EBOM 2009 SSc8: Light Pollution Reduction

I have not. And reading the text for this is confusing. It does look like plan view but the example they show doesn't make sense to me.

I understand if this was a can light. But they're showing a linear light. As long as the closest point to the window makes an angle greater than 75° it seems to make the whole fixture compliant. But if the fixture was shortened by 2 feet it's all of a sudden non-compliant even though there's less light in the room.

I think this was intended for small fixtures but was shown poorly in the reference guide. Sorry I can't help you.

Always good practice to double check the LEED Interpretations database
This credit had an addenda posted August 1, 2011 (#10000098) with a revised diagram for Rule #3 that clearly labels window and fixture.

Now that I understand the rules better, for existing buildings, it seems the only way to reasonably comply is automatic controls because most typical office buildings have lights in-line with windows that are closer than 150% of window height. And it is unreasonable to re-configure lighting plans for LEED without a larger facility alteration.

I have a couple ideas. All of the lighting might be on the same control but they may be fed from different circuits. Look at the construction drawings and see if each level is on a different circuit breaker. Maybe all you need to do is switch off the circuit breaker for the top floor.

You could hire an electrician to disconnect the lighting on the top floor for a few hours while the measurements are done. Be sure to keep the public from accessing this floor while the lighting is disabled.

Why are all lights on the same control? Does the open-air top have the lights on all day too?

Just spoke with the property and they were incorrect. The very top portion of the parking garage is controlled seperately from the rest of the structure. Some lower floors are below grade and others are open air. As this is an exterior structure, seperate from the building, do the lower levels of the structure that have a ceiling but are partially open need to be turned off for the second measurement or can the measurements be taken while the exterior lights including the top, open layer is off, but keep the lower level lights on for both measurements? I'm just not sure how reviewers would classify these levels requiring them to be on or off.

I hope this parking garage is not the only building in this LEED project. Refer to MPR #5 about minimum occupancy rates.

Lighting in the covered portion of the parking structure is considered interior lighting and must comply with the interior requirements of this credit. You should not have to consider them when doing the exterior perimeter measurements.

Per CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide:
12/18/2007
The applicant is seeking clarification as to the interior/exterior area classification for a four level open air parking ramp building. For the purposes of SSc8, parking structure covered floor area is to be considered interior area and uncovered area is to be considered exterior area. Thus, any lighting within covered area must meet the interior lighting requirements of this credit and any lighting within uncovered area must meet the exterior lighting requirements of this credit, including being below specified foot candles horizontal and vertical at all locations outside the boundary of the propert

Have you run into projects trying to certify a parking garage alone? Interesting. No, this is an office building. Thank you very much for your help on how to address the levels of the garage. Incredibly helpful.

I doubt the Reference Guide can overrule the Credit language.

Agreed, the credit language takes precedence over RG language.

There is no LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. category for flag lighting. You just add it to the project design total. The wattage of a flag light is usually small compared to the project as a whole and shouldn't have much impact on the ASHRAE 90.1 compliance for the site.

The blinds have to close automatically every night. Explain how they work and their long term reliability being exposed to the elements. If those all work well you should be able to earn the point.

The credit only says they have to be 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. or reduced light output by 50%. I don't think partially shieldedIn a partially shielded exterior light fixture, the lower edge of the shield is at or below the centerline of the lamp, to minimize light emitted above the horizontal plane. complies.

Without the automatic blinds the best way to document interior lighting is to have the lights on occupany sensors. If the space will be regularly used during night time hours then install two ballasts in each fixture and control with a photocell to keep half of the lighting off at night.

Thank you very much Bill,

Then will be complicated for our building to achieve this credit due the building concept is “passive building-active persons", even when we encourage people to turn off the lights and computers after hours, we have no automatic controls.

What if the ballast were changed for 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. in interiors, would this comply??

Unfortunately no. The interior lighting doesn't matter if uplight is shielded or not. No direct light from the interior fixtures can go outside of the building envelope. This is really difficult for all types of lighting along the building perimeter.

I do not have experience with this situation but I understand the concerns about life-safey issues since stairwells for garages are specifically designed to be highly visible from the street or sidewalk.

Most garage lighting is installed above the low points of the concrete structure so cars or trucks don't clip them. This should prevent most from having a direct line of site to the exterior. You may have to create some sort of shield for the few that are visible outside. To add light to the stairwells and perimeter parking you will need to mount the lights on the exterior wall facing in and/or down. This is the only way I can think of to light the space and prevent the lights from being seen outside of the glass box. Lighting the corners will be tricky. I think it's possible but you'll be having to do a lot of things different. Expect to spend a lot of time proving your design to the reviewer too. Good luck.

If you follow option 3 for exterior lighting then your pond lighting should be irrelavant. It does not meet the intent of this credit but option 3 does not measure uplight.

We were following option 2 for everything- so what should we do with the underwater lights? they are only on at night for about 2 hours starting around sunset.

Are you able to change your strategy and comply with Option 3? A 500W flood light cannot comply with Option 2 for this credit. Either rethink if you want/need to uplight this fountain, or if you want/need to earn this Credit.

The only way to get everything you want is to install multiple fixtures around the fountain, each having a wattage of less than 50W. Wattage is based on lamp/ballast combo. The cost of so many fixtures and the burden of relamping them all is not worth the effort.

thanks Bill; can you recommend a device that can be used to measure the illumination around the project boundary? also, what time of night should we aim to take these measurements? (or does it just have to be dark out)

I don't have any preference. Even the cheapo ones did the job. Just do a websearch for "light meter" and you'll get a bunch of results. Prices will range from $100 - $300. Look for one that can measure low light levels of 0.1fc and has a button to lock/hold the display reading. This will push you up to $150 I think.

As long as it's dark it shouldn't matter what time. Maybe start 1 hour after sunset. If it's cloudy you should be able to start even earlier.

The Reference Guide says that measurements need to be taken after "civil twilight" in the evening or before civil twilight in the morning. This U.S. Navy site is the referenced tool for determining civil twilight for your location and date: http://aa.usno.navy.mil/data/docs/RS_OneYear.php.

If you are going to follow Option 2 for exterior lighting then keep the wattage below 50. And for HID, wattage is the combination of lamp and ballast. For incandescent, wattage is the largest rating of the socket.

If that's a proplem then Option 3 is another way. It only measures perimeter light levels.

It sounds like you're combining Option 2 and Option 3. You only need to comply with one of these for exterior lights.

v2 required light levels to be no more than 10% greater at the property line when the lights are on. v2009 increased that to no more than 20% greater. Any 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. requirements for lights near the property line might be a little less strict but nothing specificly has been eliminated. This is Option 3.

I don't have that Reference Guide. If you have a question about the wording could you copy the sentence here.

The parts refering to shielding and lights less than 50 watts is about Option 2. If all light fixtures 50 watts and over are partially shieldedIn a partially shielded exterior light fixture, the lower edge of the shield is at or below the centerline of the lamp, to minimize light emitted above the horizontal plane. so that they do not emit light directly into the night sky, then you comply with Option 2 and can ignore the language in Option 3 about the boundary light levels.

Light levels have not increased. Sounds good for submittal.

You can have the calculation on the outside edge of the wall.

Since the credit is meant to reduce light trespass the wall will be very helpful. You'll probably get the same light level with your site lights on and off.

How tall is the wall? Where are the wall lamps? on top of the wall, inside surface, or outside surface?

Thank you Bill.

The wall is 3m tall and the wall lamps are installed on top of the wall.
You rightly guessed, same light level observed with the site lights on and off.

For credits like light pollution reduction, which are largely about the equipment choices made for a building (shielded fixtures) or equipment setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. (programming time clocks to turn off lights at night), the expectation is that the equipment and program are in place for the entirety of the three-month performance period.

CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide from NCv2.2
9/25/2008 - Ruling
[3] Residential spaces may not be exempted from the interior lighting requirements. ... However, as an alternative for residential spaces, demonstrate that less than 10% of the total lumens emitted by each luminaire are not directly emitted out of the building through any fenestration.

Thank you Bill.Another doubt that I have is that my project building is 16 years old.We do not have any lighting plans for the common areas but all are 100% automatic control with fixed lighting schedule.For my submission is it mandatory to provide the lighting layout for areas which fall under automatic lighting control or would it be enough to mention or mark out the zones on a space layout plan?

I have never submitted for a LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. project so I'm not sure but just from reading the credit it seems you do not need a plan showing interior lighting. Just comment that all interior lights have automatic controls and the total programmed hours of after-hours time is 2,190 hours or less for the year.

Thank You.

For interior lights this credit is looking for a direct line of site to an opening in the building envelope, either wall or ceiling.

What type of ceiling hung T-8 fixtures are these? What does the photometric curve look like? I'm guessing that there's at least some up-light from these lights. If you were at the windows would you be able to see direct light from the T-8 fixtures?

I think a section of the building with light fixture location shown is good for showing compliance. Also attach a copy of the light fixture cutsheet showing what type of fixture this is. Usually the last page of the cutsheet shows the photometric output. If it shows no light coming out of the top of the fixture (between 90 and 180 degrees) then you're good.

If there is direct light going out the windows then automatic controls will need to be shown stating the lights are off 50% of the night hours. At least for the lights within site of the windows.

If this doesn't answer your question let me know.

Well, the specifics here can be fairly important. If the lights are 'on' the boundary and owned by the city, they clearly fall outside of your sphere of responsibility. If they are, in fact, within your project boundary, I can imagine two options: the first would be to make the 'control' argument to the GBCI, which I think would be a fairly compelling argument. There's really nothing you can do about city-owned fixtures. Alternately, and perhaps more reliably, you could use the Option 3 approach (with the city-owned lights 'on' in both scenarios) to illustrate that the contribution of the lights you DO control to the nighttime lighting situation is marginal.

The main thing I want to respond to is about your whole project, not SSc8. Are you planning to certify just the office space within the warehouse? According to the LEED Minimum Program Requirements for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems., "LEED projects must include at least one existing commercial, institutional, or high-rise
residential building in its entirety."

In principle, I don't know of an obstacle to achieving this credit if it just involves one exterior light fixture. Make sure to address the interior requirements as well.

It sounds like it does not comply. The credit states "The illumination
level measured with the lights on must not be more than 20% above the level measured with the lights off."

A couple ideas come to mind. Can you shift the measuring points? It states that you need at least 6 points and no more than 100' apart along the perimeter. Sometimes a 20-50' shift can show surprisingly different results.

If that doesn't work you have a small chance getting this by increasing your accuracy. Does you light meter measure hundredths? If the 0.3 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. value is 0.33 fc with lights off and the 0.4 fc is 0.39 fc with lights on it would be compliant. It's not likely but if you're looking for any ideas it's something to try.

I think your interpretation is consistent with the credit intent - the objective is to reduce illumination to the night sky, and reducing wattage certainly does so. Depending how much you reduce wattages, it may be more or less ultimately effective than 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., but it does meet the requirements.

One or the other should be sufficient Kevin; in most instances my suspicion is that horizontal foot-candles are the right measurement, but I don't think either method is specifically required by the credit language, nor is it required that you perform both methods of measurement at each measurement point.

Sorry for chiming in, but I have a question that is along these lines...should the 100' measurement protocol be used as the standard for measuring light transmittal in an NC (warehouse) project where shading the windows are not an option, but the lighting is so high compared to the clerestory windowsPronounced and sometimes spelled "clear-story," these are vertical, or close-to-vertical, windows high in the wall of a building that bring daylight deeply into the building and, if operable, can help ventilate the space. that very little light will be emitted? Any ideas on how to measure the true affect? LEED does not specify in BD&C.

Sorry for chiming in, but I have a question that is along these lines...should the 100' measurement protocol be used as the standard for measuring light transmittal in an NC (warehouse) project where shading the windows are not an option, but the lighting is so high compared to the clerestory windowsPronounced and sometimes spelled "clear-story," these are vertical, or close-to-vertical, windows high in the wall of a building that bring daylight deeply into the building and, if operable, can help ventilate the space. that very little light will be emitted? Any ideas on how to measure the true affect? LEED does not specify in BD&C.

One measurement every 100 feet until the entire perimeter has been completed is the correct approach. Gaps of larger than 100 feet would allow for too large undocumented spaces, or at least that is the concern.

A re-visit to this question... Our convention center project site perimeter is 11,000 linear feet. In order to satisfy the credit, we would need to do 220 measurements (measuring every 100 ft with lights on and off). This would take over 7 hours of testing and the info would not be valid since we would still be testing at sunrise. Is submitting a CAD drawing with 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. detail and confirming accuracy with spot testing acceptable? If not, what do you suggest? Thanks!

I have not heard of any variations of this option being accepted. A CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide would be the only way to know for sure.

I don't see why you couldn't do this over two nights. Just try to make sure the start times, measurement points, and neighbor's lights are all the same.

That was our next option, BUT, Page 71 of the Ref guide says take them on the same night. Would you suggest explaining the obstacle in the survey report and submit?

It would seem silly for them to deny this credit because of the size of the site.

I was looking at the sample form for this credit and I don't see anything specifically asking that all measurements were taken on the same night. There was a box that you may want to mark.
"Special circumstances preclude documentation of credit compliance with the submittal requirements outlined in this form."

If you check this box and explain to them that due to the size of the project and the available night time hours for measurement that work was divided up over two nights. "We were unable to do all light level readings in a single night because of the 2 miles of perimeter of this site. Measurements averaged 2 minutes each and total time required would be over 7 hours when we only have 6 hours of full darkness available."

Then go out of your way to reassure them that all conditions between the two nights were identical. Just list everything that is the same. "All points has markers placed on the ground to make sure same location was used each night. The start time and path around the site were the same. All project interior lights were on. All surrounding neighbor lights were the same each night. The same person and meter were used." etc. etc.

Most reviewers seem to like knowing that you took a lot of effort to do it right. If the submittal allows for some exceptions and you can show you did your due diligence to comply then I don't see a reason you couldn't earn this credit. But that's just my opinion.

Sounds like a plan! Thank you for your help

Let us know how it goes.