After more than five years of reconstruction, Notre-Dame de Paris Cathedral finally reopens its doors to the public on December 8. To prevent another disaster from damaging it, a new fire protection system was installed.
An ultra-modern facility. Notre-Dame de Paris, restored identically while respecting its original materials, now benefits from new fire safety in its oak frames. A mechanism that can create a fine mist of water to “fight directly” an outbreak of fire, notes Rémi Fromont, one of the three chief architects in charge of the restoration.
This unique misting system in a cathedral in France is “a response to the disaster of April 15, 2019. The spread of the fire was studied in detail”underlines Philippe Jost, president of the Rebâtir Notre-Dame public establishment. Stating that “the entire protection system has been redesigned by also integrating prevention, detection, etc. ».
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Microdroplets to smother flames
Discreet pipes were installed in the attic, “ready to release via nozzles produce microdroplets which can saturate the atmosphere, lower the temperature and smother the flames. The water, pressurized using devices installed in a crypt under the nave, is sent immediately in the event of an alert. » The food was also “reinforced on the Île de la Cité to be available at the cathedral”.
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This fire-fighting mechanism is accompanied by two fire walls in the frame. “We inserted plaster partitions on a steel structure between the wooden trusses (large triangle-shaped assemblies) at the base of the spire, continues Philippe Jost. This makes it possible to divide the large attic into three airtight volumes, to combat the spread of a fire. » The “containment was also improved with a thickening of the battens”, thin wooden planks on which the lead plates of the roof rest.
To complete the arsenal, the effort finally focused on detection. “The key is responsiveness. Dozens of detectors and thermal cameras are deployed and connected to a very well-equipped security PC to allow immediate intervention.” All this correlated “to new electrical equipment which, when brought up to standard, improves prevention”, underlines the president of Rebâtir Notre-Dame, convinced of the benefits of this new system. Like Rémi Fromont, who nevertheless assures with a smile: “I don’t want to test it. »
