The Light Pollution Reduction credit has been rewritten to make it easier to understand while maintaining both flexibility for lighting designers and applicability to different kinds of light pollution. The exterior requirements are split into two areas: uplight and light trespass. For both requirements, an optional path allows teams to demonstrate compliance by selecting luminaires with an appropriate BUG rating and placing them appropriately. These optional paths do not require point-by-point calculations. The calculation path has also been simplified and now requires calculations for fewer locations. Many projects can achieve the credit by simply complying with ASHRAE 90.1–2010 and selecting luminaires with an appropriate BUG rating. This revision also introduces a new term, lighting bound-ary. All light trespass requirements are met relative to the Lighting Boundary, rather than the LEED site boundary. Uplight requirements are still met based on all non-exempt exte-rior luminaires located within the LEED site boundary.
BUG Rating: A luminaire classification system that classifies luminaires in terms of back-light (B), uplight (U) and glare (G) (taken from IES/IDA Model Lighting Ordinance). For this credit, the BUG ratings supersede the former cutoff ratings.
Lighting Boundary: The Lighting Boundary is located at the property lines of the property, or properties, that the LEED project is within. The Lighting Boundary can be modified un-der the following conditions:
A multi-tenant complex is defined as a site that that was master-planned for the devel-opment of stores, restaurants and other businesses. Retailers may share one or more services and/or common areas.
1.) Register for Pilot Credit(s) here. 2.) Register a username at LEEDuser.com, and participate in online forum3.) Submit feedback survey; supply PDF of your survey/confirmation of completion with credit documentation
Option 1 BUG Rating Method:
Option 2 Calculation Method:
A point-by-point calculation showing initial vertical illuminances. Each vertical plane shall include:
Provide proof that the project complies with NC, CS, Schools, Retail, Healthcare above.
Excerpted from LEED Pilot Credit Library
To increase night sky access, improve nighttime visibility, and reduce development impacts on wildlife environments.
NC, CS, SCHOOLS, RETAIL, HEALTHCARE
Meet either Option 1 or Option 2 for Uplight and either Option 1 or Option 2 for Light Trespass based on the photometric characteristics of each luminaire when mounted in the same orientation and tilt as specified in the project design.
Use the definitions of Lighting Zones provided in the Illuminating Engineering Society/ International Dark Sky Association (IES/IDA) Model Lighting Ordinance (MLO) User Guide. Use the lowest-numbered MLO lighting zone of the LEED Project and of all areas immediately adjacent to the LEED Project Boundary at the time construction begins.
Internally-Illuminated Signage: Any exterior signage within the LEED Project Boundary shall not exceed a luminance of 200cd/m2 (nits) during nighttime hours and 2000 cd/m2 (nits) during daytime hours.
Meet either Option 1 or Option 2 for all exterior luminaires located within the LEED Project Boundary.
Do not exceed the following maximum luminaire uplight ratings, based on the 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. output of the lamp(s) as defined in IESNA TM-15-11, Addendum A:
Table 1. Maximum uplight ratings for luminaires
Do not exceed the following maximum percentage of total lumens emitted above horizontal:
Table 2. Maximum percentage of lumens above horizontal
Do not exceed the following luminaire backlight and glare ratings, as defined in IESNA TM-15-11, Addendum A, based on the lumen rating of the lamp, mounting location, and distance from the Lighting Boundary.
Table 3. Maximum backlight and glare ratings
Do not exceed the following maximum vertical illuminances at the Lighting Boundary. Calculation points shall be no more than 5 feet (1.5 meters) apart. The MLO lighting zone for each calculation point is based on the lighting zone of the immediately adjacent property at the time construction begins.
Table 4. Maximum vertical illuminance at Lighting Boundary
The following are exempt from the requirements, provided they are controlled separately from the nonexempt lighting:
FOR PROJECTS THAT ARE PART OF A MULTITENANT COMPLEX
Meet the requirements above and develop a comprehensive master lighting plan that includes the project site and the surrounding buildings. The lighting master plan must incorporate:
Meet the Light Pollution Reduction requirements for:
For all spaces with luminaires having a direct line of sight to exterior fenestration, all inte-rior lighting exiting the space shall be automatically reduced by at least 90% whenever the space becomes unoccupied during nighttime hours.
Meet the requirements of one of the options below:
OPTION 1. Fixture 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.Shield all exterior fixtures (where the sum of the mean lamp lumens for that fix-ture exceeds 2,500) such that the installed fixtures do not directly emit any light at a vertical angle more than 90 degrees from straight down.
OPTION 2. Meet BD&C RequirementsIf the project is certified under LEED for New Construction, Schools, demonstrate that the project complies with the exterior lighting requirements of the latest pub-lished LEED for New Construction SS Credit, Light Pollution Reduction.
If the project is certified under LEED for Core & Shell Development and 75% of the floor area is LEED for Commercial Interiors, demonstrate that the project complies with the exterior lighting requirements of the latest published require-ments for both rating systems.
Measure the night illumination levels at regularly spaced points around the LEED Project Boundary, taking the measurements with the building’s exterior and site lights both on and off.
At least 8 measurements are required at a maximum spacing of 100 feet (30 me-ters) apart. The illumination level measured with the lights on must not be more than 20% above the level measured with the lights off.
The homepage for the LEED Pilot Credit Library. The LEED Pilot Credit Library is intended to facilitate the introduction of new prerequisites and credits to LEED. This process will allow USGBC to test and refine credits through LEED 2009 project evaluations before they are sent through the balloting process for introduction into LEED.
Background for the LEED Pilot Credit Library is provided in this foundational document.
we have underground parking areas in the project. ASHRAE 90.1 2007 says 0.3 W/ft2 for garages (around 3.23 W/m2)
should we use that as teh standard to design our lighting for the underground car park.
more of a question to find good standards for lighting than following the standard to submit a LEED project
I'm working on a project and the owner selected a decorative post top fixture to line the drive into the site. The site is small enough where this fixture is the main site fixture. One look at it and I said it won't comply with SSc8. I was told to look at it and do what I can.
The fixture had 10% uplight. Then I was told it had a special glass optic to limit uplight. That knocked it down to 4% uplight. This is in an LZ2 location so I need a total site uplight of 2% or less.
I thought I'd try for Pilot Credit 7. I imported the IES file into Visual's photometric viewer to see it's BUG rating. It had a U3 rating. Tried the lowest wattage version of the fixture and it's still U3 rating.
I looked closer at the values and realized they already updated the software to TM-15-11. But PC7 is based on TM-15-07. The uplight values were reduced from 100 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. in '07 down to 50 lumens in the '11 version. This low wattage version has 88 lumens in one of the uplight zones. So it is actually a U2 rating until LEED v2012 comes out.
Just found it odd that this fixture can be non compliant for SSc8 in both v2009 and v2012 but manages to comply with PC7.
Interesting observation. And I think I understand what you are saying. It brings up a few issues.
1. The MLO and TM-15-11 were just issued this summer with the U rating change right in the middle of the development of LEED-2102 and the final stages of IGCC. This caused quite a bit of consternation because previous versions had already been used for basis of LEED 2012 drafts, 189.1 and IGCC. It will all get sorted out eventually, but I'd expect some confusion over BUG ratings, because if you happen to be using old software that hasn't been updated for TM-15-11 you are going to get bogus results (or if the BUG tables in a particular standard haven't been updated but you are using TM-15-11 BUG ratings.)
2. LEED 2012 public draft #3 will be out soon (next few months?) and I'm assuming that PC7 will be updated to be this draft. So if you comply under PC7 now, I'd say you best get your submittals in :-)
I think you will like draft #3 of the credit - it has really been cleaned up a lot and is much clearer.
3. Do not expect the same stringency results under the "old" 2009 methods and the "new" BUG methods. There was never any intention for this. These methods were developed independently and at different times. The "old" method was developed for LEED by methods unknown to me, but the LZ concept and the idea of using vertical illuminances for trespass limits probably came from RP-33. The "new" BUG method came from the MLO development process. The idea was to add MLO/BUG methods to LEED in order to get consistency across standards and rating systems, and because BUG is will make compliance much simpler - no computer simulation required. It was decided to leave the "old" methods as an option, I think partly because BUG is new and untested, and partly to give designers another less prescriptive/more performance option for compliance and/or to stick with what they are familiar with. It will be interesting to see which options are chosen as PC7 and LEED-2012 start getting used. I predict that eventually the "old" methods will be dropped and LEED will follow the MLO as it develops.
I see from the description that Pilot Credits can be achieved only as an ID credit, which leads me to ask: Does that mean that we could get the regular LEED 2009 SSc8 credit, and also this one? I can see the argument both ways, but to me it seems logical that we could get this point instead of the regular compliance path. Is it defnitely only ID?
For the time being, pilot credits are only available as ID credits, not as alternative compliance paths to existing credits. This means that in the case of light pollution reduction, a project could earn both SSc8 and Pilot Credit 7 on the same project. What we can learn from these projects is whether the new credit is an improvement on the old one in terms of clarity, stringency, ease of use, etc. It gives us a good apples to apples comparison since the project specifics are the same.
I was just thinking. If this Credit allows us to exclude adversiment lighting and theme park lighting why is it so difficult to exclude flag lighting. It just sends such a bad message.
The Micky-D's sign can glow all night without concern but a couple flood lights on the flag is.
Or the castle in the Magic Kingdom can have flood lights but not the flag.
It's just my suggestion to USGBC to reconsider this. Make some people happy. Add an exclusion for flag lighting. If it still bothers you then as a compromise have a max 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. allowance per flag pole. Just an idea.
The lighting experts and I actually just discussed this issue today. The credit language is being revised. Flag lighting, according the new language, is allowed in Zones 3 and 4 as a landscape feature, but not in Zones 1 and 2. The revised credit language will be available for second public comment, so please have a look when that is released in early summer.
I'll try to respond during the second public comment but most schools and government buildings will be in LZ2 locations.
So I'm guessing this flag light exception never got included because it differes from the MLO and we must match the MLO. At least the McDonalds sign is safe.
Good point, Bill. Can anyone shed some light (no pun intended) on why an exception for flag lighting (with a 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. allowance, or similar) is not acceptable? I can say it does not help the cause of LEED to have to say to a client, "we can do all of these sustainable things, but we won't get the credit unless we get rid of the flag." Doesn't sell well to many clients, especially government clients. Having the staff to maintain (e.g. raise and lower) the flag every day is often not feasible, and if the flag is left flying, it must be lit.
I searched thru some TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system. meeting minutes and there's a brief mention about 2 years ago that downlighting exists for flag poles so no exception is needed. Now I've never seen downlighting on a flag so I googled it and found products like this. http://www.eaglemountainflag.com/cat-flagpole-down-lighting.html
I don't see how any of these products could properly light a flag directly below it. I'd love to see a night time photo of one of these in use.
Regarding the flag lighting they seem to think market transformation is possible to make people change to downlighting. But for advertisment lighting they don't want to shock the market with radical changes.
Let me jump in here and comment on your comments going back to Mar 04 2011.
1. As you know the credit now regulates signage. There still may be some confusion regarding the exemption for "internally illuminated advertising signage". This is only an exemption to the lighting requirements, not the signage requirements. I think this language will get cleared up for the 3rd PRD.
2. There is no mandate that says LEED "must match the MLO". Certainly it would be ideal to have one light pollution control standard that was used universally (in MLO, IGCC, 189.1, and LEED) But in practice that seems to be not possible for various reasons. For one, LEED is a voluntary rating system not a code, and also SS8 does not exist in isolation and has connections with other credits. The MLO has provided a valuable new method with the BUG system that promises to make it easier to produce the submittals for the credit (no computer simulation required). What we are trying to do is develop a credit that is appropriate for the LEED rating systems.
3. I'm not sure you're right that "most schools and government buildings will be in LZ2". Per 90.1-2010, LZ2 is now "Areas predominantly consisting of residential zoning, neighborhood business districts, light industrial with limited nighttime use and residential mixed use areas." But I guess we'll just have to see how this is interpreted in the ref guide and by GBCI.
4. Pole top flag lighting systems are not viable in my opinion. In the discussions I've participated in I don't think anyone suggested this as a solution to get the credit. The thought process was that flag lighting is possible in LZ3 and LZ4 and in LZ0/1/2 you can lower the flag, leave it up at night (it happens a lot without negative consequence), or light it and not get the credit. So, should there be a special exception for the flag? Just the U.S. Flag? the Canadian flag, State and Provincial flags, war memorials, public monuments? etc.? Where do you draw the line?
Thanks for the response.
1) The signage limit is measured in cd/m2. This is how video monitors are measured. No one is going to know how this applies to traditional signage or how to prove what they have is compliant. How do people use this at time of submittal?
2) The response I got from the 1st public comments is, "TM-15 is the referenced standard and cannot be changed." The may not be anything officially written saying this credit must match the MLO, but it's being implemented as if there were.
3) The majority of schools are in Residential neighborhoods which fits into the definition of LZ2. It will be impossible to convince a reviewer that the definition of LZ3 (none of the above) is more applicable to this neighborhood site when LZ2 already describes the neighborhood.
"The TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system. discussed how LEED 2009 projects should handle lighting of the
American flag, and determined that flag lighting is not exempt from the
requirements of the credit, and that downlighting may be used."
Then from the public comment responses, "In the interest of minimizing light pollution and since these objects do not have to be illuminated (flags may be taken down during nighttime hours) it has been decided that they should not be given an exemption."
No school or office building has the staff available to raise and lower the flag every day. And if the US flag is up at night it should be illuminated per the Flag Code. There are no flag police true, but I'd rather tell a building owner we can't earn this credit than to suggest not lighting the flag. It's better for our relationship. And some buildings will always have flags flying at night, like Capital buildings.
I don't even see the exemption for LZ3 or LZ4 that was discussed. Maybe if you add these exemption you can allow LZ2 if the light has a full hood. This should reduce 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. since it's the low angle light that is mostly the cause.
Allowing this for any government flag is easy enough. And the amount of light from these locations is insignificant. Streetlights and advertisement is 80% of the source of light pollution. I doubt flags are more than 0.01%.
Luminance (cd/m2) is the only reasonable metric. It should be available for LED/video type signs. But yes, it may be an issue for signage guys producing typical backlit sign, channel letters, etc.
This bears more thought.
Just so you know some thinking behind the new signage requirement. There is a big loophole in the credit now because you could have a giant blinding sign on the side of your building and get the point for SS8. Also these "media facades" which are more decoration than information could be called "signage" instead of facade lighting and be exempt.
TM-15 is an IES "Technical Memorandum". TM's are developed and published by the IES. TM-15 is referenced by the MLO, but is not part of it.
The idea was that flag lighting would be exempt in LZ3/4 since it would be considered landscape lighting and covered by the exemption: "lighting that is used solely for façade and landscape lighting in lighting zones 3 and 4 and is automatically turned off from midnight until 6 a.m.";
But I realize we added the midnight shutoff - so, oops, I misled you.
Personally I think we need to look at some sort of exemption for national flag lighting in LZ2-4.
1) How about W/sf or W/m2 of illuminated surface area for signage? Most lighting technology is a similar efficacyIn lighting, the ratio of light output (in lumens) to input power (in watts). Higher efficacy indicates higher efficiency.. In a few years, as LED technology improves, we can lower the limit further.
2) The IES wrote TM-15 and they wrote the MLO around TM-15. They are integral enough to be the same in my mind and apparently in the mind of the person writing the response to my public comment.
3) Thank you.
Where did our discussion go on this topic? Why was it removed? There were no website rules violated.
Has anyone been following the PC7 conversation, who has an email notification of Bill's comment and Chrissy's follow-up on their computer? The missing comment is from 11/29.
I apologize for an inadvertent screw-up on my part, and unfortunately not one that I can repair. The skeleton of each credit page on LEEDuser is called a metadata page, and this is what comments get attached to. I noticed recently that there mistakenly had been two metadata pages created for PC7. I deleted the one that I thought was inactive, and only very recently noticed that the comments had gone missing -- I deleted the wrong one. The only practical way to get those comments back is if anyone following the conversation received the email notifications of yours and Chrissy's posts, and can repost them. Or if what you said is replicable. I don't remember if it was as long and detailed as many of your posts are. I'm sorry.
Here are the last 2 comments (Bill & then Crissy). The earlier ones are cut off after a few sentences so they don't make much sense now.
Bill Swanson 11/29/2010:
" Thanks for actually responding. Seems I talk to the wind about this credit most of the time.
1) Now it is available. For all of 1 week prior to the launch of LEED-2012.
I don't understand why this was a pilot credit then.
2) I think projects with good lighting and little pollution should be able to earn this point following either option. I've never seen a numbers argument for the tight limits that the BUG system has in the 80-90 range. With them being as tight as they are it seems this is very important and the other option should be modified to follow suit.
4) I was referring to the 1st draft. After posting I realized I again missed the public comment. It's a bit frustrating having to find and argue elsewhere for items added into LEED.
5) Yes, the MLO 1st draft had a mistake, which was wholly adopted by LEED-ND.
I complained about the BUG system during that public comment and the system was adopted as is. If obviously bad oops can't be vetted, the system has a flaw. The desire to have MLO and LEED match has over-ridden the public comments. Public comments are useless if you try to offer anything that is different from the MLO.
6) Glare is less affected by night time ambient light level variations then it's being made out to be. It really doesn't need 5 zones. The idea to just "go with it for now" is how bad laws spread. The 0.01 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 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. 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 luxMeasurement of lumens per square meter., or lumens per square meter. limits was terrible. Once LEED issued it out it spread anywhere. And then it gets entrenched because people don't want variations in different Codes. Like you matching the MLO with LEED, or 189.1. It's mind numbing trying to change bad law. I want it stopped before it starts. I hate just "going with it". That is not science.
7) People will always look for loop holes. Ten might be extreme but I know someone will put two or three poles in the same footing and do this. Should there be a minimum 1 pole-height spacing between each pole? I don't even know if this BUG system counts a 4-head pole with one BUG rating. What good is a back-light shield on a 4-head pole?
8) I think you'll find most spill light under this version will be coming from the sides of fixtures which this BUG system doesn't address. It's over complicating a system while glossing over holes.
9) I've been trying to make the case it should be at the neighbor building or building set back line. The property line or opposite curb has been my compromise point.
10) I would really demand that the handbook provide people examples for how to document this when they make funky rules like a vertical calc grid.
Chrissy Macken 11/29/2010:
Hi Bill -
With reference to the schedule of releasing the Pilot credits: all pilot credits that are also in the next version public comment documents will be available throughout the entire public comment process, which is proposed to be about 1.5 years long in total.
The point of the dual process is so that we get public comment feedback from the market, and also feedback from projects that are able to test the new credits and compare across versions of the credits. The pilot credits will be available for testing until it is determined that a credit is ready to enter member ballot for a vote and become part of a balloted rating system.
I will let the lighting experts address your other points.
Thanks for the feedback!
Thak you very much for reposting it.
Thank you for the comments, Bill. I am incorporating them into our discussion of this credit. As I said above, we're revising this language, and I think many of your comments will be addressed when the language is released for second public comment. We've caught the errors and are addressing the issues raised in regards to the BUG system and MLO.
Based on the LEED Site, it would appear this credit also is available for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems., is that correct? We are looking at a feasiblity study related to a campus application that would make this ability to extend beyond the boundry, for good reason, a way that the project could show compliance.
Scott, yes, this pilot credit was recently revised and is available for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. projects.
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