Risk Management for Tunnels

Road and rail tunnels have unfortunately remained a matter of debate following the catastrophic losses experienced in recent years. Fire protection is inadequate in many tunnels, making the rapid evacuation of victims almost impossible in some cases.

The result is frequently a large number of tragic injuries and fatalities (examples are fires in the Mont Blanc and the Hohe Tauern tunnels, both located in the Alps, as well as in the Kitzsteinhorn glacier railway in Kaprun), considerable infrastructural damage, liability losses and loss of income due to the break in operations.

The risk which the accumulation of property and liability losses poses for insurers is difficult to calculate. The most recent tunnel fires – mentioned above – were tragedies involving the loss of numerous lives, although other worst-case scenarios are conceivable from the point of view of property insurance.

What was probably the largest tunnel loss to date occurred in Kabul, Afghanistan, in 1982, when a military vehicle collided with a tanker truck in the 3-km-long Salang Tunnel and caused an explosion. It was never established whether the military vehicle was carrying explosives. According to official statistics, 700 people lost their lives, but experts claim the figure to be as high as 2000. Large sections of the tunnel collapsed on account of the immense heat.

The loss potential and magnitude will be presented here from the point of view of property and third-party liability insurance with the aid of examples. Insurers will have to consider the safety standards and contractual conditions for underwriting the tunnel risk even more closely in future. This will have a major effect on insurability and on premiums.

It will be crucial to develop a tailor-made risk management concept for every single tunnel. Attention will primarily focus on the long tunnels with high traffic density. In addition to suitable escape and approach routes, as well as efficient ventilation systems, the requirements for structural, operational and organisational fire protection must also be taken into account – as for every building.

Loss analysis and statistics

Tunnel structures must be viewed as highly exposed risks during the construction phase and when the completed risks cover is in force. The main risks during operation are inflow of water, earthquakes, collapse and above all fire.

The most probable loss scenario for underground traffic facilities (tunnels, railway stations) is an uncontrollable fire, for instance if a vehicle in a tunnel were to be consumed by a total fire. Depending on the cause, a total fire involving a motor car can develop within roughly 10 minutes and within 20 to 30 minutes in the case of a lorry.

A total vehicle fire in a road tunnel can generate so much heat that the fire may spread to nearby vehicles. The maximum heat is reached after roughly half an hour. Experience has shown that a fire spreading from car to car at a distance of between 0.4 and 0.8 m is fairly rare. In the case of the 1999 Mont Blanc Tunnel fire, however, the fire spread very rapidly because the lorry was laden with margarine and flour. The high fire load and ventilation conditions contributed to the rapid spread of flames to other vehicles.

Moreover, fuel and plastic components in motor cars are additional fire loads leading to high smoke emissions. When a fire burns out of control, people are in acute danger on account of the toxic fumes, immense heat, severely restricted visibility, inadequate possibilities for escape and evacuation and as a result of panic on the part of those affected. These factors usually prevent the emergency crews and fire fighters from reaching the scene of the fire quickly.

There are two main causes for tunnel fires: either they are caused by technical defects or they are the result of a traffic accident. The former is the more common cause. Fire is 20 times more likely to break out in a road tunnel than in a railway tunnel.

There have been no major fires with large numbers of people suffering bodily injury in railway tunnels in the recent past, although very many people would be affected if a train were to catch fire, as serious fires in underground railway stations have shown.