A tunnel with defective safety measures can become a deadly trap. A collapse of the false tunnel ceiling at one of the ends of the old Vielha road tunnel in February did not cause any victims by pure good luck. There are about 30 tunnels through mountains on Gipuzkoa province’s road network. In fact, there have been also collapses in Gipuzkoa province’s tunnels, although of small magnitude and without victims. One of the most important incidents took place in December 2000 on the Irun-bound Beasain tunnel, when part of the vault lining collapsed. The tunnel remained shut down for various months. In 2002, the tunnel was closed again due to repeated falls of fragments from the vault.
Eibar-Vitoria highway AP-1
Until a few years ago, most of Gipuzkoa province’s tunnels were short and, therefore, did not represent any special danger. This situation changed with the construction of the Navarre motorway, which includes the Belabieta and San Lorenzo tunnels, respectively 1,840 metres and 780 metres in length. The record length held by these tunnels will be largely beaten by the new tunnels of the Eibar-Vitoria highway AP-1. This highway includes what will be the two longest Basque tunnels, the Arlaban (or Isuzkitza) and Gallastegi tunnels, respectively 3,377 metres and 2,370 metres in length. This leap forward has obliged to maximize the safety measures inside the tunnels. Currently, there are eight tunnels under construction in Gipuzkoa province and construction of another eight tunnels is planned to commence in the near future. State-of-the-art technology will be implemented in each tunnel.
The disastrous fire at the Mont Blanc tunnel in 1999 obliged the French authorities to improve the safety systems planned in tunnels. Leading the way, Gipuzkoa’s provincial government decided in 2002 to adopt the new French standards to enhance safety measures initially approved for the AP-1 tunnels. Consequently, the tunnels have been equipped with fire hydrants, public address system and safety barriers at the entrances to prevent the entry of vehicles in case of accident in the tunnels. These improvements complement the initial project design which planned basic devices, like pedestrian cross passages each 250 metres and vehicular cross passages each 750 metres or SOS telephone bays with fire extinguishers.
It is not strange that safety measures have been strengthened, since 40% of the AP-1 highway runs in Gipuzkoa through several tunnels: Gallastegi (2,370 metres), San Martial (1,400 m), Lezarri (1,200 m), Ikastaundi (1,200 m), Gurutzetixiki (710 m), Eitza (700 m), Zarimutz (400 m), Apotzaga (300 m), Arizti (300 m) and Izurieta (260 m). The Arlaban tunnel, 3,377 metres in length, will add to the list.
These efforts paid off in return. The Gallastegi tunnel on the section between Eibar and Bergara, open to traffic in December 2003, has been rated as one of the safest tunnels in the last risk assessment report by the European Tunnel Assesment Programme (EuroTAP).
As for the Arlaban tunnel, safety has been the backbone of the project. The tunnel will be fitted out, among other things, with general lighting for emergency guidance in case of fire, SOS bays, six stations for real-time data recording each 560 metres, CCTV cameras, visibility and CO2 sensors, and a fire detection system that will indicate to firemen the exact point where they have to intervene.
The AP-1 has a control centre in Bergara from which all incidents occurred on the highway are recorded. Click es/60.
Navarre freeway A-15
Special safety equipment was installed both in the Belabieta and San Lorenzo tunnels. Both are equipped with 47 video cameras, six emergency doors, 35 fire extinguishers, dozens of safety lights, as well as sensors under the asphalt that constantly send information to the control centre, allowing fast intervention by the sanitary and rescue services.
The room that records the incidents is situated in a building outside Belabieta, a few metres away from the entrance towards San Sebastian. The television screens in this room receive the images recorded by the cameras situated at the entrances and inside the tunnels. Other information on the pollution rate, visibility and temperature is also received on these screens. The control centre is operated permanently by two people, twenty-four hours a day.
The Gipuzkoa province’s officials ensure that a fire erupting on board a vehicle in one of its tunnels would be detected immediately in this control room. The cameras would show the fire and the temperature sensors would also record it. Rescuers would be sent to the fire scene immediately and the jet fans would be activated. The speed of these reversible jet fans can be regulated, so that the smoke can be gradually forced out of the tunnels in any of the two directions, thus avoiding the formation of swirls.
In case that people remain trapped inside any of the two longest tunnels of freeway A-15, they would be able to escape through emergency doors purposedly signalled. These doors lead to the parallel, twin tunnel, used by vehicles travelling in the opposite direction. One of the doors allows the passage of rescue vehicles and even of a firefighting vehicle, despite its reduced dimensions.
The safety equipment is complemented by SOS bays installed each 150 metres, as well as fire extinguishers. In addition, there is a line of lights on the walls situated at eyes’ height to help trapped people find their way out to the emergency doors and tunnel entrances, in case of dense smoke. The electric system includes back-up transformers that ensure the power supply in case of blackout. The equipment also includes luminous panels and signs to inform drivers about any incident or danger.
A-8 and N-I
The tunnels on road N-I, also operated by the Gipuzkoa provincial authorities, do not entail special safety measures, since they are not very long.
The Bilbao-Behobia highway A-8 in Gipuzkoa includes the Meagas, Itziar and Istiña tunnels, with respective lengths of 465 metres, 488 metres and 186 metres. Data on accidents on the A-8 indicate that the tunnels are the least troubled spots.
Despite their short length, a minimum safety policy is implemented. All have fire extinguishers approximately each 100 metres, which means that in case of problem, a driver will have to walk a maximum of 50 metres to find a fire extinguisher. Also there are sidewalks to leave the tunnel without risk of being knocked down. These tunnels, like those on the A-15, have generators that supply emergency lighting in the event of blackout. 32/07.
