Cities around the world face a variety of natural disasters, including floods, hurricanes, earthquakes, heat waves, cyclones, and tornadoes.
In addition to the suffering inflicted by the storms themselves, the built environment’s design and construction shortcomings also cause avoidable problems. Fortunately, improved building designs can improve the performance, functionality, and resilience of buildings when disasters hit.
In an urban context, improving the resilience of buildings requires a holistic approach along with various infrastructure improvements. In other words, improving each building is necessary, but won’t sufficiently address the issues that people and cities will face as sea levels rise, for example, if hurricanes grow stronger and more frequent and cities become more dense and urbanized.
In October of 2012, Hurricane Sandy plowed across the Caribbean and up the eastern US coast, devastating the New York City metropolitan area. The largest Atlantic hurricane on record, Hurricane Sandy caused $68 billion in damage and left at least 268 people dead in seven countries.
Following the storm, New York City assembled the Building Resiliency Task Force, a varied team of experts and stakeholders, to determine steps that would lead to resilient buildings and a resilient city - one that was better able to handle disaster conditions during and after each event.
Task Force members included architects, engineers, contractors, utility representatives, real estate owners, property managers, subject matter specialists, city officials, code consultants, cost estimators, and attorneys. Their report “represents the consensus of more than 200 Task Force members on how to strike the right balance between resiliency, cost, and other issues.”
The report outlines 33 steps that address stronger buildings, backup power, essential safety, and better planning. Each step is classified as:
● Required: existing building must comply by a specified date.
● New code: New buildings and renovation projects must comply.
● Remove barrier: Streamline rules and remove obstacles to allow changes.
● Recommended: Beneficial projects but not required.
● Further action: More work or study is needed, but could be beneficial.
The Task Force recommended few required changes to existing commercial and multi-family buildings, preferring code updates that apply to new construction and renovation. In the interest of affordability, buildings housing one to three families have no required changes, but will have to comply with eight updates when renovating or being rebuilt.
As New York City and its residents were still dealing with the aftermath of Hurricane Sandy at the time the report was commissioned, many steps focus on flooding and water issues. That’s understandable, and highlights the importance of locally sensitive design.
Within the context of stronger buildings, the following recommendations deal with design:
Prevent Storm Damage to Homes: Wind and water can damage homes, so windows and doors must be wind resistant, house framing should be securely anchored to the foundations, and foundations and basements must be strengthened as necessary.
Launch A Design Competition for Raised Homes: New buildings and renovations of existing buildings will be required to build above the flood line. That will change the appearance and character of neighbourhoods, so the task force suggested a design competition to create a model for attractive streetscapes of attached and detached raised homes that remain accessible to people with disabilities.
Relocate and Protect Building Systems: HVAC systems and water heaters, for example, should be relocated to spaces above the flood line, which will require re-design in many existing homes. Commercial and multi-family buildings have already used this approach more extensively than single-family homes, but many will need to move equipment from basements to upper floors.
Remove Barriers to Elevating Buildings & Building Systems: In many cases, existing codes and zoning prohibit changes that would increase the overall height of buildings. Those restrictions should be loosened to permit raising buildings and relocating equipment.
Remove Barriers to Sidewalk Flood Protection: Sidewalk-mounted flood barriers should be allowed on a temporary basis.
Capture Stormwater to Prevent Flooding: Some basic design changes can help cities to manage water more effectively. Designing sloped sidewalks to funnel rain water into tree pits and other permeable areas can keep water from overloading storm sewers.
Use Cool Surfaces to Reduce Summer Heat: Dark roofs, pavement, and even sports fields can be replaced with light-colored materials to reflect light and heat back into the atmosphere. During urban heat emergencies, rooms on upper floors of buildings with dark roofs can become dangerously hot.
Other measures ensure that buildings can maintain basic functionality during emergencies so residents can stay in their homes, and some buildings can remain usable.
Supply Drinking Water Without Power: This is one of the few required changes. Some buildings use electric pumps that not only fail during emergency situations, they prevent access to water that is present in the building. Providing water to a common area is acceptable. Maintaining existing water towers and adding water towers to new builds is another solution.
Ensure Toilets and Sinks Work Without Power: Toilets and faucets should be able to operate without grid power, enabling continued use of the building.
Ensure Operable Windows in Residential Buildings: Without electricity, most HVAC equipment is useless, so operable windows are crucial for cooling and ventilation. In hot weather, many buildings with fixed windows are uninhabitable without a functioning cooling system.
Maintain Habitable Temperatures Without Power: Operable windows ensure ventilation, while insulation helps to lessen rapid temperature swings, keeping buildings comfortable without grid power.
Resilient design offers the potential to mitigate the effects of natural disasters, helps people endure disasters when they occur, and also offers better functionality day-to-day.