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Credit language straight from USGBC
Need to check up on the exact LEED credit language from the LEED Rating System on the fly? LEEDuser includes the verbatim language. Members get:
- Easy access to the official LEED credit language with just a couple of clicks.
- On the jobsite without your bulky LEED Reference Guide? Check up on the credit language details here.
- Credit language content is used by permission of the U.S. Green Building Council.
26 Comments
2-Year, 24 Hour Storm Data
I have found that storm data is not widely available or accessible - Has anyone found a good source?
Jenny Carney replied Director, YRG sustainability Jul 31 2009
The best resource we've found is NOAA's Hydrometeorological Design Studies Center Precipitation Frequency Data Server: http://hdsc.nws.noaa.gov/hdsc/pfds/
For some states, the site allows you to navigate to a specific locale and generates a table of rainfall intensities, including for the 2-year 24-hour design storm. For the other states, it lets you download isopluvial maps. We'll post more info soon about how to use the tool / read the maps, but either way this resource has the data you need for any US-based project.
Steve Offutt replied Jul 29 2010
The data for Washington DC may be found here:
http://ddoe.dc.gov/ddoe/lib/ddoe/stormwaterdi/2009.05.07_SWM_Appendix_A.pdf
15% Runoff determination
I want to be clear on the definition of the 15% reduction of runoff. Does this mean a 15% reduction in runoff assuming the entire property is hardscape and then you create areas or schemes to reduce runoff by 15%?
Thank you for any information.
Mark
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Mar 08 2010
Mark, you have the right general idea. To quote the credit language (shown above):
Implement a stormwater management plan that infiltrates, collects and reuses runoff or evapotranspirates runoff from at least 15% of the precipitation falling on the whole project site both for an average weather year and for the 2-year, 24-hour design stormA 2-year, 24-hour design storm is a nationally accepted rate that represents the largest amount of rainfall expected over a 24-hour period during a 2-year interval. The rate is the basis for planning and designing stormwater management facilities and features..
Rain fall event interval
In the calculation section of the guide it says that we need to have the rainfall event interval to calculate the minimum drawdown rate.To what is this event interval refers to? is it the maximum gap within a year or a average gap interval within a year which can be determined by the rainfall data.(we have annual rainfall data).
Further i am unclear of the fact that we need to have the system to address 15% of both AVERAGE YEAR and 2-YEAR,24-HOUR DESIGN STORM..
how to we cater to both of that requirements at once??
please post your ideas..
Jenny Carney replied Director, YRG sustainability Mar 25 2010
Hi Rashid,
The rainfall event interval only comes into play if you are collecting rainwater in a cistern or other detention facility as part of your stormwater management strategy. If that is the case, you basically need to know the interval between rainfalls so you can figure out if you empty your cistern before the next rains come. If you aren't collecting rainwater, you don't need to worry about this particular aspect of the calculations.
Regarding the average year vs. the 2-year, 24-hour design stormA 2-year, 24-hour design storm is a nationally accepted rate that represents the largest amount of rainfall expected over a 24-hour period during a 2-year interval. The rate is the basis for planning and designing stormwater management facilities and features., in most cases it's appropriate to focus on showing compliance during the 2-year, 24-hour storm, with the idea being that if you can handle that volume on water you'll also be able to deal with the volume of rain that falls during the average year.
Hope this helps.
RASHID HAMEEN replied Mar 26 2010
Thanks Jenny, as you have mentioned it seems like it will be better for us to comply with the 2 year 24 design storm in setting up our rainfall collecting system..
Where Can I Find the Calculator?
Hi - You say the LEED Online credit form contains a built-in calculator that uses runoff coefficients of different surface types to determine infiltration volumes. I am having such trouble finding calculators on LeedOnline. When I load the forms there are no calculators - Just Beta forms. Would appreciate some help finding it...Thanks!
Jenny Carney replied Director, YRG sustainability Mar 31 2010
Dianne, the v2009 forms offer a bit of a goose chase, in that you can't see certain things until you click through the associated options on the form. When you are at the SSc6 form page in LEED Online, click on "LEED EB:OM Compliance Path", then "Full Documentation Path", then "Stormwater Calculator".
With any luck, the calculator will magically appear after you do this!
Dianne Herrin replied Mar 31 2010
Thank you, thank you, thank you!!
3 Questions
Three questions (Sorry about that last inadvertent post!):
1-The corporate campus on which my building sits has an NPDESThe National Pollutant Discharge Elimination System (NPDES) is a permit program that controls water pollution by regulating point sources that discharge pollutants into waters of the United States. Industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. demonstrating that the infiltration is =/> that of the pre-development site. Can we use this to qualify for SSC6 or do we still need to do the stormwater calcs?
2-The building is just one of a multi-building campus that shares impervious and pervious spaces, so whether we can use the NPDES or whether we need to do our own stormwater calcs according to the LEED SSC6 form, we will need to submit for the whole campus -- even though we're seeking certification of just one building. Is this acceptable or would this approach require 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?
3-How exactly can I use the Licensed Professional Exemption in this particular case? I have a stormwater specialist who is a P.E. What's the benefit of this exemption and what's required of him - besides his completing the LPE form?
Thanks much!!
Jenny Carney replied Director, YRG sustainability Apr 09 2010
Dianne,
Some responses:
1. I've seen previously conducted stormwater studies work to document this credit. It kind of depends on what information is included in the report, and whether it can be translated into showing management of at least 15% of the 2-yr, 24-hr volume.
2. In my experience, showing compliance on a campus-wide basis shouldn't be a problem. I'd recommend just making it really clear what the boundary is for the campus included in the stormwater analysis, and that the LEED project boundary falls completely within the larger campus boundary.
3. The form from LEED Online will show you exactly what documentation aspects you do not have to provide if you do an LPE exemption. In generally, the LPE exemption requires that you complete the associated form, and then you get a pass on providing a subset of the usual documentation. Which documentation is excused varies by credit, and the form will show this.
Calculations without LEED Online
My project is not yet registered, so I do not have access to any of the templates or calculators built into LEED Online. I think I have most of the inputs required for this credit, but its impossible to tell from the Reference Guide how the calculation works exactly. Can anyone help me?
Jenny Carney replied Director, YRG sustainability Apr 23 2010
Jordan,
You might try accessing the sample EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. v2008 forms here to learn more about how the calculations work: http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1447
The calculations shouldn't have changed between the 2008 and 2009 versions, though personally I've had trouble with the calcs in the v2009 form working properly. I'm trying to get in touch with GBCI about the issue to see when an updated version of the v2009 form will be released.
Ultimately, you'll need to rely on the calculations embedded within the v2009 forms, so you might want to prioritize getting registered so you can access the right tools.
Form Woes
I'm not sure if people have run into some funny numbers when trying to calculate the percent mitigation for their projects, but we have reason to believe the v2009 form with the embedded calculator has some functionality problems.
A fixed up form should be available soon, I'm told.
John Beeson replied Chief Mystic in Resident, betterENVIRONMENT, LLC May 28 2010
Any updates to this? I'm back checking the mitigation percentages and it is close, but not seemingly exact.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 02 2010
I love your new job title, John. What's that about?
According to LEED Online's list of form updates, EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. SSc6 hasn't been updated. So this problem is probably persisting.
Jordan Friedberg replied Jul 08 2010
Is there a way to include more than one surface type? My site has a mixture of pavement and grass, but I only see a spot for one surface type in the form.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 12 2010
Jordan, just click "Add Row" to get more rows to show up, where you can enter more surface types.
System from LEED NC v2 but no points awarded. O&M Option?
Dear Users,
After researching this credit for my building, it seems when the building was first constructed it was designed to take advantage of storm water quantity control, pervious services and the green roof but for some reason during the original LEED NC Certification it did not receive the points for storm water management. I think this was a documentation issue but when I looked on the USGBC web site under case studies this is posted under my building's landscape.
The landscape design includes climate-adaptive perennials, groundcovers, flowering shrubs, and trees in mulch beds; a highly efficient irrigation system; and an underground rainwater cistern. This system captures water from 100% of the impervious roof areas of the building for an estimated 47,966 gallons in the peak watering month of July, providing nearly 60% of the July demand. In July, the net 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. demand is reduced to 35,221 gallons compared with the baseline turfgrass case of 176,120 gallons—an 81% reduction during peak periods. Since 95% of the parking is provided in structured parking below the building, the only non-captured stormwater generated by the site is that falling on the impervious driveway and sidewalk areas.
With all this said, what do i have to do to receive this credit? Do I still need to re run all of the calculations and create a storm water management plan?
Thank you again for your help,
Kash
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jun 10 2010
In short, you do need to run EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems.-specific calculations to earn this credit. I am not an expert on this credit so I can't comment on your chances of earning it, but it does sound like you have a good chance.
Simultaneous Exemplary Performance and Regional Priority?
Hi - We qualify for an 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. point here (>30% mitigation). This is also a Regional Priority credit in our area. Does this mean we can get both; i.e., 2 extra points (3 points total) for meeting and exceeding SSC6? I am not sure if we are permitted to claim both EP and RP for the same credit? Thanks.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jun 10 2010
I don't see why not. They are really being awarded for separate reasons, and RPc1 is tied to earning the normal threshold, while IDc1 is tied to the exemplary threshold.
I believe these are calculated automaticaly through LEED Online, so you can input the credit documentation and see how it goes—let us know!
Inspections
The form wants me to upload documentation of the most recent inspection. My site has no stormwater management facilities - its just a flat site with grass. Do I just need to (annually?) confirm that there have been no changes?
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 12 2010
A flat site with grass is a stormwater management facility that according to the credit requirements does need inspection. It could be a pretty simple inspection.
If there were some massive deluge that eroded the grass and led to increased runoff to a local waterway, etc., you would want to be on top of that—so the inspection is that all that frivolous.
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