Self-evacuation and smoke extraction devices for the Marseille L2 ring road (link A7-A50), certified SIL2

CLEARSY is carrying out the safety documentation for the closure, self-evacuation and smoke extraction systems for the tunnels of the L2 ring road in Marseille, with and as a subcontractor of Bouygues Energies & Services, leader of the EFE consortium (Bouygues Energies & Services, Aximum and Egis Projects). The EFE consortium is in charge of the design/implementation of all the safety and traffic management systems for the Marseille L2 bypass and all the roads and motorways operated by DIR Méditerranée.

The L2 or A507 bypass (see http://www.l2-marseille.com) is a new 2×3 lane European intra-urban motorway passing through Marseille. It links the A7 and A50 motorways and comprises eight tunnels in covered trenches, two of which are over 1000 metres long. These structures are subject to obligations related to the risk of tunnel fire, which have been particularly studied and reinforced by the French Tunnel Study Centre (CETU). In the event of a fire, it is imperative that users evacuate the tunnel quickly in accordance with the systems defined by the CETU: messages, guidance, barriers, smoke extraction, etc.

Functional safety related to these devices is essential; this is why the CETU has recommended the use of the functional safety standard IEC 61508 and its derivatives for safety functions relating to the tunnels of the L2 bypass. The hazard analysis conducted by CLEARSY and Bouygues Energies & Services has determined a SIL2 IEC 61508 safety integrity level for the functions concerned.

The functional safety approach was carried out from start to finish for the tunnel safety functions (from the supervision station to the equipment). It resulted in a world first: the certification by Bureau Veritas of the safety functions of the tunnels of the Marseille L2 bypass with the SIL2 safety integrity level in accordance with the IEC 61508 standard.