Abstract: The assembly is designed to contain a leak arising from a damaged gasket positioned between the flanges of a pipe connection forming part of a pipeline carrying pressurized fluid. The assembly comprises a pair of steel half rings that are hinged together at one end so that they can be mounted to the connection in the form of a split ring. Each half ring contains an elongate seal element having an annular configuration. The ends of the half rings are lapped so that the split ring can be contracted with the ring ends overlapping. A chain and clamp assembly is tightened around the split ring to compress the seal elements into sealing engagement with the flanges. Shoulders formed by the half rings squeeze the abutting seal element ends together to effect a seal at the split ring breaks.