Thermal Ceramics wins Bjorvika fireproof lining contractSome 675 m of the centre section of Bjorvika tunnel comprises six immersed tube elements containing three traffic lanes in each direction. Each element is 112.5 m-long, 28-43 m-wide and 10 m-high. They were built in pairs in dry dock and towed by sea to their positions, where they were sunk onto the prepared seabed and connected to each other to form a continuous structure, the roof of which lies 8-11 m below MSL.The fire protection to be installed by Thermal Ceramics creates a permanent passive protection against physical breakdown of the structure, damage to waterproofing, and spalling of concrete. It will withstand a sudden temperature change caused by extinguishing a fire by water or other agents, in a way that constitutes no hazard for fire and rescue crews, and will prevent catastrophic collapse of the prestressed concrete structures. The fire load is dimensioned for a 300MW fire for a minimum of two hours, as per RWS fire curve. The surfaces to be protected in the Bjorvika tunnel comprise 39,400 sq m roof, 10,850 sq m walls, and 4,950 sq m joint seals. The Firebarrier 135 system was put through a year of intensive testing to prove its passive fire protection performance. The SP Swedish National Testing and Research Institute in Boras, Sweden, supported by Firemaster staff from Thermal Ceramics Italiana, carried out several tests for fire resistance, physical characterization and longevity. To satisfy the rigorous requirements at Bjorvika, less than 40 mm thickness of Firemaster Firebarrier 135 will be needed. This material is cement based, made with refractory materials, and is installed by gunning. The individual components are ready to be mixed with water, and are not toxic or irritant. The resultant lining is incombustible, alkali and sulphur resistant, and is not damaged by carbon dioxide, road salts or normal washing up to 150 bar water pressure. The joints between the concrete modules are protected from fire risks by high temperature resistant Thermal Ceramic Felt. The life expectancy for the fire protection and mechanical anchoring is 100 years, the same as that for the structure of the tunnel, and its design takes into account the effects of 100,000 vehicles/day.The official European Thermal Ceramics distributor, IFS, will undertake installation of the Firemaster lining at Bjorvika starting from February/March, 2009. Visit www.thermalceramics.com