Experimental study at reduced-scale of fire spread between electrical cabinets located opposite each other

Abstract

The ability of an electrical cabinet fire to spread to neighbouring cabinets is a major concern for fire safety in nuclear power plants. Twelve intermediate-scale fire tests were performed to determine the fire spread conditions (FSCs) from a burning enclosure (BE) to an opposite enclosure (OE) equipped with either a non-combustible (glazed or metallic) or a combustible (poly(methyl methacrylate), PMMA) front panel. The effects on the FSCs of the separation distance (SD) between the enclosures, the target type (electrical component) contained in the OE and overhead electric cable trays were also investigated. Fire spread to the OE equipped with a glazed panel when the total transmitted heat flux led to the spontaneous ignition of the target. This outcome was not obtained for the metallic panel. For the PMMA panel, fire spread when flames coming from the BE reached the flammable gas mixture produced by the panel. For both glazed and PMMA panels, the FSCs were obtained for higher SDs when overhead electric cable trays were used. The tests also revealed that the faster and more powerful PMMA panel fire was not obtained for the minimum SD studied. Finally, total transmittances of the glazed and PMMA panels were assessed.