Many will remember the fire that closed the channel tunnel on 17 January. It was widely reported in the press, sometimes well and sometimes not so well. We can now share some facts. Following the last major fire in the tunnel in 2008, the decision was taken to fit each tunnel with two water mist extinguishing zones. Extensive fire tests were run to prove the system design. In a fire the train should continue to the next zone, or leave the tunnel if it has passed both. Momentum will ensure that the train reaches the zone or leaves the tunnel even if electric catenary power is lost. At the extinguishing zone the train is evacuated and water mist deployed where there is fire. Each extinguishing zone is made up of 29 individually-operated water mist deluge zones, themselves each 30m long.

The system cost €20 million. After a four-year insurance claim process, Eurostar settled on a payment of €253 million for the 2008 fire. It is likely that this did not cover all the losses. By contrast the fire on 17 January completely closed the tunnel for a day and reduced services ran for a second day. Losses would have been far less than the cost of the water mist system and a small percentage of those in 2008.

Regarding the details, shortly before midday on 17 January a France-bound train carrying trucks set off carbon dioxide detectors shortly after passing the first of the two extinguishing zones in the tunnel. The train stopped at the next extinguishing zone and all the truck drivers evacuated into the service tunnel which runs between the two train tunnels. French fire-fighters entered the tunnel and after searching the train found a cargo smouldering on one truck. The water mist deluge system was activated at that point and supplementary ventilation evacuated the smoke and carbon dioxide. Contrary to some alarmist reports, the amount of water released by the water mist system was small and the tunnel’s drainage pumps could easily cope with it. The water mist system and emergency procedures ran exactly as designed, nobody was hurt and damage was minimal.