Electrical cable is a common fire risk and hazard, and once ignited, a cable fire can spread to other rooms and floors by following the direction and location of cables. This work investigated the ignition and upward flame spread over the 1-m long cable under a growing heat flux. Results showed that the flame-retardant cables could be easily ignited by a small flame after a weak irradiation (5 kW/m²) if preheated to 70°C. As the external radiation increases, the cable surface temperature increases, and the upward flame spread rate increases significantly. Once the cable surface reaches 240°C, piloted ignition can be achieved. With the combined effect of external heating (> 18 kW/m²) and smoldering, auto-ignition could be achieved once the cable sheath reaches 500 °C. Moreover, flame-retardant cable fire is intense with severe melting, dripping, swelling, and cracking. The falling cracks and dripping flow can form a pool fire to increase the fire hazard. Finally, a new fire-zone diagram with the surface temperature and critical mass flux was proposed to quantify the cable fire hazard. This work provides important information about fire behaviors of the flame-retardant cable under a real fire scene and may guide the design of fire-resistant cables.

Graphical abstract

中文翻译：

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阻燃电缆着火区图：着火和向上火焰蔓延

电缆是常见的着火危险和隐患，一旦被点燃，电缆着火会通过遵循电缆的方向和位置传播到其他房间和地板。这项工作研究了在不断增加的热通量下，在1米长电缆上的着火和向上火焰蔓延的情况。结果表明，如果将电缆预热至70°C，则在弱辐照（5 kW / m ²）后容易被小火焰点燃。随着外部辐射的增加，电缆表面温度升高，并且向上的火焰蔓延速率显着增加。一旦电缆表面达到240°C，就可以实现引燃。结合外部加热（> 18 kW / m ²）和阴燃，一旦电缆护套达到500°C，就可以自动点火。而且，阻燃电缆着火非常激烈，会发生严重的熔化，滴落，膨胀和破裂。下落的裂缝和滴流会形成水池着火，增加火灾隐患。最后，提出了一个新的具有表面温度和临界质量通量的火区图，以量化电缆的火灾隐患。这项工作提供了有关阻燃电缆在真实火灾现场下的燃烧行为的重要信息，并且可以指导耐火电缆的设计。

图形概要