Schools 2009 SSc8: Light Pollution Reduction

Why do you think this is an Alternative Compliance Path? This sounds like you are complying with Option 1 for interior lighting. How do you know the lights will be off at night? Are they on occupancy sensors or is this some sort of promise to turn off the lights before leaving for the night?

Thanks I reread the option 1... didn't see less than wording

I'm not understanding your question well. Are you refering to my post on Aug 18 2011?

"LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. per fixture" does not make sense.

The website I mentioned on Aug 18 2011 can use any IES file to show you the % of uplight and the BUG rating.

"If you want the information for the IES file on your hard drive then click the "My Files" tab at the top."

Bill, The IES file for any brand name will be listed?
Not just those indicated?

Also relative to canopy vs Main entry door lighting.LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space.
We meet the criteria for canopy at the Main door.

There is no other lighting at the Main entry. Is this
compliant then?

No. The website only has the IES files from Acuity Brand companies. But they allow you to upload any IES file that you have.

Click this link,
http://www.visual-3d.com/tools/photometricViewer/default.aspx

Click "Open" at the top left of the screen.

Now, at the top center of the screen are 3 tabs. The first one is "Catalog" and is blue. That just shows the companies they have IES files for. The second tab "My Files" is black. Click that one.

Now click the "Browse" button. Find the IES file you want information about on your hard drive or network drive. Then "Select". Now you should see all of the tables and graphs.

Still not sure what you mean regarding LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space.. I can't tell you if the main entry is compliant or not. Canopies and doors are part of the tradable surfaces. The site is either compliant or not. The entry is just one piece of the site.

Thank you - this is very helpful. Can you explain
tradable surfaces again? If we are a little over in one
area but the total site is fine are we on track to get the
point?

Just like using the space-by-space method for interior lighting. You can be low in some areas and high in other areas as long as everything combined is low.

The power these use would be excluded from your 90.1 compliance calculation because they are advertising.

You still need to count it for light pollution. It probably won't have an affect on perimeter light levels but it does affect uplight. I assume 50% of the signage light is uplight. Count that in your calculation for total site uplight.

Let's look at an example.
http://www.visual-3d.com/tools/photometricViewer/default.aspx?id=27333

The first table on this page is down a little bit and called "Zonal 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. Summary"
In the 90-180 Zone they show 3.2 lumens. This is less than 0.1% of the total output of 6,173.7 lumens for the whole fixture. Almost nothing but it still prevents this fixture from being used in LZ0 or LZ1 because it's more than 0% uplight.

Now let's assume there's also a typical wall pack on the building exterior.
http://www.visual-3d.com/tools/photometricViewer/default.aspx?id=13334

This fixture has 523 lumens in the 90-180 Zone. Out of 2,662 lumen total output.

If you had a project with (5) area lights from the first link I sent you and (2) wall packs from the second link I sent you, the total uplight would be, (5 * 3.2) + (2 * 523) = 1,062 lum.
Total site light is (5 * 6,173.7) + (2 * 2,662) = 36,192.5 lum.
% Uplight for site is: 1,062 / 36,192.5 = 2.9%

This sample site would only comply with LZ3 or LZ4 locations. If your project is located in LZ2 then you'd either have to remove a wall pack or change the style of wall pack to something with less uplight.

If you can't find a table like this for your light fixture all you need is the IES file.

Go to this page.
http://www.visual-3d.com/tools/photometricViewer/default.aspx

Click "Open". Then the brand names they have available files for will be listed. If you want the information for the IES file on your hard drive then click the "My Files" tab at the top.

If the Owner has the shop drawings you may find a sheet showing light levels outside of the field.

There is nothing officially shown anywhere that excludes sports lighting for this Credit. Even with 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. these fixtures will have a sizeable amount of spill light and uplight.

I've suggested to others with advertising and directional markers to argue they are excluded because ASHRAE 90.1 and the Pilot Credit exclude them. You can try this approach with the athletic playing area lighting. Say you are trying to be consistent in applying this credit.

If they reject that arguement then you can always try the Pilot Credit which does specifically exempt this lighting.

This is also interesting because I've never heard of a reviewer asking for existing fixtures to be compliant before.

If its within the LEED boundary and included in your EAc 1 calcs, then you need to include for SSc 8. If it is not under LEED for Schools, i recommend that you document the credit following the LEED for Schools requirements for Sports Lighting.

Bill - comments are back and the credit was denied. My question is - in the LEED for Schools 2007 (which is what this project is registered under) it says "note that physical education spaces (playing fields) do not need to comply with the lighting power density requirements of this credit, as per ASHRAE 90.1 section 9.4.5, exception E." What am I missing here? The lights exist to light the baseball field - the field is included in the boundary because the field is being replaced - lighting remains. Your thoughts? I am assuming I will need to appeal but this just doesn't seem right.

ASHRAE 90.1 is different than the lighting trespass levels. It sounds like the reviewer is following this by the letter of the Credit. So the sports field doesn't have to comply with the W/sf but they are still demanding that light levels around the project boundary and uplight % comply with this Credit. I don't see how sports lighting can comply with either of these requirements.

You can try appealing and argue these are existing fixtures. And the very nature of sports lighting makes this compliance impossible which is why the Pilot Credit excludes this type of lighting. I personally hate spending the customer's money in an appeal but if this credit is needed then you may have to. At least a different reviewer will be looking at it and they may be more sympathetic to you.

If you have any unused ID credits try going for the Pilot Credit.

I am interested in this too. The new AGMBC came out in October and under the old one you could do that, but from my understanding of the new one, you can't anymore. Our preliminary design reviewers came back (before the new guide was published) and said light traspass beyond the project boundary but within the campus boundary was unacceptable because we didn't do photometrics for the entire campus. (which is impossible)
It seems replacing all fixtures on a campus because you are doing one LEED project would be prohibitively expensive. Especially since the light that does trespass is providing a necessary level of light for life safety.

You need to either show the project meets the LEED boundary requirements or that the campus meets the LEED boundary requirements. Most universities are not going to have IES files for 20-50 year old lights to be able to do the calculation with.

I've seen Harvard earn this point by providing a copy of their design standards for the campus and they promised that all lights will comply with LEED requirements for the campus as a whole. No promises that this same tactic would work now.

I'm wondering if anyone has any further guidance on these matters since this topic was posted. I'm working on a project on a campus, but it is the only anticipated LEED project on the campus. I read through the 2010 AGMBC and it seemed that it only really applies if you have multiple projects pursuing LEED on the same campus. In our case, we have just one project, and I am assuming that we can structure our LEED project boundary in a reasonable way that makes sense to us without using the campus approach. However, if we do that, we will have trouble with the Site Lighting credit because we will definitely have light spilling onto other parts of the campus, which really should not be a problem as a practical matter.

I have not heard anything new but would love to hear from others.

What Bill said above remains true. Campus projects can choose whether to comply with the requirements for the building site boundary or to meet the light trespass requirements for the campus as a whole. The latter case is going to be common for projects taking the AGMBC approach. Either approach can be very difficult, as you indicate.

Yes, they need to be considered in the exterior lighting calculations. Per USGBC's 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 response. I think the second paragraph is what you're looking for.

Question:
The firm that will occupy this office building works on many projects of a sensitive nature so security is a significant concern, both for employees arriving early or working after dark and for protection of the facility from intrusion.

Is it acceptable to include motion-sensor activated lights that do not fall within the allowable site lighting wattage? These lights would be located in the immediate vicinity of the building and would only be enabled to turn on when other site lights are off. They would only remain on for a limited time following activation.

If such motion-sensor activated lights are allowed, can they be excluded from the other requirements of this credit, property line illuminance and uplight components, since their purpose is only safety and security?

5/6/2009 - Ruling
The applicant is requesting confirmation if it is acceptable to exceed the lighting power density requirements with motion responsive after‐hours security lighting that is only enabled when the other site lighting is off. Based on the description provided, this strategy is only acceptable provided that when the security lighting is ON, the combined security and general lighting that remains ON, does not exceed the lighting power density thresholds and the security lighting is capable of being controlled to prevent simultaneous operation with the offsetting exterior luminaires.

The second question asks if the lights can be excluded from the other requirements of SSc8 and the answer is no. These luminaires must meet the light trespass requirements relative to their declared environmental zone at the applicable site boundary, as well as the 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. requirements of the credit.

I don't think it matters. As long as you're consistent with all fixtures on the site.

The credit reads "initial fixture lumens". If you want to calculate it out that way then you're meeting the letter of the credit. But most people just use initial lamp lumens. It's faster than looking up the efficiencies of each fixture. And if metal halide fixture 'A' is 80% efficient and metal halide fixture 'B' is 78% efficient, it's not going to matter much. The ratio of up and down light will be near identical for fixture lumens and lamp lumens.

If you don't know what I'm talking about then a lamp puts out X lumens. The fixture we put the lamp in bounces the light around but not all of it gets out. Some stays trapped inside of the fixture. The amount of light that gets out compared to the bare lamp lumens is called the fixture efficiency.

1000 lumen lamp put into a fixture and the fixture puts out 800 lumens means the fixture has an 80% efficiency. Most cutsheets will say what the efficiency is if you look hard enough.

LED lights will not have an efficiency. If they are tested per LM-79 the listed 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. value is the fixture lumen value.