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A revolutionary active firefighting system is selected for the A86 tunnel project around Paris
14 November 2006

Is the first large active protection system against tunnel fires to be marketed in Europe. In terms of structure, it is also the largest on which work has started.

The first section of the A86 West tunnel, the missing link in the Paris 'super-ring road',is to be opened in October 2007. Built, financed and operated by Cofiroute, this 10 km tunnel linking Rueil-Malmaison and Versailles will revolutionise traffic flow in the West Paris region. With a particularly innovative design, made up of two superimposed road levels, one in each direction, and reserved for light vehicles, this tunnel will be equipped with the latest safety devices, exceeding the requirements of the new regulations concerning safety in tunnels.

This is the context in which an active firefighting system is being installed in the tunnel. Under the terms of the examination of the safety concept, the administrative monitoring commission requested trials and assessment of the effectiveness of a fixed water spraying system. The contractors deemed it useful, in the context of completing the A86 West as validated by the government, to install a fixed water fog system to limit and contain the spread of a fire.  The system will reduce ambient temperature, facilitate the evacuation of motorists to the emergency exits located at 200 metre intervals, and improve the conditions for the emergency services arriving on scene.

The contract was awarded to the Marioff Corporation, world leader in water mist firefighting systems, by Socatop (Société de Construction de l’Autoroute de Traversée de l’Ouest Parisien), acting as designer/builder for Cofiroute (franchise holder for the A86 motorway).

This decision could result in significant modifications to the safety equipment and procedures used in European tunnels. In-depth studies have already been conducted with the aim of complementing passive safety equipment in tunnels, such as escape routes, with active firefighting systems but, until now, these have only been used in trials and small-scale applications. The final section of the A86 West of Paris is the first major installation of a fixed firefighting system in Europe. As it will also be the largest water fog fire protection system ever built, it will be an interesting example for the transport ministries in the various European Union member states.

Petteri Saarinen, President of Marioff, stated that: “The decision by Cofiroute and Socatop to invest in an active firefighting system for the A86 could, in the future, set a new standard in terms of safety in road tunnels. We are very proud to be associated with this major project. This firefighting system, combined with the innovative design and operation of the tunnel, will ensure an optimum level of safety, for the clients and the emergency services as well as for the tunnel infrastructure.”

The contract is for the design, manufacture, installation and maintenance of a fixed water fog firefighting system. This is sub-divided into sectors, throughout the length of the tunnel (10 km long on two levels, each level with two traffic lanes and a hard shoulder). The fire protection technology developed by Marioff was selected after two intensive trials. The company’s references in this sector of activity influenced the choice of the solution selected.

The HI-FOG safety system to be installed uses patented high pressure nozzles, which spray very fine droplets of water over uniformly-sized tunnel sections 33 metres long. Three sections will be triggered simultaneously in order to cover a zone about 100 metres long around the seat of a fire. The water droplets rapidly absorb the heat, particularly by evaporation, giving very effective cooling. They greatly reduce the amount of smoke a fire gives off, by limiting the development of its heat intensity. This contributes to safer evacuation of persons present and saves lives during the first critical phases of a fire, and also gains time to allow the arrival of the emergency services to contain and totally control the fire and extinguish it.

Fog, composed of millions of fine droplets, is a very effective way of using water to extinguish a fire. This technology was originally developed to combat emergency situations on board ships. In more than 5,000 fire trials under operational conditions, conducted over more than a decade, water fog generated by HI-FOG technology has proved extremely effective for extinguishing fires. Compared, for example, to a conventional spraying system, HI-FOG technology uses ten times less water, thus increasing the capability of the system to combat big fires, while minimising the risks of spreading fuel around.

Editor’s notes

Fire safety measures in tunnels: active or passive

Most tunnels are currently protected against fires by 'passive' safety measures. This term covers the use of construction materials that slow down the spread of the fire, and safety structures such as special escape tunnels, emergency exits to a neighbouring tunnel or to the surface, and refuges where people can shelter. These types of measure contribute to safety, but can prove insufficient during major fires, such as those that occurred in the Mont-Blanc and Gothard tunnels. This is due to the fact that at very high temperatures, fuel spillage, toxic smoke and other dangers inherent to fires can develop very quickly in confined spaces. These phenomena can, in certain circumstances, kill people who are just a few metres away from an escape route during a fire.

The first 10 to 15 minutes of a tunnel fire are crucial for the protection of human lives and to minimise the material damage. In this context, active firefighting systems that integrate processes such as high pressure water fog spraying represent significant progress. The division of the water into very fine droplets spectacularly increases the surface covered and the rate of absorption of the heat given off by a fire. In a few moments, the temperature a few tens of metres away from the fire drops to 50°C. Without a firefighting system, it can exceed 1,200°C.

The consequences of a tunnel fire disaster can be catastrophic. 39 people were killed in the Mont-Blanc tunnel fire alone.

The worst fires in road tunnels have always involved one or more heavy goods vehicles. Heavy goods vehicle traffic will be prohibited in the A86 West tunnel.

About Marioff

More than 15 years ago, Marioff Corporation Oy was the first company to develop HI-FOG water mist fire protection technology. This was initially designed to protect passenger ships, in which it is essential to use the minimum amount of water for firefighting. In addition to saving lives and safeguarding traffic flow, a HI-FOG system protects the structure against major material damage.

Marioff Corporation Oy is a global business, specialised in the production of very high efficiency water fog fire protection systems, designed for the industrial, commercial and infrastructure development sectors. Marioff is also the world leader in the production of firefighting systems for the maritime and offshore sectors. The company has dominated this market since the start of development of water mist systems, and holds more than 1,300 patents. For more information about Marioff, consult www.marioff.com.

About Cofiroute

Cofiroute (2,000 employees) manages a 985 km motorway network covering the Centre-West region of France (A10, A11, A28, A71, A81, A85). Cofiroute is also present in the United States, the United Kingdom, Chile and Germany. Cofiroute’s main shareholders are VINCI (65.35%), Eiffage (17%) and Colas (16.66%). The Company’s 2005 turnover was 889 million Euros. With an investment programme of 3 billion Euros for the 2004-2008 period, Cofiroute is one of the most important private-sector infrastructure Companies in France. For more information, consult the website www.cofiroute.fr.

About the A86 tunnel project

The construction and operation of the A86 West is 100 % financed by Cofiroute, designated by the government as project manager and future operator. Cofiroute is responsible for the entire cost of the project (nearly 1.7 billion Euros for the two East and West tunnels), without any state or local government contribution. In exchange, Cofiroute will operate the tunnels for the seventy years following their opening. Cofiroute has contracted the construction of the tunnel to Socatop, a Company that includes three major French construction groups – VINCI, Eiffage and Colas – and also the companies Campenon Bernard, Entreprise Jean Lefebvre, Dumez GTM, GTM Construction and Fougerolle.

Marioff press contacts:

Marioff Corporation Oy

Petteri Saarinen
President
Marioff Corporation Oy

Tel.: +358 9 870 851
E-mail: petteri.saarinen@marioff.fi