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Design for Resilience

Alan Scott

Resilience is the capacity of an entity to recover quickly after a strain. It is a term now heard frequently in reference to the built environment, cities, neighborhoods and buildings, but often narrowly focused on disaster preparedness or structural design. However, an expanded view of resilience is taking hold with design professionals and local/regional governments. This view looks not only at public safety during and immediately following hazard events, but also at recovery and resumption of normal activities.

An integrated approach to resilience addresses the region's most common natural disaster (tornados, hurricanes, or earthquakes), as well as other hazards like severe weather from a changing climate, economic shocks, and even new threats like cyber-terrorist attacks on the electric grid. Most importantly, resilience and sustainable design strategies should to be integrated, so investments pay dividends rather than mirroring insurance models, where premiums are paid, but the insured hopes to never file a claim.

In last month's column, we touched on resilience in the neighborhood context using the EcoDistricts Protocol. Here we will explore the role of architects in guiding resilience integration for individual buildings and campus-scale projects. Why resilience? It is human nature to focus on the tangible issues in front of us and discount more remote threats, and many owners mistakenly assume new buildings designed to code will withstand the natural forces they will likely encounter.

For example, in my state, Oregon, we know a 9.0 magnitude earthquake is likely within the next 100 years. Buildings designed to current code are likely to remain standing during such an extreme seismic event, allowing safe evacuation, by absorbing the lateral forces with their structural frames (the way crumple zones on cars absorb collision impact). Like the car, though, these buildings will lose structural integrity and need rebuilding before they are again habitable. After the 2011 earthquake in Christchurch, New Zealand, more than 70 percent of downtown buildings-many built to current code-were demolished after repairs were deemed cost-prohibitive. Resilient design includes hazard assessment and continuity planning, building systems enhancements, and consideration of passive survivability.

Architects can start this process in the programming phase by asking clients about business continuity planning. What is the risk posed by potential hazards, what costs could result from disrupted operations, and how can these costs and risks be mitigated? If a hazard event occurs (be it an extended power outage or a major natural disaster), human safety claims top priority. But afterward, what is needed to keep businesses running? Similar questions can be asked about disruptive impacts in schools, government facilities, and even apartment buildings:

  • What would it take for a business to remain viable and contribute to community and economic recovery?
  • What small changes would optimize a school's gymnasium to serve as a comfortable shelter?
  • Could a supermarket be designed to preserve perishable food inventory during a power outage and become an emergency relief center after a natural disaster?
  • What would make an affordable housing project safe enough for vulnerable populations to stay in place?

The outcome of hazard assessment and continuity planning will inform both design decisions by the architect and operational planning by the owner.

With the results of this assessment and planning in mind, the architect and engineering team can consider building enhancements designed to mitigate the identified project risks. In some cases, this might mean a specific design change, like strengthening the structure above code minimums in earthquake zones, or locating emergency electrical systems above the ground floor in flood-prone areas. In other cases, high-performance building systems can be designed with an emergency operation mode so they provide operational benefits in ordinary conditions and also serve essential functions during a hazard event.

For example, a grid-connected PV system can be designed to switch into islanding mode to provide power for limited lighting, phone charging, etc., during an extended outage. Likewise, automated components of a hybrid-natural ventilation system could revert to manual operation when the power goes out. Design teams can also consider future-proofing the building. The project budget may not support the inclusion of on-site energy and water storage systems; but at little or no cost, provisions can be made in the building systems to allow a future energy and water system to be plugged into the building without expensive retrofits.

Some useful resources for resilient design include:

In addition to the above enhancements, a third level of building resilience can be achieved by designing for passive survivability-maintaining habitable indoor conditions during normal climate extremes, even when all utilities (electricity, gas, water, etc.) are out of service for an extended period. Modern, sealed, air-conditioned buildings become ovens when the power goes out in summer, but the thoughtful provision of a natural ventilation mode could ensure indoor temperatures never exceed outdoor temperatures while mechanical cooling system are down.

When designing for passive survivability, the same strategies employed for a high-performance, low energy-use building during normal operations (including daylighting, exterior shading and enhanced thermal envelope) go a long way toward preparing a building for habitability after a hazard event. The addition of advanced systems like on-site renewable energy production and storage and rainwater collection systems (which provide a positive return on investment during typical operations) can also be life saving elements during emergencies. Look for the expected release of three LEED resilience pilot credits by the USGBC, providing standards for the concepts discussed above.

The practical consideration of resilient design begins with asking the right questions. Architects have a great opportunity to bring these valuable considerations to their clients, helping to raise awareness and integrate resilience with other high-performance building design considerations. Architects can also provide leadership by informing the development of materials, systems, and design innovations that enhance the resilience of our built environment. You can find additional resources on this topic at the American Institute of Architects and the Resilient Design Institute.

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Alan Scott, FAIA, LEED Fellow, LEED AP BD+C, O+M, WELL AP, CEM, is an architect with nearly 30 years of experience in sustainable building design. He is a director with YR&G Sustainability in Portland, Ore. To learn more, visit www.yrgxyz.com and follow Alan on Twitter @alanscott_faia.