Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Thermal Performance of Fire Fighter's Protective Clothing 1. Numerical Study of Transient Heat and Water Vapor Transfer



Kuldeep R. Prasad, W H. Twilley, James R. Lawson


This study is the first in a series of reports on understanding the performance of fire fighter clothing, in protecting skin from thermal injury resulting from exposure to high intensity thermal radiation. A detailed mathematical model is constructed to study transient heat and moisture transfer through multi-layered fabric assemblies with or without air gaps. The model accounts for changes in thermodynamic and transport properties of the fabric due to the presence of moisture. Numerical simulations are performed to study heat and mass transport through wet thermal liners (used in fire fighter protective clothing), when subjected to a radiative heat flux from a gas fired radiant panel. Results were found to compare favorably with experimental measurements. The numerical solution is further analyzed to provide a detailed physical understanding of the governing processes. Moisture in the cloth tends to vaporise upon heating and part of it recondenses in the interior of the cloth. It was observed that the temperature of the fabric layers and total heat flux to the skin is significantly influenced by the amount of moisture and the distribution of moisture in the protective clothing. Finally, simulations are performed for a wet turnout coat assembly, to demonstrate the flexibility of the model for designing firefighter protective clothing.
NIST Interagency/Internal Report (NISTIR) - 6881
Report Number


fire research, heat, mass transfer, mathematical modeling, protective clothing


Prasad, K. , Twilley, W. and Lawson, J. (2002), Thermal Performance of Fire Fighter's Protective Clothing 1. Numerical Study of Transient Heat and Water Vapor Transfer, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 24, 2024)
Created August 1, 2002, Updated November 10, 2018