Comprehensive assessment of the thermal aging effects on fire risks of PVC cable

There is still a disagreement on how aging affects the risk of cable fire. In order to comprehensively assess the aging effects on cable fire risks, a series of cone calorimeter tests and flame spread experiments on accelerated thermal aging PVC cables were carried out with various thermal aging time. A large amount of fire characteristics was measured, including the ignition time (TTI), heat release rate, critical heat flux, fire performance index (FPI) and fire growth index (FGI) by cone calorimeter tests, as well as flame spread and dripping behaviors by flame spread experiments. Results showed that the values of TTI, FPI and the dripping frequency are increased with thermal aging time, but the maximum heat release rate, flame spread rate, FGI are decreased. It is evidenced that the thermal aging PVC cables have lower ignition risk, heat release risk, fire growth risk, but have a higher risk of dripping and igniting surrounding combustibles. This work may provide an in-depth understanding of fire risk of thermal aging cables.