Researchers at the National Institute of Standards and Technology
(NIST) are stepping up the pace for designing safer building
evacuations by releasing large, numerical data sets that track the
movement of people on stairs during high-rise building evacuation
drills. The data sets will ensure that architects, engineers, emergency
planners and others involved in building design have a strong technical
basis for safer, more cost-effective building evacuations.
“While stairs have been used in buildings for ages, there is little
scientific understanding of how people use them,” explained NIST
researcher Erica Kuligowski. “For example, we know little of how the
width of the stair affects the flow rate, whether people grow fatigued
as they descend from tall buildings, or how people merge into a crowded
stairwell.”
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Working with the Public Buildings Service at the U.S. General
Services Administration (GSA), NIST researchers made video recordings of
evacuation drills in stairwells at nine buildings ranging in height
from six to 62 stories tall. The first data sets being released
(available at www.nist.gov/bfrl/fire_research/building-occupant-evacuation.cfm)
come from four of the buildings and include movement information on
more than 3,000 people. Other evacuation data will be posted on the NIST
Web site as it becomes available.
NIST researchers have already reported analysis of some of the
underlying data at human behavior and fire conferences and will report
more in the future. These reports, like most egress studies, provide
their findings, but without the raw data.
“The raw data NIST is providing will help to ensure that GSA and
others have the scientific basis necessary to provide safe and
cost-effective building evacuation,” said Kuligowski.
GSA provided research funding support for the project. NIST
researchers hope that making the data available will help to develop new
evacuation models, provide assessment of the accuracy of existing
egress models, and ensure that building owners and managers have a sound
basis for evacuation planning.
Before each drill, researchers positioned video cameras to record an
overhead view of the evacuation that would not interfere with occupants
evacuating the building. Images were pixilated to protect the identity
of the building occupants. In most experiments, cameras captured a view
of that floor’s main landing, the door opening into the stairwell and
two to three steps on both sides of the main landing.
Using the videos, researchers developed spreadsheets of data on
people's movements. For each occupant, researchers noted the time the
individual first entered the video and captured data about their
movements until they left the building. Additionally, researchers noted
other factors that might influence speed, including the number of people
in close proximity, whether they were helping another person, and
whether they were carrying something. They also noted if the occupant
handrail was used and how much space the person occupied in the
stairwell.
“These data will allow researchers to calculate movement speeds of
people traveling down stairs as a function of stair width, occupant
density, total distance traveled, and merging characteristics at stair
landings that could influence updating building safety requirements,”
Kuligowki said.
This knowledge also will assist in building design and perhaps
influence standards on how occupants evacuate during emergencies, she
added.
Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661
The width of stairways will directly affect the effectiveness of an evacuation. In an emergency situation, where volume of occupants increases, there must be allowances for those helping others without impeding the general flow of traffic. Most difficulties occur in buildings where the narrowness of the emergency access reduced the speed and effiency of the evacuation effort.