Experimental Study on Combustion Characteristics and Hazard of the Flame-Retardant Cables in Urban Utility Tunnel

Using a cone calorimeter, considering multiple heat radiation powers, multi-scale research on the ignition and combustion performance of ZRC-YJV22 flame-retardant cables laid in a power cabin of urban utility tunnel, and multiple types of evaluation indicators are used to evaluate each of the ZRC-YJV22 flame-retardant cables. The component is subjected to risk assessment. The results show that: ZRC-YJV22 flame-retardant cable wrapping material is a thermal medium-sized material, and its ignition performance can be judged by the thermal medium-sized material ignition formula; the combustion products of the inner and outer sheath PVC materials obviously contain black grease substances, and droplets may occur during the fire process. Accelerate the development and spread of fire; filling material PE and insulating material XLPE have high heat resistance and good flame retardancy. When the inner and outer sheath PVC material and the filling material PE are fully burned, the HRR curve has a maximum peak value, and the peak value can be maintained for a long time; the HRR curve of the insulating material XLPE has two maximum peak values, and the time interval between the peak values is long; When the power of the heat source is low, the copper sleeve can protect the lining material. The analysis method of FIGRA, FGI and THR are suitable for fire risk research of flame-retardant cable wrapping materials. The research results are expected to provide technical support for the fire safety of ZRC-YJV22 flame-retardant cables laid in the urban utility tunnel.