Fighting Fire with Knowledge
The danger of dust explosions, the subject of research at WPI, was highlighted in 2008 when a spark ignited a dust cloud at the Imperial Sugar Co. plant in Port Wentworth, Ga. The massive explosion took 13 lives.
by Joan Killough-Miller
Through studies of fire dynamics, computer models, policy development, and state-of the- art engineering, researchers in WPI’s Fire Protection Engineering Department are helping shape everything from how buildings are designed to how products are manufactured, how fire codes are crafted, and how laboratory research on fire is conducted. By advancing a dynamic, multifaceted, new engineering discipline, they are making the world a safer place.
Keeping Communities Safe
Over the past three decades, the role of local fire departments has expanded well beyond fire prevention and suppression to include emergency medical services, hazardous materials response, and special rescue. As threats from natural and manmade disasters, including terrorism, grow, expectations for fire departments continue to rise. At the same time, as communities struggle to balance shrinking budgets, emergency personnel are being asked to do more with less.
To help communities focus their resources where they will have the most impact, Kathy Notarianni, associate professor and head of WPI’s Fire Protection Engineering Department, is directing a multi-year study that will produce scientifically based tools that can help fire departments and city and county managers make sound decisions about the allocation of resources and the delivery of services. Conducted in concert with the International Association of Fire Fighters and the National Institute of Standards and Technology, and with significant funding from the Department of Homeland Security, the study will help officials assess possible outcomes of decisions about prevention, deployment, and staffing so they can be more effective at reducing the loss of property and civilian and firefighter lives.
"My passion is developing scientifically derived quantitative methods to allow for better decision making and improved codes, standards, and policies," Notarianni says. "Through this study, we are working with more than 400 fire departments to compile detailed demographics of each and building a database of hundreds of thousands of fire department deployments. These will be analyzed statistically to determine how crew size, level of training, equipment deployed, and other factors affect the outcome." —Kathy Notarianni
The researchers have also conducted experiments at a fire training facility. Fire crews, ranging in size from two to five, were dispatched at staggered rates to perform 22 timed tasks while heat and toxic chemical levels inside the burn building were measured. The crews faced either slowly evolving blazes or quickly developing fires. In combination with computational fluid dynamics simulations, the tests demonstrated the effectiveness of various deployment and response configurations in assuring the survival of building occupants. With the addition of observations of the severity of each of the test fires, the researchers were able to estimate how well crews using a range of deployment configurations could intervene against fires of varying severity.
Fire chiefs and city managers across the country eagerly await the results of the landmark study, which Notarianni says is likely to make the fire service rethink commonly held assumptions about the most effective practices for keeping communities safe.
"We can build buildings to a certain standard, but it’s really hard to know for sure what people are going to do."
Learning without Burning
Associate professor Brian Meacham, a leader in performance based design and regulation, conducts research in these areas and teaches students how to appropriately apply fire incident data and statistics, engineering knowledge, and computational models to help make sound predictions about how buildings will perform in a fire and whether people can safely exit. By analyzing actual events around the world, studying human behavior, and developing better frameworks for fire protection engineering design and regulation, he hopes to improve regulations and standards to better reflect how fire, buildings, and people interact in the real world.
Brain Meacham, left, and Alberto Alvarez discuss their research on human factors in performance-based building design. Meacham believes the design of fire safety and evacuation syatems for buildings must take into account how people are likely to behave.
Meacham's work helps reinforce the fact that building design must take into account the people who use the building, and that "human factors" can sometimes hinder best planned escape routes and the most sophisticated fire protection systems. "We can build buildings to a certain standard and test the reliability of the technology," he says, "but it’s really hard to know for sure what people are going to do. When the fire alarm blares, will office workers finish a task or gather belongings before fleeing? That 'pre-movement' time needs to be quantified and factored into the evacuation calculations," Meacham says.
To better understand how people respond in fires, Meacham and computer science professor Mark Claypool, director of WPI’s Interactive Media and Game Development program, are seeking funding to develop “virtual environments” where emergency scenarios can be presented to human subjects much like videogames, to capture data on the actions people take. Other proposed research would use video cameras to record traffic patterns at crowded junctures, such as subway turnstiles.
"Every time a fire causes a large number of deaths or considerable damage, we have a responsibility to learn from that event and make changes to design practices, standards, and regulations."
"Every time a fire causes a large number of deaths or considerable damage, we have a responsibility to learn from that event and make changes to design practices, standards, and regulations," Meacham says. With support from the National Science Foundation, he and colleagues from Michigan State University, the University of Texas at Austin, and the Netherlands have been collecting information and conducting preliminary analysis of a high-rise building fire that occurred at the Delft University of Technology to learn why a significant portion of the building collapsed during the fire. With associate professor Nicholas Dembsey, an expert in compartment fire modeling, and the international engineering and consulting firm Arup, he is assessing the vulnerabilities of passenger rail vehicles to different size fires, under a grant from the Department of Homeland Security. He’s also looking ahead to how we might address extreme event scenarios like terrorism, earthquakes, or even global climate change, which could result in stresses on buildings unanticipated by design practice or local building codes, including the unavailability of water for fire suppression.
"As fire protection engineering matures," Meacham says, "we need to question some of our long-standing assumptions: that people will hear alarms and exit, that there will be water, that protection systems will be left intact, and take a risk-based approach or design for the worst credible event. This is as broad a field as you can get, drawing on all the engineering disciplines, as well as psychology and sociology. You really have to bring it all together to do a good job."
Where There’s Dust, There’s Danger
Ever since coal has been mined and grains have been milled, explosions from dust buildup have been causing countless deaths in mines, mills, factories, and storage facilities. Assistant professor Ali Rangwala is employing fundamental physics to understand this phenomenon on a theoretical level. He recently received a five-year, $429,000 CAREER Award from the National Science Foundation to conduct groundbreaking studies on dust layer ignition and flame propagation in dust clouds.
Ali Rangwala, right, and PhD candidate Scott Rockwell are is seeking to better understand and prevent cataclysms caused when dust ignites in commercial settings, like coal mines, grain silos, and factories. In the laboratory, they use a laser to study the chemical and physical properties of airborne dust.
Using novel small-scale experiments, and in some cases designing equipment just for the study, he will quantify critical parameters, such as particle size, cloud density, chemical makeup, heat release, and flame spread. This will help answer questions such as, what are the parameters that control ignition, at what density does a cloud becomes dangerous, how does turbulence affect flame propagation, and what size safety vent is required to release built-up pressure and prevent an explosion? "No one has asked these questions," he says. "It's been a hit-or-miss approach."
The results will help define the risk in different environments and establish industrial safety guidelines. "This essentially sets the housekeeping standards," Rangwala explains. "We’ll be able to say to industries, 'This is the probability, and you can reduce it this percentage by doing x, y, and z.'" In practical terms, plant managers need to know how often floors must be swept and surfaces cleaned to prevent dust layers from building up to a critical thickness that could self-ignite, smolder unnoticed, and trigger explosions.
In other work, Rangwala and Forman Williams, professor of engineering physics and combustion at the University of California, San Diego, are taking a scientific look at a serious and poorly understood industrial fire risk: large commodity storage facilities. "Warehouses are getting bigger," he says, "with more merchandise stacked on taller shelves." And when they burn, which they do all too often, the sprinklers don’t extinguish the fires as they should, resulting in large losses and firefighter injuries and deaths. These unfortunate situations drive Rangwala to find answers to important questions: "What level of suppression system is required? Could changing the configuration and height of stacks reduce the hazard?" he wonders. "We need to understand the burning behavior of cardboard boxes and the effect on the contents."