Forum discussion

NC-v4 SSc5:Heat island reduction

SRI value for concrete

Hi, In LEED v2009 BD+C Sustainable Sites Credit 7.1 there is a table with solar reflectance index for standard paving materials, where the typical new gray concrete is 35. Are these values acceptable for LEED BD+C v4 or is testing necessary? Thanks in advance,

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Thu, 04/16/2015 - 22:02

Changes from the v2009 requirement indicate that the v2009 table wouldn't be sufficient to demonstrate compliance. The v4 requirement is calculated using the three-year aged SRI values for roofing material and the SR values instead of SRI values for non roof hardscape. Note that if the three-year aged value information is not available from the manufacturer, projects can meet the roof requirement with an initial SRI value of 82 for Low-sloped roofs or 39 for Steep-sloped roofs. Your best resource will be the Cool Roof Rating Council standard rated products directory [http://coolroofs.org/] which is listed in the v4 Reference Guide as an acceptable compliance reference if manufacturer information is unavailable. Hope that helps!

Fri, 08/07/2015 - 18:11

Thank you Karen, How are 3 year aged SR values determined for concrete? And can regular concrete be used which has about a .28 SR value roughly if their is a cleaning program established.

Thu, 10/15/2020 - 11:13

Been awhile on this thread but why not...  Is there a source that would be acceptable to provide default SR of concrete to use in the weighted performance option 1?  We live in an area where the concrete supplier is in the dark on LEED and will only be helpful if we help them to help themselves.  So it'd be nice to have a reference to point to rather than pulling teeth or spending a ton of cash on testing.

Thu, 10/15/2020 - 12:19

Check out LI #10411 which gives typical SR values that can be used for standard nonroof materials including typical gray cement concrete and typical white cement concrete. I find using the typical SR value for concrete advantageous in the weighted calculation.

Thu, 10/15/2020 - 14:40

Thank you Summer!  That was quick.  And helpful, though not helpful to achieve the credit as no thought was given to the concrete color but it's good to know we'll need to test if we want any specific results to apply.  Cheers,

Thu, 10/15/2020 - 15:26

HI all, this info is also summarized in the LEEDuser guidance for this credit for easy access.

Fri, 05/14/2021 - 12:43

Hi everyone on this thread! We have grey concrete in our ROOF, so we need SRI value. Are there any standard value as in NON ROOF strategy? Or are manufacturer's cutsheet, searching in Cool Roof site or independant testint the only way out this case?  Thank you for your time!

Sun, 05/16/2021 - 23:08

Hi Victoria, The paths you listed are likely the only options for finding a useable SRI. If this were on my project, I'd contact LEED Coach and see if there's an acceptable way to convert the default SR available to an SRI...we're just missing the emittance value... The only other path mentioned in LI 10411 is if you can find an equivalent product cut sheet/info that has the values you need, and showing that your mix and that product have comparable ingredients.

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