Addressing both interior and exterior lighting, this credit seeks to reduce light pollution that can block our view of the night sky and cause human health problems as well as ecological problems for many birds, insects, and other animals. Light pollution often represents nighttime lighting that isn’t needed, wasting energy while causing light trespass and contrast, reducing visibility.
Many people think that more lighting means better nighttime safety and security. However, too much exterior lighting can make outdoor and parking areas less safe by creating high contrast between lit and unlit spaces. Among other problems, when the human eye is flooded by bright light, it becomes harder to adjust to darker areas and shadows. Too much exterior lighting also means unnecessary energy consumption. Some objectives to keep in mind when striving for safe, efficient, and aesthetically pleasing lighting design are lighting uniformity, low contrast, no glare, and preventing light from spilling off the site. This can be achieved through judicious selection of fixtures with 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. that direct light toward the ground but prevent it from shining up into the night sky.
Full-cutoff luminaires reduce light pollution, improving views of the night sky.
This credit has four separate requirements, which can make compliance complicated—though not necessarily difficult. One addresses indoor lighting spilling to the outdoors, and three deal with exterior lighting, including façade lighting, site lighting of areas like pathways and parking lots. In most circumstances, these requirements are relatively easy and cost-neutral to meet. The biggest challenge often comes in dealing with light-trespass limits—light bleeding off the project site into a neighboring site—on projects with small or constrained sites. You will also need to attain low lighting power densities per ASHRAE 90.1-2007, which is a good general practice and won’t require you to compromise on aesthetics or cost.
You’ll need to pay careful attention to establishing a LEED project boundary, which plays an important part in meeting light trespass requirements. Involve an exterior lighting designer (or landscape architect) early in the design process to develop photometric plans and guide fixture selection during design.
Yes, as of 4/1/12 per LEED for Homes 2008 Interpretation #10147, “residential spaces (dwelling units only) within the scope of other LEED projects are also exempt from the interior lighting requirements.”
Yes, if they are within the LEED project boundary.
Yes, as long as the entire site meets the requirements.
No, hospitals are not exempt from the interior lighting requirements.
Significant reductions for tradable surfaces in LZ1 and LZ2 and some in LZ3. See the new table for details. It also added lighting power allowances according to light zones, removed a 5% adder, and introduced a base site allowance. Suggest revising response and adding a link to the Addendum i available for free download on ASHRAE website.
According to LI #10114, you can extend the lighting boundary to the centerline of the road.
According to the ASHRAE/IES interpretation of Standard 90.1, you can use the whole facade area. This is still a non-tradable allowance.
At grade level. A reviewer may request a 10’x10’ grid (5’x5’ for schools) on one side of the site from grade level to the height of the tallest light fixture.
No, per ASHRAE table 9.4.5, you can exclude lights in display windows, advertising, and directional signs as long as they are switched separately from other lighting.
If the canopy blocks 100% of the light then yes, but this is unlikely. Any light spillage needs to be counted toward the uplighting limit, but calculating this can be difficult. Using downlights is recommended instead.
Not currently, but USGBC is looking at exempting flag lighting from LEED v4 requirements.
According to 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, street lighting that is required by the governmental authorities to be installed within the LEED project’s lighting boundary (whether existing or new) does not need to be included in any of the calculations.
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 Interpretation #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.
Advertising and directional signage, as explained in Addendum i of ASHRAE 90.1-2007, and further defined in the Users Manual for ASHRAE 90.1-2007, is exempt. Essentially, that means that internally illuminated advertising signs are exempt, but those illuminated by lighting that is not ‘integral’ to the signage itself must be included in the calculations.
Designate one responsible party to oversee exterior lighting-related LEED credit requirements. For large projects, this person may be the civil engineer or landscape architect. For small projects it may be the architect, lighting designer, or other relevant team member.
Identify the building owner’s goals for occupant safety and comfort as well as for architectural lighting, including façade lighting. Include these goals in the Owners Project Requirements for EAp1: Fundamental Commissioning.
One of the biggest barriers to reducing light pollution is the cultural and aesthetic affinity for brightly lit buildings. Owners can play an important leadership role in contending with these expectations, establishing aesthetic goals that do not include excess lighting for purely aesthetic purposes. The design team can play an important role by maintaining low levels of lighting and highlighting specific façade architectural features with focused, low intensity lights.
Projects that demand brightly lit facades and entrances, such as casinos, hotels, theatres and commercial complexes, may have a hard time reconciling these desires with the requirements of this credit. Deliberate lighting design can forge a compromise between the desire to emphasize the building facades and the need to eliminate light pollution in order to meet the credit requirements.
Identify the urban lighting zone as defined by IESNA RP-33, based on the population density of the neighborhood, in order to establish lighting requirements.
Finalize the LEED project boundary in coordination with other LEED credits. The responsible party and the project team should identify the lighting fixtures close to the boundary that will be part of the lighting trespass analysis.
Projects with a zero lot line may choose to use the curb as the LEED boundary for the purposes of documenting light trespass only, while using the site boundary for other credits. This is one of the few exceptions to the rule that the LEED boundary and corresponding site area be consistent across multiple credits. Sites that abut public rights of way may similarly use the curb to establish the site boundary for the purposes of LEED documentation. It can be challenging for projects with zero lot lines or with little open space to meet the maximum exterior illuminance requirement of 0.1 footcandles at the site boundary. Project teams are only responsible for lights that are part of their project. For example, municipal lights about which the project has no control do not need to be considered.
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. For a project on a campus, choosing to meet the light trespass requirements at the building level can be very difficult.
Identify local or regional lighting laws or required lighting levels for rights-of-way that may apply to the project site. These regulations may help teams identify areas to focus on when dealing with lighting trespass in the design.
Discuss fixture and lamp options with the landscape designer, civil engineer and other project team members, focusing on both reducing overall lighting power density, and on avoiding light trespass. Avoiding light fixtures that shine up into the sky is the easiest way to reduce light pollution and make better use of lighting. This can be done by eliminating exterior lighting entirely or by selecting “cut-off fixtures” with opaque covers that direct light downward.
Core and Shell projects must comply with LEED requirements for all the exterior and façade lighting within the project scope and construction budget. Interior lights fitted by the owner must also comply with LEED’s control requirements. Fixtures not installed within the scope of the LEED project are exempt from credit requirements.
Local or regional laws that regulate lighting levels typically do not require minimum input power in watts. Going beyond these local requirements by selecting energy-efficient fixtures can help your project meet codes for comfort and safety goals without compromising energy efficiency.
The credit requires a photometric study on site lighting that may add minor consultant costs but will add value by optimizing the design.
Optimizing lighting can eliminate unnecessary costs for extra lights and high-power fixtures.
Many smaller fixtures may make for a better layout than fewer high-wattage ones. The designer should be able to advise about additional infrastructure costs associated with an atypical lighting design. Low power density and light intensity may require higher first costs for fixtures that will save electricity costs during operations.
Rebates and incentives on the federal, state, and local levels are available for low-power and Energy Star lamps.
Safety concerns are not typically a valid excuse for higher exterior lighting allowances. Despite a perception of better safety with brighter lighting, floodlights can often create areas of deep shadow, and the high contrast can be difficult for the human eye to navigate. Use good design, downlights, and work with the owner to address any concerns.
Be aware of all requirements for interior lights so that fixtures do not direct light through windows to the outdoors. Identify locations where fixtures might have a direct line of sight to a window or other opening. The lighting designer should either eliminate those fixtures from the design, provide shades to prevent more than 10% of light from shining outdoors, or include controls to reduce the input power by 50% between 11 p.m. and 5 a.m.
Interior lighting cannot spill out of the windows after business hours, defined as 11 p.m. – 5 a.m. in the credit requirements. Window coverings or automatic controls like timers, occupancy sensors, or master switches have to shut off or reduce the input power by 50% for all non-emergency indoor lights during that time.
Fixtures that throw 50% or more of the cone of light out a window are likely to present problems.
To avoid letting this credit slip through the cracks, project owners or architects should ask the lighting designers at the outset of the project how they plan to achieve each aspect of the credit.
Additional light controls and automatic window screens may add to construction costs, but controls can reduce electricity consumption.
Identify the project location and IESNA-designated zone to determine the threshold for exterior lighting levels. Utilize resources like the website www.citydata.com to identify relevant population density and appropriate designation.
The lighting designer includes the design intent in Basis of Design for EAp1: Fundamental Commissioning, for all outside lighting requirements, listing minimum illuminance in footcandles, lumens, or candela for all spaces with controls, fixture requirements and design approach.
The lighting designer then develops the exterior lighting layout and selects fixtures that optimize light with low power use.
To determine the total power density for the project, the lighting designer tabulates all exterior space and identifies the wattage of selected fixtures to compare it with the LPD allowable by ASHRAE 90.1-2004, Exterior Lighting Section. The selected fixtures should have full shielding or cutoff to reduce light directed toward the night sky.
The lighting designer develops a photometric study for exterior lighting intensity, the impact of shades and cutoff fixtures, and light trespass from the project boundary. Use the photometric study to inform any changes in the design.
The key to achieving this credit is to find the optimum balance between lighting quality and lighting energy consumption. It is often assumed that more light is better, but a low level of uniform lighting throughout a site will eliminate the need to install bright halogen lamps that illuminate some areas and leave others dark in contrast.
Exterior lighting includes all ground lighting, all façade lighting, flag lighting, any rooftop or terrace lighting, and any other fixtures outside the building. Pay careful attention to exterior light fixtures and light levels at building entrances close to the LEED site boundary.
Revisit the LPD calculations to make sure any design changes maintain the threshold limits.
ASHRAE’s exterior lighting density table lists exterior spaces under two categories. Tradable surfaces are those where the average LPD of all those surfaces are within the total LPD limits. For example, in LZ4, both sales canopy lighting and stairway lighting have a maximum of 1.0 Watts/ft2. The project may decide to increase sales canopy lighting to 1.1 Watts/ft2 as long as the stairways compensate with a decreased LPD of 0.9 Watts/ft2 (given that the surfaces are the same area) so that the average of the two is 1.0 Watts/ft2. For non-tradable surfaces, such as bank ATMs, each space must individually comply with the ASHRAE requirements. Identify whether exterior surfaces are tradable in order to provide flexibility.
A photometric study will facilitate communication about lighting levels among the designer, owner and the design team. The study entails computer modeling simulating the lighting intensity of the designed layout in footcandles, lux or candela. It allows the designer to see the resulting output, with iterative design options as the fixtures are reduced or replaced. Typically the photometric study measures light levels in a 10’x10’ grid. The analysis also investigates the maximum initial illuminance value at horizontal and vertical limits on the site boundary to ensure they are within the limits of the project zone. If you find that lights are above the threshold, the designer may want to explore alternative numbers of fixtures and fixture types and present these alternatives to the owner, who makes the final decision.
Avoid aiming light at highly reflective site and ground surfaces, such as white pavement and water features, which can exacerbate light pollution. The photometric study may not capture these characteristics.
Some lighting manufacturers will offer to perform a photometric study of your site if your team selects their product for the project.
Security-oriented lighting designs such as those for prisons, parking lots, and walkways often focus too much on big, bright lamps. This can be counterproductive, creating high contrast between lit and unlit spaces, worsening visibility in both places. Use more moderate, uniform light levels for improved designs.
Some types of lighting are exempt from the ASHRAE limits on power density. Examples include advertisement signage, transportation signage, athletic fields, storage, and historic landmarks and other public monuments. Refer to Exceptions under ASHRAE 90.1 2004 Section 9.4.5.
The lighting intensity of conventional fixtures such as halogens, incandescents, and sodium halide lighting, drops off significantly after the first year of operation. LED or fluorescent fixtures will better maintain their lighting intensity at the level of the installation—contrary to the common perception that low power wattage fixtures, such as LEDs or fluorescents, have low lighting intensities.
Full cutoff fixtures can generally be specified at zero cost premium.
Cost premiums for this credit may come from the higher number of (shorter) poles and fixtures needed to achieve greater lighting uniformity.
New fixtures like LEDs with high lighting levels but low power density may cost more than conventional halogen fixtures, but most of the new fixtures have longer life and are less expensive to operate due to low electricity use and infrequent lamp replacement.
Costs for the photometric study can be decreased if manufactures agree to do their own calculations, which is common if you select their fixtures.
Come to an agreement among the owner, landscape designer and lighting designer about the appropriate lighting levels and site lighting distribution.
Demonstrate to the owner the project team’s decision about lighting levels for the final design. Owners may need to be shown similarly lit areas to understand the implications of a shift from a brightly lit façade and terrace.
Locally mandated lighting levels for exterior fixtures higher than LEED-mandated ASHRAE levels have been a stumbling block for credit compliance, but with proper documentation supported by a clear narrative, this challenge can be overcome. There is an option to not include those fixtures in the LPD calculations and light trespass requirement, but you must demonstrate that these fixtures are full cutoff. To document the credit, make the case that the legally mandated fixtures are beyond the control of the project. Demonstrate that the project has met the requirements with rest of the lighting. Provide a detailed photometric plan, the municipal regulations, and a narrative describing how the project has achieved all requirements of the credit except where the municipal regulations overrule it.
Confirm all the lighting fixtures are listed on the lighting plan. This ensures that the correct components are purchased and installed to maintain the credit requirements.
The designer reviews the final bid documents and budget estimates to confirm that the fixtures have not been substituted for by another type, and that interior lighting controls and window shades are not omitted.
If your team undertakes a value engineering process, make sure the full cutoff fixtures are not eliminated from the list or replaced by incandescent or high-powered halogen fixtures. These changes are often overlooked and may cost the project this credit.
If the project is going for multi-party contractor bid, make sure the bid’s package reflects the fixture specifications and performance. Otherwise the contractor may replace the specification with a similar lower-cost fixture that doesn’t have the same wattage or a cover for cutoff.
Full-cutoff luminaires should not cost more than conventional fixtures, but other common strategies for meeting this credit may add costs. These include controls, timers, sensors, and low-power lights like LEDs. Ensure that these features are not eliminated during value-engineering.
The designer should review shop drawings and visit the site for installation inspection. This ensures that the fixtures have a cut-off for uplighting, the ballasts are as specified, and the controls are all included.
The commissioning agent carries out the functional testing for all control sequences and timers if installed for lighting design.
Timer controls and automatic switches should be commissioned and inspected for performance periodically throughout their life to ensure they continue to serve the intent of the credit requirements.
The facility manager should be involved in the decision of whether to select light timers or automated blinds to comply with interior lighting requirements. Both solutions offer opportunities and challenges during building use, depending on how the building is used and occupied.
Long-life, low-power lamps like fluorescents and LEDs will help keep costs low for operations and maintenance.
Excerpted from LEED 2009 for Core and Shell Development
To minimize light trespass from the building and site, reduce sky-glow to increase night sky access, improve nighttime visibility through glare reduction and reduce development impact from lighting on nocturnal environments.
Project teams must comply with one of the two options for interior lighting AND the requirement for exterior lighting.
Reduce the input power (by automatic device) of all nonemergency interior luminaires with a direct line of sight to any openings in the envelope (translucent or transparent) by at least 50% between 11 p.m. and 5 a.m. After-hours override may be provided by a manual or occupant-sensing device provided the override lasts no more than 30 minutes.
All openings in the envelope (translucent or transparent) with a direct line of sight to any nonemergency luminaires must have 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. (controlled/closed by automatic device for a resultant transmittance of less than 10% between 11 p.m. and 5 a.m.).
Light areas only as required for safety and comfort. Exterior lighting power densities shall not exceed those specified in ANSI/ASHRAE/IESNA Standard 90.1-2007 with Addenda i for the documented lighting zone. Justification shall be provided for the selected lighting zone. Lighting controls for all exterior lighting shall comply with section 18.104.22.168 of ANSI/ASHRAE/IESNA Standard 90.1- 2007, without amendments1.
Classify the project under 1 of the following zones, as defined in IESNA RP-33, and follow all the requirements for that zone:
LZ1: Dark (developed areas within national parks, state parks, forest land and rural areas)
Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.01 horizontal and vertical footcandlesVertical footcandles occur on a vertical surface. They can be added together arithmetically when more than 1 source provides light to the same surface. (0.1 horizontal and vertical luxMeasurement of lumens per square meter.) at the LEED project boundary and beyond. Document that 0% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).
LZ2: Low (primarily residential zones, neighborhood business districts, light industrial areas with limited nighttime use and residential mixed-use areas)
Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.10 horizontal and vertical footcandles (1.0 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandlesHorizontal footcandles occur on a horizontal surface. They can be added together arithmetically when more than 1 source provides light to the same surface. (0.1 horizontal lux) 10 feet (3 meters) beyond the LEED project boundary. Document that no more than 2% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).
LZ3: Medium (all other areas not included in LZ1, LZ2 or LZ4, such as commercial/ industrial, and high-density residential)
Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.20 horizontal and vertical footcandles (2.0 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandles (0.1 horizontal lux) 15 feet (4.5 meters) beyond the site. Document that no more than 5% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).
LZ4: High2 (high-activity commercial districts in major metropolitan areas)
Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.60 horizontal and vertical footcandles (6.5 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandles (0.1 horizontal lux) 15 feet (4.5 meters) beyond the site. Document that no more than 10% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).
LZ2, LZ3 and LZ4 - For LEED project boundaries that abut public rights-of-way, light trespass requirements may be met relative to the curb line instead of the LEED project boundary.
Illuminance generated from a single luminaire placed at the intersection of a private vehicular driveway and public roadway accessing the site is allowed to use the centerline of the public roadway as the LEED project boundary for a length of 2 times the driveway width centered at the centerline of the driveway.
Adopt site lighting criteria to maintain safe light levels while avoiding off-site lighting and night sky pollution. Minimize site lighting where possible and use computer software to model the site lighting. Technologies to reduce light pollution include full cutoff luminaires, low-reflectance surfaces and low-angle spotlights.
SUPERLITE 2.0 is a lighting analysis program designed to accurately predict interior illuminance in complex building spaces due to daylight and electric lighting systems.
Lighting simulation software.
For someone who does not design lighting as their primary service, this free lighting calculation software can be downloaded here.
Elights sells full cut-off light fixtures.
A comprehensive source for understanding the lighting models underlying the commercial lighting power limits developed in ASHRAE/IESNA 90.1-2004.
This paper describes a method of measuring and predicting glow, glare and trespass in outdoor lighting.
This publication from the Illuminating Engineering Society defines urban lighting zones according to population density.
Links to manufacturers with IDA-approved fixtures, information sheets and practical guides, and resources for learning.
This website is associated with the Lighting Research Center at Rensselaer Polytechnic.
This organization provides general exterior lighting design guidance.
Perform calculations to demonstrate credit-compliance with exterior lighting power density requirements.
Refer to manufacturer cut sheets for the angle of light spilling above horizontal, the candela graph for maximum candela notation, and watts.
This graphic illustrates SSc8's particular rule for how the site boundary relative to illuminance can expand when a driveway meets a public roadway.
The schedule lists all the exterior fixtures that will be accounted for in the the lighting power density calculations required for this credit.
Provide documentation like this example to showcase the exterior lighting layout plan. You'll refer to this plan in providing fixture and photometric analysis.
This set of annoatated photometric plans was created by Bill Swanson, P.E. for LEEDuser as a teaching tool for SSc8 documentation issues. They are not intended as examples of actual documentation, though a lot can be learned from them. These documents include a detailed plan showing a compliant site with light levels in the site and as required around the boundary, with advice and useful tips. The fixture comparison document is a means to better understand and compare the spill light from different light fixtures and placements. Think of the purple line as the edge of a cutout with a pin thru the paper where the pole is. Move the cutout over the site when locating poles, if the cutout overlaps the line beyond the property line then that fixture cannot be located and aimed as placed. The driveway entrance example shows the impact of fixture placement around driveway entrances, and the special allowance for the site boundary around those entrances.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each CS-2009 SS credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions on these forms; for more information, visit LEED Online and click "Sample Forms Download."
Documentation for this credit can be part of a Design Phase submittal.
Our project is substituting the LEED v4 light pollution reduction credit requirements for the v3 requirements. Are we still eligible for exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. for the v3 requirements? Is there an alternate exemplary performance path for interior lighting since the v4 credit does not address this?
As far as I know there is no exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. path for v4 Light Pollution reduction. FYI, Interior lighting requirements were NOT removed from v4 to reduce stringency, so they wouldn't be a good candidate for exemplary performance anyhow. Interior lighting was removed because it was felt that current energy codes already require lights to be shut of when spaces are unoccupied, which would meet the intent of the requirement for most buildings. There was a suggestion for exemplary performance if you met the requirement for the LZ one lower than your project LZ, but USGBC did not accept that idea.
I am working on a LEED C&S project for a Building within a large business campus. In relation to the light trespass of the external lighting I need to determine the site and project boundary. The owner of this building also owns the whole campus. The car park that serves this LEED building is surrounded by existing car park. Therefore the new car park will be an extension to the existing scheme. Can you please clarify how I might define the site and project boundary for this project. Do I just ensure that the the new carpark which serves the LEED project we are working on complies ?
Does anyone know an answer to my question above ?
I'm not sure I understand your questions, but let me try to answer. The LEED Project Boundary has to be established by the design team members working on site credits, because there are several credits that use the LEED project boundary, and you have to use the same boundary for all. All of the exterior light fixtures whether on the building or on the site that are within the LEED Project Boundary must be included in any light trespass or uplight calculations. If they are outside the LEED project Boundary they don't "exist" as far as the Light Pollution credit is concerned. BUT, the light trespass calculations are made at the Lighting Boundary, which is not necessarily the LEED Project Boundary. The Lighting Boundary is based on the Property Line but can be significantly modified. The Lighting Boundary is defined in the LEED v4 version of the credit, and in a credit interpretation:
"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."
Hi, We are proposing to use a small percentage of lighting bollards. These lighting bollards do not shine light upwards when I review the photo metrics. However do I need to look at the light reflectance off the ground ?
You do not need to worry about reflectance off of the ground.
How can in prove SSc8 for interior lighting, when my warehouse don't have windows?
The building is just a warehouse. For exterior lighting it's ok, but for interior i don't know how to prove the requirements.
Thanks a lot!
The top of the form has a few options for interior lighting. Select the one that says, "No non-emergency interior luminaires have a direct line of sight to
openings in the building envelope."
That should be enough. I don't see anywhere on the form they are asking for any more documentation for interior lighting. If you want you can upload a floor plan of the building. Someone may ask about the main entrance since there is usually glass there. But I doubt it. Don't stress over it.
If my building operations is 24h, the interior lighting can be consider a exception, or the automatic device must be instaled anyway?
Neither. If there are no windows or any other way for light to get out then the interior portion of the project complies. It's not an exception, it just complies. No automatic device controls are required for the interior lighting in this credit.
And if my building operations is not 24h, need to complies with interior lighting?
I ask this because i'm working on other project, and the operations is 08:00 until 18:00.
They should already comply because you have to comply with ASHRAE 90.1 in EAp2. Automatic shutoff of lights in spaces not in use. Either schedule the lights to turn off from 18:15 to 07:45, or install occupancy sensors.
So if my project comply with ASHRAE 90.1 and my interior lighting schedule is turn off from 18:15 to 07:45, the focus of analysis is the exterior lighting project, correct?
Sounds good to me.
To be sure we answer the initial question, a windowless building (assuming zero other luminance to the outdoors - aside from occasional opening of opaque doors and similar) will automatically comply with the indoor requirements of SS credit Light Pollution Reduction for LEED 2009 (also v2.2 and earlier), while LEED v4 doesn't include an indoor lighting requirement.
Be sure to state the full windowless nature of the building (or portion of the building) in your credit narrative, and it should be clear to the certification reviewer that the indoor requirements are met.
Why you would want a windowless building (given the free light in a semi-conditioned warehouse space) is beyond me.
We are working on a project where the back of the building is very close to the property line that abuts a railway track. This railway track is used only for freight and not for any passenger trains. Does anyone know of any allowances that would allow for extra distance of the lighting boundary?
The building is LZ3 classified and on the other side of the railway track is a scarp yard.
Any help would be great.
We have the same issue in Tucson, AZ. City asked us to light the railway line for safety/security but it's significantly beyond the LEED boundary and the full cut-off light is cast on both the rail line and a windowless warehouse adjacent. Crossing fingers the Reviewers will understand the overriding need to illuminate adjacent tracks despite the spill onto the warehouse building.
Kristopher - You can try calling the rail line a transit corridor and use the centerline of the rail easement as your lighting boundary.
Joyce - I doubt it will help with the city's request that you light the whole railway for security. Maybe if the city took ownership of the lights focused on the railway line. There have been a lot of problems with this credit from a safety/security point of view. The V4 version that you can use for this credit is more generous for spill light.
We are working on a project where each exterior luminaire can be controlled and dimmed separately. For reasons of aesthetics, the lamps were placed at certain points. The original illuminance of the lamps exceeds the requirements of SSC8 at project boundary and 10 feet beyond. For this reason, each luminaire will be individually dimmed so that the requirements of LZ2 will be achieved.
As we reach the requirement from the credit from our perspective, we would like to implement this. Has anyone experience with dimmable outdoor lighting and the documentation? Is it permissible within LEED? Or do you think that requirements are not met?
Thank you for feedback.
Interesting question. I don't know if anyone has tried to meet the credit requirements using dimming. I think you could propose it and describe your solution in a narrative. But I would strongly recommend that you specify a dimming system where the dimming level settings are protected from tampering, either physically protected or via password protection on software. You should also describe a commissioning plan that says how the dimming levels will be set in order to meet credit requirements, and those settings recorded or documented in some way, and some sort of commitment by the building operator to not change those settings. Assuming the fixtures are LED, can you have the manufacturer provide the fixtures with a driver giving you a customized output? Then there would be no dimming control and no way to change the output.
I've come across a similar situation where directionally adjustable lamps needed to be mechanically fastened to prevent a typical user from being able to tamper with them. This added step allowed the reviewer to accept the luminaires as (effectively) fixed-position.
I've also gotten approval on a LEED-CI project to limit 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. by implementing a control-based "cap" on the fixture output. The specific system used allowed "tuning" of the fixtures maximum output so that typical users could not increase the light output beyond the determined cap. The process of fixture tuning was detailed in the commissioning plan. With users unable to turn the fixtures up, we were able to avoid installing a current limiter.
All that said, Glenn's suggestion above to work with the manufacturer to implement hard caps based on the driver is the best option, as it prevents the operator from simply turning up the output at a later date.
Hello, I am a little perplexed by the Online Form LPDs for exterior lighting for which the ASHRAE allowable LPD case becomes smaller according to the lighting zone (LZ1,LZ2 and LZ3). Although this is completely logical , the credit says to use (ASHRAE 90.1-2007 with errata but WITHOUT ADDENDA) for exterior lighting. ASHRAE table 9.4.5 Lighting Power Densities for Builing Exteriors does not refer to different LPDs for different lighting zones. If I understand correctly, the LPD reductions are part of a later ADDENDA but in principal we can overlook the addenda. Am I missing something?
I'm perplexed by it too. When this was changed I complained that it violated LEED's own rules. But they made the change and insist that they are right.
Yes, the Credit says to use ASHRAE without addenda. But these are referring to addenda that are published by ASHRAE. USGBC will publish their own addenda every 3 months to make small changes to LEED. About 4 years ago, someone in USGBC saw the addenda that ASHRAE published that reduced 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. for site lighting and thought it was really important. So USGBC published an addenda saying to followed this one addenda by ASHRAE.
So, technically, we are following an addenda to LEED. The rules for issuing these addenda are written in the Foundations of LEED document that USGBC wrote. http://www.usgbc.org/resources/foundations-leed
"Addenda are changes to LEED that include both substantive and non-substantive changes. A request for addenda may come from USGBC staff, the Green Building Certification Institute (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).) or LEED committees and may be applied to the current version of LEED on a regular basis without following LEED balloting procedures. LEED projects are required to use current addenda available at time of registration."
But these substantive changes are suppose to be limited to 3 things. Either corrections, define or expand upon existing content, or to provide additional option to show compliance.
This change should either have waited until the next version or it should have been issued as an update. Updates are also described in this Foundation of LEED document. They are for modifications to existing credit language that change stringency. But an update requires a ballot vote by members. Like how EAc2 was changed in v2.2 to require earning a minimum of 2 points. They didn't want to go thru a vote so they called it an addenda. It's not like there is someone to force them to follow their own rules.
Sorry, I'm a little bitter about this topic.
Thankyou for your answer and the situation is clearer - it does seem a bit abusive though....
We have a CS project, in which the wall mounted side lighting fixtures has been installed on the boundary wall on all sides. The height of the boundary wall is 2.5 meters. The mounting height of the wall fixture is .5 meters only. If we run the simulation with this scenario, the result shows 10-30 luxMeasurement of lumens per square meter. levels on and near to the boundary wall. As per SSc8 of LEED CS 2009, the project falls under LZ3 which states that “The exterior lighting should be designed such that all site and building mounted luminaries produce a maximum initial illuminance value no greater than 0.20 horizontal and vertical foot-candles at the site boundary and no greater than 0.01 horizontal foot-candles 15 ft. beyond the site.
The simulation results shows more than .20 horizontal and vertical foot-candles at the site boundary, which does not comply the LEED intent.
My question is – What is the definition of site boundary for this credit and whether to consider the point beyond the boundary wall or on the boundary wall itself to check the required 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. to comply the credit requirement.
Are the lights mounted on the inside edge or the outside edge of the wall?
If this wall is part of your project and on the property line then the outside edge of the wall is where the lighting calc is measured. (I'm assuming you have to build your wall all the way on your property.)
If your lights are on the inside edge, no problem. The wall is 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. the light.
If your lights are on the outside edge, then you may want to try spacing your lights to avoid the calc points. Or shift the calc points to miss the lights. (This is easier if your calculation points at the boundary are a line and not a plane) Do a test and increase the number of calcs so they are no more than 12" (or 30cm) apart. How far away from the light does a calc point need to be to be below 0.20 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.? Use the original calc line and adjust the lights or calcs so they are at least this far from each other. Recalculate and it should pass.
You can consider using the v4 version of this credit. There is no horizontal calculation. Only a vertical calculation that you should pass.
No Nontradable Surfaces are illuminated; nothing to enter into Table SSc8-2. When we Check Compliance, this table is highlighted. Tempting to invent tradable surface illumination just to satisfy it. Surely there's a legitimate solution!
This has come up a couple times in the NC forum. This seems to work.
"In the form for the table of non-tradeable surfaces. Describe the location as "None". Pick the first item in the drop down menu. Enter an area of 1. Enter a wattage of 0. That should do it."
We are having a fence around our proposed building and this fence will be lit with lights (may be bollard lights or buried up lighting). The distance from the fence and the building itself has the paved parking and the plantation area, driveways etc. My question is under which category 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. will be calculated on leedonline forms? The total perimeter of the fence around the building is 245.35 meters. The sub contractor is proposing bollard lighting of 100W per piece. Will this comply with LEED?
If not how can we comply the external lighting per LEED while lighting around the fence?
Fences don't gain anything in 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. calculation. They are not listed in the table as either a tradable surface or a nontradable surface. If there is excess watts in your allowance from the paved areas then this can be used for the bollard lighting along the fence.
If the proposed bollard lighting is using 100W metal halide lamps then the bollard is actually using closer to 130W each when you consider the ballast and lamp together.
You have to work thru the lighting power allowance calculation for the whole site to know if it will comply with LEED. Everything else has to be included. What lighting zone you are in? How many bollards total? How many watts for each light and how many lights of each type? How large is the parking lot and drives? How many doors into the building? How many sidewalks, stairs, landscaping, canopies, facades, ........? There is no way I can tell you if your site is compliant with this Credit. The best way to comply will be to use less light in the parking lot then you are allowed to and then to use the excess watts from the allowance and apply it to the perimeter fence lighting.
Yes you are right. I still dont have all the information actually. Moreover, This credit has always bee difficult for me to understand. I need to know all the details first. We are in LZ2 and the allowance will be 600W. If we assume the façade lighting is complying and all other lights are also compliant (less than) with the LPDs mentioned in the file what will be the LPD for the bollard light then for a length of 245.35 meters or what number of pieces can be installed in such a length?
Façade lighting is non-tradable. This means if you use less than allowed it doesn't help you anywhere else on the site. If the façade light is compliant then it doesn't help you with the bollards or anything else.
Your question cannot be answered. There is not enough information. I cannot even guess if you are close because there is too little information. I have $600 in my account, do I have enough to cover rent this month? I don't know. How much is your rent and what else do you need to spend money on?
The length of the fence is irrelevant. Count how many bollards total and multiply this by the wattage of the fixture (not the lamp). This is just one of your "costs" in your site lighting budget. Every other light has to be added up also.
Think of it like a budget with many costs that have to be paid. You have to do 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. calculation to know how much money you have in your pocket, your budget (measured in watts instead of dollars). Then every light fixture you add to the site will be a cost you have to pay in watts from the budget. You only know if you can earn the credit if you have not gone negative, owing more than you have.
Just put this credit as a "maybe" and when you get more information you can do the LPD calculation and determine if the project can earn this credit.
I understand that more information is needed to cover all types of lgithing on the site. But as you took the example of it as budget if we have $600 budget then how much am I supposed to spend on food from it if the rent has been cleared? This is the same thing here, how much LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. (or fixtures of 100W0 will we need for the bollards lighting if everything else lies in the acceptable allowance?
(Please forgive my little understanding if you are feeling that I am arguing a lot. I am really trying to get more and more knowledge from you).
If everything else is compliant with no excess then all you have is the 600W from the base allowance. If the bollard is 100W then you can only install 6 bollards along the fence. If the bollard is 130W then you can only install 4 bollards.
I think you are limiting yourself thinking that each type of light is either compliant or not compliant. The site needs to be thought of as a whole.
Yes you are right. I am just thinking and assuming and none of it is going to add anything in real. As you said, I will try to gather all the data for lighting and then check whether everything will comply or not.
Thanks a lot, discussing with you really helped me in understanding this credit much more than I had previously.
We are working in a CS project and we want to know if the tenant spaces lights must accomplish the requirement of the options or not. The tenants are required to implement this requirements after the CS certification?, The indoor parking also must accomplish the requirements?
The tenant lighting is not required to meet these requirements to earn the credit. But if you added language into the Tenant Lease agreement that forced them to comply then you can earn an exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. point in the ID section.
The indoor parking is required to comply with this credit if it is within the scope of the LEED submittal. Most likely it is.
We have a project where we are restoring an historic building as part of a much larger office tower in an LZ4 zone. The current exterior lighting design includes up lighting of the registered heritage building. ASHRAE 2007 90.1 sec 9.4.5 says that 'i) lighting to be used to highlight features of public monuments and registered historic landmark structures or buildings' are exempt. Does that mean that LEED also considers this as an exemption?
Nope. You can only exempt the lighting from the energy use calculation per ASHRAE. But the uplight calculation is different, and nothing in the credit excludes it. This is a problem for just about every type of lighting listed in that ASHRAE exemption.
The v4 version of this credit has added several exemptions for lights that match up with some of the ASHRAE exemptions, but not all. Historical buildings are not one of the exemptions allowed.
If you use the v4 version of the credit (which you are allowed to do on 2009 projects) you can exempt facade lighting from the uplight and trespass limits as long as you are in LZ3 or LZ4 and you shut the lights off at midnight.
Also, i'd be careful about claiming LZ4 - it's really only intended for "times-square" type areas. You are likely to be questioned by the reviewer if you claim LZ4 without any explantion
Thank you Bill and Glenn. We will review v4. Thank you also for the comment on zone classification. I gather that what you are saying is that we could be in a high density commercial district in a major metropolitan area (which we are), but if it does not have high nighttime activity then it should really be LZ3. I would classify night time activity in this area as medium compared to other areas in the city.
James, were you successful using the LEED v4 exemption for your facade lighting? We are in a similar situation: v2009 project, building in a LZ3 area, and would like to take advantage of the v4 exemption. Do you just note on the v2009 form that you are taking the v4 exemption for facade lighting? Do you need to upload and meet all requirements on the v4 credit form?
You have to completely follow the v4 version of the credit. You can't mix-and-match requirements between the versions. You can use the v4 submittal form that is in the credit library, make a pdf and then upload it, and you other documentation in LEED Online, and put in a note that you are using the v4 version.
Thanks Glenn, I thought that would be the case; we're evaluating now if we can meet the v4 requirements.
Pay attention to the Lighting Zone definitions. They are different and potentially more stringent in v4. Make sure you are in LZ3 under v4 definitions (MLO users guide definitions)
Is it acceptable to set up exterior lighitng to turn off automatically after 10:00 p.m. so when using an illumination model these show up as to be turned-off?
No. Nothing in the exterior lighting portion of this credit mentions time of use. If you have exterior light fixtures then they need to be considered on for the model. If you have two sets of light fixtures that will never be on at the same time then you need to model the worst case.
Thank you Bill.
Hello, We are working to certify a building with heliport on the rooftop. Do we need to include the lighting project of the heliport for the calculation of this credit?
This heliport will only be working on emergencies, it will NOT provide an on going service, so the lighting will only be on use on these emergency occasions.
You can use the v4 version of this credit on LEED-2009 projects. The v4 version of the credit exempts lighting that is "specialized signal, directional, and marker lighting for transportation" from the uplight and trespass limits.You might be able to claim that your helipad lighting is this kind of lighting. If this is a hospital then the lighting is definitely exempted as lighting for "hospital emergency departments, including associated helipads".
You could also look at Healthcare v3 which also excludes the helipad lighting and is the same rating version.
I would try to apply 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. ID#5724 made on 07/06/2004
This excluded helipads for v2.1 projects.
Our project has a garden on 30th floor where a canopy will be constructed directly above it. To lit the area, lighting fixtures will be placed on the canopy aside from bollard lighting (iGuzzini typha) and strips of led beneath the planter/seating on the garden. 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. calculation, 1.) will it be possible to separate the LPD of the garden as ‘plaza’ having 0.20W/f2 to ‘canopies and overhangs’ with 1.25W/f2? 2.)will the bollard lighting (iGuzzini typha) be considered in the calculation?
i'm not sure I understand you questions, but here is my opinion:
For the area of the garden that is under the canopy you can take the canopy allowance or the plaza allowance, but not both. So obviously you'd want to take the canopy allowance where you can.
The bollards count . For all the calculations (trespass, uplight, LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space.) all exterior light fixtures (except gov't mandated street lighting), whether building or ground mounted, have to be counted in all calculations. Technically for the LPD calc only, if a fixture is not powered from the projects electrical system, then it wouldn't be counted.
To what height does the vertical calculation grid need to go?
I don't think it's defined. Typically we go to the height of the highest fixture. But note that in the new v4 version of the credit, the vertical grid is required to go to 33 feet above the highest luminaire - so I suppose that would be safe.
Thanks, Glenn. That's helpful. I was thinking that we should at least go up as high as the tallest poles, but wasn't sure if we should go beyond. 33' does sound a bit extreme, but would be safe for sure.
will we get an Exemplary PerformanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. credit by installing automatic shut-off controls for interior lighting in tenant spaces by means of a tenant lease agreement if we dont achieve SSc8 in general?
Project is a health Center with a variety of medical practises, a pharmacy and a franchise of a food market chain that is not willing to omit its illuminated facade logo.
Thanks for your advice!
Doreen, you can only earn an EP point by first earning the underlying credit. Also, SSc8 is not an EP-eligible credit. So it seems like this credit it not a good fit for the project.
in CS Appendix 4 it says:
EP under Tenant Lease or Sales Agreement is available for the following credits:
SSc8: Light Pollution Reduction. Require automatic controls within 100% of the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space..
There are 3 more EP credits listed in CS Appendix 4:
EAc2, IEQc3 and IEQc4 (4.1, 4.2, 4.3, 4.4)
However, to earn any of the above EP credits the project must achieve the regular credit in the CS scope as well.
Is this correct?
I agree with Tristan that the base credit must be earned before you can get the EP bonus point.
To add to the discussion:
SSc8 is listed as an EP eligible credit within CS Appendix 4 of the BD+C reference guide.
The online template we recently submitted on a C&S precert project allowed us to reserve one point in the Innovation in Design credit category for exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. in SSc8. (C&S precertification template Version 4.0)
However this morning we received the review report with this comment:
"there is no exemplary performance path for this credit"
I have a query into USGBC, i will post once i receive a response.
At this time, exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. is available for SSc8, here is the response from USGBC on 5-19-14:
"IDc1.2 has been marked as Anticipated, and the credit review language has been revised to indicate that Exemplary Performance can be earned for this Core & Shell project. We apologize for this oversight. These changes can now be seen in the Credit Details section of your Review Report."
Is there any exemptions for Sensor Security Lights, if the only time they come on is when they detect motion after hours?
Per 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. ID#5192 made on 05/06/2009
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. Applicable Internationally.
My project is a Core & Shell and will work 24 hours in operation, so how should I proceed to the requirements of the interior lighting?
Any interior lighting within the scope of work of the Core & Shell project will need to comply with either Option 1 or Option 2 of the interior lighting requirements.
Tenant spaces are not required to comply but should be encouraged. If the tenant spaces are required to comply with this Credit and it is enforced then you can earn an extra point as exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements..
Key considerations for this credit presented at Greenbuild 2009.
PE, LEED AP
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