LEED, or Leadership in Energy & Environmental Design, has been a product of the USGBC (United States Green Building Council) since 1998. Since 1998, LEED has grown and is a valued resource for many buildings across the country. I will provide a series of posts concerning different LEED points/credits in terms of potential improvement areas. The first credit that I would like to highlight is SS (Sustainable Sites) Credit 5.2.From LEED 2009 for New Construction and Major Renovations Rating System:
Credit 5.2: Maximize Open Space
To promote biodiversity by providing a high ratio of open space to development footprint.
CASE 1: Sites with Local Zoning Open Space Requirements
Reduce the development footprint and/or provide vegetated open space within the project boundary such that the amount of open space exceeds local zoning requirements by 25%.
CASE 2: Sites with No Local Zoning Requirements (e.g. some university campuses, military bases)
Provide a vegetated open space area adjacent to the building that is equal in area to the building footprint.
CASE 3: Sites with Zoning Ordinances but No Open Space Requirements
Provide vegetated open space equal to 20% of the project site area.
Image created by Duany-Plater Zyberk & Company, James Wassell
So all of this sounds great, right? Who doesn’t like open space? Open space allows for a building’s stormwater to be managed on each site, creating zero runoff, less site impervious surface, trees, etc. All great environmental features, so how can anyone consider that this is bad?
The issue is in the consideration of cities and communities on a macro scale or holistically. On a macro scale, a city continues to demand more people, which demand more jobs, services, etc. All of which demand more development and land. By focusing on each site to manage its stormwater with “open space” (which by the way, still undergoes compaction and far from its native state), we demand more land for each structure, therefore spreading out our city’s infrastructure. Imagine if all of our cities and campuses were planned with “open space” as a requirement for each building. Not only would the city services and infrastructure be spread out more, but the urbanity and walkability of the city would be lost. Perhaps this credit is targeted towards suburban developments where it may be argued that it is appropriate. I would still argue that a city is better off with greater densities and allowing the peripheral spaces to remain at the natural state with low coefficients of runoff and native vegetation.
Suggestions for improvement: LEED could quantify appropriate uses of this credit as they relate to the urban-to-rural transect. For those familiar with the urban-to-rural transect (image to the right), SS Credit 5.2 is most appropriate in the T-2 transect zone (Rural) or the T-3 transect zone (Sub-urban). It is not appropriate in the T-4 through T-6 transect zones unless it is applied with green roofs exclusively. Another option is to allow a property owner to apply the open space requirement to a non-contiguous site in a T-1 transect zone (Natural) where open space is preserved in its natural state. This could apply in a similar manner as a TDR (Transfer of Development Rights) with a conservation easement on the non-contiguous site.
I would like to summarize by saying that LEED is a great marketing tool that has assisted the building industry in sustainable performance with unfathomable results. This blog post is not intended to devalue the strong merits of LEED and its long list of benefits. It is simply a critique of credits within LEED that could use modification to avoid contradictory results to the intentions of the US Green Building Council.
Originally posted 2010-09-19 15:20:40. Republished by Blog Post Promoter