Thermal Performance of Fire Fighter's Protective Clothing Part 1. Numerical Study of Transient Heat and Water Vapor Transfer.
Thermal Performance of Fire Fighter's Protective
Clothing Part 1. Numerical Study of Transient Heat and
Water Vapor Transfer.
Prasad, K. R.; Twilley, W. H.; Lawson, J. R.
NISTIR 6881; 36 p. August 2002.
Order number: PB2003-10085
protective clothing; fire fighters; mass transfer;
mathematical modeling; fire research; water vapor; heat
transfer; thermal radiation; numerical models; moisture
This study is the first in a series of reports on
understanding the performancThis 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 fire fighter protective clothing.