回燃，又分为爆燃、复燃，泛指在火灾现场为缺氧燃烧时，因大量的新鲜空气冲入现场，而导致爆发式的剧烈燃烧现象。

爆燃现象，意指在现场通风不良之密闭空间内，当火势已维持了一段时间，空气内氧浓度递减，因燃烧产生的未完全燃烧的碳粒子、一氧化碳——即可燃性气体——积聚，当足够的空气引入火场，与浓烈的可燃气体混合，并达燃烧界限范围内，则在原有火源瞬间引燃下，燃烧猛烈地发生，并引发出一股爆发性的火焰扩散，朝空气入口处冲出室外的现象。

此现象一般在火警发生的后期出现。

A backdraft is a dramatic event caused by a fire, resulting from rapid re-introduction of oxygen to combustion in an oxygen-depleted environment; for example, the breaking of a window or opening of a door to an enclosed space. Backdrafts present a serious threat to firefighters. There is some controversy concerning whether backdrafts should be considered a type of flashover (see below).