Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
Fire fighters, astronauts and racecar drivers among others use protective clothing made of fire retardant fabrics in order to prevent injuries such as skin burns in the case of a fire. Once ignition occurs, fire retardant fabrics reduce or stop the spread of fire depending on the environmental conditions. Fire-retardant fabrics are primarily intended for use in air (21% O2 and 79% N2), however there are some applications in which oxygen concentration can be higher than 21%, such us space shuttles. This research examines the effects of oxidizer flow velocity, oxygen concentration and external radiant flux in the flammability of Nomex, which is a fire retardant fabric currently used by NASA to make space suits. Experiments are conducted by exposing a sample to a decaying radiant heat flux until it reaches steady state; at this point an igniter wire is used to ignite the fabric. Results showed that as oxygen concentration increases the amount of radiant flux required for flame propagation decreases. Moreover, the experiment demonstrated that the flammability of fire-retardant fabrics is affected by environmental variables such as externally applied heat fluxes, oxygen concentrations, and oxidizer flow velocities.