Stairwell evacuation study finds 'what we know we don't know'

March 25, 2009

Most of the time, we use the stairs in buildings—especially in high-rise structures—only as a back-up for faster elevators and escalators, but during a fire or other emergency, stairs become our primary passage to survival. In a new study, researchers at the National Institute of Standards and Technology examined what we know about how stairs work as an emergency evacuation route and found that the answer is—not nearly enough.

NIST researchers studied people movement speeds during three full-building drill evacuations and compared the data to already published results—including those from NIST’s investigation of the World Trade Center disaster on Sept. 11, 2001— to try to identify the factors that could hamper rapid using stairways. Their conclusions: research to date provides limited insight into how people react and behave during evacuations, and that for the most part, variances in speed cannot be explained by the evacuation models currently used in design and emergency planning. Or as the title of the new NIST report acknowledges, “What we know we don’t know.”

typically use five factors to describe occupant descent down stairwells during building evacuations: pre-evacuation delay, distance traveled during evacuation (movement from higher floors versus lower), counterflow situations (such as firefighters moving up a stairwell while occupants are moving down), stairwell geometry and density of persons in the stairwell. Models make use of such variables to predict the performance of egress systems and the expected speed for a complete evacuation.

However, the NIST researchers found that these engineering parameters could only explain about 13 percent of the differences they observed in evacuation speeds for the three fire drills. Since these speeds were similar to ones reported by previous studies, the researchers suggest that psychological and behavioral factors may be more important in determining how fast occupants can actually exit a building. They also note that inaccurate evacuation data based on simplifications about behavior could lead to unsafe building designs and procedures.

“Clearly,” the researchers state in the report, “there is a need to better understand all the factors that impact the ability of building occupants to take appropriate protective action in the event of a building emergency.”

More information: As a start toward improving understanding, the NIST Building and Fire Research Laboratory has posted a Web page, , with links to all four building occupant research studies completed in 2008, including the report Stairwell Evacuation from Buildings: What We Know We Don’t Know (NIST Technical Note 1624).

Provided by National Institute of Standards and Technology (news : web)

Explore further: Probable Cause Sequences for WTC Collapses Finalized

Related Stories

Probable Cause Sequences for WTC Collapses Finalized

April 12, 2005

At a press briefing in New York City on April 5, the National Institute of Standards and Technology (NIST) presented its analysis of how the World Trade Center (WTC) towers collapsed after two aircraft were flown into the ...

'Smart' Buildings to Guide Future First Responders

November 3, 2005

NIST researchers are studying how "intelligent" building systems can be used by firefighters, police and other first responders to accurately assess emergency conditions in real-time. One of the biggest problems faced by ...

NIST Test Fans the Flames for High-Rise Fire Safety

November 22, 2006

Reseearchers from NIST, the Chicago Fire Department and the Chicago Housing Authority recently set controlled fires in an abandoned Chicago apartment building to test a new fire-fighting technique -- using powerful fans to ...

NIST releases final WTC 7 investigation report

November 20, 2008

The National Institute of Standards and Technology (NIST) today released its final report on the Sept. 11, 2001, collapse of the 47-story World Trade Center building 7 (WTC 7) in New York City. The final report is strengthened ...

Recommended for you

Chimpanzees shed light on origins of human walking

October 6, 2015

A research team led by Stony Brook University investigating human and chimpanzee locomotion have uncovered unexpected similarities in the way the two species use their upper body during two-legged walking. The results, reported ...

The hand and foot of Homo naledi

October 6, 2015

The second set of papers related to the remarkable discovery of Homo naledi, a new species of human relative, have been published in scientific journal, Nature Communications, on Tuesday, 6 October 2015.

How much for that Nobel prize in the window?

October 3, 2015

No need to make peace in the Middle East, resolve one of science's great mysteries or pen a masterpiece: the easiest way to get yourself a Nobel prize may be to buy one.

The dark side of Nobel prizewinning research

October 4, 2015

Think of the Nobel prizes and you think of groundbreaking research bettering mankind, but the awards have also honoured some quite unhumanitarian inventions such as chemical weapons, DDT and lobotomies.

Who you gonna trust? How power affects our faith in others

October 6, 2015

One of the ongoing themes of the current presidential campaign is that Americans are becoming increasingly distrustful of those who walk the corridors of power – Exhibit A being the Republican presidential primary, in which ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.