Finally the newspapers have managed to get their teeth into a tunnel fire story that has been seen, albeit slightly perversely, as a ‘good news’ story. The recent fire during construction of the A86 road tunnel near Paris has proved a golden example of the value of accepting the possibility of risk and acting upon this well before the fact. Once the risks are anticipated, subsequent mitigation and minimisation become clearly definable goals. From an early stage the Socatop construction JV on the A86 tunnel worked alongside the local fire brigade to act out nearly every possible scenario associated with a fire in the confined space of the TBM-driven tunnel. This allowed rigorous and effective emergency procedures to be set in place. At the onset of the fire all 19 workers in the tunnel knew immediately to take shelter inside the TBM and wait to be rescued. The TBM had fire safety features incorporated at the design stage, including a sprinkler system, fire resistant hydraulic oil and emergency oxygen supplies that ultimately proved their worth. Some four hours after the fire started all the workers emerged unscathed, with just one firefighter needing medical attention for smoke inhalation. The regular fire drills combined with the safety feature packed TBM went a long way to prevent an accident turning to tragedy.
Its important not to overlook the implications of this widely broadcast event. It is vital for the tunnelling industry to bury the negative public and media vision that fire + tunnel = multiple casualties. This notion provides a real threat to the possibility of at least some tunnel projects, where alternatives may be sought purely on a perceived safety basis.
Accidents will happen; there are too many variables in construction to believe they won’t and it is a dangerous arrogance to believe otherwise. However small the actual risk, it’s imperative to anticipate the worst-case scenario. Forewarned is forearmed and the foresight shown by all involved in the risk assessment and procedures in the A86 tunnel team should be held as an example.
