CS-2009 SSc7.2: Heat Island Effect—Roof

  • NC_Schools_CS_SSc7-2_Type3_CoolRoof Diagram
  • Straightforward to achieve

    This credit is fairly straightforward and easy to achieve through prescriptive design measures such as using a light-colored roofing material or vegetation on a majority of the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1.

    The heat island effectHeat island effect refers to the absorption of heat by hardscapes, such as dark, nonreflective pavement and buildings, and its radiation to surrounding areas. Other sources may include vehicle exhaust, air-conditioners, and street equipment. Reduced airflow because of tall buildings and narrow streets exacerbate the effect. is more of a problem in urban environments with long stretches of hot weather. If your project is in such a location, this credit might be a higher priority from a comfort and energy perspective. Incorporating a reflective roof or green roof will help to reduce cooling loads, thereby lowing energy consumption and making for a more comfortable space.

    What’s “SRI”?

     “Solar reflectance index” or SRI is the measure of a surface’s ability to reflect solar heat. Higher reflectivity is desirable, because it helps combat the urban heat islandA densely populated area in which pavement and buildings absorb, store, and release solar energy, making the vicinity warmer than it would be if the pavement and buildings were not present. effect. SRI can range from zero to over 100, with darker surfaces closer to zero and lighter surfaces approaching 100.

    Go green?

    Installing a vegetated, or “green” roof can be more expensive and complicated than installing conventional roofing. However, a green roof will be more effective in combating the urban heat island effect, can offer additional energy benefits to the building through insulation, and can offer stormwater and wildlife habitat benefits. 

    SRI diagramHigh-SRI roofing materials ensure that solar radiation is reflected back into space, rather than heating the building and the surrounding area. Image – BuildingGreen, LLCUsing a green roof to gain this credit helps contribute to many other LEED credits such as:

    FAQs for SSc7.2

    We don't have enough SRI-compliant roofing to earn the credit, but we have a lot of relatively high-SRI roofing (SRI 70). Is there any way to earn the credit?

    Yes, the credit allows for a weighted calculation approach. Many projects in this situation are able to comply. You will need to enter all the roof area that you hope to use to comply. See the calculator in LEEDuser's Documentation Toolkit.

    We don't know the SRI value of some roofing materials we are using. What should we do?

    If it’s not possible to obtain values from the manufacturer, or a reliable industry source, then getting the material tested in a lab according to ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services standards is recommended.

    You can always simply exclude these materials and submit based on known materials.

    What do I do about roof area covered by solar panels, skylights, space for occupants, helipads, etc.?

    “Appurtenances” such as these are excluded from the credit. To quote from 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. #10235 made on 10/01/2012, “Roof area that consists of functional, usable spaces—such as helipads, recreation courts, and areas covered by equipment, solar panels, and appurtenances—can be exempted from the roof calculations for SSc7.2. Projects are not eligible for SSc7.2 if the exempted spaces encompass the entire roof area.”

    Speaking of appurtenances, there is a rooftop pool. Should that be included? Do I need to figure out the SRI value of water?

    You may exclude it. While pools are not specifically mentioned in LEED Interpretation #10235, GBCI has informed LEEDuse that it would probably count them as an appurtenance and exclude them. This is also supported by LEED Interpretation for SSc7.1, #1412 issued 2/7/2006, that excludes water features.

    Do balconies and terraces need to be counted towards the roof square footage?

    Yes, if they protrude from the building and serve as a roof surface for conditioned spaces below.

    How does one calculate the square footage of a pitched roof?

    The square footage of a pitched roof (or a dome) should be determined by calculating the surface area of the roofing material itself, not the area as seen from above.

    What type of ongoing maintenance of the roof is required?

    Materials with high-reflexivity should be cleaned periodically to maintain their reflectance properties. An interval of every two years is usually sufficient. However, this is not a LEED credit requirement.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • This credit is fairly straightforward and simple to achieve by using light-colored roofing, a vegetated roof, or both, on a large area of the roof. (See the credit language for exact thresholds—which are higher for light-colored roofing than for vegetated roofs.) 


  • Hold an integrated design meeting with the entire design team, including the architect, structural engineer, civil engineer, landscaper, owner, and others to help determine what kind of roof is most feasible and desirable for your project building. 


  • The following are a few of the many factors to consider:

    • Roof Pitch: If for climate or architectural reasons you need a sloped roof, a vegetated roof is less likely. Sloped roofs are also typically visible to passersby, so aesthetics are more of a consideration.   
    • Energy and comfort: The heat island effect is more of a problem in urban environments with long stretches of hot weather. If your project is in such a location, this credit might be a higher priority from a comfort and energy perspective. Light-colored and vegetated roofs reflect sunlight, thus lowering cooling bills. Green roofs also add insulation value to roofs, helping prevent both heat gain and heat loss. 
    • Climate and water: Does your site's climate support the use of a green roof? Will a vegetated roof require permanent irrigation? How does roof impact overall water balance of the site? Does your site need to control stormwater runoff?  Would a green roof help achieve stormwater runoff goals?
    • Structure: Does your project building have sufficient structural support for a green roof?  
    • Glare: Particularly for pitched roofs, consider impact of reflective or light-colored roofing on surrounding buildings and roadways. A glare study may be helpful in some cases.
    • Views: Often a green roof can enhance views compared with conventional roofing.
    • Maintenance: Light-colored roofs will benefit from periodic cleaning to maintain their reflectivity. Green roofs will need some level of landscape maintenance depending on the type of vegetation installed. 

Schematic Design

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  • Determine the total square footage of your building's roof surface, then subtract the space taken up by mechanical equipment, such as mechanical rooms for boilers and chillers, HVAC units, PV, skylights and other rooftop systems. The remaining area is the focus of calculations for this credit.


  • The square footage of a pitched roof should be determined by calculating the surface area of the roofing material itself, not the area as seen from above.


  • Treat terraces and balconies as roof square footage if they protrude from the building and serve as a roof surface for conditioned spaces below. The top layer over conditioned space counts as a roof. For example, in some high-rise applications a rooftop pool deck will need to factor into equations.  If an architectural covering or balcony does not have conditioned space below, it is counted as non-roof surface covering and is covered under SSc7.1: Heat Island Effect—Non-Roof.


  • Consider whether high-SRI materials are appropriate for any given application. Partcularly for occupiable roof spaces and roofs adjacent to glazing, there is a danger that some roofing materials will be too reflective, and cause glare problems. Not all high-SRI materials are the same in this regard because the metric is determined by both reflectivity and emissivity, so examine your choices for materials that work well.


  • Determine the square footage of the roof needed to be light-colored roofing or  a green roof by following one of the options below.


  • Most projects choose to go with a light-colored roof because there is less maintenance and upfront costs. However, low-rise buildings in particular (in which the roof is relatively important in maintenance and cost considerations) should consider the life-cycle cost benefits of green roofs, due to improved insulation and better roof durability.  


  • Option 1: Light-Colored Roofing Material on 75% of the Roof Area


  • The “solar reflectance index” or SRI is the measure of a surface’s ability to reflect solar heat. Higher reflectivity is desirable, because it helps combat the urban heat island effect. SRI can range from zero to over 100, with darker surfaces closer to zero and lighter surfaces approaching 100.


  • Sloped roofs have different minimum SRI requirements because of the different angles at which the sun’s rays will hit the roof. For example, flat roofs receive more of the sun’s rays at direct angles, thus the SRI requirement for flat roofs is higher (i.e., for lighter material) than for sloped roofs. (See chart, from the credit language.)


  • Why are sloped roofs treated differently? A surface absorbs more energy from the sun when it is parallel to the ground plane. In the summer months when the heat island effect is more of a problem, the sun is nearly overhead, and flat roofs are in a position to absorb more heat, so it’s more important for them to have a higher SRI value.


  • If your roof has multiple pitches and material types, you can use a “weighted- area SRI” value, using "Equation 1" as follows from the LEED Reference Guide. See the Roof Weighted Average Calculator in the Documentation Toolkit for more examples and to see if your roof complies.   

    SSc7.2 Equation 1


  • The Lawrence Berkley National Laboratory has a database of typical roofing materials and their SRI values. The LEED Reference Guide has reproduced these values, which can be used as a guide, but not as actual SRI values, which must be obtained from your product manufacturer.   


  • The use of a light-colored roofing material typically reduces cooling bills, especially for low-rise buildings. 


  • Generally, there is no cost differential between light-colored roofing material and darker roofing materials.


  • Some municipalities and utility companies offer rebate for projects that install “cool” roofs.


  • Option 2: Green Roof on 50% of Roof Area


  • There are many options for building a green roof. For a more comprehensive approach to designing green roofs, see LEEDuser’s green roofs strategy page


  • While modular, or tray, systems can count as a green roof, LEED does not consider potted plants on the roof as a green roof.


  • Installing a green roof can contribute to many other LEED credits:

    • SSc5.1: Site Development—Protect or Restore Habitat 
    • SSc5.2: Site Development—Maximize Open Space 
    • SSc6.1: Stormwater Design—Quantity Control 
    • SSc6.2: Stormwater Design—Quality Control 
    • WEc1: Water Efficient Landscaping
    • EAc1: Optimize Energy Performance.

  • Although green roofs cost more than conventional roofs, a green roof can have a favorable life-cycle cost by increasing the life of the roof system below via sun protection. Their energy savings can also contribute to long-term financial benefits. 


  • Some municipalities, like New York and Chicago, offer incentives in the form of tax credits, rebates, and density bonuses for building green roofs. Check with your municipality for incentive opportunities. 


  • Green roofs create habitat for birds and wildlife and, if accessible, add amenities and learning tools for building occupants.  


  • A green roof can be used as a space to grow local food.


  • Option 3: Combination Light-Colored and Green Roof 


  • When a combination of green and light-colored roofs, use the formula below (from the official credit language):

Design Development

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  • Select the materials for your roof, and revisit your roof surface area calculations to ensure that you are still meeting the requirements for a light-colored, green, or combination roof.  


  • There are several online databases that help consumers choose roofing materials. The Energy Star Roofing Product site, for example, lists compliant SRI products. (See Resources.)  


  • You'll need to find the SRI value of the roofing materials you use from the manufacturer of the material. The typical values listed in the LEED Reference Guide are reproduced here for reference—but don't rely on them!

    Typical SRI values - table


  • Create a roof plan for LEED submittal that clearly indicates the following:

    • Square footage of the roof surface, broken out to indicate the specific areas of different types of roofing materials, as well as mechanical and aperture areas. 
    • SRI values, green-roof areas, and slope for all areas.

  • It is best to show the credit math right on the plan: total applicable roof area versus compliant, heat island-reducing roof area.  This makes it easier for the LEED reviewers to confirm compliance with the credit.

Construction Documents

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  • Include all specific material properties and SRI criteria in your construction and landscaping specifications. Roofing materials are important, of course, but also remember other materials on the roof such as pavers, walking pads, and other roof accessories (mechanical equipment is excluded).


  • Fill out the LEED Online credit form and upload your roof plan and material cut sheets with SRI values clearly indicated.

Construction

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  • Ensure that the correct materials and landscaping are used.

Operations & Maintenance

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  • Include regular cleaning practices of roofing materials, especially for light-colored surfaces, as they will lose their ability to reject heat as they get darker and dirtier.


  • Include regular cleaning, watering, and weeding for green roof areas.

  • USGBC

    Excerpted from LEED 2009 for Core and Shell Development

    SS Credit 7.2: Heat island effect - roof

    1 Point

    Intent

    To reduce heat islands1 to minimize impacts on microclimates and human and wildlife habitats.

    Requirements

    Option 1

    Use roofing materials with a solar reflectanceAlso known as albedo: 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 index2 (SRI)equal to or greater than the values in the table below for a minimum of 75% of the roof surface.

    Roofing materials having a lower SRI value than those listed below may be used if the weighted rooftop SRI average meets the following criteria:

    Area Roof Meeting Minimum SRI

    ————————————————

    Total Roof AreaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1.


    x SRI of Installed Roof

    ——————————

    Required SRI


    75%


    Alternatively, the following equation may be used to calculate compliance:

    [ Area of Roof A x SRI of Roof A

    ———————

    Required SRI


    ] + [ Area of Roof B x SRI of Roof B

    ———————

    Required SRI


    ] + ... Total Roof Area
    0.75


    Roof Type Slope SRI
    Low-sloped roof ≤ 2:12 78
    Steep-sloped roof > 2:12 29


    OR

    Option 2

    Install a vegetated roof that covers at least 50% of the roof area.

    OR

    Option 3

    Install high-albedoAlbedo is synonymous with solar reflectance. and vegetated roof surfaces that, in combination, meet the following criteria:

    Area Roof Meeting Minimum SRI

    ————————————————

    0.75


    + Area of Vegetated Roof

    ——————————

    0.5


    Total Roof Area


    Roof Type Slope SRI
    Low-sloped roof ≤ 2:12 78
    Steep-sloped roof > 2:12 29


    Alternatively, a weighted approach may be used to calculate compliance for multiple materials:

    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 ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services 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 desk, under roof, or under a building.


    Potential Technologies & Strategies

    Consider installing high-albedoAlbedo is synonymous with solar reflectance. and vegetated roofs to reduce heat absorption. Default values will be available in the LEED Reference Guide for Green Building Design and Construction, 2009 Edition.. Product information is available from the Cool Roof Rating Council Web site, at http://www.coolroofs.org, and the ENERGY STAR® Web site, at http://www.energystar.gov.

    FOOTNOTES

    1. Heat islands are defined as thermal gradient differences between developed and undeveloped areas.

    2. The solar reflectanceAlso known as albedo: 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 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 standard black 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 ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services E 1980. Reflectance is measured according to ASTM E 903, ASTM E 1918 or ASTM C 1549. Emittance is measured according to ASTM E 408 or ASTM C 1371.

     

Software Tools

Radiance—Lighting Design Software

This daylight modeling tool is widely accepted in the lighting industry.

Web Tools

Cool Roof Rebate Database

This is a database for local utilities that offer rebates for cool roofs.


U.S. EPA, ENERGY STAR Roofing Products

This site provides solar reflectanceAlso known as albedo: 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 levels required to meet ENERGY STAR requirements for qualified roof products.


Lawrence Berkeley National Laboratory, Heat Island Group—Cool Roofs

This site offers a wealth of information about cool roof research and technology, including links to a cool roofing materials database. 


Cool Roof Rating Council

This website includes a page where you can plug in the roofing type, color, and SRI and emittance values you're looking for, and it will provide a variety of products and manufactures who meet your criteria.

Organizations

Green Roofs for Healthy Cities

This nonprofit industry association consists of individuals and public and private organizations committed to developing a market for green roof infrastructure products and services across North America. 


Penn State University, Center for Green Roof Research

The Center has the mission of demonstrating and promoting green roof research, education, and technology transfer in the Northeastern United States.

Technical Guides

Whole Building Design Guide, Extensive Green Roofs

This article by Charlie Miller, PE, details the features and benefits of constructing green roofs. 

Sample Plan – Cool Roof

Option 1

The project shown in this sample plan complies with the requirement to have greater than 75% of the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. light-colored.

Product Cut Sheets

Option 1

Look to product cut sheets like these examples to find high SRI values, indicating roofing materials that comply with the credit requirements.

Roof Weighted Average Calculator

As described in the LEED Reference Guide, a weighted average calculation may be performed for buildings with multiple roof surfaces to demonstrate that the total roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. has an average SRI greater or equal to a baseline theoretical roof with 75% at an SRI of 78 and 25% at an SRI of 30. Use this spreadsheet (with sample calculation) to determine if your roof complies—and if not, what adjustments need to be made.

LEED Online Forms: CS-2009 SS

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."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

92 Comments

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Carine Guenand Assistant Design Manager Skanska Construction UK
Feb 10 2014
Guest
11 Thumbs Up

SS7.2 Heat Island Effect Roof - Material with no SRI

We are currently appealing this credit as we were informed there was information missing in ours submission (mechanical plant and other areas were not clearly labelled).
We've now done this. Part of our roof is aluminium and we have no SRI value for this as the material has not been tested. We have however run the calculation with the worst case scenario for this roof - an SRI of 0 and we are compliant. Has anyone ever taken this approach?

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Daniel Joseph GLHOMES
Oct 01 2013
Guest
24 Thumbs Up

Heat Island Effect - Roof Exemplary Performance

Does any one know how the 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 this credit is achieved?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 04 2013 LEEDuser Moderator

It's in the Reference Guide... I believe you have to hit a higher percentage threshold.... yes, 100%.

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SW LEE Project Manager
Jun 27 2013
LEEDuser Member
100 Thumbs Up

Coating - SRI

Is paint or coating with proper tested SRI standard can earn this credit?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 04 2013 LEEDuser Moderator

Yes, if the paint or  coating is appropriately (i.e. durably) applied to the roofing material.

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Mario Pinoli
May 17 2013
Guest
89 Thumbs Up

green roof cover - ivy

Hello,
I'm working on a project which is considering to use the ivy as green cover.
My worries in considering this system as a green roof , consist of the definition of greenroof which is supposed to have a layer of soil.
At the same time I'm sure that our system can reduce heat island effectHeat island effect refers to the absorption of heat by hardscapes, such as dark, nonreflective pavement and buildings, and its radiation to surrounding areas. Other sources may include vehicle exhaust, air-conditioners, and street equipment. Reduced airflow because of tall buildings and narrow streets exacerbate the effect., bacause of heat absorbition through the leave.
Looking forward to having your advice.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 04 2013 LEEDuser Moderator

Mario, I would say that this application of ivy is shading the roof, but not providing a vegetated roof per the credit language. Shading is a viable strategy on some other credits, such as in non-roof hardscapes, so the fact that LEED does not offer it here is significant, I think.

I think you could seek a 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. or otherwise make the case to GBCI, but at the outset I would not count on this strategy being accepted.

If you learn more, please let us know.

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Christina Nybergh LEED AP BC+D Skanska Talonrakennus Oy
May 13 2013
LEEDuser Member
41 Thumbs Up

How to define ‘Roof Area’

Hi,
I’m working on a C&S project and have a problem with defining the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. of the project. The project has parking underground and three floors of retail spaces. Above one part of the building there will be unenclosed parking spaces (2 floors in total) with roof parking. Does the roof parking of the parking tower need comply with the SRI requirements or can this area be excluded from the roof area?

The roof parking covers the unenclosed parking floors and could be excluded from the roof area according to “‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1.“ However the roof parking is also the roof of the retail spaces under the unenclosed parking floors and should be included in the roof area according to “Roof area is the area of the uppermost surface of the building which covers enclosed Gross Floor AreaGross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.).”

Any ideas?
Thanks.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 04 2013 LEEDuser Moderator

I would pick one and go with it consistently, as either could be justified. Calling it non-roof seems most logical to me, since it is more like a hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios. parking lot than like a roof, in practice.

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Mario Pinoli
May 10 2013
Guest
89 Thumbs Up

exempted area from SSc7.2

Hi all,
our office building has a roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. that consists of some functional, usable spaces. In detail this area will be used as playground for children and as chill out area for office's employees.
Could this areas be deducted from the total roof surface area ( as I do for mechanical equipment?).
Thanks.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. May 12 2013 LEEDuser Moderator

Mario, I could see an argument being made for this, but in my opinion, no. It's very common to have functional space on roofs, but this is not mentioned in LEED as an excludable space, and I haven't seen this question come up before. Also, just as non-roof hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios., including pedestiran-oriented hardscape, is counted in the nonroof credit, it seems that space of this nature should be counted in the roof credit.

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Mario Pinoli May 13 2013 Guest 89 Thumbs Up

Thanks Tristan.
We have recently found a 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. saying:
"Roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. that consists of functional, usable spaces- such as helipads, recreation courts, and areas covered by equipment, solar panels, and appurtenances- can be exempted from the roof calculations for SSc7.2. Projects are not eligible for SSc7.2 if the exempted spaces encompass the entire roof area. Applicable Internationally."
In my opinion, functional and usable spaces can be exempted, considering that a high SRI value makes the roof area impossible to use due to the glare. What's your opinion?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. May 13 2013 LEEDuser Moderator

Mario, you are correct. I should have revisited that LI before posting my earlier response. I agree you can exclude the space.

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Petr Vogel Specialist Consultant, EkoWATT CZ Nov 27 2013 LEEDuser Member 136 Thumbs Up

Mario, Tristan,
does this mean that wide paved area (wooded flooring) acting as a chill-out area for building users can be excluded of the total relevant roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. for this credit?
Thanks for any kind of help.

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Nov 28 2013 Guest 1497 Thumbs Up

Hi all.
I will ad up my opinion to Petr's comment...
If yes, then it is up to Design team to decide what brings the most outcome from such use of the roof... energy savings by reflective surface (or local microclimate temperature rise which affects surrounding buildings as well), or user comfort... In my opinion this interpretation allows for "chasing points" if used widely without setting in a wider context. I would say it should be applied for projects where a point for SSc5.2 has been awarded which wouldn't be possible without this kind of roof usage. That would make more sense to me... Opinions? :-)

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Dec 20 2013 LEEDuser Moderator

Petr Vogel—I agree.

Petr Lhotak—I do see how this can lead to creative interpretations of the credit, but that's how it's written.

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Michael E. Edmonds-Bauer Edmonds International
Apr 16 2013
LEEDuser Member
1188 Thumbs Up

Mechanical room covered by greenroof

By definition the mechanical room will be excluded from roof calculations. However, we are considering covering a mechanical room with a greenroof in order to apply for this credit.

The issue here is that space is so limited and we need to provide 3300 sqft in order to comply with SSc7.2 and SSc5.1 as well.

We ran out of space because, however if we covered a big mechanical room where hvac and elevators machinery are we will be able to comply with these two credits.

But we dont want to run into a review saying the greenroof at the machinery room will be excluced from calculations.

Does anybody have any experience of greenroof in machinery rooms being accepted in order to comply with credits regarding vegetated spaces?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 16 2013 LEEDuser Moderator

Michael, it's hard for me to imagine there being a problem with this. Excluding appurenances is a way to simplify the credit calculations and ease the requirements. You are choosing to make things a bit harder for yourself to earn the credit. I would simply include this area in your roofing calculations.

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Michael E. Edmonds-Bauer Edmonds International Apr 17 2013 LEEDuser Member 1188 Thumbs Up

Great to hear this opinion Tristan. If at the end we submit it this way and get a positive response from the reviewers we'll post the results on the forum.

Thank you!!

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Rosamaría Mellone Green Building and Alternative Energy
Feb 05 2013
LEEDuser Member
951 Thumbs Up

Weighted calculation - lower SRI value

Hello!
We have a project in which the client will install a roofing material with an SRI value of 70 (low slope: requirement-78) for 100% of the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1..
Can this be compliant with this credit, using the weighted calculation? Even though 100% of the roof has an SRI value lower than 78?
Thanks!!!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Feb 05 2013 LEEDuser Moderator

Rosamaria, run the calculations and find out! There is a calculator in the Doc Toolkit above.

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Rosamaría Mellone Green Building and Alternative Energy Mar 05 2013 LEEDuser Member 951 Thumbs Up

Thanks, Tristan. Yes, running the calcs and using the formula, it passes.
But the question was more if this formula applies to a project where all the roof areas will have the same material with an SRI of 70 (when it should be 78), or does it apply only to projects where they have SEVERAL roof materials and one or some of them DO have SRIs higher than 78, and others don't?
Thanks! :)

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Mar 22 2013 LEEDuser Moderator

Yes, it applies.

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Michael E. Edmonds-Bauer Edmonds International
Nov 13 2012
LEEDuser Member
1188 Thumbs Up

SRI values for marble

Has anybody had any experience documenting SRI values for marble? We have a few greenroofs that, as part of design, implement some white marble pebbles but I just havent had a clue about how to document SRI number.

The American Institute of Marble recomends, according to the Natural Stone Council, that any claim of stone being a high SRI product must be substantiated through professional material testing. They also provide a few natural stones SRI measured by the American Institute of Marble but they show an average of 60, you can find this document at this link:

http://www.marble-institute.com/pdfs/CaseStudy4_SolarReflectanceOfStone.pdf

I know testing material through and accredited facility is the obvious option but that would increase cost and it is really difficult that and investor will be willing to do this just a few pebbles.

Any idea of a source that can be used as a SRI documentation for white marble?

Thank you very much.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 24 2012 LEEDuser Moderator

Michael—sorry, finding SRI values for specific cases like this can be tough. I don't know if a source for marble SRI.

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Michael E. Edmonds-Bauer Edmonds International Dec 04 2012 LEEDuser Member 1188 Thumbs Up

Thank you Tristan. How come that the GBCI does not accept a white marble as a given SRI compliant material?

I'm thinking about not specifying this anymore since it does not help achieving the credit.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Dec 04 2012 LEEDuser Moderator

Michael, GBCI would accept white marble, as it would any other material with valid SRI values.

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Michael E. Edmonds-Bauer Edmonds International Dec 05 2012 LEEDuser Member 1188 Thumbs Up

That's the thing Tristan, since no documentation exists for marble, then specifying marble at a rooftop (in a sky terrace application for example) will not help you anyhow to achieve the credit, even though white marble will for sure comply with SRI requirements like I said no documentation exist.

I think this should be reviews by USGBC.

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Susann Geithner Global Sustainability Manager, Predictive Service Dec 05 2012 LEEDuser Expert 10292 Thumbs Up

Mike. You can always get the material tested. There are plenty of testing companies out there that do that. Of course that costs.
Someone posted a contact for a US based testing company here in the forum. I just can't find it right now.

In Europe : Fraunhofer Institut" in Stuttgart, Germany does SRI testing. They need a product sample to do that. They will also translate it into English for an extra fee. http://bit.ly/pHZG5Z

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Charline Seytier CEO, Co-owner. LEED AP BD+C, ThemaVerde, France Apr 17 2013 LEEDuser Member 244 Thumbs Up

Thank you Susann!
Do you have a contact person in Fraunhofer Institut by any chance that I could reach out?

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MOHAMED A. SAID, LEED AP Design Manager-Mechanical Projacs International
Jul 19 2012
LEEDuser Member
48 Thumbs Up

High Rise Tower with pointed crown

I am working on a HR tower with "virtually" no roof. The upper most portion of the tower is converging to a very narrow; curved glazed concrete-framed structure with no flat roof. Does it contribute to credit SSc7.2 compliance?

Also, for credit SSc7.1; does vertical surfaces of the tower providing shade to adjacent hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios. contribute to credit compliance; or it should be only horizontal shading surfaces?

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Susann Geithner Global Sustainability Manager, Predictive Service Aug 09 2012 LEEDuser Expert 10292 Thumbs Up

Even if you have no flat roof at all, the steep-sloped roof does count too. See the graphic above. You will probably count from the point the vertical surface starts angling towards the top.
As for SS 7.1 you may want to ask you question there, so other LEEDUser can find the answer also.

Good luck with your project!

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Mary Ann Santos
May 03 2012
LEEDuser Member
1965 Thumbs Up

Roof or Non-roof?

Hi All,

We are working on a high-rise office project that will sit on top of an existing structure. The existing structure (5-storey retail building) has a larger footprint compared to the proposed building.

We included the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. of the existing building to our project boundary where proposed landscape vegetation will be placed.

Should the top most floor (roof level) of the existing structure be considered as roof or non-roof in relation to the proposed high-rise office building?

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Emily Catacchio Sustainability Specialist, Wight and Company May 08 2012 Guest 6832 Thumbs Up

Mary Ann,

I would suggest taking a look at the AGMBC which you can find on LEEDuser here

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Alessio Zampaglione Architects StudioAZA
Jan 23 2012
Guest
575 Thumbs Up

Mechanical equipment compartments as roof surface

Hi everyone,

I’m working on a project registered under LEED 2009 C&S Rating System. I understood that roof surface is a surface that covers usable interior space, defined as a space which is both conditioned and occupied. On my project’s roof, there are some mechanical equipment compartments which are enclosed but not conditioned and not occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space.. Does my roof surface final count must include the roof surface of those mechanical equipment compartments or are those exempt from the SSc7.2 credit calculation?

Thank you in advance!

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Susann Geithner Global Sustainability Manager, Predictive Service Jan 25 2012 LEEDuser Expert 10292 Thumbs Up

It use to be a bit more like you describe it, depending the space being conditioned. But with the new definition of roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. the roof above your mechanical room will be included in the calculation, since it's enclosed gross square footageSum of the floor areas of the spaces within the building including basements, mezzanine and intermediate-floored tiers, and penthouses with headroom height of 7.5 ft or greater. It is measured from the exterior faces of exterior walls or from the centerline of walls separating buildings, but excluding covered walkways, open roofed-over areas, porches and similar spaces, pipe trenches, exterior terraces or steps, chimneys, roof overhangs, and similar features. of the building. However form my experience these mechanical rooms a lot of time are more like a enclosure to prevent direct exposure to rain. So those walls often times are lovers all around and no actual wall separating inside from outside. I think in this case I would excluded such an area form the calculation. I hope that helps.

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Michael E. Edmonds-Bauer Edmonds International Apr 10 2013 LEEDuser Member 1188 Thumbs Up

I would consider it an area that need to be included, after all is an area that otherwise would be heating up and remember the intent of the credit is to avoid the heat island effectHeat island effect refers to the absorption of heat by hardscapes, such as dark, nonreflective pavement and buildings, and its radiation to surrounding areas. Other sources may include vehicle exhaust, air-conditioners, and street equipment. Reduced airflow because of tall buildings and narrow streets exacerbate the effect..

The only think I could possibly think that can be exluded from the roof of a mechanical room is insulation since it typically is not a comfort area.

Has anybody had any experience about incluidng mechanical room's roof as part of the SSc7.2 scope?

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Petr Vogel Czech Green Buidling Council + EkoWATT
Nov 30 2011
Guest
17 Thumbs Up

HVAC on a green roof calculation

Hello,
we are working on the project of a new commercial building where green roof is about 50 % of the whole roof.
There are some HVAC installations consisting of a mechanical part (located on the non green roof) and of a ductwork (located mostly above green roof and partially above non green roof).
How can we handle this situation? Should we deduct all the HVAC installations of the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. OR should we deduct the mechanical parts only? What do do with the ductworks above the green area?
We would prefer to deduct all the HVAC or to deduct mechanical parts only for reduction of a roof area. Is it correct?
Thanks for any advice.
Petr

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Susann Geithner Global Sustainability Manager, Predictive Service Nov 30 2011 LEEDuser Expert 10292 Thumbs Up

You can deduct both the equipment and the duct work. see also the definition of roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1.: http://www.leeduser.com/credit/NC-2009/SSc7.2#comment-16498
In many countries you are required to have gravel strips around and under equipment for fire security and people safety reasons. Even thought I don't think that was the reason for excluding these areas.
Good luck with the project.

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Sara Neff Director, Sustainability Programs Kilroy Realty Corporation
Nov 09 2011
LEEDuser Member
748 Thumbs Up

Awnings?

Are awnings part of roofs? My project has a large roof and then some metal awnings over entrances, do the tops of the awnings also need to comply with/be counted in the roof credit documentation?

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Susann Geithner Global Sustainability Manager, Predictive Service Nov 09 2011 LEEDuser Expert 10292 Thumbs Up

You don't have to include the awnings since there don't cover an enclosed space see also this comment with the definition of a roof. http://www.leeduser.com/credit/NC-2009/SSc7.2#comment-16498

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Markus Henning M.Eng Facility Management LEED AP BD+C Alpha Energy & Environment
Sep 28 2011
Guest
133 Thumbs Up

SSc7.2 Option 3

In my project I will achieve the requirements of SSc7.2 with option 3. The roof is covert by 10% green roof and 60% white gravel and ….. My question is if I don’t get the SRI value from the manufacture of the gravel can I use the value of 79 from the LEED reference guide for calculation?

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Susann Geithner Global Sustainability Manager, Predictive Service Oct 10 2011 LEEDuser Expert 10292 Thumbs Up

The SRI can vary a lot depending on, what exactly your gravel looks like and is made of. You will need the actual SRI either per manufacturer's data or testing. See also George's question below.

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Luis Miguel Diazgranados Green Factory
Jun 24 2011
LEEDuser Member
1051 Thumbs Up

Pool SRI

Hi

What about a pool? In this project we are working on, there will be a pool in a terrace on the roof. What would it be it's SRI? Or does it depends on the tiling used under water?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jun 24 2011 LEEDuser Moderator

Luis, this gets into some tricky issues which have been discussed in more detail on the NC version of the SSc7.2 forum, but my recommendation is to not try to count the pool for your SRI-compliant surfaces.

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Mathilda Jonsson Environmental Certification Engineer (LEED AP BD+C) Skanska
May 09 2011
LEEDuser Member
803 Thumbs Up

Solar cells and green roof

Hi
My project is having green roof (less than 50 % of the total roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. though) and the rest of the roof area will be covered of solar cells. Can I somehow use this toward this credti?

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Luis Miguel Diazgranados Green Factory May 23 2011 LEEDuser Member 1051 Thumbs Up

For this credit, according to Leed Online, you have to consider total roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. excluding mechanical equipment, photovoltaic panels and skylights. If your project's roof consist of only photovoltaic panels and green roof, in terms of this credit, 100% of this roof is a green roof and therefore you achieve it. Actually you can apply 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. with this percentage.

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Vivien Fairlamb Jul 11 2011 LEEDuser Member 800 Thumbs Up

The project i'm looking at has a green roof with PVs sitting on a framing system slightly above the vegetative material. Is it possible to include the plan view area of PV in the roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1. calculations as on other projects we've seen a better growing result in the shade of the PV than elsewhere . Sun angles etc would also mean that the green area is alos doing its job. The project's ecologist has given the all clear for walk on access for maintenance purposes. thanks

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Jul 11 2011 Guest 1497 Thumbs Up

Vivian,
do you have other materials on the roof as well? Or is it only green roof with PV panels? If there is only vegetated surface and PV panels, why do you want to include it?

The reason for excluding mechanical equipment and PV panels from this credit calculation is that it would be contraproductive. HVAC systems are very often situated on the roof, because it is not possible to put it anywhere else. And without it you wouldn't achieve some other more relevant credits...

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Vivien Fairlamb Jul 11 2011 LEEDuser Member 800 Thumbs Up

Yes there are other roof areas - two difference types of roof material and also some other plant enclosures. I'd exclude the plant areas easily enough but if we can include the area of PV within the green roof area on which the PV sits the calculations should be favourable for the 50% vegetative roof area

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Jul 11 2011 Guest 1497 Thumbs Up

I see... my guess is that if you wish to do it this way, you will need to submit a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide on this.

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Patrick MacPherson Project Consultant Sustainable Design Consulting
Apr 14 2011
LEEDuser Member
295 Thumbs Up

SSc7.2 Inquiry - Subterranean 'Roof'

Hello,

The project I am working on consists of a tower with subterranean spaces that lie beyond the tower's footprint. Could we consider the vegetated area over the subterranean as "roof" and include it in the calculations for SSc7.2? Thoughts?

Thanks!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 14 2011 LEEDuser Moderator

Patrick, I would say that depends in part on the function of the underground spaces. Are they conditioned and occupied?

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Apr 15 2011 Guest 1497 Thumbs Up

Hi guys.
We have it the same, but on the contrarary. My guess is that if the underground floors serve as a garage, then the "roof" at the ground level can be considered a terrain instead of a roof and we do not have to count that towards achieving SSc7.2. Any comments on this?

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Apr 15 2011 Guest 1497 Thumbs Up

Yet I forgot to mention that besides the green "roof" aka vegetated surface above garage there is a portion of asphalt drive way. That is why we want to exclude it.

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Patrick MacPherson Project Consultant , Sustainable Design Consulting Apr 15 2011 LEEDuser Member 295 Thumbs Up

Yes they are, both conditioned and occupied.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 15 2011 LEEDuser Moderator

Patrick, in that case I would consider it a roof.

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Emily Clark Project Coordinator Chapman Construction/Design
Apr 14 2011
Guest
58 Thumbs Up

Existing White Roof

We are working on a Core & Shell major renovation which has an existing white roof. I've been having a hard time finding if we can just leave this roof and achieve this credit. Also, if we can achieve it do we need to count the materials for our total materials cost even though it's already in place?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 14 2011 LEEDuser Moderator

Courtney, as with other existing materials on the project, you would not have to include the roof in your project cost. You could earn the credit by leaving the white roof in place, but you'll have to show that it has  compliant SRI value. That will probably require finding specs from the manufacturer, or testing.

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Omar Katanani
Jan 19 2011
LEEDuser Member
6904 Thumbs Up

Skylight with Fins

Dear all,

My project is a retail mall with a very big skylight across the mall's width.

The skylight has alternating horizontal fins made of 19mm thick mild steel, meaning that one half of the skylight's area is going to be glazed and the other half is going to be white-painted steel.

Do I have to demonstrate SRI compliance for the glazing and the metal sheets of the skylight?

Thanks!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 20 2011 LEEDuser Moderator

George, skylights are excluded from the calculations for this credit. I think that puts these fins, which you describe as an appurtenanceAn appurtenance is any built-in, nonstructural portion of a roof system, such as skylights, ventilators, mechanical equipment, partitions, and solar energy panels. on the skylight, in a bit of a gray area. Sounds like it would be a good idea to include them, though.

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Omar Katanani
Dec 20 2010
LEEDuser Member
6904 Thumbs Up

Using Table 1 of the LEED Reference Guide

Dear all,

It is being really hard to obtain Manufacturer data for the roof materials SRI in my country.

There is a table in the LEED Reference Guide that lists the "Solar ReflectanceAlso known as albedo: 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 Index (SRI) for Typical Roofing Materials". Is there any possible way that I can use this table in my calculations by any chance?

Thanks!

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Susann Geithner Global Sustainability Manager, Predictive Service Dec 20 2010 LEEDuser Expert 10292 Thumbs Up

We have had the same issue on our projects. There are no SRI values for roofing materials and the only way of getting them is to perform an rather expensive testing. As far as I know and have read so far you will have to prove the actual SRI. You can not use that table. We haven't actually tried a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide or submitted the credit with presume values. So maybe they will except it, but my guess is not.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Dec 20 2010 LEEDuser Moderator

I would second what Susann says. You have to show actual SRI. I think part of the hope of LEED in general and perhaps in this credit is that manufacturers will be more motivated to provide this kind of information.

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Omar Katanani Dec 21 2010 LEEDuser Member 6904 Thumbs Up

In this project, the gravel or cement on the roof is going to be painted white. The white paint is produced locally by manufacturers who do not know what SRI means!

As such, can I use the SRI value for the white coating in Table 1? I do not think that the SRI will vary significantly among white coatings.
Any suggestions?

Thanks!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Dec 21 2010 LEEDuser Moderator

Again, I think you need to use actual values, not rely on the table. The value for something that appears "white" can in fact vary a lot, especially when it's applied to something like roof ballast.

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Petr Lhoták Sustainability Consultant, Skanska Czech Republic Mar 18 2011 Guest 1497 Thumbs Up

Does GBCI want to document SRI of materials that have SRI lower than required by this credit as well as of complying materials?
For example, part of roof is covered with bituminous material and part of roof covers high albedoAlbedo is synonymous with solar reflectance. EPDM foil. We have documents only for EPDM foil. In calculations for this credit I intent to use actual SRI for EPDM and for bitumin a value from the table or other sources. Could this be acceptable? Obviously, bitumins do not have high albedoAlso known as solar reflectance: 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 so the manufacturer doesn't even want to test the material for SRI. This sounds logical to me...

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Mar 25 2011 LEEDuser Moderator

Petr, you do not need to document SRI for materials that you are not using to comply with the credit. I hope that answers your question.

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Marcio Orofino ENE Consultores Sep 12 2011 LEEDuser Member 157 Thumbs Up

I have the same problem in Brazil. Difficulties to obtain SRI value for some materials. One of most respected tech institutes performs SRI test according to ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services E 1980. However, the refletance value is obtained by ANSI/ASHRAE 74-1988 - "Method of Measuring Solar-Optical Proprerties of Materials - E procedure". Emittance is measured according to ASTM C1371, as indicated by the LEED RG.
Can USGBC/GBCI accept SRI values for a material performed ​​in accordance with these standards referenced, using ANSI/ASHRAE Standard, instead of ASTM standard, to determine the reflectance value?
We have not submmited any CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide or 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..

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Susann Geithner Global Sustainability Manager, Predictive Service Sep 16 2011 LEEDuser Expert 10292 Thumbs Up

The reference Guide page 119, see footnote 2, listes both ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services 1980 and ASTM c1371. So you should be fine. No CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide necessary.

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