Roof assemblies are known to be vulnerable to firebrands in urban and wildland-urban interface fires. In the 2016 urban fire in Japan (Itoigawa-City Fire), at least 10 structures were ignited by firebrand showers and three of these structures were ignited by firebrand penetration under roof tiles. In this study, the vulnerabilities of Japanese-style roof tile assemblies to firebrand exposures were investigated by using a continuous-feed firebrand generator with applied nominal wind speeds of 6 m/s and 9 m/s. It was observed that Japanese-style roof tile assemblies were more vulnerable than concrete flat, concrete profile, and terracotta flat roof tiles for an applied wind speed of 6 m/s. When the experiments were performed with debris placed underneath the roof tiles, penetrated firebrands ignited debris. Flaming ignition was observed under 9 m/s where flame was observed to protrude from the tiles in an effort to reach necessary oxygen for combustion.

中文翻译：

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日式瓦屋顶组件对火炬暴露脆弱性的实验研究

众所周知，屋顶组件在城市和荒地 - 城市交界处的火灾中容易受到火种的影响。在 2016 年日本的城市火灾（丝鱼川市火灾）中，至少有 10 座建筑物被火焰阵雨点燃，其中 3 座建筑物被屋顶瓦片下的火焰穿透点燃。在这项研究中，通过使用连续馈送火火发生器，应用标称风速为 6 m/s 和 9 m/s，研究了日式屋顶瓦组件对火火暴露的脆弱性。据观察，对于 6 m/s 的应用风速，日式屋顶瓦组件比混凝土平面、混凝土型材和赤陶平面屋顶瓦更脆弱。当在屋顶瓦片下放置碎屑进行实验时，穿透的火把点燃了碎屑。