SSc8 vertical grid points

Bill Swanson

Sr. Electrical Engineer

Integrated Design Solutions

LEEDuser Expert

516 thumbs up

February 16, 2012

Some commentors are stating that regarding SSc8, Reviewers are asking for vertical calculation points spaced 5' apart. The Reverence Guide specifically states 10'x10' grid spacing for the site calculations. It's a bit vauge about the vertical calculations.

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Megan Ritchie Saffitz

Director of LEED Support

U.S. Green Building Council

LEEDuser Premium Member

25 thumbs up

Fri, 04/13/2012 - 17:09

Hi Bill - Thanks for bringing this up. Regarding grid spacing: The requirement for a 5 foot x 5 foot calculation grid is specific to a submittal requirement listed in the LEED-Schools 2007 Reference Guide which on Page 114 indicates calculations must be done at a 5 foot grid interval. GBCI is aware of this discrepancy between the Submittal Requirements section (page 114) and Calculations section (page 112) of the LEED-Schools 2007 Reference Guide and we are working to resolve this discrepancy. Meanwhile, please note that according to the LEED Reference Guide for Building Design and Construction, 2009 edition, and the LEED Reference Guide for New Construction v2.2, third edition, the calculation grid spacing should be at a maximum of 10 feet x 10 feet (both for horizontal and vertical illuminance calculations). Regarding vertical illuminance calculations: Often, the vertical illuminance calculations are not requested from project teams as the information provided in a horizontal photometric plan is sufficient to determine light trespass compliance. As a result, the LEED Online SSc8 Form for LEED 2009 only includes exterior photometric site plan(s) as a required upload to demonstrate light trespass compliance. However, the LEED reviewer may request the vertical photometric if for some reason it is not possible to determine compliance based on only the horizontal photometric plan. For example, if there are exterior light poles near the LEED project boundary and the footcandle levels are high near the boundary, the reviewer may request a vertical photometric as additional documentation to ensure compliance is achieved. Please note that the LEED Reference Guide for Building Design and Construction, 2009 edition, requires that the photometric analysis measure both the horizontal and vertical footcandle levels, and as such, the request for a vertical photometric by GBCI reviewers is appropriate. Refer to page 136 in the Reference Guide for additional information. Hope that helps - MRS

Bill Swanson

Sr. Electrical Engineer

Integrated Design Solutions

LEEDuser Expert

516 thumbs up

Fri, 04/13/2012 - 17:44

Hi Megan, Thanks for replying. I hope you can understand the confusion and frustration that can occur when a team works on one project and the Credit is approved and then the next project gets a request for additional documentation that is not listed nor previously required. Vertical calc grids are not simple. Grids are planar while calculation boundaries are often irregular. Each segment of a curved boundary is a separate grid. A project may have 100 vertical grids to cover the whole boundary. And there is zero guidance on what is expected. Or how to display all of these grids so the data is legible. And the pressure to get this correct on the first try since it was requested during the final project review. And for what benefit? The Reviewers don't seem to understand lighting. I've seen approved submittals with the fixtures oriented 180° from how they were obviously installed and because the boundary showed 0.0 fc no questions were asked. I can make any site show 0.0 fc on every vertical grid at the boundary. So why ask for something that the Reviewers can't interpret anyways? It's only adding paperwork for the sake of paperwork.