New Article Examines Firefighter PPE Performance Under Routine Fire Conditions
A majority of turnout gear research focuses on extreme heat exposures. However, firefighters get burned in lower exposure, ordinary fire conditions, despite wearing full personal protection equipment. It is important that new research tests how firefighter PPE performs under the routine temperatures encountered in typical structure fires.
UL Research Institutes' fire safety research experts recently published a paper in Fire Technology on this topic, “Operational limits of firefighter protective ensembles in non-flaming, pre-flashover exposures.” This article outlines how researchers exposed PPE to typical pre-flashover temperatures and measured the potential safe operational time for firefighters.
Testing Firefighter PPE Under Realistic Firefighting Conditions
To determine the potential safe operation time, the researchers developed a novel instrumentation package. They used a copper slug calorimeter — a sensor whose predictable thermal response is used to estimate how human skin would absorb heat. Then, they exposed swatches from PPE used by two major U.S. fire departments to temperatures ranging from 100°C to 300°C (212°F to 572°F). These temperatures represent what firefighters encounter during routine structure fire operations.
Each type of firefighter PPE was monitored during temperature exposure to determine exactly when the copper calorimeter reached the critical temperature at which second-degree burns can occur in skin (55°C or 131°F). This approach also allowed researchers to measure the thermal protective performance in convective (i.e., moving air) environments up to 300°C (572°F), with air speeds of 0.5 meters per second, closely mimicking real fire conditions.
Key Findings Reveal Critical Gaps in Firefighter PPE Protection
The study's results challenge current assumptions about how long firefighters can safely operate in pre-flashover fire environments while wearing standard protective gear. The key findings are as follows:
- Time for potential second-degree burn injury ranged from approximately 1,000 seconds (about 17 min.) at 100°C to approximately 100 seconds (less than 2 min.) at 300°C, falling below estimated safe operational times for firefighters once exposure exceeds 100°C.
- There were no significant differences in performance between the two types of firefighter PPE, suggesting that these trends are not specific to a single ensemble of PPE.
- There is an exponential decay relationship between potential burn injury time and exposure temperature, meaning protection time drops dramatically as temperature increases. This relationship can be used to predict burn risk at temperatures not directly tested in this study.
"These results indicate that current thermal operating guidelines may not adequately protect firefighters in routine fire conditions. This research reveals a potential gap between expected safe operating times and actual thermal protective performance, providing firefighters with important data about how their protective clothing responds to varying heat exposures."
—Thomas DiPietro
Research Engineer
UL Research Institutes | Fire Safety Research Institute
This research provides the foundation for developing more realistic safety guidelines and offers a method for estimating safe operational times for firefighter PPE in pre-flashover fire conditions.
About Fire Technology
Fire Technology is a scientific journal that publishes original contributions, both theoretical and empirical, that contribute to the solution of problems in fire safety science and engineering. It is the leading journal in the field, publishing applied research dealing with the full range of actual and potential fire hazards facing humans and the environment. It covers the entire domain of fire safety science and engineering problems relevant in industrial, operational, cultural, and environmental applications, including modeling, testing, detection, suppression, human behavior, wildfires, structures, and risk analysis.
