Fire spreading from a real open-doors electrical cabinet to overhead multiple cable trays into a confined and mechanically-ventilated facility

Pascal Zavaleta (1) , Laurent Audouin (1)

1 IRSN/PSN-RES/SA2I/LEF - Laboratoire d'Expérimentation des Feux

Electrical cabinet fire is one of the main fire hazards in Nuclear Power Plants (NPPs). The ability of the fire to spread beyond the burning cabinet is therefore a major concern for fire safety analyses in NPPs. In the framework of the OECD PRISME-2 programme led by the French ‘‘Institut de Radioprotection et de Sûreté Nucléaire’’ (IRSN), three fire tests, named CFS-5 to CFS-7, involving a real open-doors electrical cabinet and three overhead cable trays, are performed. In this study, the main objectives are to investigate the effects of ventilation and types of electrical cable on the fire spread from the electrical open-doors cabinet to the three overhead cable trays. The fire tests are carried out into a confined and mechanically ventilated facility, named DIVA. Both CFS-5 and CFS-6 tests involve a ventilation renewal rate (VRR, defined as the room volume number renewed per hour) of 15 h-1, while the third CFS-7 test early implements a significantly lower VRR of about 1 h-1. For this last one, fire dampers are indeed shutdown 2 min 30 s after the starting of the cabinet ignition. In addition, the overhead trays are filled with two types of electrical cable used in NPPs, named cable C for the CFS-5 test and cable A for both CFS-6 and CFS-7 tests. These tests highlight that fire spreads from the real open-doors cabinet to the overhead cable trays for a VRR of 15 h-1 and whatever the type of cable. However, this last one influences the fire behaviour of the upper cable trays. The cable A trays indeed ignite once and later than the three ignitions highlighted for the cable C trays. Moreover, the cable A tray fire is longer than the three cable C tray fires. The former mainly grows after the cabinet fire while the latter match with the cabinet fire. Finally, for the CFS-7 test, the fire dampers shutdown shortens the cabinet fire and prevents the upper cable trays ignition.

Mots clés: electrical cabinet; overhead cable trays; DIVA facility; fire spread

Domaines: Physique [physics]

Pascal Zavaleta, Laurent Audouin. Fire spreading from a real open-doors electrical cabinet to overhead multiple cable trays into a confined and mechanically-ventilated facility. Interflam 2016 - 14th International Conference on Fire Science and Engineering, Interscience Communications, Jul 2016, Windsor, UK, United Kingdom. 1739 pp. ⟨irsn-04068958⟩