High Throughput Flammability Characterization Using Gradient Heat Flux Fields

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Abstract The quest for small-scale flammability tests useful for predicting large-scale fire test performance is an enduring undertaking. Often, this work is motivated by limited access to larger quantities of samples, in the case of materials development efforts, and by the slow turn-around and high cost of large scale flammability testing. Use of Cone calorimeter data such as heat release rate (HRR) and ignition data has been coupled with various models to attempt to predict the performance of materials in medium and large scale fire tests. In some instances this has been successful; however, the extensive amount of data that needs to be acquired has motivated the High Throughput (HT) Flammability program at the National Institute of Standards and Technology (NIST) to develop flammability characterization methods which significantly increase the rate of data generation. The goal is to keep pace with our sample preparation rate, which is a significant challenge since our capability to produce samples, either extruded rod, or gradient coatings, has developed to a rate of one sample per minute! The efforts described here are those specifically focused at developing HT flammability analysis methods. The method of evaluating the flammability of a sample at a variety of fluxes simultaneously involves use of a radiant panel to create a gradient heat flux field. Samples are ignited in the high flux region and burned until they self-extinguish. The local flux at this position is termed the minimum flux for flame spread (MFFS). The same general technique has also been accomplished on a smaller scale using the Cone calorimeter. Here MFFS and HRR can be measured concurrently.