Nazaré Shonali, Pitts William M, Shields John, Davis Rick
Fire Research Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8665, USA.
Polymers (Basel). 2016 Sep 19;8(9):342. doi: 10.3390/polym8090342.
The main objective of the work reported here is to assess factors that could affect the outcome of a proposed open flame test for barrier fabrics (BF-open flame test). The BF-open flame test characterizes barrier effectiveness by monitoring the ignition of a flexible polyurethane foam (FPUF) layer placed in contact with the upper side of the barrier fabric, exposed to a burner flame from below. Particular attention is given to the factors that influence the ignitibility of the FPUF, including thermal resistance, permeability, and structural integrity of the barrier fabrics (BFs). A number of barrier fabrics, displaying a wide range of the properties, are tested with the BF-open flame test. Visual observations of the FPUF burning behavior and BF char patterns, in addition to heat flux measurements on the unexposed side of the barrier fabrics, are used to assess the protective performance of the BF specimen under the open flame test conditions. The temperature and heat transfer measurements on the unexposed side of the BF and subsequent ranking of BFs for their thermal protective performance suggest that the BF-open flame test does not differentiate barrier fabrics based on their heat transfer properties. A similar conclusion is reached with regard to BF permeability characterized at room temperature. However, the outcome of this BF-open flame test is found to be heavily influenced by the structural integrity of thermally degraded BF. The BF-open flame test, in its current form, only ignited FPUF when structural failure of the barrier was observed.
本文所报告工作的主要目标是评估可能影响拟议的阻隔织物明火测试（BF - 明火测试）结果的因素。BF - 明火测试通过监测与阻隔织物上侧接触的柔性聚氨酯泡沫（FPUF）层的着火情况来表征阻隔效果，该FPUF层从下方暴露于燃烧器火焰中。特别关注影响FPUF可燃性的因素，包括阻隔织物（BF）的热阻、渗透性和结构完整性。使用BF - 明火测试对多种具有广泛性能的阻隔织物进行了测试。除了对阻隔织物未暴露侧进行热通量测量外，通过目视观察FPUF的燃烧行为和BF的炭化模式，来评估BF试样在明火测试条件下的防护性能。在BF未暴露侧进行的温度和热传递测量以及随后根据其热防护性能对BF进行的排名表明，BF - 明火测试无法根据热传递性能区分阻隔织物。对于在室温下表征的BF渗透性也得出了类似的结论。然而，发现这种BF - 明火测试的结果在很大程度上受到热降解BF结构完整性的影响。目前形式的BF - 明火测试只有在观察到阻隔层结构失效时才会点燃FPUF。
