EBOB - Solar cell installations on buildings. Fire spread and safety for fire services.

The aim of the project has been to answer the following four research questions: 1. How do wind speed and air gap size affect the fire development in the cavity between the solar cell module and the underlying roof structure, and how do these factors affect the extent of damage to the underlying roof structure? 2. How do solar cell modules affect a fire on a realistic, Norwegian, pitched roof? 3. What work is ongoing in Europe and internationally to developing test methods for fire technical documentation of photovoltaic modules, and how should this be implemented in Norway? 4. How should fire service personnel be secured in their work when the fire includes solar cell installation? In this research question, larger installations beyond residential houses and detached houses are also relevant, including larger buildings, flat roofs and BIPV. To answer research questions 1 and 2, a total of 29 experiments were performed with fire spread in the cavity behind solar cell modules on pitched roof surfaces. The experiments were performed at RISE Fire Research's laboratory in Trondheim in 2021. This main report (RISE report 2022:82) summarizes the entire project, and additional details from the experiments performed are given in a separate technical report (RISE report 2022:83). The main findings from the experiments are that solar cell modules mounted parallel to the roof surface on pitched roofs can affect the fire dynamics of a fire on the roof surface. It was found that both the length of the damaged area on the roof and the temperature rise inwards in the roof (below the chipboard) increased when the distance between the simulated solar cell module and the roof surface decreased. Furthermore, the findings indicate that there is a relation between the size of the gap between the roof surface and the solar cell module, and how large initial fire is needed for the fire to spread. A larger distance between the roof surface and the solar module requires a larger initial fire for the fire to spread. The temperature increase inwards in the roof structure was not large enough in the experiments performed to pose a danger of immediate fire spreading inwards in the structure. Work is ongoing internationally on the development of test methods for fire technical documentation of solar cell modules. This work has so far not resulted in new standards or procedures that can be implemented in Norway. Information has been found from various guidelines and reports on what equipment and expertise the fire service needs to secure their efforts. It is important that the fire service has sufficient knowledge about the working principle of a solar cell installation, so that they understand that parts of the installation can conduct electricity, even if the switch-off switch is activated. The fire service must also be given training in how to handle a fire in a building with a solar cell installation, as well as what protective equipment and tools are needed. The answers from the various fire services to a questionnaire show that solar cell installations rarely are included in the risk and vulnerability analyses (ROS analyses). As a consequence, they do not currently have good enough training and knowledge about handling fires in buildings with solar cell installations. The questionnaire also shows that it seems somewhat unclear to the fire service what responsibility they have in the event of a fire in solar cell installations. This should be clarified, and in cases where solar cell installations pose an increased risk, the fire service must be provided with resources so that they have the right equipment, the right competence, and the right staff to handle such fires.