Background and objectives
A series of fire incidents involving photovoltaic (PV) systems installed on flat roofs has prompted a critical evaluation of their implications for overall fire safety, both in new constructions and in the refurbishment of existing buildings.
In response, EUMEPS and IVH have initiated a comprehensive program of full-scale fire testing under realistic conditions to investigate the dynamic interaction between PV components and flat roof assemblies.
This document presents targeted experimental setups designed to assess the effectiveness of cement-bonded particle boards, installed beneath the waterproofing membrane, as an additional 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 cement-bonded particle board installed beneath the roof waterproofing layer prevented the fire from penetrating into the underlying flat roof structure during the test setups. Fire spread above the cement-bonded board was extremely limited and confined to the footprint of a single PV module.
- The test results demonstrate that the cement-bonded board acts as a reliable fire barrier, successfully inhibiting vertical fire penetration into the roof assembly and, by extension, into the building interior. In all test scenarios, the fires self-extinguished within a short timeframe.
- These observations confirm that even in the event of prolonged, undetected PV system fires, there is no immediate risk of full-scale fire development in EPS-insulated flat roofs with PVC membranes, provided that cement-bonded particle boards are incorporated beneath the waterproofing layer.
According to the results of the large-scale fire tests conducted with the specific setup and materials described, the increased fire risk for an EPS flat roof system caused by the installation of a PV system can be mitigated by the additional protection provided by cement-bonded particleboards installed beneath the waterproofing layer. This applies to both solid flat roof constructions and lightweight industrial roofs. Consequently, the fire performance of EPS flat roofs incorporating photovoltaic systems can be improved through appropriate design and material selection. EPS offers a viable option for both new builds and retrofit applications, with considerations for safety, installation efficiency, and cost management.
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