies should have some sort of file for people doing computer models. Contacting the company or sales rep may be required. If they have nothing, then I agree with Max's comment above to avoid them.

The LM-79 report might have the BUG rating included in it. I don't think you could use it for the calculation method to show compliance.

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Bill Swanson PE, LEED AP Integrated Architecture
Jan 20 2017
LEEDuser Expert
24296 Thumbs Up

Minimum light levels are now required

This has come up on a project and we lost on appeal so I'm sharing this information with everyone.

Any area being claimed in the wattage baseline calculation must be illuminated to a minimum light level of 0.2 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter..

In the past, if there was a section of a parking lot that the Owner didn't want lights installed I would still claim the square footage of that hardscapeThe inanimate elements of the building landscaping. It includes pavement, roadways, stonewalls, wood and synthetic decking, concrete paths and sidewalks, and concrete, brick, and tile patios. because it created a higher baseline wattage. The reviewers will not permit this practice anymore. An area must be illuminated in order to claim any reduction for it. Meaning wattage must be added if you want to show an energy savings.

The actual comment from the reviewer.
"The energy savings reported for exterior lighting do not appear to be substantiated because it is unclear if only surfaces that are provided with exterior lighting have been included. Note that the uploaded site photometric plans include areas which have as low as 0.01 and 0.02 footcandles. Areas should receive at least 0.2 footcandles of lighting to be considered illuminated. Review the exterior lighting calculations and ensure that only surface area with sufficient lighting has been included. Provide sufficient information regarding the energy inputs in the Section 1.4 Tables and an accompanying narrative to justify the reported energy savings."

Why 0.2 fc as a minimum? Excellent question. It is a phantom rule. There is no mention of this in any USGBC document. I did some searching when this came up and it seems an early draft of the MLO noted a minimum light level of 0.2 fc. The final version of the MLO does not have any mention of a minimum light level. That is the only source I can find. And now LEED has adopted this obsolete language.

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Jan 24 2017 LEEDuser Expert 1595 Thumbs Up

This is an unfortunate position for the reviewer to take, especially without any justification as to why they are holding projects to this apparently non-existent rule. It is doubly unfortunate that they stuck to this position even upon appeal. Back in my days as a reviewer, appeals would be reviewed by a completely different team - I'm not sure if this is still the case.

I expect that this won't be an issue for SS Credit: Light Pollution Reduction in version 4 because the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. requirements were purged from this credit and are addressed solely in the energy model. That said, I'd expect even bigger issues if energy modeling baselines were similarly discounted to only include tradable surfaces that reach specific illuminance thresholds.

I don't agree with every decision that has been made by the developers of LEED, although in almost all cases the requirements are documented somewhere in the program. The adoption of new and undocumented requirements is very destructive, and I encourage GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). to quickly address this issue by explaining why this is a requirement based on the Rating System language or by correcting this overreach by an undoubtedly well intentioned, but perhaps overzealous reviewer.

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Bill Swanson PE, LEED AP, Integrated Architecture Jan 24 2017 LEEDuser Expert 24296 Thumbs Up

It always feels like reviewers are following a checklist. I would love for these checklists to be made public.

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Megan Ritchie Saffitz Director of LEED Support, U.S. Green Building Council Feb 02 2017 LEEDuser Member 1165 Thumbs Up

Hi all - Posted this in another area of the site, and reposting here for reference. Thanks - MRS

+ + + +

Per ASHRAE 90.1 and LEED requirements, tradable exterior lighting surfaces must be designed to be illuminated in order to be counted in the Baseline exterior lighting power allowance:

For LEED v4 EA Prerequisite: Minimum Energy Performance submittals, ASHRAE 90.1-2010, Section states: “The total exterior lighting power allowance for all exterior building applications is the sum of the base site allowance plus the individual allowances for areas that are designed to be illuminated and are permitted in Table 9.4.3B for the applicable lighting zone."

Similarly for LEED 2009 EA Prerequisite: Minimum Energy Performance submittals, the ASHRAE 90.1-2007 User’s Manual, Section 9.4.5 – Determining Exterior Building Lighting Power Compliance, indicates that the exterior lighting power allowance (ELPA) “is calculated by multiplying each lighted area or width of door opening by the appropriate exterior lighting unit power allowance.”

However, if the LEED ASHRAE 90.1 Exterior Lighting Power documentation confirms that each surface where the exterior lighting power allowance is applied is “designed to be illuminated” or “lighted”, there is no defined minimum threshold that the project must adhere to in order to be counted in the Baseline lighting power allowance. A minimum 0.2 footcandle requirement does not apply.

Note that the IESNA Lighting Handbook recommends a minimum horizontal illuminance level of 0.2 footcandles for basic parking lot lighting applications. To support the claim that the surface is “designed to be illuminated”, a project team may optionally reference these IESNA values. However, this minimum footcandle level is a recommendation only, and is not stipulated by ASHRAE 90.1. Other justification supporting the claim that the surface is “designed to be illuminated” will also be accepted.

We followed up with Bill offline to ensure the reference to a “0.20 footcandle” requirement is corrected for this project. Thanks, as always, for flagging these so we can have these discussions and make improvements as necessary. Best, MRS

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David Makee
Sep 26 2016
Guest
2 Thumbs Up

Glare requirement exemption

I saw a similar question regarding uplight, but is it possible for a building-mounted light fixture to be excluded from the glare requirements if it is shielded from the lighting boundary by another part of the building itself? The project is in LZ2. Could I use Option 2 to determine compliance for only those fixtures? Any guidance would be much appreciated.

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Sep 27 2016 LEEDuser Expert 1595 Thumbs Up

This is a great question, which gets right to the root of the difference between Option 1 (B.U.G. Method) vs. Option 2 (Calculation Method) for light trespass, as the calculation method only really considers light trespass, while B.U.G. looks at backlight and glare which are similar (but not interchangeable) with light trespass. What this means is that while building-mounted luminaires might not meet the correct glare rating (and not qualify under B.U.G.), they could be sufficiently distant from the lighting boundary to not exceed the trespass thresholds.

This highlights that the two assessment methods, while both credible, don't align perfectly. With that in mind, it should not be possible to selectively pick a hybrid approach to assess light trespass, as doing so would lower the bar for both options.

For your specific project, assuming the fixture output is fully shieldedIn a fully shielded exterior light fixture, the lower edge of the shield is at or below the lowest edge of the lamp, such that all light shines down. from the boundary, it does seem reasonable to apply the glare requirements for fixtures > 2 times the mounting height from any boundary, which would potentially allow some added flexibility in the allowable glare rating for the fixture. While this alternate isn't spelled out in the literature (unless I missed it), it logically makes sense, and an open minded reviewer might allow it.

All that said, it would be a whole lot simpler to just specify a fixture that meets the required glare rating.

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Rita Haberman Brightworks
Aug 29 2016
LEEDuser Member
401 Thumbs Up

Existing Lighting Included?

Is existing lighting required to be included in the BUG rating prescriptive method? We have a project where only some site lighting is being upgraded; the rest will remain. Since these features are older, it will be difficult to determine the BUG ratings.

Thank you.

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Bill Swanson PE, LEED AP, Integrated Architecture Aug 29 2016 LEEDuser Expert 24296 Thumbs Up

All lights within the project boundary should be included to show compliance with this credit.
There are two exceptions that I know of:
- if the lights are owned by the City or other entity that the property owner doesn't have control over.
- if the lights are in a larger campus.
6/15/2004 ID# 3108
"Ruling

The intent of the credit addresses a project's "building and site." The bracket-mounted lights above the secondary doorways are part of the building, and thus certainly need to meet the LEED requirements. Site/pathway lighting is not as straightforward a scenario. Applicable Internationally.

Your building project is within a university campus context and thus site lighting choices are possibly controlled by a central design plan for reasons such as security and consistent aesthetics. Granted this situation presents challenges in applying LEED-NC, but SSc8 is about delivering a specific type of lighting performance for the entire project, not for selected pieces of it. As stated in your narrative, the site definition is being applied consistently to all aspects of the LEED submission as USGBC requires.

Given the project's context, however, USGBC is willing to offer an alternative compliance path on university campuses for existing site lighting that falls within the site boundaries per the LEED application (in this case, the low pole fixtures that are not slated for replacement) IF it is shown that the Campus Exterior Lighting Master Plan (if it exists) has been officially upgraded to a SSc8-compliant level (assumably after the low pole fixtures were installed) by the time of LEED application submittal, whether or not it has been inspired by striving for this LEED point. In addition, since the "property boundary" in this case is created for administrative purposes only, defined for the project's scope (as well as LEED application), the SSc8 requirements relating to the property line need only be followed for the REAL campus property boundary, rather than the PROJECT boundary. This compromise ensures that all future site lighting installations on the campus will serve the intent of the credit and thus achieve performance beyond what would be accomplished through solely replacing the project siteÆs pole fixtures.

If no Campus Exterior Lighting Master Plan exists, or it has not been updated to comply with SSc8, then the site lighting in question must be changed to comply with SSc8 in order to achieve the credit. Look into the possibility of retrofitting (via lumen1. A lumen is a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of 1 candle intensity. 2. A measurement of light output. and shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow. changes), or replacing the fixtures outright."

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Laura Marchand
Jun 29 2016
Guest
5 Thumbs Up

Scoreboard as Signage?

Does anyone have experience on whether a scoreboard for a sports stadium would fall into "internally illuminated exterior signage"? I am assuming no, because the scoreboard is within the stadium and it's a scoreboard, not a sign. However, the stadium itself is open to the air, so the scoreboard is actually outdoors (just inside the stadium boundary) and it's probably also visible from outside of the stadium itself.

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 30 2016 LEEDuser Expert 24296 Thumbs Up

I would consider it as an internally illuminated exterior signage.

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Bill Swanson PE, LEED AP Integrated Architecture
Jun 24 2016
LEEDuser Expert
24296 Thumbs Up

Illuminated area

I just had this come up on a project. The reviewer will only allow me to count hardscapeThe inanimate elements of the building landscaping. It includes pavement, roadways, stonewalls, wood and synthetic decking, concrete paths and sidewalks, and concrete, brick, and tile patios. area for the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. table if that area has over 0.2 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter..

In the past people have asked me if they can count a parking lot or sidewalk if it doesn't have any lighting. My answer has always been yes. Now, USGBC is saying no. I'm trying to find out why and where this 0.2 fc limit came from.

Rereading the language of ASHRAE 90.1 v2007 and v2010 I see the difference. v2010, section 9.4.3 states, "...for areas that are designed to be illuminated..." Back in v2007, section 9.4.5 has no mention of "illuminated areas." Letting you know that this appears to be a change that will affect v4 documentation of this credit.

So what does "illuminated area" mean? I cannot find any description in ASHRAE 90.1. Doing some Google searching I have found that in a 2010 draft of the Model Lighting Ordinance (MLO) it had a definition for "illuminated area" that stated, "An exterior area for which lighting of reasonable uniformity (20:1 or less maximum to minimum illuminance ratio) and illumination (average greater than 0.2 fc) is provided; not incidentally lighted or partially lighted."

But that was just draft language and said an average of 0.2 fc, not a minimum. The final version of the MLO does not have any definition of "illuminated area".

I can't find any other mention of 0.2 fc anywhere. This looks like an artificial limit created by the reviewers.

So, ASHRAE 90.1, v2010 does state that the LPD can only be used for areas designed to be illuminated. But they fail to explain what this means. LEED also does not define this term.

I will try to challenge this 0.2 fc requirement since I hate made up rules by LEED reviewers. I'll let everyone know my result.

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Sep 27 2016 LEEDuser Expert 1595 Thumbs Up

Thank you for the update Bill, and for your efforts to get this cleared up.

I do appreciate the sentiment of the language change in 90.1-2010 (which would avoid "gaming" of the requirement by having large unlit areas offset overlit areas), but without a formal definition of what this means, it becomes too arbitrary to enforce except in areas where there isn't any exterior lighting.

Keep us posted!

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Michele Helou Principal Sage Design & Consulting
Jun 07 2016
LEEDuser Member
1446 Thumbs Up

Interior Uplighting

Am I missing something or does v4 no longer have any requirement on interior lighting that has a significant uplighting component?

We have an interior atrium that will have this issue - and it just seems silly to require this throughout the site and miss the hole in the roof.

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 07 2016 LEEDuser Expert 24296 Thumbs Up

There are no interior lighting requirements in v4 for this credit.

I never saw a benefit to having interior lighting requirements. Documenting all of the interior lighting shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow. and controls was a lot of time for design teams. I think it was a good decision to have this removed from the credit. If one or more projects end up showing this to be a big problem I'm sure they can add it back in the next version.

My reasons for not wanting interior lighting in this credit.
- Every project has to comply with EAp1 which has automatic shutoff requirements for lighting when rooms are not in use. Most spaces are empty from 11pm to 5am so the lights should be off anyway.
- The rules and exceptions for interior lighting were confusing and arbitrary. Residential spaces are exempt but hotel rooms are not. Motorized shades show compliance but manual shades that are closed 90% of the time at night are not. Hospitals were once exempt but now are not. If we could show that 10% or less of the light from any fixture visible from outside actually exited thru the window it was considered compliant. Why was 10% magic. There was no study supporting what this threshold did.
- Most lights are going to be compliant anyway. With the 10% value, it was difficult to find lights that actually had more than 10% exit a window. After calculating how much light from a typical fixture actually hits the glass, and what the visible transmission of the glass is, it's often less than 10% exiting the window. But proving this on each light is difficult. Now uplighting a glass roof like you describe, yes, I can see more than 10% leaving the glass. How bright are these lights compared to the total downlighting in the space? Does it make a difference if one light or more are over the 10% limit while the space as a whole is under?

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Heather Holdridge Sustainability Coordinator Lake/Flato Architects
May 13 2016
LEEDuser Member
2153 Thumbs Up

Exemptions

I am working on a project with exterior fixtures that are not illuminating a building facade but more artwork/ sculptural landscape screenwork. I see that there are exemptions for lighting for theatrical purposes for stage, film, and video performances, but not artwork specifically. Has anyone had experience with applying artwork for an exemption?

A little more background info in case it is instructive: The fixtures are mounted to the sunscreens and not the building proper. The fixtures are 8.5 watts per foot placing us over the 5 watts per linear foot requirement for building lighting. Thanks!

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Bill Swanson PE, LEED AP, Integrated Architecture May 18 2016 LEEDuser Expert 24296 Thumbs Up

I've been waiting for someone else to respond. I don't personally have experience with lighting artwork/sculptural landscape screenwork on a LEED project.

You might be able to exempt the wattage via ASHRAE 90.1-2010 compliance. But I don't think the performances exemption applies.
Exempt items:
h. Theme elements in theme/amusement parks.
i. Lighting used to highlight features of public monuments and registered historic landmark structures or buildings.

Are you using LZ4? This is intended for very rare locations. (California doesn't have any LZ4 in the whole state. Think Vegas strip and Times Square) You may get challenged in your submittal on this lighting zone designation.

LZ4 has a base site allowance of 1,300W that can be used on anything. If you have 8.5 W/ft with an allowed 5W/ft. The difference is 3.5W/ft. That is 371 linear feet if you use the entire 1,300W base. (157 ft if in LZ3)

Are you using the exemption for separately controlled façade and landscape lighting that is off between 12-6am?

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Heather Holdridge Sustainability Coordinator Lake/Flato Architects
Nov 12 2015
LEEDuser Member
2153 Thumbs Up

n/a

If I understand the LEED requirements for exterior lighting, we will be following the BUG guidelines for all lighting that will remain on from sunset to sunrise. For the building and landscape uplighting a astronomic time clock will turn these fixtures off at midnight, which the LEED guidelines state is acceptable. Am I missing something?

If we are following the BUG option and we have a fixture that will be completely shielded, but doesn’t have a BUG rating, how do we document that for LEED? Use software that will calculate the BUG rating using the IES file for the luminaire?

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Gustavo De las Heras Izquierdo Arch. Eng. LEED AP BD+C; O+M; CxA: Green Rater in Training, Revitaliza Consultores Nov 12 2015 Guest 2417 Thumbs Up

Hi Heather,

You have to meet both requirements:

1.Uplight
2.Light trespass

For each requirement there are 2 available options and you can choose either of them. If you follow the BUG rating method for Uplight AND for Light trespass, that is fine and you re done!

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Bill Swanson PE, LEED AP, Integrated Architecture Nov 13 2015 LEEDuser Expert 24296 Thumbs Up

There is nothing in the Credit that allows you to exclude some of the exterior lights if they turn off at a specific time.

All of the exterior lights have to comply with the Uplight limits, either option 1 or option 2.

All of the exterior lights have to comply with the Light Trespass requirements, either option 1 or option 2.

If using the BUG option and there is no published BUG information, then you will need to use the software with the IES files to get the BUG rating.

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Samuel Gelfand Nov 19 2015 LEEDuser Member 90 Thumbs Up

Are these not exemptions?:

"Exemptions from uplight and light trespass requirements
The following exterior lighting is exempt from the requirements, provided it is controlled separately from the nonexempt lighting:

specialized signal, directional, and marker lighting for transportation;

lighting that is used solely for façade and landscape lighting in MLO lighting zones 3 and 4, and is automatically turned off from midnight until 6 a.m.;

lighting for theatrical purposes for stage, film, and video performances;
government-mandated roadway lighting;

hospital emergency departments, including associated helipads;

lighting for the national flag in MLO lighting zones 2, 3, or 4; and
internally illuminated signage."

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Bill Swanson PE, LEED AP, Integrated Architecture Nov 19 2015 LEEDuser Expert 24296 Thumbs Up

You are correct Samuel. If the project is in LZ-3 or 4 and is automatically turned off from midnight until 6am, and the lighting is only for façade and landscape, separately controlled, then it is compliant. Because those are exempted as you noted. I might not have understood what Heather was asking so thanks for questioning. I should have asked more.

When I hear building uplighting I think this sounds different than façade lighting. I react pretty quick to say that a timer alone does not exempt a light.

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Rita Haberman Brightworks
Nov 03 2015
LEEDuser Member
401 Thumbs Up

BUG ratings for recessed down lights

Hi Bill,

Do you know how to account for exterior lighting that does not have published BUG ratings? We are trying to get this information from the architect but he says that most of the exterior lighting does not have published BUG ratings and that "recessed down lights do not have BUG ratings." He also says that since some of the lights are wall mounted, they do not have backlight and therefore the rating would be B0. Lastly, he says that "all other luminaires are fully shieldedIn a fully shielded exterior light fixture, the lower edge of the shield is at or below the lowest edge of the lamp, such that all light shines down., full cut-off fixtures. Per the IES Standard TM-15 for BUG ratings, as these fixtures are pointed down, their BUG ratings would all be B0-U0-G0."

The credit language makes it sound like all lighting types will have an associated BUG rating whether they are wall-mounted or not. Can you provide any clarification on this? I am not sure how to respond since I have not worked much on this credit under v4.

Thank you.

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Bill Swanson PE, LEED AP, Integrated Architecture Nov 03 2015 LEEDuser Expert 24296 Thumbs Up

If a fixture is wall mounted then the backlight rating doesn't matter. It's hitting a solid surface. The backlight rating is for pole mounted fixtures to make sure they are oriented properly. Glare is the main concern for building mounted fixtures.

Just because a light is recessed and points down doesn't mean it will have a B0-U0-G0 rating. I will say it is safe to assume it has a U0 rating.

No interior light fixtures, like can lights, will have published BUG ratings. A lot of exterior fixture do, but a lot don't. Just about every light fixture in a commercial building will have an IES file available. Using this IES file you can generate your own BUG rating in a couple of minutes.

I've posted this before but use this link.
http://www.visual-3d.com/tools/PhotometricViewer/default.aspx

In the bottom left of the screen is "My Computer" button. Use this to find (Browse) the IES file you have already saved on your computer or network. Then "Select" to accept this file.

Look on the second page. There should be a LCS Table showing the BUG rating. For interior lights you will need to click the "Settings" button on the top and turn on the "LCS Table", and click update.

Here is an example of an interior downlight that I've used in canopies since it is damp location listed.
http://www.visual-3d.com/tools/PhotometricViewer/default.aspx?id=77093
B2-U0-G0. If something shows up with a 'Ux' that just means there was no uplight data in the file. Assume 'U0'.

Now if there is a lens on the fixture it can change more. A lens can make more vertical light which can increase glare. Wattage of the fixture can also impact the rating.
http://www.visual-3d.com/tools/PhotometricViewer/default.aspx?id=77093
B2-Ux-G1.

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Jon Penndorf
Aug 27 2015
LEEDuser Member
42 Thumbs Up

No exterior lights?

We are looking at a project that would be considered a major renovation, but we are not touching the outside face of the exterior walls of the building. As such we are making no modifications to existing exterior lighting (literally would be outside of the project LEED boundary). If the project contains no exterior lighting, can you comply with the intent of the credit (and achieve the point)?
Thanks.

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Bill Swanson PE, LEED AP, Integrated Architecture Aug 27 2015 LEEDuser Expert 24296 Thumbs Up

I suggest you reread MPR 2 to verify the scope of the project meets the LEED requirements for placing a reasonable project boundary.

"The LEED project boundary must include all contiguous land that is associated with the project and supports its typical operations. This includes land altered as a result of construction and features used primarily by the project’s occupants, such as hardscapeThe inanimate elements of the building landscaping. It includes pavement, roadways, stonewalls, wood and synthetic decking, concrete paths and sidewalks, and concrete, brick, and tile patios. (parking and sidewalks), septic or stormwater treatment equipment, and landscaping. The LEED boundary may not unreasonably exclude portions of the building, space, or site to give the project an advantage in complying with credit requirements. The LEED project must accurately communicate the scope of the certifying project in all promotional and descriptive materials and distinguish it from any non-certifying space."

Should this be a LEED-CI project?

I can't see a way to justify earning this credit while old lights with glare are on the exterior of the building. It would be like trying to earn the reflective roof credit when you are excluding the roof from the scope of the project.

If the project boundary includes the exterior of the building and there are no lights then I can say that yes this credit can be earned. But not if the walls are excluded.

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Michelle DiPenti Project Coordinator HDR, Inc.
Jul 06 2015
LEEDuser Member
172 Thumbs Up

Sports Field Exceptions

Has anyone received an exemption for uplight and light trespass for sports fields? Or know the reason why the exemptions from v3 were not carried over?
V4 has trespass exemptions for theatrical purposes for stage, film, and video performances...I was surprised that sports fields were not on the list.
Thank you!

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Jul 06 2015 LEEDuser Expert 1595 Thumbs Up

The exemption for sports field lighting was related to the lighting power density A measure of the total building floor area or dwelling units on a parcel of land relative to the buildable land of that parcel. Units for measuring density may differ according to credit requirements. Does not include structured parking.(which is no longer addressed in SS Credit Light Pollution Reduction in LEED v4) and sky glowSky glow is caused by stray light from unshielded light sources and light reflecting off surfaces that then enter the atmosphere and illuminate and reflect off dust, debris, and water vapor. Sky glow can substantially limit observation of the night sky, compromise astronomical research, and adversely affect nocturnal environments.. LEED 2009 did allow slightly higher trespass levels, but these were never actually exempted.

I'll have to leave it to someone who worked on the credit for v4 to comment on why special accommodations weren't carried forward (maybe improvements in commercial lighting products?), but it would have been a step backwards in terms of stringency if it had been fully exempted (including light trespass).

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Michelle DiPenti Project Coordinator, HDR, Inc. Jul 16 2015 LEEDuser Member 172 Thumbs Up

Glen, thank you for the quick reply! I just received information from GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). explaining that the exemptions were retired as part of the incremental improvement of LEED.

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Quentin Jackson Sustainable Design Leader, Aurecon Feb 29 2016 LEEDuser Member 57 Thumbs Up

Could we clarify though if sport field lighting would/could be considered exempt?

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Feb 29 2016 LEEDuser Expert 1595 Thumbs Up

Sports field lighting is not exempt in LEED v4, and needs to meet both the uplight and light trespass requirements using the calculation method and/or the bug method.

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Max Pierson Principal, Minuscule Lighting Design May 03 2016 Guest 3 Thumbs Up

What about stadium sports lighting, which would be controlled separately from general lighting and used only during sporting matches? I would think that would be more similar to theatrical performance lighting than sports field lighting that is used every night, has anyone had experience with this issue?

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Bill Swanson PE, LEED AP, Integrated Architecture May 04 2016 LEEDuser Expert 24296 Thumbs Up

The reference guide was updated on October 1, 2015. A bullet point was added with the text,
"- Sports field lighting (including Schools projects) is not exempt from the credit requirements."

This would include stadium lighting. I don't think it's possible to limit the uplight enough on a project with sports lighting. Maybe an opportunity for some manufacturer to design a great optic.

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Linda Anderson Principal Lighting Language & Design
Jun 15 2015
Guest
16 Thumbs Up

Lighting Zones

Who determines the exterior lighting zone LZ0-LZ4 for a LEED project? I am working on a project in a state that isn't mine and I don't know much about the city. My only info is what I see on Google Earth and knowing it is across a highway from an airport. Does a LEED team member assign this zone? Thanks.

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Gustavo De las Heras Izquierdo Arch. Eng. LEED AP BD+C; O+M; CxA: Green Rater in Training, Revitaliza Consultores Jun 17 2015 Guest 2417 Thumbs Up

The zone must be assigned based on your honest opinion following the definitions that you can find in the credit literature. Based on your description, I definitely would discard zones LZ1 and LZ4. If your project is located close to an airport, you will probably end up selecting LZ3.

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Linda Anderson Principal, Lighting Language & Design Jun 17 2015 Guest 16 Thumbs Up

Thanks Gustavo. That's the way I was leaning, glad you agree!

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Jens Apel
Jun 01 2015
LEEDuser Member
1465 Thumbs Up

Walkway versus public street

This may be an academic question but I am unsure on the wording. The modification of the lighting boundary depends on adjacency to a walkway or a public street. What if there is a walkway in front of the main entrance and a public street after the walkway. Thus, the street is not directly adjacent to the project
Do I move the lighting boundary by 5 feet or to the street's center line? This is a very common situation in Germany / Europe.

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 02 2015 LEEDuser Expert 24296 Thumbs Up

I would use the centerline of the street.

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Vince Briones Sustainable Design Manager Atkins
May 27 2015
Guest
314 Thumbs Up

Specialized transportation lighting

Hi all,

Is "Specialized transportation signal, directional & marker lighting" subject to the interior lit exterior sign illuminance limits? The Uplight/Trespass exemption section of the Ref Guide lists this separately from interior lit exterior signage, which leads us to interpret it is not subject to these same requirements. In which case, is there a industry definition of such "transportation" related lighting?

We ask as we have an airport project that includes a fleet vehicle que line "call board" which is used to pace the flow of commercial shuttle/taxi traffic through the landside terminal pick-up locations . It is LED but does not meet 200/2000 nit limits due to visibility needs. However, because this feature relates to transportation functions we weren't sure whether this precludes credit achievement.

Thoughts?

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Bill Swanson PE, LEED AP, Integrated Architecture May 27 2015 LEEDuser Expert 24296 Thumbs Up

I've never seen a detailed list of what is in or out of this category. Looking in the ASHRAE User's Manual there is a sentence that says, "These include traffic signals, directional signs and other similar luminaires."

This is going to judgment call.

I would suggest the dividing line be drawn based on where the person using the sign is at. Inside the vehicle or outside of it. Is the sign intended for the driver while in the vehicle, or for the passengers who are looking for which vehicle to get in?

Maybe Glen or someone who had a hand in the drafting of this can help with background on intent of what is considered exempt.

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. May 27 2015 LEEDuser Expert 1595 Thumbs Up

Short answer: Specialized signal, directional, and marker lighting for transportation is exempt from the uplight (sky glowSky glow is caused by stray light from unshielded light sources and light reflecting off surfaces that then enter the atmosphere and illuminate and reflect off dust, debris, and water vapor. Sky glow can substantially limit observation of the night sky, compromise astronomical research, and adversely affect nocturnal environments.) and light trespass requirements, and does not have a secondary requirement like internally illuminated exterior signage. Essentially, these are completely exempt from the credit.

Regarding the definition of transportation lighting, Bill's guidance above is insightful as always.

For some context: The requirements for Internally Illuminated Exterior Signage (which during development of LEED for Retail was initially was a blanket exemption for the trespass/skyglow elements of all advertising signage), was added late in the development cycle for due to the complexities of modeling this type of signage. It was reigned in a little bit to apply only to internally illuminated exterior signage (diverging from the ASHRAE exemption for "advertising signage or directional signage and temporary lighting") since exterior luminaires (like uplighting a billboard) should not be exempted.

In LEED v4, the exemption for certain types of luminares was expanded to include most of the 90.1 exemptions, although it retained the more narrow definition of advertising signage (including only internally illuminated signs).

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Vince Briones Sustainable Design Manager, Atkins May 27 2015 Guest 314 Thumbs Up

Thanks for the quick input gents! So if I understand the fundamental intent, the interior lit signage requirement is geared more for branding/naming signs as seen in monumental signs by roadways, mounted directly on buildings and used to identify businesses in retail plazas?

Our "sign" in question is a process related item used to communicate to commercial vehicles when its their turn to drive the loop for passenger pick-up. In this case, it sounds like we have a strong argument that it is transportation related and not just "signage" per se.

Thanks!

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Jens Apel
Apr 08 2015
LEEDuser Member
1465 Thumbs Up

definition "nighttime hours"

Is there a definition of nightime hours for internally illuminated signage? I would assume midnight to 6 AM as in the excemption for facades but I can't find any statement.

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Bill Swanson PE, LEED AP, Integrated Architecture Apr 08 2015 LEEDuser Expert 24296 Thumbs Up

Sunset to sunrise.

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Jens Apel Apr 08 2015 LEEDuser Member 1465 Thumbs Up

Ok, thanks. I think that should be included in an addenda as it is pretty different from facades / landscaping or ASHRAE 90.1, section 9.4.1.7 c.

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. Apr 08 2015 LEEDuser Expert 1595 Thumbs Up

Thanks Jens for asking the question (and Bill as always for being here with an answer). I agree that this should be clarified, as the current reference to "daytime hours" and "nighttime hours" can be interpreted by reasonable people to mean different time periods.

I can certainly imagine retailers who would want to use the higher daytime threshold between the (longer) dawn to dusk period.

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Bill Swanson PE, LEED AP, Integrated Architecture Apr 08 2015 LEEDuser Expert 24296 Thumbs Up

9.4.1.7(c) refers to after hours, when a business is closed. The writers of ASHRAE 90.1 likely assumed that exterior lighting would normally be off during the daylight hours, as required in 9.4.1.7(a). Neither daylight nor nighttime are defined by ASHRAE.

I generally don't hear ASHRAE getting referred to for internally illuminated signage. The Scope in 9.1 is a bit vague. But I don't think these signs count as either an exterior building feature, façade, roof, architectural feature, entrance, exit, loading dock, illuminated canopy, or as part of the exterior building grounds lighting.

When I read 9.4.1.7(c) about advertising signage, I think of a billboard that has flood lights shining on it. The lights turn on at sunset, then are dimmed by 30% between 12am and 6am, back to 100% output until sunrise when they aren't needed any more.

Since internally illuminated signs aren't covered by ASHRAE, LEED is attempting to have some restrictions on how bright they can be. I think many consider terms like daylight or nighttime to not need definitions since most will understand the meaning.

I know USGBC reads these forums but that doesn't mean they read everything. If you feel strongly that a definition is needed it would be best to either contact USGBC or submit a definition during the next Public Comment.

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Yvonne Fan Lighting Designer
Mar 18 2015
Guest
44 Thumbs Up

Uplight - Option 2 Calculation method

Would appreciate very much if anyone can clarify that the maximum allowed percentage of total lumens emitted above horizontal (by lighting zone) is applied to each luminaire or the sum of all lumens from all luminaires inside the project boundary.

Thanks a lot in advance!

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 20 2015 LEEDuser Expert 24296 Thumbs Up

The sum of all luminaires. One or more may exceed the limit as long as the site as a whole is compliant.

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Yvonne Fan Lighting Designer Mar 23 2015 Guest 44 Thumbs Up

Thank you very much Bill!

I have a follow-up question - If there is a canopy that obstructs some of the total lumens, they can be deducted from the allowed lumens, correct?

Thanks a lot again!

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 23 2015 LEEDuser Expert 24296 Thumbs Up

If anything built blocks the light then it can be considered shielded for the uplight calculation.. You'll have to do some math to show the reviewer what percentage is blocked by the canopy. Draw a cross section or two thru the lights to show what angles are shielded from the light.

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Yvonne Fan Lighting Designer Mar 23 2015 Guest 44 Thumbs Up

Thank you Bill!

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Yvonne Fan Lighting Designer Mar 25 2015 Guest 44 Thumbs Up

I'd appreciate your help very much with another question -

We are estimating the effort required to put together documentation for the Light Pollution Reduction SS credit. Can you kindly point me to the online documentation / application required to submit via LEED online for this credit so we can get a better sense of the effort involved? We just need to take a look at the documentation / application required for this particular credit as a consultant for the project at this early stage before the project team registers the project.

Really appreciate your help!

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Glen Phillips Director of Sustainable Education, GreenCE, Inc. May 27 2015 LEEDuser Expert 1595 Thumbs Up

Yvonne,
All of the LEED credit forms (past and present versions) are available here: http://www.usgbc.org/sampleforms.

Assuming this is a LEED v4 project, I expect that consulting fees (and required skill sets) would vary significantly if the project was using the prescriptive (BUG) method instead of the photometric site plan to assess light trespass.

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Vince Briones Sustainable Design Manager Atkins
Feb 23 2015
Guest
314 Thumbs Up

Campus setting, trespass boundary criteria clarified?

The V4 BD+C reference guide notes "When additional properties owned by the same entity responsible for the LEED project are contiguous to the
project site and have the same or a higher lighting zone as the project, the lighting boundary may be expanded to include those properties. In these cases, it is best if a lighting master plan is developed."

If the LEED project boundary is a smaller area that occurs within the interior of a larger primarily developed campus property, is is sufficient to demonstrate there is no potential for property boundary trespass from the LEED site as used to suffice in v2/v3 projects?

Or does this mean photometrics must be conducted including existing (potentially unidentifiable) light fixtures outside of the LEED project boundary that are more adjacent to the property line to demonstrate there is no trespass at the actual property line for the overall campus lighting?

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Bill Swanson PE, LEED AP, Integrated Architecture Feb 23 2015 LEEDuser Expert 24296 Thumbs Up

This would probably be better asked in the v2 or v3 credits.

(Note The lighting boundary and the project boundary are different.)
In the FAQ that Tristan put together for this v3 credit it states...

Q: For campus projects, do all existing light fixtures need to comply with credit requirements at the time of a project's submittal?

A: All existing fixtures within the LEED project boundary would need to comply with the SSc8 requirements at the time the project is submitted for review. However, if the project elected to use the campus property boundary as the "lighting boundary" for SSc8 as allowed by LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10236, existing fixtures within the lighting boundary, but outside the specific LEED project boundary would not have to comply with any of the SSc8 requirements. Essentially, the "lighting boundary" is only used in such circumstances for evaluating that the light trespass requirements are met at that boundary by lighting located within the LEED project boundary.

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Vince Briones Sustainable Design Manager, Atkins Feb 23 2015 Guest 314 Thumbs Up

Bill,

Thanks for the quick response and sorry if we confused the issue. We are pursuing a v4 NC project but trying to understand how the trespass criteria to demonstrate compliance in a campus setting differs in v4 (if it does) from past v3/v2.

Do you think the quoted v3 FAQ guidance would still be safe to rely on for a v4 project?

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Bill Swanson PE, LEED AP, Integrated Architecture Feb 23 2015 LEEDuser Expert 24296 Thumbs Up

I think it would be safe to use for v4.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal Ecoworks Studio
Feb 12 2015
LEEDuser Expert
3704 Thumbs Up

Uplight

We have fixtures that are located in a covered area (under a plaza) which exceed the allowable uplight rating. It seems reasonable to exclude these fixtures from the uplight requirements since they are covered, but there isn’t any clear guidance on this issue. Any feedback would be most helpful.

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Jun 28 2017
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