Analysis of fire spread behavior and influencing factors in flat roof photovoltaic arrays

With the widespread application of flat-roof photovoltaic systems, the risk of fire spread in photovoltaic arrays has gradually attracted attention. To study the influence of different factors on the fire spread behavior of flat-roof photovoltaic arrays, this paper uses the Fire Dynamics Simulator (FDS) to establish a 7 × 7 photovoltaic module array model. Based on the control variable method, it analyzes the effects of roof materials, the inclination angle of photovoltaic modules, and the vertical spacing between the modules and the roof on the flame spread process and the changes in the flame front. The results show that concrete roofs have a better inhibitory effect on longitudinal fire spread, and the time required for the flame to spread to the next row is 105 s longer than that of the asphalt felt roofs; when the inclination angle is 15°, 25°, and 35°, the time for the flame to spread to the next row is 238 s, 230 s, and 245 s, respectively, with small differences; and when the distance between the module and the roof is increased to 3.0 m, the time for the flame to spread to the next row is 305 s longer than that of the 1.0-m condition. The study showed that roof materials, module inclination angles, and the distance between the roof and the photovoltaic modules affect the fire spread behavior of flat-roof photovoltaic arrays. Among them, roof thermal feedback, the flame adhesion state, and the conditions under the plates are important factors affecting flame propagation, which can provide references for the analysis of fire risk and fire prevention design of flat-roof photovoltaic arrays.