The Fréjus cross-border tunnel, opened on 1980, was initially designed as a single lane bidirectional tube, equipped with a transverse ventilation system and 11 safety refuges, around one per kilometer.


The European directive of 2004 about the trans-European network tunnels demands these refuges to be located every 500m max. The technical solution selected for the Fréjus Tunnel was to dig a new safety gallery with 34 linking hallways between the existing tunnel and this gallery. In parallel to this, the Project Owner decided to replace the entire ventilation system of the tunnel in order to adapt to its design life’s end issues as well as increase its performance rate.


In 2012, the tunnel’s capacity was reassessed, and it passed to a single lane monodirectional tube tunnel. The ventilation system had to be updated to cope with the new operations conditions.




setec tpi ensures the Design & Construction Project Management of the replacement of the existing tube’s ventilation system for both operational and construction phases. During the latter, very important to respect the most optimal safety requirements in an infrastructure that remains operational while under construction. At the same time, setec tpi supports the tunnel’s Project Owner and Operator in:

  • The management of the ventilation interfaces with the new tube
  • The management of the implementation of both temporary and operational ventilation systems
  • The production of the Safety File of the double-tube infrastructure in cases of fire and evacuation


Finally, setec tpi also ensures the D&C PM of the lay-out of the French face of the tunnel, including the integration of a retention basin and the shifting of the fresh air inlet of the ventilation facility.


Key information


Client: SFTRF (French side) et SITAF (Italian side)

Operator: Groupement d’Exploitation du Fréjus (GEIE GEF)

Design & Construction PM JV:

  • setec (setec tpi leader) for the replacement of the ventilation of the tube 1
  • setec (setec tpi leader), BG for the management of the ventilation interfaces  between the 2 tubes and the production of the Safety File for the project’s extension to 2 tubes
  • setec (setec als leader) for the lay-out of the French face of the tunnel

Duration: 2011-2022


©setec tpi

In a Nutshell

1new monodirectional tube
34new linking galleries
1retention basin


Fréjus Tunnel: 13Km-long cross-border tunnel opened in 1980


Existing project’s key features:

  • 1 no. single lane bidirectional tube
  • Transverse ventilation: “stratify” and extraction of smoke in ceiling
  • 11 safety refuges, one every kilometer


Configuration 2021 :
 2 no. monodirectional double lane tubes with 34 linking galleries


  • Replacement of the ventilation system of the existing tube

  • The new ventilation equipement's exceptional features: 1MW engine and variable blade setting.
©setec tpi