Tuesday, November 30, 2010

SSc7.2: Exclusions for calculations

Question: What is included and excluded from roof calculations for SSc7.2, Heat Island Effect, Roof?

Short Answer:
    Excluded:
       - equipment
       - solar energy panels
       - appurtenances
       - parapets
       - skylights
       - parking below grade
       - upper deck of parking garage building
       - podium deck – unconditioned spaces

    Included:
       - podium deck – conditioned spaces*
       - roof canopy
       - terraces

* “the deck could be considered as a roof” (see below for more detailed information).



Long Answer:
The following is a list based on information found in the CIRs that can be applied to LEED rating systems before LEED 2009 and in a lesser degree to rating systems LEED 2009 and beyond.
Exclusions: The following areas may be deducted from the calculations.
- equipment (1)
- solar energy panels (1)
- appurtenances (1)
- parapets (2)
- skylights (2)

Parking Below Grade:
The portion of parking garage not under a building is considered non-roof area. It cannot be counted in the calculations for SSc7.2. The vegetated area can be counted towards open space for SSc5.2. (3)

Parking Structure:
“The upper deck of a parking garage is considered a non-roof impervious surface” for a project with a parking structure adjacent to the office building. (4)

Podium Roof:
The podium deck, which covers on-grade parking, cannot be considered a roof area for purposes of this credit. The top deck of an above-grade parking structure is considered non-roof impervious area. If the podium deck covered conditioned space, then the deck could be considered as a roof (for portions not being used for parking). (5)

Roof Canopy:
A free-standing roof canopy which stands over mechanical equipment, connected to the building envelope only at column bases is “effectively part of the roofing systems as it relates to reflectivity and should be included in calculations for this credit.”(6)

Terraces:
If the terrace space acts as a roof, then the area must be included in SSc7.2 calculations.(7)

Neighboring Buildings:
Neighboring buildings that shade the site cannot be counted. “There is no way to ensure that the surrounding and shading buildings will remain in place for the life of the roofing product that is installed.”(8)


(1)  LEED-CS Version 2.0 Reference Guide, pg.107
(2)  LEED-NC v2.1 SSc7.2 CIR Ruling 6/7/2004
(3)  LEED-NC v2.1 SSc7.2 CIR Ruling 5/10/2005
(4)  LEED-NC v2.1 SSc7.2 CIR Ruling 9/24/2001
(5)  LEED-NC v2.2 SSc7.2 CIR Ruling 9/5/2008
(6)  LEED-NC v2.1 SSc7.2 CIR Ruling 9/20/2004
(7)  LEED-NC v2.1 SSc7.2 CIR Ruling 3/11/2003
(8) LEED-NC v2.1 SSc7.2 CIR Ruling 5/24/2004

SSc7.1: Parking on roofs

Question:  Does a multi-level parking structure with parking on the top level, need to have a roof that meets the SRI requirements of 29 or greater?

Short Answer:  No, as long as exposed parking is less than 50 percent of the total parking surface area.

Long Answer:
SSc7.1, Heat Island Effect, Non-Roof, Option 2:
Requires placing “a minimum of 50% of parking spaces under cover (defined as underground, under deck, under roof, or under a building). Any roof used to shade or cover parking must have an SRI of at least 29.” (1)

Originally for a project that “has a multi-level parking structure that will contain parking on the top level… the top level is considered to be both a parking area and a roof cover and needs to have a minimum SRI of at least 29.” (2)  However, this has been overturned as of 5/6/2009. The current accepted approach is as follows:

“Roofs used to shade or cover surface parking in order to meet the Option 2 requirement, must have an SRI of at least 29. However, an SRI requirement does not exist for parking placed underground, under deck, or under a building, so long as the exposed parking surface area, if any, is less than or equal to 50 percent of the total parking surface area.”(3)


(1) LEED-CS Version 2.0 Reference Guide, pg.99
(2) LEED-NC v2.2 SSc7.1 CIR Ruling 5/23/2008
(3) LEED-NC v2.2 SSc7.1 CIR Ruling 2/14/2008, overturned 9/3/2008

Purpose

What's LEED Corner?  I'm sure it will change and evolve over time and I hope it does.  But for right now, it's a place for me to park, in one place, information and approaches to sustainable design. 

There is a lot of information out there.  There are a lot of great forums and websites that have pieces of information.  My great dream would be to have a place that brings all this information together.  I haven't found that place yet so in the meantime, I've decided to set up and share the information I gather into this little corner of the web.

Before I begin, I need to set the record straight on two things.  First, myself. I have experience in the sustainable building industry but the more I work on projects and explore new areas the more I realize there is so much to learn.  Roughly translated - take everything you read, here and elsewhere, with a grain of salt, and please feel free to correct/add to anything I post.  I look forward to expanding my knowledge through items shared.

Second thing to address: what this site focuses on.  One way to boil the issue of sustainable buildings down to the simplest terms, is to realize they fall into two categories:
1. The design and implementation of sustainable measures (for new or existing buildings) and
2. The metric used to measure the magnitude of the measure (i.e. LEED).

The posts mainly focuses on providing resources for the second item for the simple reason that the majority of our time should be spent on focusing on the first item - designing sustainable buildings. I don't want to spend gobs of time searching for a sample of a thermal comfort plan.  I want to spend that time working with the owner figuring out what the best fit is and how they can use this resource as a tool most effectively.  Partly through looking at sample plans done by others.
There is a third thing I should clear up at the start.  LEED.  Yes, I think there's lots of improvement that can be made in both the rating system and the administration by the USGBC/GBCI.  Yes, I think there is a lot more out there beyond LEED.  And yes, I find myself continually reminding team members that LEED is a metric, not a code.  We should be designing a sustainable building first and foremost, not building to LEED.  That being said, I do support LEED for many projects.  I have seen time and time again projects that ended up pushing the envelope (no pun intended) further then they normally would have simply for a LEED point.  Sometimes that carrot is needed.

That pretty much sums it up and I look forward to using and sharing this new knowledge management tool.