This European Standard is a product standard for clay/ceramic flue liners operating under wet conditions with solid walls or walls with vertical perforations for use in the construction of multiwall chimneys and flue pipes which serve to convey products of combustion from fireplaces or heating appliances to the outside atmosphere by negative or positive pressure. It includes the flue liners used for domestic and industrial chimneys which are not structurally independent (free-standing). This European Standard specifies the performance requirements for factory made flue liners and chimney fittings. Testing including thermal testing with or without insulation