Thermal Capacity of Fire Fighter Protective Clothing

Fire Protection Research Foundation report: "Thermal Capacity of Fire Fighter Protective Clothing" (PDF, 980 KB)
Author: National Institute for Occupational Safety and Health, The National Personnel Protective Technology Laboratory, National Institute of Standards and Technology and North Carolina State University
Date of issue: October 2008


Thousands of fire fighters sustain burn injuries every year. Line of duty injuries to fire fighters have been estimated to cost between 2.8 to 7.8 billion dollars a year. The most devastating off all injuries by every measure of pain, suffering, and cost is the burn injury. Significant numbers of these injuries occur when energy stored within the layers of the protective equipment are suddenly transferred to the fire fighter, resulting in burn injuries.

Protective equipment including turnout coats and pants are designed to insulate a fire fighter from the thermal environment. A series of protective layers and air gaps prevent the energy of the fire environment from being transferred to the fire fighter. However, if the protective layers are compressed, the energy stored within the material can suddenly be transferred to the user and cause burns.

Current product standards and testing protocols do not adequately evaluate the risk caused by this stored energy. Better understanding of the risk and the underlying physics will allow better designs for protective gear to prevent this type of burn injury. A performance metric addressing the amount of stored energy that accumulates in protective clothing under low heat flux conditions characterizing stored energy will lead to the development of more advanced materials.

This project provides helpful information for manufacturers to determine if the choice of materials for a particular design of protective clothing increases or decreases the potential for a low heat flux burn injury. This information supports current standards development activities underway at NFPA and ASTM based on the implementation of a stored energy test apparatus developed at North Carolina State University.

The goal of the project is to understand the thermal performance of fire fighters' protective clothing over a range of fire fighting exposures. This is accomplished by developing new information on the impact of stored energy on the thermal response of fire fighters' protective clothing, and improve test methods to measure this property so that this may be integrated into national consensus standards and training materials. This should ultimately translate into a reduction in the number of fire service burn injuries.

The Research Foundation expresses gratitude to the report authors and the primary team that has prepared this report, including Angie Shepherd and Bill Haskell of NIOSH NPPTL, Roger Barker, Shawn Deaton and Kevin Ross of NCSU, Nelson Bryner and Jeff Taylor of NIST, the Project Technical Panelists, and all others who contributed to this research effort. Special thanks are expressed to the U.S. Department of Homeland Security for providing the funding for this project.

The content, opinions and conclusions contained in this report are solely those of the author.