For many years, fire safety engineers worked under a simple assumption: When a fire alarm rings, people will evacuate immediately. How quickly people manage to vacate a building, they believed, depends mainly on physical abilities, the location of the nearest exit and the behavior of the fire.
But work by psychologists and other behavioral scientists has found that this idea fails to consider the often-surprising behavior of people during emergencies. In fact, research shows that as much as two-thirds of the time it takes occupants to exit a building after an alarm sounds is start-up time--time spent milling about, looking for more information.
Such a finding has big implications for architects, engineers and emergency planners hoping to design safer buildings. And now, after the 9/11 terrorist attacks, this kind of human-based evacuation research is getting more attention and funding, say researchers in the area. In fact, a number of researchers have landed government grants--from the U.S. Centers for Disease Control and Prevention (CDC) and the National Institute of Standards and Technology (NIST)--to learn about human behavior in large-scale building evacuations by studying what happened at the World Trade Center during the attacks.
Studying how occupants reacted as events unfolded and finding out what helped or hindered the evacuation efforts could provide invaluable information for future high-rise designs, says Robyn Gershon, DrPH, a professor in the Columbia University Mailman School of Public Health who studies high-stress, high-risk work environments and is leading the CDC study of the evacuation.
"This is going to impact high-rise emergency preparedness in a major way," says Gershon, an APA member whose doctorate is in public health. "Just like the Triangle shirtwaist factory fire [in New York City in 1911] led to the first fire codes ever, this is going to be a turning point."
Psychologists have been studying how people react during fires for more than 25 years. The late 1970s and early 1980s were a particularly productive time, says Norman Groner, PhD, a psychologist who has studied human behavior in fires since the 1980s. At that time, he says, the National Bureau of Standards--the precursor to today's NIST--funded the research through its Center for Fire Research. But much of that funding dried up in the mid-1980s, as NIST began to focus on things like computer modeling of fire dynamics instead.
The post-9/11 renewal of interest in this area is a testament to the importance of the work for helping to design better evacuation systems, Groner and others note. In fact, over the years, the research has debunked many of the myths that used to, and to some extent still do, guide building design, says Guyléne Proulx, PhD, a senior researcher at the National Research Council of Canada and an architectural planner by training (though she says that she's often mistaken for an environmental psychologist because of her interest in human behavior).
The classic myth, as described above, is that people exit immediately when they hear a fire alarm. That they don't should be obvious to anyone who's ever taken part in a fire drill, says Groner, a professor in the department of public management at the John Jay College of Criminal Justice in New York.
"People's natural inclination is to want to define a situation before they respond," he explains, "and an alarm bell is inherently ambiguous."
So instead of immediately vacating a building, people will wait for more cues--such as the smell of smoke or a co-worker urging them to leave--or seek out more information about what is happening.
"You could say that people are too smart for their own good," Groner says. "They understand that the probability that an alarm indicates a real fire, and one that actually threatens them, is extremely low."
Using both of the most common research methods--observing evacuation drills through hidden cameras and interviewing fire disaster survivors--Proulx has found it takes people an average of three minutes to begin leaving a high-rise apartment building. Although that doesn't sound like much, during a real fire those three minutes could be deadly, she says, because fire develops so rapidly.
Researchers have discovered other tenets of people's behavior during fires. Some examples include:
People generally do not panic. There's still a myth in the public mind that people "panic" in an emergency, but in fact panic is very rare, says Groner. "Usually when people say they panicked, they just mean that they became fearful, not crazy or irrational," says Proulx.
People are often altruistic. In an emergency, strangers will often help each other out even when they put themselves at greater risk by doing so, says Groner. Gershon adds that altruism is also linked to familiarity. That is, people are even more likely to act in helpful ways when they know each other.
Most people will try to exit through the door they entered. This is true even when emergency exit signs are well marked, says Proulx. "When you think about it," she adds, "that makes sense. During an emergency occupants don't want to use an exit they have no experience with--they don't know where it will lead."
People will move through smoke when necessary. Fire-safety engineers used to believe that people would turn back when they encountered thick smoke. "In reality, researchers have found that people will move through terrible smoke if they feel they must in order to survive," Groner says.
People are inertial creatures. People don't like to stop what they're doing, and often a fire alarm isn't enough of a cue to get them to drop their everyday tasks and exit a building. It's the accumulation of multiple cues--fire alarm, smoke odor, urging from co-workers and such--that will finally convince them to do so.
The key now, says Groner, is to incorporate findings like these into buildings and building evacuation systems. Proposed solutions include:
Vocal alarms. A vocal alarm that instructs building occupants to evacuate is more convincing than a simple bell, Groner says. And, if that alarm were operated by a security desk or fire-command center that could monitor the course of the fire, a vocal alarm could even alert building occupants to the location of the fire in the building and recommend safer evacuation routes, he adds.
Automatic exits. An alarm system might automatically open emergency exit doors, notes Proulx, showing people those doors are safe to use.
Comprehensive building orientations. In the World Trade Center, many employees had never tried to walk down the emergency stairwells from their offices to the ground floor, and had no idea whether they could do so or how long it would take, says Gershon. New-employee or new-tenant orientations in high-rises should include a comprehensive introduction to the building's emergency-exit system, she suggests.
Gaining mainstream acceptance
Findings like these have begun to convince even nonpsychologists of the importance of human behavior in any study of fires. A case in point is mathematician Ed Galea, PhD, who develops computer models that estimate how a fire would spread through a particular building and how its occupants would get out. Head of the Fire Safety Engineering Group at the University of Greenwich in the United Kingdom, Galea says he cannot create accurate models without understanding people's typical fire behavior.
Galea says he's a research "magpie," incorporating many behavioral researchers' findings into his models. He also conducts his own research, sometimes in consultation with psychologists. Recently, for example, he studied an evacuation drill at the University of Greenwich library, and he's planning to conduct a similar study in Brazil to determine whether there are cultural differences in people's response to fire alarms. Psychologist Andrew Dixon, PhD, is helping to analyze the videotapes from these studies.
Several recent fire-safety conferences sponsored by NIST and other organizations have focused on human behavior in fires, bringing together people from many different backgrounds, including psychology. And this fall, the International Association of Fire Safety Science will hold its third symposium on human behavior in fires.
The new studies have begun to have some practical effects as well. Gershon and her colleagues have developed some preliminary recommendations based on their World Trade Center study.
"Some of those recommendations are starting to make their way into legislation," she says. On June 7, the New York City Council passed a building code bill that requires, among other things, that high-rises hold full-building evacuation drills at least once per year.
These studies will also continue to add to the growing body of knowledge about human factor considerations in emergency planning and building codes.
"The basic premise," says Groner, "is that design should be human-centered, because human-centered design provides information that people need to adapt to the chaotic and uncertain ways that fires develop."
Letters to the Editor
- Send us a letter