A National Institute of Standards and Technology construction safety team is conducting a technical study on the Joplin, Mo., EF-5 tornado that destroyed about 8,000 structures and killed more than 150 people — marking it as the deadliest tornado in U.S. history. The team is assessing building performance, emergency response and evacuation procedures, as well as the large death toll and comparatively substantial warning time.

NIST first sent a four-person team of engineers to Joplin from May 25–28 to conduct a preliminary reconnaissance of building performance and emergency communications during the tornado, said Marc Levitan, leader of the NIST study.

“As engineers we can study… computational methods, but at the end of the day the real-world is our laboratory,” he said. “So to be able to understand how buildings performed and the performance of emergency communication systems, as well as the civilian response to those communications, we needed to study in the real-world, not just the laboratory.”

As far as construction, the reconnaissance team found that reinforced-concrete- and steel-frame buildings suffered total loss of function but the structural frame remained largely intact, Levitan said. They also found a large number of casualties despite the fact local first responders provided a 24-minute warning time, almost double the national average reported by the National Weather Service as 13 to 14 minutes.

The engineering team now has moved into the second phase, proceeding with a more comprehensive study. The team consists of the original survey personnel as well as an expert on severe storms from the National Oceanic and Atmospheric Administration, Levitan said.

Specifically, this phase of the study will determine wind hazard characteristics from the tornado and performance of residential, commercial and critical buildings as well as “lifelines (natural gas, electrical distribution, water and communications) as they affected maintaining building operations. The study also will examine the pattern, location and cause of injuries and fatalities, and how these numbers were affected by emergency communications and the public response.

Levitan said after the data are collected, his team will make recommendations if appropriate for improvements to building codes, standards and emergency-communication practices based on their findings.

“NIST next will translate the lessons learned from the studies into understandable reports and make recommendations for improvement to codes, standards and practices,” he said.