Background
Recent fire incidents involving photovoltaic (PV) systems installed on flat roofs have raised critical concerns regarding the fire safety of such roofing configurations, both in new constructions and during retrofitting projects. In response, the IVH, in collaboration with EUMEPS, has undertaken a series of comprehensive, large-scale fire performance tests.
This paper specifically examines the effectiveness of adding a glass fleece layer beneath the waterproofing membrane as an extra fire protection measure for Building Applied Photovoltaic Systems (BAPV) on flat roofs.
The results indicate that expanded polystyrene (EPS) flat roof systems, when properly configured, can achieve safe fire safety performance even when PV systems are installed. These findings provide validated design strategies for improving the fire safety of EPS-based flat roofs in both new buildings and refurbishment projects.
Summary of Results
- The highest overlapping installation of glass fleece sheets led to a reduced horizontal spread of fire on the flat roof in the test setup than the test with single-layer glass fleece installation between PVC waterproofing and EPS insulation
- The cement-bonded particleboard, which was installed as the lower layer of the flat roof, effectively prevents fire from penetrating through the roof into the building, thereby stopping vertical fire spread
- The fire self-extinguished during the observation period
- The tests conducted with the specific described setup and materials demonstrated that the fire risk associated with an EPS flat roof system, with BAPV systems installed, can be mitigated. This can be achieved by adding an additional layer of glass fleece or by maximizing the overlap (by overlapping the sheets by half their width) between the PVC waterproofing and EPS insulation. These findings apply to both solid flat roof constructions and lightweight industrial roofs. The results reveal feasible solutions to enhance fire safety on EPS flat roofs equipped with PV systems. Therefore, EPS can be utilized for safe, efficient, and cost-effective new construction and modernization projects.
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