The Heat Island effect occurs when warm temperatures are experienced in urban areas compared to adjacent rural areas because of solar energy retention on constructed surfaces. Basically, all of that black asphalt and concrete on the ground makes areas a lot warmer. This credit reduces this effect.
This credit also mentions the Solar Reflectance Index (SRI). It’s a way to measure a materials ability to reject solar heat. It ranged from 0 (black) to 100 (white). This is not to be confused with emissivity, which is the ratio of the radiation emitted by a surface to the radiation emitted by a black body at the same temperature.
Non-roof
Intention:
- Reduce heat islands
- Minimize impact on microclimate and habitats
Implementation:
- option 1:
- provide shade to 50% of site area (within 5 years of occupancy)
- provide open grid area (parking, roads, sidewalks) with paving material of SRI 29 or higher.
- option 2:
- provide 50% parking underground or under roof
- provide paving material with SRI 29 or higher.
- provide 50% parking underground or under roof
Codes/Standards Applied:
- ASTM
Extra Credit:
- option 1: provide 100% (instead of 50%) of site shade for 5 year occupany
- option 2: provive 100% (instead of 50%) of parking underground or under roof
Submittal Phase:
- construction
Links from Reference Guide:
Other Sustainable Sites Credits
- SS P1 – Construction Activity Pollution Prevention (prerequisite)
- SS 1 – Site Selection
- SS 2 – Development Density & Community Connectivity
- SS 3 – Brownfield Redevelopment
- SS 4.1 – Alternative Transportation – Public Transportation Access
- SS 4.2 – Alternative Transportation -Bicycle Storage & Changing Rooms
- SS 4.3 – Alternative Transportation – Low Emission & Fuel Efficient Vehicles
- SS 4.4 – Alternative Transportation – Parking Capacity
- SS 5.1 – Site Development – Protect or Restore Habitat
- SS 5.2 – Site Development – Maximize Open Space
- SS 6.1 – Stormwater Design – Quantity Control
- SS 6.2 – Stormwater Design – Quality Control
- SS 7.1 – Heat Island Effect – Non-Roof
- SS 7.2 – Heat Island Effect – Roof
- SS 8 – Light Pollution Reduction
43 Comments On This Post
Shade is calculated at different times of the day at a particular time of the year, at a certain height. I forget the nos., but it was something like Summer Solstise at 10am,12am,2pm, and 4pm. Please confirm. Thanks!
if still useful,
it’s 10am, noon, and 3pm
and they FAIL to say what time of year..maybe it will be in the errata..
Landscape Architecture practices have the specific calc for shade and shadow casting for different times of the year.(but not in Ref guide)
my fine tooth comb day! Test is coming up this week
Valeria, good luck on your exam. I’m glad you’re getting involved with the posts here. You’re doing an awesome job and I know you’ll perform excellently on your exam. Keep up the good work and let us know how you do!
p.s. I’ll hopefully answer your SS6.X questions later tonight =)
Shade coverage is calced at 10, 12, and 3 on the summer solstice.
Pat and mikedee,
Thanks Pat, for your encouragement! Your website is a stroke of genius!
it’s the Uber study group! Are you aiming on working on a LEED Project?
Grazie mikedee, Summer Solstice makes perfect sense. where was that little nugget mentioned!
Same spot as the times. Are you using the 3rd edition? I cut and pasted that right from the text.
no,I have the first edition in print so I will add in..
When are you planning to test?
I test today-you have been very helpful,
Thank you!
Hi, I am barely starting to study for the NC AP, and I don’t understad what they mean by 50% shade within 5 years of ocupancy. Does this mean that the shading materials should last for 5 years? or I might be over thinking this but, does it mean that if you use trees for shade, you expect the tree to grow into providing 50% shade at a 5 year period???
Hello Mario,
You are not over thinking, it is correct when you say the trees must shade 50% in a 5 year period.
(The usual in Landscape Architecture is to design for 10 yrs maturity)
Good luck with your studying, This web site really helped me.
Under Option 1: Do your open grid pavements need to have a SRI of 29?
It appears that they don’t based on the calculation which states that each surface should only be counted once, but I want to make sure!!
Has anyone ever questioned the validity of
this credit? How can planting a few trees in front of a 100-storey skyscraper reduce the Urban Heat Island Effect? I would make sense if the trees shaded the top of the building, but we rarely see this in urban settings.
It would make sense for this credit to focus on heat reflective exterior wall coatings with a minimal SR 60 and a TE of 85.
Most buildings within inner cites are tall with small roofs but lots of side walls. A cool roof would shade the top 3-4 floors and cool wall coatings would shade everything else.
This is anecdotal, but when I have used trees in my landscape design, at least in proximity of the building, whether they actually shade the whole roof area or none of it, they create a microclimate under them that definitely lowers the heat island effect..
In San Francisco, the Transamerica bldg has a grove of redwoods and folks hang out and have their lunches there. The rest of the neighborhood is concrete and skyscrapers (financial district)
My house is near 3 redwood trees and the temperature gauge always goes down as I drive into my gravel driveway.
Perhaps that is why they don’t specify that they cover x amount of the roof..
Note: This credit is intended to shade hardscapes not the roof or portion of the building.
Also under option 1. All of the options have to be 50% or a combination of the 3 for a total of 50% of the site area.
yes, that is the rule as written in this credit.
We were discussing the wisdom of the credit, not how the credit is written..
some question the rules, I see it as a beneficial ‘reality check’ type discussion.
Some think, I am sure, what for?
Pat,
Option 1 should read like this:
provide the following for 50% of the site hardscape:
Shade within 5 years
Paving materials having SRI values more than 29
Open grid pavement system at least 50% open
Q=S+P+O. Q is the qualifyng area
Q> T/2 (50%) with T being the sum of all non roof hardscape surfaces.
I think you are saying to provide shade only for 50% of the hardscape area.
Thanks
According to the reference guide, shading within five years, SRI 29+ paving materials, and open grid pavement can all be combined to handle 50% of the hardscape area – not 50% of the site area. Which makes more sense, if you think about it.
Sustainable Sites 7.1 – Heat Island Effect – Non Roof
should Submittal phase for this credit be design phase instead of construction? since the decisions for placing parking under cover should be made during design phase.
You need to look at it from GBC’s perspective. Something can be changed during construction to deny the credit. It doesn’t make that much sense since you can do all the WE credits in design, but that is the way they wrote it.
But if you look in the Reference Guide, it is completed in the design phase. Of course none of the credits are granted until after construction.
Hi Sara,
I think you are right about combining those three to make 50% of hardscape. Same for the exemplary performance. The combination is to be 100% of the hardscape.
Question on parking. If you reduce the parking by stacking it, do you count the footprint of the parking that is covered by other parking? ie- 50% is covered since it is under parking- on the other hand, the other 50% which is not covered could be a large portion of the site area, leaving a big heat island. And then if you cover the parking deck which is on top, does that portion of the site area count twice?
Question on Technologies
On the gray 7.1 page with requirements and stretegies they mention vegetated roofs as a strategy for this credit. How can this be, if this is the NON-roof section. Does this credit count as one that should take green roofs into account?
pretest exam question
Which methods will not reduce the heat island effect for SS Credit 7.1?
A
Planting small shrubs
B
High emissivity, high reflectance materials
C
Shading
D
Open grid paving
Answer is A. I understand why small shrubs do not qualify because that is clearly stated in the REF guide, my question is why B isn’t wrong too.
Isnt High emissivity (value closer to 1) what we want to avoid? I thought it was low emissivity and a high reflectance that creates high(er) albedo surfaces.
Granted most surfaces are in the .9 range but you do have some with less like aluminum.
How is the contractor the responsible party for credit SS 7.1: Heat Island Effect, Non Roof?
Parker,
High emmissivity= high SRI which is the intent of the credit
This may be a silly question but:
If you place 50% of your parking under your building, does that mean that your roof needs to be and SIR of 29 for Option 2.
~Amy
Amy
you are correct.
I am trying to understand what is a open grid pavement
If you want to reduce the heat island effect- and you do so by eliminating hardscape altogether and replacing it with fully permeable landscape rather than semi-permeable paving- do you lose the chance of obtaining this credit?
Here in the middle east all products come with UV value not SRI. Does anyone know how to convert UV to SRI?
Does anyone have a good definition of emissivity vs. albedo vs. reflectance so that any idiot (i.e., me) can understand? Thanks in advance.
I’m taking the test on Thursday.
“provide paving material with SRI 29 or higher” in option 2 refers to the roof of the parking, they are not talking about the floor.
somebody can answer jessie on the green roof issue, I do not understand that either.
thanks
High emmissivity= high SRI which is the intent of the credit
Is right, it is on Approach and Implementation on page 99 of credit 7.2
thanks
I am really confused with LEED mumbo jumbo. Sometimes you get “extra credit” for going the extra step (example: 100% shading in SS c7.1), other times you get “exemplary performance” point for doing similar thing (example SS c7.2) and in other cases you get ID credit for doing the same thing. There seems to be no freaking rhyme or reason. My fifth grader can come up with a more logical system.
Another thing, shading percentage is not really base on site area (50% of site area requirement). If you look at the credit template it is actually 50% of “site hardscape area”, big difference.
Can anyone recommend reliable links listing SRI values for a variety of hard landscape surfaces? I am looking for deteriorated granite and varying gravels. -THX
does any one know if I had to submit documents from the manufacter or lab to prove the SRI value?
of course for USGBC
Hello Azoz and Jobe,
I am a landscape designer and am LEED AP (2007) so my information may have changed, but as far as submitting documentation on any materials to the USGBC, you should collect any verification for any credit.The reason is in the audit, they will choose which credits to ask the required paperwork. In other words, you need to collect all the paperwork as if they would have you submit it all, they choose which ones you need to actually submit.
It is always handy to take a look at the templates on the website as well.
The hardscape issue,Jobe, I haven’t found a gravel company that has tested the SRI value, you might.. but roofing materials are, I might guess those materials matching the colors of the roof would have a similar SRI.
I would be interested if someone does know differently and found a company who has tested decomposed granite for reflectance.
if we take option of using open grid pavement for SS 7.1 of 95% of parking area then there posiibility to get innovation credit for the same.
Valeria, Azoz and Jobe
Our company had test performed on a number of exposed aggregate concrete samples with different aggregates so we could decide which aggregates were appropriate. We had samples made and sent to a lab for an ASTM C 1549 report. YOu could do the same for decomposed granite. Whatever the result you would want the contractor to do the same test to make sure the material performs as specified. This is something you would want written into the spec.
BTW does anyone know if “standard” cast in place concrete needs to have an SRI test performed or is reference to the 7.1 table sufficient? There are a lot of variations in concrete color an texture.
Does anyone know if a Photovoltaic Shade Structure Meets the requirements for cover under Option 2? On credit 7.2 PV is basically expmpted along with equipment but for non-roof I don’t know if LEED would accept this in lieu of SRI 29.