Gasket assembly with elastomer expansion area

A pipe joint assembly comprises a pair of cylindrical pipe ends of the same internal diameter in axially contiguous aligned relationship. Connecting flanges extend radially outward of each of the pipe end and have opposed faces defining a circumferentially continuous packing groove including a first axially narrow portion opening to the cylindrical interior of the pipe ends and a second axially wider portion radially outward of the first portion. An elastomeric gasket positioned in the packing groove. The gasket is sized and dimensioned to completely fill the first axially narrow portion and extend to within the second portion. The radial inner extent of the gasket provides a smooth continuation of the cylindrical interior surfaces of said pipe ends when the flange faces are at their limit of movement toward one another. The second portion of the packing groove is sufficiently large to provide expansion space into which the gasket can expand when subjected to temperature increases to thereby reduce extrusion of the gasket beyond the cylindrical interior surfaces of the pipe ends.