Modelling of heat release rate of horizontal cable trays fire in long-narrow confined spaces

The occurrence of cable fire accidents will cause casualties, large-scale power outages, communication interruptions, traffic chaos, property losses, etc., which will have a serious impact on social life and the economy. Compared with the fire in open spaces, the consequences of the fire in confined spaces will be more serious. In this study, the cone calorimeter test of cable samples and the experimental study of flame spread of horizontal cable tray in a long-narrow confined space are carried out. The effects of layer spacing and cable spacing on flame front and extinction front, mass loss rate and heat release rate (HRR) are systematically investigated. Results indicated that the peak value of HRR is the largest when the cable spacing is one or two times the cable diameter, and the peak value increases first and then decreases with the increase of the layer spacing. Based on flame spread and average heat release rate per unit area of cable (HRRavg), a prediction model of heat release rate in long-narrow confined space is established. Compared with the previous models, the accuracy of prediction is improved, especially the prediction of HRR peak. The research results can improve the understanding of the danger of cable fire hazards in long-narrow spaces and provide a reference for the development and revision of cable laying standards.