Replace the definition of "solar reflectance (SR)" with "the fraction of solar energy that is reflected by a surface on a scale of 0 to 1. Black paint has a solar reflectance of 0; white paint (titanium dioxide) has a solar reflectance of 1. The standard technique for its determination uses spectrophotometric measurements, with an integrating sphere to determine the reflectance at each wavelength. The average reflectance is then determined by an averaging process, using a standard solar spectrum, as documented by ASTM Standards E903 and E892."
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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To reduce heat islands1 to minimize impacts on microclimates and human and wildlife habitats.
Requirements
Option 1
Use any combination of the following strategies for 50% of the site hardscape (including roads, sidewalks, courtyards and parking lots):- Provide shade from the existing tree canopy or within 5 years of landscape installation. Landscaping (trees) must be in place at the time of occupancy.
- Provide shade from structures covered by solar panels that produce energy used to offset some nonrenewable resource use.
- Provide shade from architectural devices or structures that have a solar reflectance index2 (SRI) of at least 29.
- Use hardscape materials with an SRI of at least 29.
- Use an open-grid pavement system (at least 50% pervious).
OR
Option 2
Place a minimum of 50% of parking spaces under cover3. Any roof used to shade or cover parking must have an SRI of at least 29, be a vegetated green roof or be covered by solar panels that produce energy used to offset some nonrenewable resource use.
1 Heat islands are defined as thermal gradient differences between developed and underdeveloped areas.
2 The solar reflectance index (SRI) is a measure of the constructed surface's ability to reflect solar heat, as shown by a small temperature rise. It is defined so that a standardblack surface (reflectance 0.05, emittance 0.90) is 0 and a standard white surface (reflectance 0.80, emittance 0.90) is 100. to calculate the SRI for a given material, obtain the reflectance value and emittance value for the material. SRI is calculated according to ASTM E 1980. Reflectance is measured according to ASTM E 903, ASTM E 1918, or ASTM C 1549. Emittance is measured according to ASTM E408 or ASTM C 1371.
3 For the purposes of this credit, under cover parking is defined as parking underground, under deck, under roof, or under a building.
SITES-LEED Equivalency
This LEED credit (or a component of this credit) has been established as equivalent to a SITES v2 credit or component. For more information on using the equivalency as a substitution in your LEED or SITES project, see this article and guidance document.What does it cost?
Cost estimates for this credit
On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.
Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.
This information is also available in a full PDF download in The Cost of LEED v4 report.
Learn more about The Cost of LEED v4 »Frequently asked questions
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Addenda
10/1/2012 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Campus Applicable
No
Internationally Applicable:
No
7/6/2012 – Updated: 2/14/2015
Global ACP
Description of change:
Delete the box that states, "Note for Projects Outside the U.S."
Campus Applicable
No
Internationally Applicable:
Yes
8/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Make the following text bold, "ASTM E408-71(1996)e1, Standard Test Methods for Total Normal Emittance of Surfaces Using Inspection-Meter Techniques".
Campus Applicable
No
Internationally Applicable:
No
10/1/2012 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the second sentence, delete "Particularly in urban areas"; revise the last clause so that it reads, "Other sources may include vehicle exhaust, air-conditioners, and street equipment. Reduced airflow because of tall buildings and narrow streets exacerbate the effect."
Campus Applicable
No
Internationally Applicable:
No
5/9/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace SRI for "Typical new gray concrete" with 38
Campus Applicable
No
Internationally Applicable:
No
7/27/2009
LEED Interpretation
Inquiry:
The intent of this credit is to reduce the heat island effect created by large expanses of pavement. For a building to earn option B of the credit, they must provide shade for at least 50% of the provided parking. This can be underground, under a deck, under a roof, or under the building itself. In addition, a building that provides 100% of its parking under cover is eligible to earn an exemplary performance point. One of our project buildings is located in downtown San Francisco and does not provide any parking for building tenants. We believe that this fulfills the intent of the credit because there are no paved parking areas whatsoever that would contribute to the heat island effect. The net heat island effect is the same as a building that provides 100% of parking underground. However, the building that does not have parking at all gets 0 points where as a building that provides 100% parking underground gets 2 points. An existing building that was designed many years ago to reduce heat island effect should still be rewarded under a rating system that was incepted later on. We would like to petition the USGBC to consider awarding 1 point under Option B to projects that have no parking provided.
Ruling:
April 6, 2018 Update: LEED Interpretation 5370 is now applicable to both LEED v2009 and LEED v4 BD+C, ID+C, and O+M projects.
A project building with no onsite parking facilities may be eligible for 1 point under LEED v2009 SSc7.1 and LEED v4 SSc Heat Island Reduction, provided that no nearby offsite parking facilities are leased or owned by the building owner, property manager, or tenants for use by the building occupants. The project team must supply evidence of this by, in single-occupant buildings declaring that no such parking is provided, or in multi-tenant buildings by declaring that no such parking is provided and by detailing the method by which this was assessed. If such offsite facilities are leased or owned, the project team may document compliance with the credit by showing that 50% (O+M) or 75% (BD+C) of the provided spaces meet the Heat Island Reduction Roof requirements.
Campus Applicable
No
Internationally Applicable:
Yes
6/27/2008
LEED Interpretation
Inquiry:
We are certifying a new manufacturing building on an existing site that currently has a manufacturing building and a parking lot for the staging of tractor truck trailers. Construction of the new manufacturing new building required that the trailer parking lot be relocated to another part of the site. The trailer parking lot relocation was completed before breaking ground for the new building. Would it be appropriate to consider the relocation of this trailer storage parking lot a separate project and to draw our LEED project boundary for the new certified manufacturing building to exclude both the relocated trailer storage area parking lot and the existing manufacturing building? We would use this boundary consistently across all Sustainable Site credits. (SSc5, SSc6 and SSc7)
Ruling:
The project is seeking clarification on whether or not it can exclude a relocated trailer parking lot and existing building from the LEED project boundary of a new manufacturing building. The parking lot was relocated in order to accommodate the new building. Project teams can determine the LEED project boundary as appropriate for the project within the context of the construction limits and/or property boundaries. The existing building can therefore be left out of the LEED project boundary. If the parking lot is relocated to provide space for the new building, it would be considered within the scope of construction and should be included in the LEED project boundary. An exception would if the following conditions are met: 1. The original parking area was returned to its undeveloped condition (for portions outside of the LEED-applicant development footprint), 2. The relocated parking lot does not serve the LEED-applicant building, and 3. The relocated parking lot is not larger in area than the original parking lot. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
8/1/2011
LEED Interpretation
Inquiry:
Many of the ASTM Standards we reference have been withdrawn, upgraded, or superseded. Provide guidance on which updated standards should be used.
Ruling:
The withdrawn ASTM Standards listed- ASTM E1980-01 and ASTM E903-96- are still the correct references for SSc1: Site Selection, SSc7.1: Heat Island Effect, Non-Roof, and SSc7.2: Heat Island Effect-Roof. These two standards were not withdrawn for technical reasons, but were withdrawn because they had not been updated within 8 years. Testing can still be performed for these as well as the superseded standards. The updated versions of the superseded standards can be used, but are not required:Old: ASTM E408-71(1996), Current: E408-71(2008)Old: ASTM C1371-04a, Current: C1371-04a(2010)Old: ASTM E1918-97, Current: E1918-06 Old: ASTM C1549-04, Current: 1549-09Note: This Interpretations is also applicable to Sustainable Sites Credit 7.2: Heat Island Effect-Roof and Sustainable Sites Credit 1: Site Selection, see LEED Interpretations dated 8/1/2011 ID number 10093 and 10094 respectively. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
12/5/2001
LEED Interpretation
Inquiry:
The credit calls for use of light-colored/high-albedo materials (reflectance of at least 0.3) for 30% of the site\'s non-roof impervious surfaces.We are using a material called UNI Eco-Stone permeable paver that has been tested in Australia at a .27 reflectance value and we are using it for 42% of the non-roof impervious surface. The eco-stone also has a permeability of 12%. We would like to know if we qualify for the reflectivity value of this credit due to the fact that we are using it for more than the recommended 30% of the site\'s non-roof impervious surface. Please advise.
Ruling:
The LEED Reference Guide (formatted version of June 2001) on page 51 states the requirements of SS Credit 7.1 as follows: "use light-colored / high albedo materials (reflectance of at least 0.3) for 30% of the site's non-roof impervious surfaces
Although the reflectance value of the material specified is below the minimum level required by the credit, the area of coverage exceeds the minimum of 30%. Therefore, the weighted area average of the net reflectivity exceeds that of the minimum performance requirement, which is calculated by these steps:
1) Assuming .05 reflectance for standard asphalt, a baseline reflectivity average can be calculated for that 70% of the site area while the other 30% of the site has a required reflectance of at least .30. [ (70% x .05) + (30% x .30) = 12.50 ]
2) Using the proposed reflectance of .27 for the project, the design case reflectivity average can be calculated. [ (42% x .27) + (58% x .05) = 14.24 ]
3) A comparison shows that the proposed combination of reflectance and area ratios exceed the LEED averaged threshold and therefore satisfies the requirements.
Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
10/1/2012
LEED Interpretation
Inquiry:
Can sidewalks, roads, and other hardscape areas located above a project building\'s underground parking structure, which are required by the governing municipality to be constructed of non-compliant materials, be excluded from the SSc7.2 and SSc7.1 calculations?
Ruling:
Similar to LEED Interpretations #2293 and #3101, sidewalks, roads, and areas that cover un-conditioned spaces (such as parking garages) are considered hardscape or landscape nonroof surfaces. Thus, they should be included in the calculations for SSc7.1 Heat Island Effect- Nonroof. In situations where infrastructure, materials, or surfaces are owned, operated and maintained by the local governing body, project teams may exclude the area of the material from the calculations for SSc7.2 and SSc7.1. This exemption can be applied only if projects do not have any control over the materials used for the surfaces in question. If the materials are owned and operated by the project, but the local jurisdiction specifies that they must meet certain criteria, the materials may not be excluded from the calculations. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
7/30/2009
LEED Interpretation
Inquiry:
The intent of this credit is to "Reduce heat islands to minimize impact on micro-climate and human and wildlife habitat." The requirements for the credit call for providing any combination of strategies for 50% of the site hardscape. Our project will implement the strategy of using paving materials with an SRI of at least 29. While some of the asphalt areas are shaded within 5 years of occupancy, our proposal aims to achieve the credit using only the SRI-compliant paving strategy. Our project is a major league ballpark in downtown Minneapolis, MN. The LEED project boundary includes the ballpark, the surrounding concrete plaza/walkway areas and an asphalt surface parking lot with shade vegetation and shade from overhead ramps. The total area of hardscaped parking lot, walkways and plaza is 337,456 SF. To comply with the credit requirements, a minimum of 50% or 168,728 SF must have an SRI of 29 or greater. A CIR dated 6/19/2008 for related credit SSc7.2 Heat Island Effect - Roof allowed the use of a weighted average formula where multiple roofing materials were used, such that the total roof area weighted average SRI exceeded the required SRI. Similarly, our project\'s concrete plaza combines standard gray concrete and multiple concrete paver colors into a pattern. While the majority of the pattern is a concrete color with an SRI of 52, a smaller portion of the pattern is a concrete color with an SRI of 12. The parking lot is asphalt pavement, some of which is shaded, but for the purpose of this calculation, we have considered all asphalt to have an SRI of 0. Using the formula for weighted average per the above CIR, we propose performing a similar calculation for each color of all site hardscape to arrive at a weighted average, as follows: [(Area of Asphalt *(SRI of Asphalt/Required SRI)) + (Area of Std. Concrete*(SRI of Std. Concrete/Required SRI) )+ (Area of Concrete Paver 1*(SRI of Concrete Paver 1/Required SRI)) + (Area of Concrete Paver 2*(SRI of Concrete Paver 2 /Required SRI)) + (Area of Concrete Paver 3*(SRI of Concrete Paver 3 /Required SRI))] >= .50 Site Hardscape Area So our calculation would be [(180,672*0/29) + (31,032*35/29) + (97,869*52/29) + (27,883*12/29) = 224,479 which exceeds the 168,728 SF (or 50%) total hardscape requirement. Will this formula be acceptable for SSc7.1 credit compliance?
Ruling:
The project team is proposing a weighted average approach to achieving SSc7.1 similar to the weighted average approach used for alternative compliance to SSc7.2 Heat Island Effect Roof. The proposed methodology for achieving SSc7.1 is acceptable. Be sure to provide all relevant submittal documentation including site plans with areas highlighted and area takeoffs as well as documentation of the measured reflectance and emittance for each material. Please be advised that any areas of hardscape counted within the weighted SRI calculation cannot be used within a shaded area calculation. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
7/29/2006
LEED Interpretation
Inquiry:
Can this credit point be achieved under the following pavement system scenario. We propose to use a tan-colored clay, open-grid pavement system filled with limestone gravel for the entire driveway and parking lot for our office building consisting of 90% of the site\'s hardscape surfaces (non-roof). You require "an open grid pavement system that is at least 50% pervious". This percentage drastically limits the pavement system choice to a plastic "egg carton-type", thin walled paving system. We have the "egg carton" system in several locations and they do not work for us because the constant traffic compacts the soil so grass will not grow resulting in bare dirt and increased runoff. (Defeating the purpose of using them.) This type of paver also presents a maintenance problem in the winter because they cannot be plowed. The thin-walled pavement systems are designed for occasional, light-duty use, not daily traffic. We are proposing the use of a clay paver for it\'s durability, ease of maintenance, and ability to have it produced in a light color which can meet the SRI requirements. The open grid in this type pavers can achieve 36% pervious openings. You define the open-grid pavement as ".pavement that contains vegetation in the open cells". In our experience, any open-grid pavement systems, even concrete cells, that have day to day traffic will not support vegetation due to soil compaction. This is why we propose that the grid be filled with gravel. This method will also allow evaporation as desired by this credit as well as infiltration and ground water recharge. The use of this system has allowed us to design the site without use of an underground storm sewer system and to infiltrate all site storm water. Philosophically we are suggesting a more sustainable method pavement system. The majority of the "egg carton-type" pavers are made of virgin plastics, require more energy to produce, and can not be recycled in this area. The clay pavers are made from a natural material and are chemically inert which allow it to be crushed and recycled as aggregate. To us this is a more sustainable choice.
Ruling:
Since the "open grid pavement" compliance option is not realistic for your application, you may achieve the credit via the SRI option. If both the clay pavers and the chosen gravel described in this strategy meet this credit\'s SRI requirements and represent at least 50% of the site hardscape, then the project has effectively met the credit requirements. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
6/27/2003
LEED Interpretation
Inquiry:
The intent of this credit is to reduce heat islands to minimize impact on microclimate and human and wildlife habitat. To meet the requirements of this credit we plan to use light-colored/high-albedo materials for a minimum of 30% of the site\'s non-roof impervious surfaces. We have approximately 62,000 SF of white colored gravel driveways on the site, 80,000 SF of asphalt and 38,000 SF of concrete. We have received documentation from the American Concrete Pavement Association stating that new gray portland cement concrete has a reflectivity between 0.35 and 0.40, which meets the requirements of this credit. Aged gray portland cement has a reflectivity between 0.20 and 0.30. Will we be able to use the documentation from the American Concrete Pavement Association as a sufficient source to show compliance with this credit? Also, will we be able to use the reflectivity ranges for new gray portland cement to fulfill the requirements of this credit? We know that black asphalt will not meet the requirements of this credit. We are unable to obtain documentation from the company supplying the gravel on its reflectivity value. We have tried to borrow or purchase a spectrophotometer to measure the reflectivity of the rocks on our own, but have not found an affordable option. We have also tried to find a federal standard on the reflectivity values of different colors and have been unsuccessful. If the rocks are essentially white, will that be enough of an explanation to factor the rocks into the calculation to comply with the requirements for this credit?
Ruling:
Credit 7.1 requires the use of "light colored/high albedo materials (reflectance of at least 0.3) for 30% of the site\'s non-roof impervious surfaces." Reflectance level of applicable materials must be adequately documented to earn this credit.Include reflectance documentation from the American Concrete Paving Association, making sure to indicate the original source of the research data and the reflectivity category that relates to your concrete mix, coupled with a site plan showing where concrete will be used. Alternatively, testing labs can be found using the ASTM lab directory at www.astm.org. Testing fees should be approximately $200 for ASTM E903.For the concrete portion of the site, it is acceptable to use the reflectivity rate for new concrete on this credit, as this will meet the intent of the credit at the time of construction. Existing old concrete can not be considered in the square footage for high-albedo materials, unless its reflectance can be measured to be 0.3 or greater, and documentation is provided showing this reflectance.For the gravel portion of the site, simply listing the gravel as white is not sufficient to meet this requirement. As stated in the credit description, it is necessary to provide the documentation indicating the reflectance of the gravel as meeting the 0.3 minimum requirement. The project can refer to the Lawrence Berkeley Labs website, http://eande.lbl.gov/coolroof/membrane as a reference source for the reflectivity of white gravel. The use of white gravel should be distinguished from white-coated gravel, which is not suitable for use in parking and driving applications. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
2/14/2008
LEED Interpretation
Inquiry:
The requirement for compliance with SSc7.1 Heat Island Effect Non-Roof Option 2 listed on page 89 of the LEED-NC v2.2 Reference Guide states that "Any roof used to shade or cover parking must have an SRI of at least 29." The first sentence of that paragraph defines "cover" as consisting of any of four possible types of parking cover, of which "under roof" is one of the four choices. From this we would conclude that the only condition with an SRI restriction is "under roof" and that there are no restrictions governing the SRI of cover materials for the other three types of cover, namely; underground parking, parking under decks, or parking under a building. For example, our project has more than 50% of the parking underground (95% of parking is underground). The underground parking is "covered" by a combination of pedestrian-oriented hardscape, vehicle-oriented pavement, and a 65-story office tower. Please confirm the intent of the credit indicates that cover materials for underground parking, parking under decks, and parking under buildings do not need to meet the SRI > 29 requirement and that only roofs covering parking are required to meet the SRI>29.
Ruling:
Roofs used to shade or cover surface parking in order to meet the Option 2 requirement, must have an SRI of at least 29. However, an SRI requirement does not exist for parking placed underground, under deck, or under a building, so long as the exposed parking surface area, if any, is less than or equal to 50 percent of the total parking surface area. ***The previous ruling for this CIR, dated 02/14/2008, has been overturned on 9/3/2008.*** Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
12/3/2008
LEED Interpretation
Inquiry:
The project building maintains 100% of its parking spaces under cover through the use of a multi-level underground parking garage located partially beneath the building and partially beneath the property\'s landscaping and hardscape. In the spirit of SS 7.1, the developer\'s decision to locate 100% of the building\'s parking below grade has resulted in a reduced heat island effect by allowing for surface vegetation where the presence of an above ground garage would have otherwise prohibited vegetation. While it is clear that an uncovered multi-level garage located above ground would have qualified for 1 point under SS 7.1, it is not clear if an underground multi-level garage would qualify for 1 point under SS 7.1 given that it is partially covered by a building with an unknown SRI value. Given that the intent of this point is related to "non-roof" surfaces, is the building required to document SRI criteria for the roof of a building that covers an underground parking garage or is the point otherwise earned automatically since 100% of the parking is located in a multi-level underground garage? Please clarify the intent and required submittals for scenarios involving a multi-level underground parking garage.
Ruling:
A parking garage placed under a building can qualify as compliant under SS Credit 7.1 if the appropriate percentage of total parking is located in the garage. Roofs that directly shade parking, such as a carport roof, are subject to the SRI requirement of 29. However, an SRI requirement does not exist for parking placed underground, under deck, or under a building. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011
LEED Interpretation
Inquiry:
Would aggregate and chat covered areas be considered hardscape or a non-hardscape, pervious paving type surface? If the aggregate and chat are considered hardscape, what SRI values should be used, or how is the SRI value for these materials determined? If no industry standard is available, is it permissible to compare the aggregate/chat to a material with a known SRI value? Or could we use the value from a comparable color on the Munsell Color Code (or similar)?
Ruling:
Aggregate and chat areas must be considered hardscape, and would not count as open-grid pavement systems, for the purposes of this credit. To determine the SRI for materials that do not have recognized standard values (e.g. new gray concrete), the materials must be individually tested (per LEED NC v2.1 CIR Ruling dated 6/27/2003). As stated in the credit description, it is necessary to provide the documentation indicating the solar reflectance index of the aggregate/chat as meeting the requirement. It is not acceptable to compare materials used on the project to a material with a known SRI value. Color values do not have direct correlation to emissivity and solar reflectance values which are the basis for the SRI calculation. Aggregate may be tested using ASTM E1918-06 (Solar Reflectance) and ASTM E408-71(2008) (Thermal Emittance) and then the SRI may be calculated using ASTM E1980. Applicable internationally.
Campus Applicable
No
Internationally Applicable:
Yes
5/6/2009
LEED Interpretation
Inquiry:
This CIR seeks clarification on whether a stabilized grass parking system can be counted in OPTION 1 calculations as open grid pavement. Our project is a cultural institution that receives a surge in visitors during the summer months. The stabilized grass system is proposed for the site\'s overflow parking areas that are required to meet the peak season parking demand. By using this system rather than other types of paving, these areas will be preserved as an open meadow during the remaining 9 months of the year. Town officials have approved the system; as a result we have been able to reduce the amount of paving required for parking by 44%. Designed to hold vehicular traffic while allowing for infiltration, this stabilized grass profile promotes healthy vegetation and prevents soil compaction. The structural base for this system is made up of a twenty inch profile consisting of twelve inches of crushed stone over eight inches of compacted sand and gravel. The strength of the profile arises from the stone on stone contact. The large pore spaces between the stones hold soil to support turf and meadow grasses. Over the crushed stone layer, a two inch veneer of planting soil provides the horticultural medium within which to grow grass. The planting soil is a sandy loam which water percolates through quickly. The water then moves through the crushed stone layer, through the sand and gravel layer, and finally to the subgrade. This system percolates more quickly than the native soils on the site. The stabilized grass parking system has a better hydraulic conductivity and therefore better infiltration rate than open grid paving. We have compared our system to Escofet Checkerblock, which is 77% open. The hydraulic conductivity of the stabilized grass system is 3"/hour. For the Checkerblock, the hydraulic conductivity of the turf soil is 1.5"/hour multiplied by the fraction of the checkerblock that is pervious (77%), the resultant rate for Escofet Checkerblock paving is 1.15"/hour. The hydraulic conductivity of the stabilized grass system will be guaranteed through conformance to the specification which reads, "The final mix shall have a hydraulic conductivity of not less that 3 inches per hour when compacted to a minimum of 94 percent Standard Proctor. Tests shall be by combined hydrometer and wet sieving in compliance with ASTM D422 after destruction of organic matter by ignition." The surface of the stabilized grass parking areas will be 100% vegetated rather than the 50% required for open grid pavement. This system was developed by the project\'s soil scientist and landscape architect. An installation using the same detail, soil profile, and soil blend was installed on an adjacent site and has been proven successful.
Ruling:
The project proposes that a stabilized grass parking system be treated comparably to open grid pavement systems as it relates to SSc7.1 credit compliance. This strategy is acceptable in this particular scenario provided that the design for the parking area is stamped by a professional engineer (P.E.). Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
2/7/2006
LEED Interpretation
Inquiry:
Our project is a 1.2 million SF science building renovation and expansion for an urban university campus. The program consists of research and teaching laboratories, lab support areas, offices, conference rooms, lecture halls, classrooms, libraries, food service, and public areas. We would like an interpretation on some hardscape materials on our site, dark granite under water and gray concrete. A water feature adjacent to the main entry for this project consists of various waterfalls over granite stone. The granite is dark and does not independently meet the albedo of 0.30. However, running water plays a significant role in lowering not only the adjacent ambient air temperature but also the thermal absorption of the granite. Hypothetically, if the outside air temperature on a sunny day is 100 degrees, then dry granite might be around 110-115 degrees, reflecting considerable heat. However, granite under water would have a lower temperature. The use of water in roof ponds, pools, fountains, cascades, waterfalls, etc. for the purpose of cooling is widely accepted. However, the hard research does not exist for the effect of water on the reflectivity and absorption of granite. If a shaded environment is typically the equivalent of 10 degrees cooler than a non-shaded area, does the water/granite combination appear to be equivalent to a shaded area? Can we include the water feature area SF under the shaded category to factor solar heat reduction into the calculations? We would like a further interpretation with regard to our pedestrian walkways to confirm we can use gray concrete. A 6/27/2003 Ruling states that "for the concrete portion of the site, it is acceptable to use the reflectivity rate for new concrete on this credit, as this will meet the intent of the credit at the time of construction. Reflectance level of applicable materials must be adequately documented to earn this credit." Is it acceptable to use the reflectance documentation from the American Concrete Paving Association, stating that new standard gray Portland cement concrete has a reflectivity between 0.35 and 0.40, to meet the requirements of this credit? Or is an actual ASTM E903 lab test on the actual mix to be used required for the project?
Ruling:
The area of the water feature does not count toward achievement of this credit. Water features are excluded from the calculation. All projects may assume that non-colored concrete meets the reflectivity criteria of 0.30 without testing. Testing is required if the concrete mix contains a colorant/stain or non-standard aggregate. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
8/2/2001
LEED Interpretation
Inquiry:
We are defining our LEED project as the building plus approximately 26% of a parking deck (and of the landscaped area around it), with the parking deck located in a block diagonally across from the building. We are operationally allocating to the project 407 out of 1550 parking spaces (26.3%), in the 7-level parking deck with 484,500 sq. ft. total. We are planning for the top deck of the parking deck to be a light-colored/ high-albedo site surface (probably regular concrete with a solar reflectance of 0.30, avoiding the darkening fly-ash content for the top floor). Allocating 26.3% of the 69,220 sq. ft. top level, the resulting area - 18,205 sq. ft. - is greater than 30% of the combined area of this plus the other hard site surfaces in the city block of our building. Thus, we exceed the requirement of providing light-colored/ high-albedo material for 30% of the sit? s non-roof impervious surfaces simply with our top parking level. Please confirm that the USGBC agrees with our interpretation. (We may still want to pursue SS Credit 5.1 without being penalized by having to apply the top deck toward the site areas of the main city block, 50% of which we may want to restore to habitat areas. Is this a separate question? SS Credit 7.1 is more important to us.)Also, it is not clear to us if the 50% underground parking option would also apply, as most of the parking is in covered levels in the parking deck; or does the parking deck indeed need to be "underground"? - Further, are the covered levels of the parking deck a non-roof impervious shaded area, qualifying the project for yet another option of meeting the credit requirements? If at all possible, for our education, please address all three options of qualifying for this credit - could we qualify under any of the options? Which one is the best to prove? Should future credit requirements address parking decks?
Ruling:
It is acceptable to allocate a portion of the parking deck to the LEED project. Allocate a proportional amount of the parking deck from the ground up, including both the covered and top deck spaces. You will need to provide a calculation that documents the allocation of areas and surfaces. If the parking deck is included in one credit, it must be included in all other applicable credit calculations. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
4/4/2007
LEED Interpretation
Inquiry:
Our project\'s operational requirement mandates large paved areas in excess of 30% of the 490,314 s.f. site area. Our goal is to specify a previously developed concrete mix that complies with ASTM C1549 and has been previously tested and presented to USGBC on a prior project. The test results for this material yielded a Reflectance Average Value of .41 for the concrete paving material. The previous test results on three concrete pavement samples ranged from 0.38 to 0.45 Reflectance (Albedo) Values. The testing lab that conducted the reflectivity testing for the prior project has the following accreditations: IAS-ES TL-189, State of Florida TST 1556, Metro-Dade 01-0727.03, and CRRC. This C.I.R. is requesting confirmation that USGBC will accept documentation certifying that the concrete mix utilized on our project is equivalent to the previously utilized and tested mix and that actual laboratory testing will not be required on a project by project basis.
Ruling:
The applicant is inquiring if test data obtained for a different project can be used to document the albedo/reflectivity of the concrete mix used on this project if the same mix is used. It would appear that the previous project being referenced was a LEED NC v2.1 project since the test data supplied relates to albedo/reflectivity. It should be noted that with regards to paving materials, LEED NC v2.2 SSc7.1 requires that paving materials have a Solar Reflectance Index (SRI) of at least 29. The SRI value of a material takes into account both a material\'s reflectivity and emissivity. It is acceptable to use the previous test data as documentation of the materials reflectivity assuming the concrete mix is identical and the test data was done in accordance with ASTM E 903, ASTM E 1918, or ASTM C 1549. This reflectivity value can then be used in conjunction with the material\'s emissivity value to determine the material\'s SRI value. To document the reflectivity value, the applicant should provide the test data along with documentation demonstrating that the concrete mixes used in both cases are identical. It should also be noted that when a range of values is provided, as is the case above for the material\'s reflectivity value, the more conservative number should be used, not the average. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
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Intent
To reduce heat islands1 to minimize impacts on microclimates and human and wildlife habitats.
Requirements
Option 1
Use any combination of the following strategies for 50% of the site hardscape (including roads, sidewalks, courtyards and parking lots):- Provide shade from the existing tree canopy or within 5 years of landscape installation. Landscaping (trees) must be in place at the time of occupancy.
- Provide shade from structures covered by solar panels that produce energy used to offset some nonrenewable resource use.
- Provide shade from architectural devices or structures that have a solar reflectance index2 (SRI) of at least 29.
- Use hardscape materials with an SRI of at least 29.
- Use an open-grid pavement system (at least 50% pervious).
OR
Option 2
Place a minimum of 50% of parking spaces under cover3. Any roof used to shade or cover parking must have an SRI of at least 29, be a vegetated green roof or be covered by solar panels that produce energy used to offset some nonrenewable resource use.
1 Heat islands are defined as thermal gradient differences between developed and underdeveloped areas.
2 The solar reflectance index (SRI) is a measure of the constructed surface's ability to reflect solar heat, as shown by a small temperature rise. It is defined so that a standardblack surface (reflectance 0.05, emittance 0.90) is 0 and a standard white surface (reflectance 0.80, emittance 0.90) is 100. to calculate the SRI for a given material, obtain the reflectance value and emittance value for the material. SRI is calculated according to ASTM E 1980. Reflectance is measured according to ASTM E 903, ASTM E 1918, or ASTM C 1549. Emittance is measured according to ASTM E408 or ASTM C 1371.
3 For the purposes of this credit, under cover parking is defined as parking underground, under deck, under roof, or under a building.
SITES-LEED Equivalency
This LEED credit (or a component of this credit) has been established as equivalent to a SITES v2 credit or component. For more information on using the equivalency as a substitution in your LEED or SITES project, see this article and guidance document.XX%
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10/1/2012 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the definition of "solar reflectance (SR)" with "the fraction of solar energy that is reflected by a surface on a scale of 0 to 1. Black paint has a solar reflectance of 0; white paint (titanium dioxide) has a solar reflectance of 1. The standard technique for its determination uses spectrophotometric measurements, with an integrating sphere to determine the reflectance at each wavelength. The average reflectance is then determined by an averaging process, using a standard solar spectrum, as documented by ASTM Standards E903 and E892."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012 – Updated: 2/14/2015
Global ACP
Description of change:
Delete the box that states, "Note for Projects Outside the U.S."
Campus Applicable
No
Internationally Applicable:
Yes
8/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Make the following text bold, "ASTM E408-71(1996)e1, Standard Test Methods for Total Normal Emittance of Surfaces Using Inspection-Meter Techniques".
Campus Applicable
No
Internationally Applicable:
No
10/1/2012 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the second sentence, delete "Particularly in urban areas"; revise the last clause so that it reads, "Other sources may include vehicle exhaust, air-conditioners, and street equipment. Reduced airflow because of tall buildings and narrow streets exacerbate the effect."
Campus Applicable
No
Internationally Applicable:
No
5/9/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace SRI for "Typical new gray concrete" with 38
Campus Applicable
No
Internationally Applicable:
No
7/27/2009
LEED Interpretation
Inquiry:
The intent of this credit is to reduce the heat island effect created by large expanses of pavement. For a building to earn option B of the credit, they must provide shade for at least 50% of the provided parking. This can be underground, under a deck, under a roof, or under the building itself. In addition, a building that provides 100% of its parking under cover is eligible to earn an exemplary performance point. One of our project buildings is located in downtown San Francisco and does not provide any parking for building tenants. We believe that this fulfills the intent of the credit because there are no paved parking areas whatsoever that would contribute to the heat island effect. The net heat island effect is the same as a building that provides 100% of parking underground. However, the building that does not have parking at all gets 0 points where as a building that provides 100% parking underground gets 2 points. An existing building that was designed many years ago to reduce heat island effect should still be rewarded under a rating system that was incepted later on. We would like to petition the USGBC to consider awarding 1 point under Option B to projects that have no parking provided.
Ruling:
April 6, 2018 Update: LEED Interpretation 5370 is now applicable to both LEED v2009 and LEED v4 BD+C, ID+C, and O+M projects.
A project building with no onsite parking facilities may be eligible for 1 point under LEED v2009 SSc7.1 and LEED v4 SSc Heat Island Reduction, provided that no nearby offsite parking facilities are leased or owned by the building owner, property manager, or tenants for use by the building occupants. The project team must supply evidence of this by, in single-occupant buildings declaring that no such parking is provided, or in multi-tenant buildings by declaring that no such parking is provided and by detailing the method by which this was assessed. If such offsite facilities are leased or owned, the project team may document compliance with the credit by showing that 50% (O+M) or 75% (BD+C) of the provided spaces meet the Heat Island Reduction Roof requirements.
Campus Applicable
No
Internationally Applicable:
Yes
6/27/2008
LEED Interpretation
Inquiry:
We are certifying a new manufacturing building on an existing site that currently has a manufacturing building and a parking lot for the staging of tractor truck trailers. Construction of the new manufacturing new building required that the trailer parking lot be relocated to another part of the site. The trailer parking lot relocation was completed before breaking ground for the new building. Would it be appropriate to consider the relocation of this trailer storage parking lot a separate project and to draw our LEED project boundary for the new certified manufacturing building to exclude both the relocated trailer storage area parking lot and the existing manufacturing building? We would use this boundary consistently across all Sustainable Site credits. (SSc5, SSc6 and SSc7)
Ruling:
The project is seeking clarification on whether or not it can exclude a relocated trailer parking lot and existing building from the LEED project boundary of a new manufacturing building. The parking lot was relocated in order to accommodate the new building. Project teams can determine the LEED project boundary as appropriate for the project within the context of the construction limits and/or property boundaries. The existing building can therefore be left out of the LEED project boundary. If the parking lot is relocated to provide space for the new building, it would be considered within the scope of construction and should be included in the LEED project boundary. An exception would if the following conditions are met: 1. The original parking area was returned to its undeveloped condition (for portions outside of the LEED-applicant development footprint), 2. The relocated parking lot does not serve the LEED-applicant building, and 3. The relocated parking lot is not larger in area than the original parking lot. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
8/1/2011
LEED Interpretation
Inquiry:
Many of the ASTM Standards we reference have been withdrawn, upgraded, or superseded. Provide guidance on which updated standards should be used.
Ruling:
The withdrawn ASTM Standards listed- ASTM E1980-01 and ASTM E903-96- are still the correct references for SSc1: Site Selection, SSc7.1: Heat Island Effect, Non-Roof, and SSc7.2: Heat Island Effect-Roof. These two standards were not withdrawn for technical reasons, but were withdrawn because they had not been updated within 8 years. Testing can still be performed for these as well as the superseded standards. The updated versions of the superseded standards can be used, but are not required:Old: ASTM E408-71(1996), Current: E408-71(2008)Old: ASTM C1371-04a, Current: C1371-04a(2010)Old: ASTM E1918-97, Current: E1918-06 Old: ASTM C1549-04, Current: 1549-09Note: This Interpretations is also applicable to Sustainable Sites Credit 7.2: Heat Island Effect-Roof and Sustainable Sites Credit 1: Site Selection, see LEED Interpretations dated 8/1/2011 ID number 10093 and 10094 respectively. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
12/5/2001
LEED Interpretation
Inquiry:
The credit calls for use of light-colored/high-albedo materials (reflectance of at least 0.3) for 30% of the site\'s non-roof impervious surfaces.We are using a material called UNI Eco-Stone permeable paver that has been tested in Australia at a .27 reflectance value and we are using it for 42% of the non-roof impervious surface. The eco-stone also has a permeability of 12%. We would like to know if we qualify for the reflectivity value of this credit due to the fact that we are using it for more than the recommended 30% of the site\'s non-roof impervious surface. Please advise.
Ruling:
The LEED Reference Guide (formatted version of June 2001) on page 51 states the requirements of SS Credit 7.1 as follows: "use light-colored / high albedo materials (reflectance of at least 0.3) for 30% of the site's non-roof impervious surfaces
Although the reflectance value of the material specified is below the minimum level required by the credit, the area of coverage exceeds the minimum of 30%. Therefore, the weighted area average of the net reflectivity exceeds that of the minimum performance requirement, which is calculated by these steps:
1) Assuming .05 reflectance for standard asphalt, a baseline reflectivity average can be calculated for that 70% of the site area while the other 30% of the site has a required reflectance of at least .30. [ (70% x .05) + (30% x .30) = 12.50 ]
2) Using the proposed reflectance of .27 for the project, the design case reflectivity average can be calculated. [ (42% x .27) + (58% x .05) = 14.24 ]
3) A comparison shows that the proposed combination of reflectance and area ratios exceed the LEED averaged threshold and therefore satisfies the requirements.
Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
10/1/2012
LEED Interpretation
Inquiry:
Can sidewalks, roads, and other hardscape areas located above a project building\'s underground parking structure, which are required by the governing municipality to be constructed of non-compliant materials, be excluded from the SSc7.2 and SSc7.1 calculations?
Ruling:
Similar to LEED Interpretations #2293 and #3101, sidewalks, roads, and areas that cover un-conditioned spaces (such as parking garages) are considered hardscape or landscape nonroof surfaces. Thus, they should be included in the calculations for SSc7.1 Heat Island Effect- Nonroof. In situations where infrastructure, materials, or surfaces are owned, operated and maintained by the local governing body, project teams may exclude the area of the material from the calculations for SSc7.2 and SSc7.1. This exemption can be applied only if projects do not have any control over the materials used for the surfaces in question. If the materials are owned and operated by the project, but the local jurisdiction specifies that they must meet certain criteria, the materials may not be excluded from the calculations. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
7/30/2009
LEED Interpretation
Inquiry:
The intent of this credit is to "Reduce heat islands to minimize impact on micro-climate and human and wildlife habitat." The requirements for the credit call for providing any combination of strategies for 50% of the site hardscape. Our project will implement the strategy of using paving materials with an SRI of at least 29. While some of the asphalt areas are shaded within 5 years of occupancy, our proposal aims to achieve the credit using only the SRI-compliant paving strategy. Our project is a major league ballpark in downtown Minneapolis, MN. The LEED project boundary includes the ballpark, the surrounding concrete plaza/walkway areas and an asphalt surface parking lot with shade vegetation and shade from overhead ramps. The total area of hardscaped parking lot, walkways and plaza is 337,456 SF. To comply with the credit requirements, a minimum of 50% or 168,728 SF must have an SRI of 29 or greater. A CIR dated 6/19/2008 for related credit SSc7.2 Heat Island Effect - Roof allowed the use of a weighted average formula where multiple roofing materials were used, such that the total roof area weighted average SRI exceeded the required SRI. Similarly, our project\'s concrete plaza combines standard gray concrete and multiple concrete paver colors into a pattern. While the majority of the pattern is a concrete color with an SRI of 52, a smaller portion of the pattern is a concrete color with an SRI of 12. The parking lot is asphalt pavement, some of which is shaded, but for the purpose of this calculation, we have considered all asphalt to have an SRI of 0. Using the formula for weighted average per the above CIR, we propose performing a similar calculation for each color of all site hardscape to arrive at a weighted average, as follows: [(Area of Asphalt *(SRI of Asphalt/Required SRI)) + (Area of Std. Concrete*(SRI of Std. Concrete/Required SRI) )+ (Area of Concrete Paver 1*(SRI of Concrete Paver 1/Required SRI)) + (Area of Concrete Paver 2*(SRI of Concrete Paver 2 /Required SRI)) + (Area of Concrete Paver 3*(SRI of Concrete Paver 3 /Required SRI))] >= .50 Site Hardscape Area So our calculation would be [(180,672*0/29) + (31,032*35/29) + (97,869*52/29) + (27,883*12/29) = 224,479 which exceeds the 168,728 SF (or 50%) total hardscape requirement. Will this formula be acceptable for SSc7.1 credit compliance?
Ruling:
The project team is proposing a weighted average approach to achieving SSc7.1 similar to the weighted average approach used for alternative compliance to SSc7.2 Heat Island Effect Roof. The proposed methodology for achieving SSc7.1 is acceptable. Be sure to provide all relevant submittal documentation including site plans with areas highlighted and area takeoffs as well as documentation of the measured reflectance and emittance for each material. Please be advised that any areas of hardscape counted within the weighted SRI calculation cannot be used within a shaded area calculation. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
7/29/2006
LEED Interpretation
Inquiry:
Can this credit point be achieved under the following pavement system scenario. We propose to use a tan-colored clay, open-grid pavement system filled with limestone gravel for the entire driveway and parking lot for our office building consisting of 90% of the site\'s hardscape surfaces (non-roof). You require "an open grid pavement system that is at least 50% pervious". This percentage drastically limits the pavement system choice to a plastic "egg carton-type", thin walled paving system. We have the "egg carton" system in several locations and they do not work for us because the constant traffic compacts the soil so grass will not grow resulting in bare dirt and increased runoff. (Defeating the purpose of using them.) This type of paver also presents a maintenance problem in the winter because they cannot be plowed. The thin-walled pavement systems are designed for occasional, light-duty use, not daily traffic. We are proposing the use of a clay paver for it\'s durability, ease of maintenance, and ability to have it produced in a light color which can meet the SRI requirements. The open grid in this type pavers can achieve 36% pervious openings. You define the open-grid pavement as ".pavement that contains vegetation in the open cells". In our experience, any open-grid pavement systems, even concrete cells, that have day to day traffic will not support vegetation due to soil compaction. This is why we propose that the grid be filled with gravel. This method will also allow evaporation as desired by this credit as well as infiltration and ground water recharge. The use of this system has allowed us to design the site without use of an underground storm sewer system and to infiltrate all site storm water. Philosophically we are suggesting a more sustainable method pavement system. The majority of the "egg carton-type" pavers are made of virgin plastics, require more energy to produce, and can not be recycled in this area. The clay pavers are made from a natural material and are chemically inert which allow it to be crushed and recycled as aggregate. To us this is a more sustainable choice.
Ruling:
Since the "open grid pavement" compliance option is not realistic for your application, you may achieve the credit via the SRI option. If both the clay pavers and the chosen gravel described in this strategy meet this credit\'s SRI requirements and represent at least 50% of the site hardscape, then the project has effectively met the credit requirements. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
6/27/2003
LEED Interpretation
Inquiry:
The intent of this credit is to reduce heat islands to minimize impact on microclimate and human and wildlife habitat. To meet the requirements of this credit we plan to use light-colored/high-albedo materials for a minimum of 30% of the site\'s non-roof impervious surfaces. We have approximately 62,000 SF of white colored gravel driveways on the site, 80,000 SF of asphalt and 38,000 SF of concrete. We have received documentation from the American Concrete Pavement Association stating that new gray portland cement concrete has a reflectivity between 0.35 and 0.40, which meets the requirements of this credit. Aged gray portland cement has a reflectivity between 0.20 and 0.30. Will we be able to use the documentation from the American Concrete Pavement Association as a sufficient source to show compliance with this credit? Also, will we be able to use the reflectivity ranges for new gray portland cement to fulfill the requirements of this credit? We know that black asphalt will not meet the requirements of this credit. We are unable to obtain documentation from the company supplying the gravel on its reflectivity value. We have tried to borrow or purchase a spectrophotometer to measure the reflectivity of the rocks on our own, but have not found an affordable option. We have also tried to find a federal standard on the reflectivity values of different colors and have been unsuccessful. If the rocks are essentially white, will that be enough of an explanation to factor the rocks into the calculation to comply with the requirements for this credit?
Ruling:
Credit 7.1 requires the use of "light colored/high albedo materials (reflectance of at least 0.3) for 30% of the site\'s non-roof impervious surfaces." Reflectance level of applicable materials must be adequately documented to earn this credit.Include reflectance documentation from the American Concrete Paving Association, making sure to indicate the original source of the research data and the reflectivity category that relates to your concrete mix, coupled with a site plan showing where concrete will be used. Alternatively, testing labs can be found using the ASTM lab directory at www.astm.org. Testing fees should be approximately $200 for ASTM E903.For the concrete portion of the site, it is acceptable to use the reflectivity rate for new concrete on this credit, as this will meet the intent of the credit at the time of construction. Existing old concrete can not be considered in the square footage for high-albedo materials, unless its reflectance can be measured to be 0.3 or greater, and documentation is provided showing this reflectance.For the gravel portion of the site, simply listing the gravel as white is not sufficient to meet this requirement. As stated in the credit description, it is necessary to provide the documentation indicating the reflectance of the gravel as meeting the 0.3 minimum requirement. The project can refer to the Lawrence Berkeley Labs website, http://eande.lbl.gov/coolroof/membrane as a reference source for the reflectivity of white gravel. The use of white gravel should be distinguished from white-coated gravel, which is not suitable for use in parking and driving applications. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
2/14/2008
LEED Interpretation
Inquiry:
The requirement for compliance with SSc7.1 Heat Island Effect Non-Roof Option 2 listed on page 89 of the LEED-NC v2.2 Reference Guide states that "Any roof used to shade or cover parking must have an SRI of at least 29." The first sentence of that paragraph defines "cover" as consisting of any of four possible types of parking cover, of which "under roof" is one of the four choices. From this we would conclude that the only condition with an SRI restriction is "under roof" and that there are no restrictions governing the SRI of cover materials for the other three types of cover, namely; underground parking, parking under decks, or parking under a building. For example, our project has more than 50% of the parking underground (95% of parking is underground). The underground parking is "covered" by a combination of pedestrian-oriented hardscape, vehicle-oriented pavement, and a 65-story office tower. Please confirm the intent of the credit indicates that cover materials for underground parking, parking under decks, and parking under buildings do not need to meet the SRI > 29 requirement and that only roofs covering parking are required to meet the SRI>29.
Ruling:
Roofs used to shade or cover surface parking in order to meet the Option 2 requirement, must have an SRI of at least 29. However, an SRI requirement does not exist for parking placed underground, under deck, or under a building, so long as the exposed parking surface area, if any, is less than or equal to 50 percent of the total parking surface area. ***The previous ruling for this CIR, dated 02/14/2008, has been overturned on 9/3/2008.*** Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
12/3/2008
LEED Interpretation
Inquiry:
The project building maintains 100% of its parking spaces under cover through the use of a multi-level underground parking garage located partially beneath the building and partially beneath the property\'s landscaping and hardscape. In the spirit of SS 7.1, the developer\'s decision to locate 100% of the building\'s parking below grade has resulted in a reduced heat island effect by allowing for surface vegetation where the presence of an above ground garage would have otherwise prohibited vegetation. While it is clear that an uncovered multi-level garage located above ground would have qualified for 1 point under SS 7.1, it is not clear if an underground multi-level garage would qualify for 1 point under SS 7.1 given that it is partially covered by a building with an unknown SRI value. Given that the intent of this point is related to "non-roof" surfaces, is the building required to document SRI criteria for the roof of a building that covers an underground parking garage or is the point otherwise earned automatically since 100% of the parking is located in a multi-level underground garage? Please clarify the intent and required submittals for scenarios involving a multi-level underground parking garage.
Ruling:
A parking garage placed under a building can qualify as compliant under SS Credit 7.1 if the appropriate percentage of total parking is located in the garage. Roofs that directly shade parking, such as a carport roof, are subject to the SRI requirement of 29. However, an SRI requirement does not exist for parking placed underground, under deck, or under a building. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011
LEED Interpretation
Inquiry:
Would aggregate and chat covered areas be considered hardscape or a non-hardscape, pervious paving type surface? If the aggregate and chat are considered hardscape, what SRI values should be used, or how is the SRI value for these materials determined? If no industry standard is available, is it permissible to compare the aggregate/chat to a material with a known SRI value? Or could we use the value from a comparable color on the Munsell Color Code (or similar)?
Ruling:
Aggregate and chat areas must be considered hardscape, and would not count as open-grid pavement systems, for the purposes of this credit. To determine the SRI for materials that do not have recognized standard values (e.g. new gray concrete), the materials must be individually tested (per LEED NC v2.1 CIR Ruling dated 6/27/2003). As stated in the credit description, it is necessary to provide the documentation indicating the solar reflectance index of the aggregate/chat as meeting the requirement. It is not acceptable to compare materials used on the project to a material with a known SRI value. Color values do not have direct correlation to emissivity and solar reflectance values which are the basis for the SRI calculation. Aggregate may be tested using ASTM E1918-06 (Solar Reflectance) and ASTM E408-71(2008) (Thermal Emittance) and then the SRI may be calculated using ASTM E1980. Applicable internationally.
Campus Applicable
No
Internationally Applicable:
Yes
5/6/2009
LEED Interpretation
Inquiry:
This CIR seeks clarification on whether a stabilized grass parking system can be counted in OPTION 1 calculations as open grid pavement. Our project is a cultural institution that receives a surge in visitors during the summer months. The stabilized grass system is proposed for the site\'s overflow parking areas that are required to meet the peak season parking demand. By using this system rather than other types of paving, these areas will be preserved as an open meadow during the remaining 9 months of the year. Town officials have approved the system; as a result we have been able to reduce the amount of paving required for parking by 44%. Designed to hold vehicular traffic while allowing for infiltration, this stabilized grass profile promotes healthy vegetation and prevents soil compaction. The structural base for this system is made up of a twenty inch profile consisting of twelve inches of crushed stone over eight inches of compacted sand and gravel. The strength of the profile arises from the stone on stone contact. The large pore spaces between the stones hold soil to support turf and meadow grasses. Over the crushed stone layer, a two inch veneer of planting soil provides the horticultural medium within which to grow grass. The planting soil is a sandy loam which water percolates through quickly. The water then moves through the crushed stone layer, through the sand and gravel layer, and finally to the subgrade. This system percolates more quickly than the native soils on the site. The stabilized grass parking system has a better hydraulic conductivity and therefore better infiltration rate than open grid paving. We have compared our system to Escofet Checkerblock, which is 77% open. The hydraulic conductivity of the stabilized grass system is 3"/hour. For the Checkerblock, the hydraulic conductivity of the turf soil is 1.5"/hour multiplied by the fraction of the checkerblock that is pervious (77%), the resultant rate for Escofet Checkerblock paving is 1.15"/hour. The hydraulic conductivity of the stabilized grass system will be guaranteed through conformance to the specification which reads, "The final mix shall have a hydraulic conductivity of not less that 3 inches per hour when compacted to a minimum of 94 percent Standard Proctor. Tests shall be by combined hydrometer and wet sieving in compliance with ASTM D422 after destruction of organic matter by ignition." The surface of the stabilized grass parking areas will be 100% vegetated rather than the 50% required for open grid pavement. This system was developed by the project\'s soil scientist and landscape architect. An installation using the same detail, soil profile, and soil blend was installed on an adjacent site and has been proven successful.
Ruling:
The project proposes that a stabilized grass parking system be treated comparably to open grid pavement systems as it relates to SSc7.1 credit compliance. This strategy is acceptable in this particular scenario provided that the design for the parking area is stamped by a professional engineer (P.E.). Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
2/7/2006
LEED Interpretation
Inquiry:
Our project is a 1.2 million SF science building renovation and expansion for an urban university campus. The program consists of research and teaching laboratories, lab support areas, offices, conference rooms, lecture halls, classrooms, libraries, food service, and public areas. We would like an interpretation on some hardscape materials on our site, dark granite under water and gray concrete. A water feature adjacent to the main entry for this project consists of various waterfalls over granite stone. The granite is dark and does not independently meet the albedo of 0.30. However, running water plays a significant role in lowering not only the adjacent ambient air temperature but also the thermal absorption of the granite. Hypothetically, if the outside air temperature on a sunny day is 100 degrees, then dry granite might be around 110-115 degrees, reflecting considerable heat. However, granite under water would have a lower temperature. The use of water in roof ponds, pools, fountains, cascades, waterfalls, etc. for the purpose of cooling is widely accepted. However, the hard research does not exist for the effect of water on the reflectivity and absorption of granite. If a shaded environment is typically the equivalent of 10 degrees cooler than a non-shaded area, does the water/granite combination appear to be equivalent to a shaded area? Can we include the water feature area SF under the shaded category to factor solar heat reduction into the calculations? We would like a further interpretation with regard to our pedestrian walkways to confirm we can use gray concrete. A 6/27/2003 Ruling states that "for the concrete portion of the site, it is acceptable to use the reflectivity rate for new concrete on this credit, as this will meet the intent of the credit at the time of construction. Reflectance level of applicable materials must be adequately documented to earn this credit." Is it acceptable to use the reflectance documentation from the American Concrete Paving Association, stating that new standard gray Portland cement concrete has a reflectivity between 0.35 and 0.40, to meet the requirements of this credit? Or is an actual ASTM E903 lab test on the actual mix to be used required for the project?
Ruling:
The area of the water feature does not count toward achievement of this credit. Water features are excluded from the calculation. All projects may assume that non-colored concrete meets the reflectivity criteria of 0.30 without testing. Testing is required if the concrete mix contains a colorant/stain or non-standard aggregate. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
8/2/2001
LEED Interpretation
Inquiry:
We are defining our LEED project as the building plus approximately 26% of a parking deck (and of the landscaped area around it), with the parking deck located in a block diagonally across from the building. We are operationally allocating to the project 407 out of 1550 parking spaces (26.3%), in the 7-level parking deck with 484,500 sq. ft. total. We are planning for the top deck of the parking deck to be a light-colored/ high-albedo site surface (probably regular concrete with a solar reflectance of 0.30, avoiding the darkening fly-ash content for the top floor). Allocating 26.3% of the 69,220 sq. ft. top level, the resulting area - 18,205 sq. ft. - is greater than 30% of the combined area of this plus the other hard site surfaces in the city block of our building. Thus, we exceed the requirement of providing light-colored/ high-albedo material for 30% of the sit? s non-roof impervious surfaces simply with our top parking level. Please confirm that the USGBC agrees with our interpretation. (We may still want to pursue SS Credit 5.1 without being penalized by having to apply the top deck toward the site areas of the main city block, 50% of which we may want to restore to habitat areas. Is this a separate question? SS Credit 7.1 is more important to us.)Also, it is not clear to us if the 50% underground parking option would also apply, as most of the parking is in covered levels in the parking deck; or does the parking deck indeed need to be "underground"? - Further, are the covered levels of the parking deck a non-roof impervious shaded area, qualifying the project for yet another option of meeting the credit requirements? If at all possible, for our education, please address all three options of qualifying for this credit - could we qualify under any of the options? Which one is the best to prove? Should future credit requirements address parking decks?
Ruling:
It is acceptable to allocate a portion of the parking deck to the LEED project. Allocate a proportional amount of the parking deck from the ground up, including both the covered and top deck spaces. You will need to provide a calculation that documents the allocation of areas and surfaces. If the parking deck is included in one credit, it must be included in all other applicable credit calculations. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
4/4/2007
LEED Interpretation
Inquiry:
Our project\'s operational requirement mandates large paved areas in excess of 30% of the 490,314 s.f. site area. Our goal is to specify a previously developed concrete mix that complies with ASTM C1549 and has been previously tested and presented to USGBC on a prior project. The test results for this material yielded a Reflectance Average Value of .41 for the concrete paving material. The previous test results on three concrete pavement samples ranged from 0.38 to 0.45 Reflectance (Albedo) Values. The testing lab that conducted the reflectivity testing for the prior project has the following accreditations: IAS-ES TL-189, State of Florida TST 1556, Metro-Dade 01-0727.03, and CRRC. This C.I.R. is requesting confirmation that USGBC will accept documentation certifying that the concrete mix utilized on our project is equivalent to the previously utilized and tested mix and that actual laboratory testing will not be required on a project by project basis.
Ruling:
The applicant is inquiring if test data obtained for a different project can be used to document the albedo/reflectivity of the concrete mix used on this project if the same mix is used. It would appear that the previous project being referenced was a LEED NC v2.1 project since the test data supplied relates to albedo/reflectivity. It should be noted that with regards to paving materials, LEED NC v2.2 SSc7.1 requires that paving materials have a Solar Reflectance Index (SRI) of at least 29. The SRI value of a material takes into account both a material\'s reflectivity and emissivity. It is acceptable to use the previous test data as documentation of the materials reflectivity assuming the concrete mix is identical and the test data was done in accordance with ASTM E 903, ASTM E 1918, or ASTM C 1549. This reflectivity value can then be used in conjunction with the material\'s emissivity value to determine the material\'s SRI value. To document the reflectivity value, the applicant should provide the test data along with documentation demonstrating that the concrete mixes used in both cases are identical. It should also be noted that when a range of values is provided, as is the case above for the material\'s reflectivity value, the more conservative number should be used, not the average. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
LEEDuser expert
Crissy Tsai
Webcor Builders
Sustainability Coordinator
