9. Tunnel response to fire
The materials used in the structures and equipment of a tunnel should neither burn nor produce large quantities of toxic smoke if a fire occurs in the tunnel. In addition, in such an event, the structures must not collapse while users or emergency services personnel remain inside the tunnel and critical safety equipment must continue to function at least until evacuation and fire-fighting operations are completed.
These general objectives are dependent upon the reaction to fire of the materials and the resistance to fire of the structures and equipment:
- The reaction to fire of a material characterises its ability to take part in a fire to which it is exposed, including by its own decomposition (e.g. combustion).This is discussed in Section Reaction of Materials to fire.
- The resistance to fire of a structure or a piece of equipment characterises its ability to keep on fulfilling its function despite the development of a fire. Structures are considered in Section Resistance to fire of structures, while equipment is considered in Section Resistance of equipment to fire.
This Chapter was written by Robin Hall and Working Group 4 of the C4 committee (2008-2011) in which:
- Robin Hall (UK) coordinated the work and wrote the full chapter
- Fathi Tarada (UK) and Ignacio del Rey (Spain) reviewed the full chapter.