Creating a protected safety zone and escape corridor for tunnel by-passes

Zitrón has developed the MODULBYP unit to provide a protected safety zone and escape corridor for transport tunnels. Each unit contains connections with the tunnel’s electricity supply grid and data network, thereby enhancing safety measures and rapid communication with support services.

The unit has been designed to comply with all national and European Union regulations and directives for tunnel safety, which stipulate the need for pedestrian cross-connections and entryways with a maximum separation of 300 metres between the two channels of a tunnel.

The cross-connections between the two channels of the tunnel are aimed at providing a guaranteed escape route to the outside and the possibility, where space permits, of a temporary shelter for the safety of users in the event of a fire.

Patent Nº MI2009A2211

Interior view of MODULBYP wall, characterised by the presence of a space for housing the electrical controls that also serves as an SOS column. It is equipped with lighting, ventilation, fire resistant closure, ethernet switch, PLC unit, installation for exterior communication, fire detection centre and extinguisher.

Outer view of the tunnel-side of the MODULBYP wall, built with an isolating panel that guarantees REI120-rated fire protection. It consists of two pedestrian doors and axial ventilation with a fire resistant valve.

Technical features

  • Built pursuant to the guidelines established by the European Directive 2004/54/CE.
  • Modular construction with a prefabricated structure that allows for precise assembly in the by-pass channel.
  • REI120-rated fire protection.
  • Double pedestrian door that opens on contact.
  • Ventilation system that guarantees the correct pressurisation of the by-pass zone.
  • Pre-installed safety and communications systems, in addition to an autonomous redundant power supply that guarantees the correct operation of the module at all times.
  • Electrical power supply with direct connection to outside substations.
  • Interface for connection to the data network.


  • Standardisation of the construction of the by-pass cross-connections.
  • Modular “turnkey” installation.
  • Reduction of the time taken to carry out installations.
  • High level of safety.

Ventilation and fireresistant closure

Presence sensor

Smoke detector

Lighting, loudspeaker
and retroreflectors

Fire fighting control

LCD touch screen
and video camera

SOS panel buttons


Response centre