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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...
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146 Comments
Spray coating asphalt shingles to acheive SRI > 28
We have a steep-sloped roof and cannot use a metal roofing material because of budget restrictions - so we are going to use asphalt shingles. There are asphalt shingles in the market with an SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. >28, however they all seem to be 'architectural' grade and have specific profiles and shapes designed to mimic wood shakes or other traditional roofing materials.
We would like to use a plain rectangular-shaped standard 'residential' (inexpensive) type of shingle but no companies seem to manufacture these shingles that meet the SRI requirement. I guess the assumption is if you're looking for a specific SRI value, you probably want the more expensive 'architectural grade' singles - but we don't! My understanding is that the 'cool shingles' that are marketed are applied with a special reflective coating to achieve the SRI >28 requirement.
Does anyone know of, or had experience with, applying a cool roof reflective coating to already installed asphalt shingle roofs? For instance, can we installed a standard asphalt shingle roof and then spray it to achieve this LEED credit? Ideally the coating wouldn't interfere with the original look and color of the asphalt shingle.
Any ideas?
here's a link to the 'SRI >28 architectural grade' shingles available:
http://www.coolroofs.org/products/results.php?keyphrase=&select_type=select&type[6]=Shingles+or+Shakes&market_type=&company_name=&brand=&model=&select_color=all&min_solar=&min_solar_3yr=&min_therm=&min_therm_3yr=&sri_init=28&sri_3yr=&slope=&crrc_prod_id=
Synthetic turf roofs?
Would a "green" roof done with synthetic turf apply to this credit under the green roofing option? Or would I need to know the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. value for the synthetic turf and count it the under high albedoAlbedo is synonymous with solar reflectance. option.
Anyone with experience using turf for a roof? THANKS!
Synthetic turf would not qualify as green roof. An actual green roof has the advantage to keep moisture and a buffer between the interior and the exterior, which will not heat up so much. It's a tiny micro climate.
If you want to count it in regards to the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100., when you will need that data from the manufacturer since it can vary so much depending on materials, color.
Good luck!
SRI for light-colored wood
Does anyone know the typical SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. range for wood (light colored to dark colored)?
I know that it differs from one product to another, and that we need the manufacturer's documentation proving the SRI, but I need an estimate range for now, if possible!
Many thanks..
Red Color High SRI?
Has anybody heard of red colored roofing membrane that could provide an SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. >78?
Thanks you for any tips.
Have you checked out the Cool Roof Ratings Council's Rated Products Directory ? You can even search by color http://www.coolroofs.org/products/search.php
Just checked in and found something that could be usable. Thanks a lot.
Low Glare High SRI Roof pavers for residential terraces
I am working on a multifamily residential project where the roof will be accessible to residents. Part of the roof will be green, and pavers will be installed on the non-green parts. I am having difficulty finding pavers with an SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. of 78 or more that do not create glare conditions. Any suggestions are appreciated. Thanks
Does your green roof cover at least 50% 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.? If so, your pavers would not need to meet the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100..
swimming pool
Our project has a swimming pool located on the building roof, can the area of the swimming pool be excluded in the credit calculation similar to those areas covered by mechanical equipment, solar panels and skylight? If not, how do I calculate the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. value of water?
Thanks!
My best guess is yes. Have you looked through the CIRs?
There is another comment about the same issue http://www.leeduser.com/credit/NC-v2.2/SSc7.2#comment-2687
This is referencing 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 stating that water features are excluded. But check the CIR data base to see if it also applies to LEED NC 2009.
Metal grating roof
Hi all,
We have a roof above an unconditioned floor with the mechanical equipment and we dont know what to do about the SS c 7.2. We have some questions:
1_ Some of the elements of the roof are some decorative weathering steel chimneys with sloped shape, shall we count only the area from the top view or which one? We think that it is the best option, count the projected area but we dont know what to do with the hole of the chimney, shall we count the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. of the mechanical floor below??
2_ The roof above the unconditioned space is divided in different areas, one with the chimneys, another with white concrete slab and another one with a metal grating. Does the metal grating counts as roof? its permeability is above 80% shall we count with the SRI of the mechanical floor below the metal grating to calculate this credit? and about the shading provided by the metal grating??
Thanks a lot!!!
For the slope roof, check the checklist section in regards to how to account for sloped roofs.
The chimney I would suggest to count as mechanical equipment as a whole so including the masonry/metal. It's for heating of the space.
In regards to unconditioned spaces, in the past you would only count the conditioned space in this credit, but judging from the more recent addendum, which defines 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. better, it is questionable if this still holds up. http://www.leeduser.com/credit/NC-2009/SSc7.2#comment-16498
MECHANICAL DUCTS
Are mechanical ducts considered among the mechanical equipments to be deducted from 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.? does it make difference the height of the duct from floor roof?
Can can also deduct mechanical ducts from 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.. I don't know of any height restriction. You should be fine.
Project in Europe
Are there any testing facilities in Europe capable of measuring SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. values? Our project can easily achieve this credit, however, we are not able to get SRI values from our suppliers.
From my point of view this is a huge obstacle for international projects.
Thank you for any suggestions.
I suggest to contact the TUV. They are testing all sorts of things and in almost all European countries. Also there are plenty of construction material testing providers in Europe. You just have to explain and provide them with the testing standard (see LEED reference guide) to be sure they are following the required procedure.
Actually one of my clients just told me that the "Fraunhofer Institut" in Stuttgart, Germany does SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. testing. They need a product sample to do that. They will also translate it into English for an extra fee. http://bit.ly/pHZG5Z
Susann, great job as usual. I will try to contact the Stuttgart institute.
Thank you!
You are very welcome. I'm always glad to help especially with international projects since they are always more difficult to document.
New equation and better definitions - Addenda August 2011
A new equation to calculate credit compliance has been added. Base on a weighted average you now may also show credit compliance. Find the new equation here: https://www.usgbc.org/ShowFile.aspx?DocumentID=9757
Also appurtenances can be deducted form 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. and are now more clearly defined as: "An appurtenance is any built-in,
nonstructural portion of a roof system, such as skylights, ventilators,
mechanical equipment, partitions, and solar energy panels."
Roof area is now more clearly defined too: "Roof 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."
With the help of Susann at HSB and our content partners at YRG, LEEDuser has posted an updated verison of our popular Roof Weighted Average Calculator. Members can acess this spreadsheet calculator in the Doc Toolkit above.
Green Roof Installation Timing
I am working on a green roof in St. Louis, MO which is due to be complete by October. We are having difficulty getting plant cuttings from local nursuries, as the planting window is so short for the fall (Sept 1 - 15). Thus, we are looking to install the plants in the Spring instead, but I can't find any mention of timing of install in the Reference Guide. If we do this, are we breaking some rule about when the green on the greenroof is actually installed?
I would check the LEED interpretation database and see if there is a ruling in that regards. If not and you can't get it done this year you might want to consider waiting with your submission for LEED preliminary construction review so you will have the green roof finished in time for the final construction review. The reasoning is that you are going to install the green roof but if you have to provide proof of it with pictures during the review than you will have to have it actually in place. I hope that helps. Good luck with the project.
Can a vegetated wall be as an area inSSc7.2?
Can a vegetated wall be as an area inSSc7.2 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. Particularly in urban areas, other sources may include vehicle exhaust, air-conditioners, and street equipment; reduced airflow from tall buildings and narrow streets exacerbates the effect.-Roof? . Actually green wall can be count in SSc5.2.
If it is possible, please let me know how to calculate it.
Even though this approach might be helping your project, I don't think you can use it for credit compliance for SS 7.2. You might be able to achieve an innovation and design credit.
In regards to SS 5.1 and SS 5.2 you might want to post the question under those credits. But I also found two CIRs ID Number 5310 and 5385. Both do not allow you to count the vegetated wall for these credits.
Asphalt Shingles and Aged Solar Reflectance
Has anyone ever used the aged or 3 - year solar reflectance value instead of the the initial reflectance? The shingle we are considering for a job does not meet the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. value of 29 initially, but does after 3 years. Other shingles start with an SRI of 29 and get lower after three years. It seems it would make more sense to use the three-year value than the initial value, but the question still stands whether a shingle has to be compliant on day one and at day 1096. Any thoughts?
Sonrisa, for LEED-NC the general practice is to use the new values. I am not sure why this is so, especially when EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. uses aged values and all new buildings become existing buildings very soon.
I think you could try to get this approved, and the logic makes sense, but it may be turned down, since LEED does aim to use the same measuring stick for all projects, even if that measuring stick is sometimes a little funky.
glass entry canopy
do I need to factor in a glass entry canopy into the calculation? I wouldn't think so since skylights are not included and it would be a comparable material.
The canopy is either covering a non-conditioned space or open to the outside anyway, I suppose? If so you would exclude it in any case. If the glass roof is covering a conditioned space than you would count it as skylight and exclude it that way. In any case you will be fine.
Compliance of Clay tiles
We are working on a Hotel project in SriThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. Lanka and planning to obtain LEED certification for the facility. Hotel is to be constructed as chalets and the project team has decided to use red color clay tiles for roofing.
The roof is a high sloped roof and the use of a roofing material with a SRI of 29 or above would meet credit requirements.
is it allowable to use the reference SRI value mentioned in the LEED guideline for Red Clay tiles as there is no testing facility available in the country to certify the SRI value of the product?
Hopefully someone can provide for you a more definitive answer for you, but I would say that since you cannot test the material, you should make the attempt to submit the credit using the "Table 1. SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. for Typical Roofing Materials."
Please note that in the Reference Guide just above Table 1, it specifically states: "These values are for reference only, not for use as substitutes for actual manufacturer's data." However, you could note a "special circumstance" due to the fact that this is a project outside the United States, the manufacturer has not tested the material, and testing facilities are not available locally. I am assuming that the clay roofing material is manufactured in Sri Lanka?
As a last resort, you could send a clay tile to a testing facility in another country (China?) or the U.S. Of course, there will be a cost involved, but you might want to get a cost estimate before ruling out this option.
The credit requirements are very clear on the requirements for the credit. You will need the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. by the manufacturer or tested by another facility. I know from my own experience that the SRI is usually not available outside North America, which makes it hard for international projects. But considering the circumstances you might be able to use your compliance approach, but this is something you will have to submit as an CIR.
While I agree that submitting 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 is your second best option (the first best option being sending out the tile for testing), you may find the testing is cost competitive with submitting a CIR ($500.00). The alternative is to go ahead and submit your "alternative compliance" or "special circumstance" to the GBCI reviewers with your first submittal for review and see what kind of response you get. If they don't buy it after the first review, your only option will be testing anyway. It's a judgment call.
Shading from trees planted on roof
We are designing a building with a "garden lounge" on the roof. The roof will have 3 large canopy trees that will shade a significant portion of the roof. The project is in South Florida so the trees will hold their leaves year round and provide shade year round. Can we count this shaded area, similar to the way we count shade in non-roof, for credit compliance? It appears we are meeting the intent of the credit and will be reducing the heat island from the roof surface.
I think you'll have a problem with the reviewers because the trees can't be considered permanent so I don't think you can count in as shade.
Susan,
Thanks for your answer and I can see the logic side of that argument but couldn't the same be true for non-roof heat island where you are encouraged to use trees for shading. These wil be large canopy trees with 6' of planting medium.
Judging by the intent for the credit you can argue as Robert did. But the difference of roof vs. non-roof is that a roof above conditioned spaces certainly needs more attention to reduce heat gain since this directly impact your cooling demand in the building. That being said I can see that there needs to be more stringent and permanent measures to reduce heat-island effect on a roof.
Also looking through the 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's on those credits, I think that you probably will have a hard time to argue just with shading by trees.
Roof - Vertical surfaces
Hello,
Must the vertical surfaces of a roof also comply with the credit requirements? We have some enclosed storage rooms located on the roof and I was wondering if the walls of these rooms should also comply with the SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. threshold of 29 ?
Thanks,
George, you should not include those surfaces—basically just everything you would see from a bird's eye view.
Transportation Canopies
We have a project where caopies at an intermodal station are considered a roof system by code yet are not attached to the facility and do not fall under the LEED definition of a roof. Moving forward, we will be using the canopies as non-roof architectural structures in our calculations. Will this discrepancy be an issue during review?
Aliesa, I think this approach is consistent with LEED, and there should not be an issue with any discrepancy from code definitions.
wooden deck
Hi, my question concern wooden deck on the roof.
Does it need any SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. value? In general wood does not emite any heat so what will be an advantage it I paint it white or not?
Does white painted wood is enought for SRI value > 78?
Thanks
Radoslaw, you would need to include the wood 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.. All materials that are warmer than absolute zero emit heat—wood is no different and needs to be included here. My guess is that painting it white will help, but you would need to use a wood product or a paint with a known SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. value to qualify the area for the credit.
Hi guys,
Anyone knows any wood product with a known SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100.? I've been searching for a long time, but I have failed to find anything related to Wood!
Thanks..
Water mirrors on a roof.
Hello.
I'm working on a project for an underground museum.
The project has a lot 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. covered by water mirrors, not transparent. Those mirrors are accesible for public and are the main reception of the building at ground level.
In the calculations for the Credit SSc7.2, this aspect is not considered by the credit. I think is a good strategy for cool roofs, but it's not mentioned. Should I take the mirrors area out from the Total Roof Area to make the calculations, or I must include the mirror area in the Total.
As you can see from other discussion on this page, water in the non-roof credit is excluded, and that logic may apply here as well.
Can you be more specific about your "water mirror"? Are there mirrors below the surface of the water?
The intent of the credit is basically to reflect light back to the sky and not absorb it into surfaces that then re-radiate it back out as heat that warms up the surrounding environment. If you can make a sound technical argument for this, then I would hope that it won't be a problem for you, but I don't know for sure.
What we heve in the roof is a water corpse of 40 cm height, with some slow reposition of water, so some water is falling in the edges. The container of this water is usually a black paint, so the water produce a good reflexion of the sky, so it's called mirror. It's not white the container, but I understand that the presence of such quantity of water acts as an insulation outside the water-proofing system, so heat doesn't get in the building even if the container is dark.
What's your opinion about this approach?
Firstable, I relly like this idea because later on you can even use this water in non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. installation inside the building.
Just in theretical point of view water as non solid "materia" can evaporate and than you will stay just with black container. So, the question is if there is any system of filling the water mirror "pond" or the container is just rainwater collctor?
I don't know about the water's insulation value but I don't think it matters. This credit is about how the water affects the site, not the building.
Doing some web searching I found some sites saying that snow reflects 90% of the sun while open water reflects only 6%. Shallow water may be less but not with the black bottom. I've got a feeling this water feature is doing the opposite of what this credit is intending. Just my opinion.
Calculating a Dome
We have a roof that consists of a flat roof with a dome.
How do we calculate the dome area since some of the surface area is actually the "sides" of the dome. How much of the dome is considered "roof"? Do we look at it in plan view and use that SF or do we need to calculate the entire surface of the dome?
With a sloped roof you would count the actual 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., not just what you see in the plan view. So I would say a dome should also be treated this way. I'm sure there's a quick way to get a reasonable calculation.
Are security guard roof and open shed roof counted?
Hi all,
Are roof of security guard house and roof of an open space (say, smoking space) counted as part of roof?
This affect 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., then determine what is the 50% roof area. I plan to go for 50% green roof.
Thanks and cheers!
Eric, I would answer these questions based on USGBC's Minimum Program Requirements supplementary guidance, page 19. The guard house should probably be included, but not the smoking pavilion.
Hi Tristan,
Thank you for the reply.
How about entrance canopy? shall it be counted as part of roof as well?
We want to aim one point under innovation by providing 100% green roof. Actually majority (about 80%) of the roof of main building is full of Air Con equipments. The rest of roof areas are green roof. I understand we can exclude M&E space from total roof area. however the walkway beside Air Con equipments (walkway is required for maintenance) cannot be planted. Can we exclude the M&E space walkway from total roof area as well?
Thanks and cheers!
can pavers around the green roof be counted as vegetated area?
Our project has green roof around 28,000sqf on the total 68,000 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. , and 2 row of 2'x2' pavers area (9074sqf )at the roof perimeter. Can we count the perimeter pavers as part of Vegetated roof?
We tried to use option 3 by counting the pavers ( higher than SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. 78) as a combination with the vegetated roof, however, the area of meeting SRI/ 0.75 + vegetated roof/0.5 is less than the total roof area. So the only hope we can get this SS7.2 LEED point is to count the perimeter paver area as part of vegetated roof area.
Please help. Thanks
First, check your form. I had a wonky form that would not calculate Option 3 accurately. In my case I knew the roof complied so it was obvious that the form was an issue. Otherwise, I would say no. Pavers are not plants. Have you excluded any mechanical equipment from 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.? What about reducing one row of pavers and adding more plants? Conversely, add another row of pavers over the other roof material. Verify the form and use it to help you solve your calculations.
By my math you are almost at 68,900 and should be ok with option 3. I always exclude pavers from green roof calculations and count them as reflective roof.
Susan, thanks for your response. Yes, I did deduct the mech. equipments, and I even deducted the parapets ( I assume it is belong to "appurtanence" ? ). You are right, single row of pavers shall be better, but I also calculated the number by using single row of pavers, we are still 1500sqf short for option 3. Also, I checked the form/ numbers for several times, and I will recheck it again if needed, but no way we can round of almost 2000sqf as required.
My question is for the vegetated roof, we need pavers to around them for maintainess purpose, and the pavers are working for green roof. If so, why can not be counted as " vegetated area" ?
Also, shall the canopy roof with a vestibule underneath be counted in 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.?
Thanks Michelle, I found I typed numbers wrong after I posted.
The total green roof shall be 26,892, so 26,892/0.5+ 9074/ 0.75=65,882< total 68,683.
Areas between PV panels and mech equipment
I see that there are rulings about not including 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. which is covered in PV or mechanical equipment.
Q: does this go as far as determining that the space between panels ( allowing for reasonableness here) or chillers in an external plant enclosure should be included in the roof area or is it sufficient that a PV array area or external plant enclosure should be excluded ?
I would probably exclude the area in question. However, you've entered into a gray area where there is some judgement (relying on reasonableness, as you say). I would try to anticipate how a reviewer would see it.
Cool Roof Resource
In searching for SRIThe solar reflectance index (SRI) is a measure of a material's ability to reject solar heat, as shown by a small temperature rise. Standard black (reflectance 0.05, emittance 0.90) is 0 and standard white (reflectance 0.80, emittance 0.90) is 100. For example, a standard black surface has a temperature rise of 90_F (50_C) in full sun, and a standard white surface has a temperature rise of 14.6_F (8.1_C). Once the maximum temperature rise of a given material has been computed, the SRI can be calculated by interpolating between the values for white and black. Materials with the highest SRI values are the coolest choices for paving. Because of the way SRI is defined, particularly hot materials can even take slightly negative values, and particularly cool materials can even exceed 100. values of materials I came across the Cool Roof Rating Council's website, http://coolroofs.org/. There's a page where you can plug in the type, color, SRI, emittance, values and it will pull a variety of products and manufactures who meet this criteria. Hopefully its helpful to you all as well.
Thanks, Garrett. I added it to the Resources that we list above.
Heat Island Effect - Roof area
To address the intent of 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. Particularly in urban areas, other sources may include vehicle exhaust, air-conditioners, and street equipment; reduced airflow from tall buildings and narrow streets exacerbates the effect. - roof credit, I should include all roofs of utility buildings also where only equipments are there?or only the roof of occupied space buildings should be included?
This depends on how you are counting them relative to MPR #3 and your LEED boundary. See page 19 of the MPR supplemental guidance document to understand what I"m referring to.
Thank you for prompt response. I understood that 2 such buildings shall be included in LEED boundary and shall be excluded from roof credit compliance. Please clarify whether my understanding is right?
I agree with your understanding, as long as the small buildings are meeting the requirements listed on that same page.
Sedum plants vs. native plants and irrigation
If pursuing this credit only, not 5.1 or 5.2, does the vegetation for a green roof need to be native/adaptive. We would like to use an extensive or ultra extensive roof with sedums and grasses, which will eliminate the need for permanent irrigation, but are concerned that these will not be compliant.
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