Abstract: A flange adapter is provided for insertion between a flanged end valve and a plastic pipe having an elongate cylindrical member with a radial outward flange at one end for fastening to a metal valve flange, a second radial outward flange intermediate the ends of the cylindrical member, the other end of the cylindrical member having an enlarged bore with a frusto conical end, said bore receiving a plastic pipe end and a surrounding elastomer gasket with a frusto conical end, a follower abutting the gasket, a compressible frusto conical jaw assembly surrounding the plastic pipe end within a frusto conical opening of a back up ring and tightening means for separately moving the follower to compress the gasket sealingly on the plastic pipe and the back up ring to compress the jaws into the pipe end.