Raw Data Enables More Accurate Planning for Emergency Evacuations

After investigating the evacuation of the World Trade Center on 9/11, researchers from the National Institute of Standards and Technology (NIST) have been conducting a variety of research and development projects that investigate the safety of building occupants. To determine how to design buildings and stairwells for safer evacuations, the researchers have been collecting raw data of the movement of people on stairwells during evacuation drills.

The first data sets have been released for public use and Erica Kuligowski, a fire protection engineer with NIST, said the information is important for three main reasons:

• Building engineers and emergency planners can feed the data along with fire calculations into safety assessment calculations when determining the best evacuation routes in existing buildings or when designing new buildings.
•  NIST is providing the technical foundation to improve current egress requirements within national building codes and standards. Kuligowski said the data can help answer questions like: What is the basis for stairwell widths? And should stairwell widths be increased when the building height is increased?
• Building model developers use computer evacuation software to determine how safe a building design is and the NIST data provides them with a way to validate their information.
   

During the U.S. General Services Administration-funded project, NIST researchers collected information during evacuation drills from nine buildings ranging in height from six to 62 stories. Kuligowski said they set up overhead video cameras in the buildings’ stairwells at every floor or every other floor and recorded how occupants evacuated during the drill. To protect the security of the building occupants, the cameras were pixilated to make faces unidentifiable.

“We’re interested in tracking people at each camera and what amount of time has gone by since the start of the drill, which is normally the sound of an alarm, until we see them at various points in the building,” she said. This allows researchers to calculate how fast people are moving and how many people are in the stairwells.

Researchers also collected data about merging behavior, delay time, door size, handrail usage, body sway and body size. Kuligowski said they noted if building occupants were carrying items like a coat or briefcase and if that influenced their speed.

NIST worked with buildings that were already planning evacuation drills. In some cases building officials gave the agency permission to film the drill, and in other instances building representatives contacted NIST to observe because it also provides feedback on what happened during the drill.

Although the research from the evacuation drills is still in the preliminary stage, Kuligowski identified a couple findings. First, there was the question of if people are moving more slowly today than they were 30 years ago, but she said the data shows that people are moving at speeds similar to data collected decades ago. And from previous research of an evacuation following a real fire, a key takeaway was the need to ensure that messages to building occupants are consistent. A follow-up questionnaire to occupants revealed that they received conflicting information about what to do during the evacuation.

“It’s important to tell people what they need to do and what’s going on — why they need to evacuate,” Kuligowski said. Another aspect that influences if the occupant responds to the message is who’s giving it, she added. “If it’s someone that they know and are familiar with and they trust that person and it’s a credible source, that also improves their response.”

The first data sets are available and detail the movement of more than 3,000 people in the first four buildings studied. They can be downloaded at the NIST website. NIST researchers are still collecting more data before publishing their findings, but Kuligowski said, “I think a big step was actually releasing the raw data for other people to use, and we’re really excited about that.”