How building science and research can help avert disaster
Researchers are exploring how to mitigate the impact of disasters via building performance testing and multi-peril research
There are two ways to learn a lesson when it comes to building performance: through testing, or after a disaster. Shortly after Hurricane Katrina struck in 2005, AIA reaffirmed its commitment to the architect’s role in disaster assistance when it created the Disaster Assistance Program, led by a Disaster Assistance Committee (DAC) of AIA member experts from around the nation. Understanding the effects of disasters is critical, especially as architects work to create more resilient communities. The building safety assessments that architects do immediately after a disaster event provide critical information on performance failures but often leave us wondering what could be done better to prevent damage and improve resilience. Luckily, there are researchers across the country that are dedicated to finding the answers necessary to improve the built environment.
In 2017, the DAC traveled to South Carolina for a tour of one of these unique facilities, the Insurance Institute for Business and Home Safety’s (IBHS) Research Center. The Institute is an independent, nonprofit scientific research and communication center. After opening in 2010, the Research Center has been used for building performance testing and multi-peril research. It can create a broad spectrum of weather—ranging from hurricane like conditions, windstorms, wildfires, and hailstorms—for the purpose of testing and monitoring the effects on actual full-size structures and devising best practices from the research. On their visit, the DAC members studied three hazard types:
With virtually every type of weather event there is one constant: wind. Whether it is a tornado, hurricane/cyclone, hailstorm, thunderstorm, or wildfire, there is always a component of wind. Most architects will be familiar with wind tunnel testing, a process that uses scale models (especially of high-rises in urban environments) to ensure proper design and detailing of the structure and its cladding system. Low-rise construction is also affected by the wind, but is not typically tested in a traditional wind tunnel. When wind velocities reach tornado, or hurricane force levels, poorly designed and constructed buildings fail. Beginning with awnings, porches and overhangs, then roofs and walls, attachments begin to disassemble, creating debris that damages or destroys adjacent structures.
IBHS’s Research Center contains a six-story test chamber equipped with 105 six-foot-tall electrical fans, capable of generating hurricane force winds (up to 140 miles per hour). With a 55-foot-diameter turntable in the chamber, researchers can rotate full scale one or two-story structure(s) to allow testing of multiple exposures for the collection of critical data. This guarantees every side of the building is exposed to the simulated weather conditions. Additionally, using a rain system of mounted sprinklers, researchers can drop up to eight inches of rain per hour on the test structure.
In one wind test, the center constructed two different structures side by side. One structure was completed using a specific code or standard while the other was not. The structures were subjected to severe wind speeds; one was destroyed while the other was left intact, illustrating the importance and difference in their resilience. The pressure data from this full-scale testing on low-rise structures emphasized the importance of load path connections, showing architects one of the most fundamental ways to reduce the impacts of high wind.
The 2017 wildfires in Southern California have shown a clear relationship between materials such as combustible roof shingles, attic and underfloor ventilation openings, and lack of appropriate vegetation clearance to the spread of the fires. With thousands of structures damaged or destroyed, a better understanding of ignition—and prevention measures—is needed to create retroactive building codes and enforce them to prevent future disasters.
As architects consider the damage encountered in the field when performing building safety assessments, one thing often stands out: sometimes even the newest structures are damaged or destroyed.
Most major wildfires are aided and spread as a result of strong winds. The IBHS facility replicates those conditions in their chamber through ember creation and fire testing, using seven ember generators that blow various sizes of burning wood embers. This testing creates awareness for the damage wind-driven embers can inflict on wood structures and communities. Understanding the mechanism by which burning embers can enter through roof and eave vents is paramount in modifying a design that will survive such an event.
In May 2017, a hailstorm in Denver was estimated to have caused $1.4 billion in insured damages, making it the costliest weather disaster in the state’s history. In 2010, a hailstorm in Phoenix caused $2.8 billion in damages. Recognizing the damaging effects hail has on structures, especially its potential to cause extensive damage to roofing and cladding, IBHS created a more realistic method of assessing these effects: a state-of-the-art custom hail production machine. This allows for the mass production of realistic hail that replicates its size, density, and hardness. Testing the effects of hail on various shingles has resulted in voluntary product improvements by manufacturers. These modifications provide more hail-resistant products for architects to spec and ultimately keeps tons of damaged roofing waste out of landfills.
Turning research into practice
As architects consider the damage encountered in the field when performing building safety assessments, one thing often stands out: sometimes even the newest structures are damaged or destroyed. While building codes are written and revised over numerous cycles as a reaction to events or disasters that have adversely affected our communities, they only represent the minimum construction standard for the protection of life safety. This is often misunderstood by the general public, who believe that “if it is built to the building code, it must be safe.” It is perfectly acceptable by code to be just safe enough to protect life safety, with no guarantee of post-disaster habitability or continuity of operations.
The research conducted at IBHS and similar facilities provides an antidote: research-backed best practices that lead to safer communities with sturdier structures, thus reducing disruption, financial impacts, and recovery time.
Through the collection of scientific data, findings are translated into building code and standards modifications, material improvements, and voluntary construction programs and guidance. These “nuts and bolts” research projects develop the necessary technical details that support either mandatory codes and standards changes or criteria for voluntary programs and rating systems such as Fortified and a variety of state insurance discount programs. Most importantly, building science research is a valuable tool for architects, enabling the design of healthier, safer buildings.
For more on disaster assistance, download AIA’s Disaster Assistance Handbook.
AIA is committed to empowering architects to use and engage in research. Learn more here.
About the authors: Dean J. Vlahos, FAIA, is a forensic architect and president of Dean J. Vlahos FAIA & Associates. He is also an AIA Disaster Assistance Committee member and past chair of AIA Los Angeles’s Building Enclosure Council. Rose Grant, AIA, is a research architect in State Farm’s Technology Research and Innovation Laboratory and is the chair of the AIA Disaster Assistance Committee.
Insurance Institute for Business & Home Safety