Abstract: Foam is widely used because of its good properties, but it is flammable and poses a major safety hazard. In this work, the effects of liquid droplets produced by electrical wires at different heights (10, 20, 30, 40, and 50 cm) on the ignition of three types of foam insulation materials (EPS, RPUF, RPUF+EG10) were investigated by means of experimental methods, including droplet fall, flame height, flame temperature, and heat changes. The results show that the droplet process of droplets at different heights exhibits different drip phenomena, there is a "flame up" and "flame out" phenomenon. The penetration or combustion behavior of the three foams are positively correlated with the number and height of droplets dropped, EPS foam will be penetrated by high temperature droplets, while RPUF and RPUF+EG10 foam will be ignited by high temperature droplets, and the burning intensity of RPUF foam is much greater than that of RPUF+EG10 foam. The flame height of the wire insulation was inversely affected by the flame height of the RPUF foam surface, with the wire insulation extinguishing at heights of 10, 40, and 50 cm. Also, at the end of the RPUF foam combustion, the droplet flame remained adhered to the carbon layer, producing two temperature peaks during the combustion of the RPUF foam. On the other hand, the RPUF+EG foam formed a small pool fire with temperature stabilisation. In the combustion process, RPUF foam has a heat received increasing zone and a heat stabilisation zone, and the heat emitted from the combustion of the RPUF+EG10 foam will keep increasing with the formation of small pool fires on the foam.

Key words: foam insulation, electrical wire, drops, flame height, flame temperature

摘要： 泡沫由于具有保温性能好、防水性好、节约能源等优良性能而常被用于建筑物外墙保温材料，但由于其具有易燃性，存在火灾隐患。本工作通过实验的方法研究了不同高度下电线燃烧产生的液滴对三种泡沫保温材料的引燃影响。结果表明，液滴在不同高度下的滴落过程存在不同的滴落现象，普通的聚苯乙烯泡沫(EPS)会被液滴滴穿；而硬质聚氨酯泡沫(RPUF)及其加入石墨(EG)的泡沫则会被点燃，被点燃的RPUF还会反过来影响聚乙烯(PE)管的火焰；但RPUF+EG10泡沫上的火焰较小，对PE管上的火焰影响较小。在RPUF泡沫燃烧结束时，PE管滴落的火焰仍可以在碳层上附着，使RPUF泡沫在燃烧过程中存在两个温度峰值，但RPUF+EG10泡沫会形成小型池火，使温度稳定在一个区间内。RPUF在燃烧过程中产生的热量可分为三个区域，而RPUF+EG10泡沫燃烧时，热量较小且会一直增加。

关键词: 泡沫保温材料, 电线, 滴落, 火焰高度, 火焰温度