When choosing boots, firefighters and departments consider a variety of factors, but one of the most common concerns tends to be cost. This quite often leads to the purchase of rubber boots over leather boots. However, many factors that relate to safety should be considered in addition to cost.
Over the years, several studies have been completed that test the differences between wearing rubber or leather firefighter boots. The primary differences that affect safety result from the materials used in the boots and the construction of the boot.
A recent National Institute for Occupational Safety and Health (NIOSH) study on the boots' physiological and biomechanical effect on firefighters confirmed the results of a 1989 University of Delaware study on the same issue. In addition, a 2008 study by W.L. Gore & Associates showed surprising results that contradict the long-standing industry belief about the effectiveness of standard decontamination procedures.
• Boot weight — Boot weight is a major factor in firefighter safety. National Fire Protection Association (NFPA) 2007 statistics indicate that firefighters suffered almost 40,000 injuries in the line of duty either because they fell or because of over-exertion. On average, a pair of rubber boots weighs about 2½ more pounds than a comparable pair of leather boots. Research has demonstrated that each pound of boot weight is equivalent to placing five additional pounds on a firefighter's back. Both the NIOSH and University of Delaware studies proved that this additional weight causes firefighters to consume more oxygen, decreasing the life of their self-contained breathing apparatus (SCBA) by as much as 9%. The University of Delaware study further indicated that 2.65 pounds of additional weight translates to 35.5% more work performed by the firefighters' legs, which increases fatigue after strenuous activities. Essentially, decreasing boot weight means increasing performance and remaining "on site" longer when responding to a fire.
• Fit, comfort and stability — Many anecdotal comments from firefighters support the need for boots to fit well, like a sneaker or hiking shoe. The better a boot fits, the more comfortable it is, with less chance of blisters, foot sores or other foot problems. The University of Delaware study indicated that better fit and stability also improve agility and response time. This study included a test for agility that compared sneakers to leather boots and to rubber boots. The difference in how much time it took each firefighter to run through a 30-foot course wearing sneakers versus leather boots was less than 0.1 second.
According to the study, the fact that sneakers seemed to provide less support for quick stops and rapid turning accounted for the similar performance of sneakers and leather boots.
Many of the participants felt that the leather boots provided more ankle support and traction than the sneakers. On the other hand, it took the firefighters a full second more to complete the course when wearing rubber boots than it did when they wore the sneakers. The study attributed this difference to the extra weight, lateral instability and narrow heels of the rubber boots.
In general, the heels of leather boots have a greater surface area that touches the ground, which in turn provides more stability for the ankle and full body weight. Rubber boot manufacturers are recognizing the need for better support and have started to develop higher-end boots that have soles similar to those of leather boots.
Another issue that affects comfort is the breathability of the boot. Feet can produce up to one full cup of perspiration a day. If perspiration cannot escape from the boot, it can lead to slipping, blisters and other problems that inhibit mobility, cause health issues and compromise safety. Therefore, when considering boots, it is essential to evaluate the boot's ability to breathe.
• Decontamination — Firefighters face a number of contaminants when responding to fires, motor vehicle accidents and other types of emergencies. Thus, when considering a boot, it is important to understand how much protection a boot offers against these types of threats at the emergency scene. However, in addition to being protected against contaminants during exposure, a firefighter must be able to remove the contaminants effectively from the boots.
A 2008 study performed in the laboratories of W.L. Gore & Associates provided surprising results about decontamination of firefighter boots. Prior to this study, the fire industry held the belief that rubber boots decontaminated better than leather boots. Gore's study, however, showed that after a standard decontamination procedure, rubber retained significantly more contaminants than leather (see chart on page 134). One of the significant results was for isooctane (gasoline), a frequently encountered chemical at emergency scenes. The rubber samples retained an average of 288 micrograms per one-inch sample, whereas the leather samples were almost fully decontaminated, containing less than 0.2 micrograms per one-inch sample after decontamination.
• Increasing safety — All of these boot features affect the safety of the firefighter:
- Reducing boot weight increases performance and lowers exertion, thus lowering the risk of injury.
- Constructing a better-fitting boot improves agility and stability, also lowering the risk of injury.
- Using breathable materials increases comfort and reduces moisture, which helps prevent blisters and sores.
- Improving decontamination reduces potential exposure to hazardous chemicals.
WILLIAM F. CANDY, PE, has been the Americas product manager for technical footwear at W.L. Gore & Associates Inc. for five years, after having been a member of Gore's new product development team for six years. He received a bachelor of science degree in mechanical engineering from Lehigh University and a master of engineering in mechanical engineering degree from Villanova University.