Abstract
Polyvinyl chloride (PVC) is widely applied in cables as insulation materials, which are vital for operation and control of industrial processes. However, PVC cables fires frequently occur, arousing public concern. Therefore, experimental methods are used to study flammability and flame-spread characteristics of PVC cable in this paper. Influences of cable structure and number are investigated, which is scanty in previous works. As cable core number of single cable or cable number of multiple cables rises, average flame height and width increase while the increment decreases. Formulas concerning dimensionless flame height and single cable diameter (or total width of multiple cables) are obtained. The former is negatively correlated with the latter. For single cable, convective heat transfer is dominant, and flame-spread rate decreases as cable core number increases. Cable maximum temperature, which drops first and then rises as cable core number increases, is observed in the cable core area. For multiple cable, the flame-spread rate increases as cable number increases. As the cable number rises, the length of pyrolysis and combustion zone increases while the maximum temperature of cable surface decreases. This work is beneficial to fire hazard evaluation and safety design of PVC cables.