How resilience will shape the future of building design
Hurricanes, flooding droughts, wildfires, landslides and terrorism.
These are the issues we’ll be addressing next in green design — if you buy into the theory that the U.S. Green Building Council’s ubiquitous LEED program helps predict future trends. Past LEED pilot credits have revealed issues we’ve neglected, such as water, transit, acoustics, ergonomics and lighting pollution.
Looking at LEED pilot credits as if they were a crystal ball, we can see in them larger trends in the future of design — for example, moving toward a greater emphasis on health and comfort, or a growing interest in site and community.
In November, USGBC’s steering committee for the LEED rating system announced it had approved three LEED pilot credits on resilience in design.
We know buildings play a significant role in climate change, which is causing more disasters and conflicts. And as world leaders met in Paris in December to address global carbon emissions, they also addressed resilience.
While we challenge ourselves to stop climate change, we are also faced with how to protect ourselves, how to be resilient, in the face of disasters already arriving.
"We must have resilience as a main objective when we talk about climate change," Manuel Pulgar-Vidal, minister of environment in Peru, told the delegates at COP21.
Seeking survival options
Alex Wilson, who heads up the Resilient Design Institute and who was a principal author and champion of the LEED pilot credits for resiliency, has been talking about resilience since Hurricane Katrina hit New Orleans in 2005.
The week following Katrina, he wrote an editorial in Environmental Building News suggesting we look carefully at how we develop buildings along the Gulf Coast and other vulnerable areas. Wilson then led a series of charrettes in Atlanta in 2005, which included people from the Gulf Coast, to create the 10-point New Orleans Principles guideline for reconstruction in coastal regions hit by a disaster.
In New Orleans, they found that older homes fared better for residents after Katrina in the days with no power than new homes designed for air conditioning. That's because the older homes were designed with vernacular architecture, with wrap-around verandas and natural ventilation keeping them cooler.
One new LEED pilot credit on resilience — credit 100 on the LEED numbering system — is titled the Passive Survivability design credit. Its purpose is to prepare building designs for functionality during emergencies, requiring the design team to create a building that provides two of these: livable conditions after a disaster; backup power; or access to potable water. (The most resilient design would have all three, but the design only needs two to earn a pilot credit from LEED.)
"This is the credit where we really broke new ground," Wilson said.
Engineers long have designed buildings to operate within certain temperature zones set by ASHRAE for the comfort of occupants. But that's not all.
"This is not about keeping occupants comfortable," Wilson said. "It’s about keeping them alive."
To design for passive survivability, engineers are not designing for standard temperature measurements. Instead they’re using a "habitability zone," which includes relative humidity and other considerations very important to human physiology. For example, being in a building after a power outage on a 90-degree day in Phoenix will affect your body temperature and health differently from being in a building on a 90-degree day in Houston.
New metrics for temperature require a new way to model buildings and will be a real challenge for the green design community.
"People aren’t familiar with designing to these temperature variables, and it will require a learning curve," Wilson said.
However, already a few new buildings could serve as models (and might have qualified for the new resiliency credits had they existed sooner. These buildings possibly could get the points retroactively).
Designing a new model
Wilson cites Chesapeake Bay Foundation’s (CBF) new Brock Environmental Center in Virginia Beach as probably the best model we have for resiliency.
CBF is a conservation organization dedicated to saving Chesapeake Bay from pollution. The Brock Center, completed in 2015, has resiliency features that include building efficiency, a PV system, wind turbines built to withstand hurricane force winds, natural ventilation, daylighting, rainwater catchment, composting toilets and recycled water.
The building is also elevated, as it’s near the bay, to avoid storm surges.
"It wouldn’t take much for the Brock Center to be able to serve as a resilience hub for the area — providing a place where residents could charge their cell phones during a power outage, fill up a water bottle and use restroom facilities,” Wilson said.
The Brock Center is targeting the strict standards of the Living Building Challenge, the rating system administered by the International Living Future Institute (ILFI). Before achieving Living Building status, the building must prove through its performance over a one-year period that it meets a standard of generating all its own energy and capturing or recycling all the water the building needs.
The Brock Center and the Bullitt Center in Seattle, a Living Building and home to ILFI, with renewable energy and potable water onsite, easily meet all the standards set by the new LEED pilot credits, except neither building has backup power. Wilson said this easily could be remedied with batteries.
The other two LEED pilot credits (Nos. 98 and 99) are more about the site. The first credit, assessment and planning for resilience, requires a design team to assess critical hazards as part of the predesign phase and complete climate resilience planning or emergency preparedness planning.
The second credit, Designing for Enhanced Resilience, asks the design team to take the top three hazards from the first credit and design for safety from them.
The Brock Center is right on the coast — a location that comes with a very specific set of hazards. The roof is designed to withstand 120-130 mph winds, exceeding the local code requirement. Triple glazed windows from Europe also have a high wind resistance. (Europe has been designing for passive survivability for some time.)
Hurricane Joaquin tested the Brock Center in October, and CBF building manager Chris Gorri captured photos of the building gracefully withstanding the severe storms and flooding that accompanied it.
Meanwhile, the Rocky Mountain Institute’s new Innovation Center in Basalt, Colorado, and new buildings planned at the University of British Columbia in Vancouver also probably could meet the new resiliency standards, Wilson said.
The LEED pilot credits for resiliency will apply to all Building Design and Construction (BD+C) rating systems, along with Homes and Mid-Rise Residential rating systems. Once tested and improved through the pilot program, the credits will become a standard part of the LEED rating system.