Gavin Horn and Denise Smith are the principal investigators leading a multidisciplinary study looking at lighter, cooler equipment to reduce firefighter injuries and deaths. Horn is the research program coordinator in the Illinois Fire Safety Institute and a visiting research scientist in the U. of I. mechanical science and engineering department; Smith is a research scientist at the institute and a professor at Skidmore College.
Photo by L. Brian Stauffer
CHAMPAIGN, Ill. - Firefighters battling wildfires like those devastating Southern California, or even a smaller structural fire, have to endure temperatures in the hundreds of degrees. A study at the Illinois Fire Service Institute on the U. of I.'s Urbana campus is examining an enhanced version of personal protective equipment that is lighter, less restrictive and uses a firefighter's exhaled breath to cool the body and help combat heat stress, which researchers believe contributes to many of the on-the-job deaths and injuries firefighters suffer each year.
There are about 1.2 million U.S. firefighters, and 106 firefighters died while on duty in 2006, according to the U.S. Fire Administration. Fifty of those deaths were related to heart attacks. An additional 600 to 1,000 on-duty firefighters suffer non-fatal heart attacks every year, and firefighters report about 10,000 injuries annually from slipping, tripping or falling.
Within the past 10-20 years, many fire departments replaced their firefighters' traditional gear of three-quarter-length coats and boots with heavy, encapsulating bunker gear. The bunker gear enhances burn protection, but it restricts air circulation around the body. The researchers are testing a new type of lighter, more breathable gear that they think may reduce heat stress and fatigue, and consequently, injuries and fatalities.
"While the number of fires in the U.S. has decreased by about 20 percent during the past 10 years, the number of heart attack fatalities has stayed relatively unchanged," as has the number of injuries from slips, trips and falls, said Gavin Horn, research program coordinator at the IFSI and a visiting research scientist in the department of mechanical science and engineering in the College of Engineering. Horn and Denise Smith, a research scientist at IFSI and professor of exercise science at Skidmore College, are the principal investigators leading the multidisciplinary study.
With the help of 120 firefighters from fire departments throughout Illinois, the researchers are investigating the effects of firefighting - which combines stressors such as strenuous physical work, intense radiant heat and heavy, restrictive personal protective equipment - on cardiovascular function and mobility. The participants are randomly assigned one of two types of protective gear, either the suits used by many U.S. fire departments or an enhanced suit that attempts to cool the body by circulating the firefighter's exhalations within it.
"The new gear is still encapsulating, and provides the standard burn protection, but it's meant to be more breathable," said Horn, who is a volunteer firefighter for Savoy, Ill. "It's lighter and less restrictive. And all of those things we believe have the potential to lessen heat stress and fatigue."
In the "burn tower" on the fire institute's training grounds, the firefighters engage in 18 minutes of simulated firefighting activities - such as searching for occupants, advancing a fire hose, and forcibly entering a room - on a two-minute work-rest cycle, under conditions similar to those they would experience at a structural fire.
"We're measuring skin and core body temperatures very carefully," Smith said. "We have the firefighters ingest a small sensor that transmits core body temperature to a recorder so we can accurately record changes in body temperature. (In a fire) their core body temperature changes slowly, but their skin gets heated quickly with a lot of blood flow near the surface, so we think it's really important to look at both core and skin temperature."
In their station uniforms and again in protective gear, both before and after the firefighting exercise, the firefighters walk through an obstacle course and on a 30-foot instrumented "gait mat" to record how their balance, mobility and stability are affected by their gear and by fatigue.
The investigators also are interested in baseline measures of cardiovascular health, and record core temperature, heart rates, and a multitude of variables - including blood cell numbers, blood chemistry levels and proclotting and anticlotting proteins - in the firefighters' blood before and after strenuous firefighting. Researchers at the department of kinesiology's Exercise and Cardiovascular Research Lab use ultrasound to measure blood flow and arterial stiffness caused by plaque buildup, which is indicative of early cardiovascular disease and may predict an exaggerated response to the environmental and physical stressors of fighting a fire.
The researchers think their study will be helpful to departmental officials in evaluating and selecting gear for their firefighters, may lead to equipment designs that will reduce injuries and fatalities, and will provide a better understanding of the effects of strenuous activity and heat stress on cardiovascular and coagulatory functions in the general population.
Horn and Smith expect to finish collecting data within the next few weeks, and the research team will issue reports on their findings by summer 2008. They have been invited to present their findings at numerous fire departments that participated in the study and at the 2008 Fire Department Instructors Conference, April 7-12 in Indianapolis.
The study is being funded in part by an $899,000 grant through the Department of Homeland Security's Assistance to Firefighters Fire Prevention and Safety Program. Industry partners Total Fire Group and International Personnel Protection designed and produced the enhanced and standard personal protection equipment being used in the study.
The interdisciplinary research team includes researchers in the departments of kinesiology and community health, psychology, mechanical science and engineering and the College of Medicine at the U. of I.