Radiative Characteristics of Fire Fighters' Coat Fabrics JAMES QUINTIERE Fire Technology Division National Bureau of Standards The implications of the results of spectral reflectance measure- ments reported here are considered for thermal protection and comfort of clothing worn by fire fighters. p ROTECTIVE clothing worn by fire fighters must serve many func- tional purposes. One important function is the thermal protection and comfort of fire fighters during exposure to fires or during work in a normal climatic environment. Optimizing clothing for these functions involves consideration of many factors. In short, the clothing must be capable of protecting the wearer from severe exposures to heat transfer from fires; it must be sufficiently ventilated to permit the dissipation of metabolic energy from the body to prevent heat stress; and it must be comfortable to wear in normal environments. Each of these factors must be quan- titatively understood before protective clothing for fire fighters can be properly evaluated. This report examines only the radiative contribution to the external heat transfer to fire fighters' coats. The more complex problem of con- vective heating in a fire environment and the internal heat transfer pro- cesses within a garment will not be addressed at this time. The radiative heating load depends on the source of radiation and on the reflectance of the surface receiving the radiation. The reflectance of the fabric will depend on the fiber material, dye, and fabric construction. The radiative heat flux, q~, absorbed and transmitted by the fabric can be expressed as co q~ = :o (i - p~) E~dx (i) where ox is the spectral reflectance and Ex is the incident spectral radiative heat flux. The quantity Ex can usually be expressed as Ex = FexMx (2) where F is a form factor, e~ is the spectral emissivity of the source, 153