An experimental study on the fire characteristics of new and aged building wires using a cone calorimeter

Author: Wang Zhi, Wang Jian

Keywords: Thermal aging, Electric cable, Piloted ignition, Cone calorimeter, electrical cables, heat, oxygen, Thermodynamics, Chemistry

Abstract:

The fire behavior of one flame-retardant PVC cable used as building wire is investigated in this work. Bench scale tests were performed using a cone calorimeter. The influence of two key factors, namely incident external heat flux and thermal aging, on the cable fire characteristics is considered. The mass fraction, heat fraction, time-to-ignition (TTI), heat release rate (HRR), emissions and residues were measured. The TTI increases with the thermal aging time, and the peak heat release rate (pHRR) decreases for aged cables. Thermal aging can modify the chemical compositions and structures, leading to further changes in combustion. The higher heat flux caused a higher HRR and a lower burning duration for the studied new and aged cables. The difference in TTI and pHRR for new and aged cables is insignificant for higher external heat fluxes. Finally, the prominent effect of thermal aging on emissions and residues was highlighted using varying external heat fluxes. This work adds to the understanding of the difference in burning performance between new and aged building wires.