US Patent 10151418 Sheath for protecting against fire

The invention relates to a protective sheath (50) for covering a fluid-transporting pipeline, comprising a flame-proof, non-inflammable layer (52) and a heat insulation layer (54) arranged beneath the non-inflammable layer, the non-inflammable layer consisting only of carbon and the heat insulation layer comprising a knitted fabric, the knitted fabric comprising a plurality of stitches and air trapped within the plurality of stitches such that the heat insulation layer comprises at least 70 vol. % of air. Furthermore, the non-inflammable layer comprises carbon fibers providing 100% coverage in order to protect the heat insulation layer from contact with flames.