The characteristics of firebrands collected from a recent urban fire in Japan are described. Specifically, this fire broke out from a Chinese restaurant in Itoigawa-city, Niigata, Japan on December 22nd 2016. On the day of the fire, strong winds resulted in rapid fire spread. With the presence of an average wind speed of 9 m/s, the fire quickly spread, resulting in the damage of 147 structures, with 120 of 147 destroyed. The fire was extinguished more than 30 h later. During the fire, firebrands were observed and 10 spot fires were reported. After the fire, investigations were performed and firebrands were collected from the burn site. The size and the mass of firebrands were measured and compared with the available literature data. It was observed that more than 60% of the collected firebrands had less than 0.10 g mass and 2.0 cm2 projected area and the size and the mass of firebrands were independent of the location. The size and the mass of firebrands from this fire were similar to those from another urban fire under similar wind speed and were also compared to those produced from a firebrand generator. The firebrand data set presented here provided valuable insights into how firebrands are generated from structures in actual urban fires. Finally, the description on how a firebrand generator may be used to produce firebrands similar to urban fires yields an important advancement to begin to study such complex phenomena in the laboratory.

中文翻译：

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从实际城市火灾中收集的火标的特征

描述了从日本最近的一次城市火灾中收集到的火把的特征。具体来说，这起火灾是2016年12月22日发生在日本新泻县糸鱼川市的一家中餐馆。起火当天，强风导致火势迅速蔓延。由于平均风速为 9 m/s，火势迅速蔓延，造成 147 座建筑物受损，其中 147 座建筑物中有 120 座被毁。30多个小时后，大火被扑灭。火灾期间，观察到火把，并报告了 10 处火灾。火灾发生后，进行了调查并从燃烧现场收集了火把。测量了火把的大小和质量，并与现有的文献数据进行了比较。据观察，超过 60% 的收集火把质量小于 0.10 g，投影面积小于 2.0 cm2，并且火把的大小和质量与位置无关。这次火灾产生的火种的大小和质量与风速相似的另一场城市火灾的火种相似，并且还与火种发生器产生的火种进行了比较。这里提供的火头数据集为了解实际城市火灾中的结构如何产生火头提供了宝贵的见解。最后，关于如何使用火种发生器来产生类似于城市火灾的火种的描述为开始在实验室中研究这种复杂现象带来了重要进展。