基于锥形量热仪的PVC电缆燃烧性能试验研究

A study on the burning behavior of PVC cables in the conic calorimeter test

采用锥形量热仪研究不同型号PVC电缆的燃烧性能。通过改变锥形量热仪的热辐射强度模拟不同规模的火灾,分析火灾中电缆样品的热释放速率、质量损失速率、烟气产生速率等重要参数,研究热辐射强度、电缆护套层厚度对这些参数的影响,以及不同火灾性能参数间的关系。结果表明,热辐射强度越大,电缆的平均热释放速率、质量损失速率和烟气产生速率的峰值越高;电缆护套厚度越大,平均热释放速率、热释放速率的峰值越高,燃烧持续时间越长。由于电缆结构的影响,电缆样品与护套标准片状样品的火灾特性存在差异。电缆样品的试验结果可以更好地反映电缆在真实火灾中的燃烧性能。

The present paper is concerned with an experimental study of the burning behavior of PVC cable by using a conic calorimeter. For the research purpose, we have tested some cables at a few different heat radiant intensities and analyzed a few key fire parameters, such as heat release rate, mass loss rate, smoke production rate, etc. Furthermore, we have also analyzed the effects of heat radiant intensity and the thickness of the jacket on these parameters and the underlying relations among these parameters. Test results of our study have shown that the burning behavior of the cable is different from that of the specimen of sheath material. Our experiments also indicate that the heat releasing process of the cable samples can be divided into four stages, that is, the acceleration stage, falling-off stage, stable combustion stage and finally the decaying stage. It is the four stages that can reflect the fire behavior of cables more comprehensively. In addition, the average heat release rate of the cable tends to rise with the external heat radiant intensity going on. The thickness of the cable sheath can help to increase the average heat release rate and the peak value, too. However, the external heat radiant intensity has litfie effect on the mass loss rate except its peak value, but the thickness of the cable sheath can does. When the residue mass fractions are almost the same, the smoke production rate tends to rise with the external heat rediant intensity. However, the thickness of sheath can only have some effect on the time to reach the peak value.