29 October 2009

Living Building Challenge - A Growing Idea

Excerpt from GreenBiz, 22 October 2009

'...The Living Building Challenge is...a voluntary third-party program of sustainable building certification that was launched by Cascadia in 2006. Its creators see it as the next step beyond LEED and a precursor to the kind of regenerative design ultimately needed...

Rather than scoring credits, the program requires that simple prerequisites be met. Simple, in this case, does not mean easy. For a building to qualify it would have to be a zero-net energy and water user, and introduce no new toxins from an established “red list” into the environment.

Additionally, it could not be built on undeveloped land. In all there are 16 requirements for such a building and the list includes a category for “beauty and spirit” that includes “education and sharing." All the prerequisites are mandatory, criteria are performance based, and that performance must be actual and documented rather than projected.

The program's developers freely admit that the bar has been set higher than current practices achieve, and have identified the biggest roadblocks to its wider adoption: Building codes and upfront costs. In some places, for instance, it is illegal to recycle water on site for drinking, and controlling the cost of sustainable materials is subject to market pathways that are still maturing.

On the other hand, there is wide latitude for innovation because the rating is performance driven. There are many different ways to achieve the general goals, and the CGBC does not concern itself with dictating best practices, reasoning that rigorous results will ensure good methods...

Three years on, McClennan says the challenge has four built structures that are completing the required 12-month performance review period and about 60 projects that have declared their intention to apply. Cascadia is also about to launch a 2.0 version of the Challenge that will include landscape and infrastructure, renovation and neighborhood-scale criteria.

One of the...candidates for certification is the Phipps Conservatory in Pittsburg...

To reach their zero-net energy and water goals, the designers have resorted to a wide combination of techniques: passive heating and lighting design, building mass, geothermal heating and cooling, dessicant dehumidification, smart building management system, photovoltaics and solar hot water collectors, wind turbines, demand controlled ventilation, sustainable materials, green roof, native landscaping, rainwater harvesting and natural stormwater collection and treatment, and constructed wetland sanitary waste treatment.

These techniques embody some of the biomimetic concepts that I have written about in this column: substituting information for energy, in the case of demand controlled ventilation where CO2 levels from occupants trigger HVAC response and therefore prevent the heating of empty rooms; surfing for free, in the case of using geothermal, where the temperature gradient between the ground and air is used to both heat and cool the building; and substituting structure for energy, in the case of all the passive forms, from shading to trombe walls to filtration beds, that harvest light, heat or clean water without the use of power...

It remains to be seen if this will hold true for the next tier of applicants with more diverse missions, but the conventional wisdom that sustainable construction always has to cost more is being challenged with the clever ways that designers are saving money...

The importance of integrating building systems was also a shared critical component, and that integration seems, by necessity, to have been forced beyond the buildings' walls. In order to close the loop on water, for instance, one has to both capture it outside from the air and return it to the earth for filtering. Landscape architects and civil engineers were important members of these teams because of their expertise in these kinds of systems. Finally, because of this, the very forms of the buildings themselves were determined by the demands of this integration and the collaborative design process necessary to achieve it.

While some of the techniques used to achieve certification in the Challenge were clearly using biomimetic concepts, with a few exceptions, such as bio-filtration system design, most have come from a strictly engineering tradition. Nevertheless, the trend toward more bio-innovation is evident...'

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