A fitting for providing a substantially fluid-tight seal between an opening in a chamber wall (10) and a pipe (4) passing through said opening, said fitting comprising: (ii) a tabular sleeve (22) adapted to pass through the opening in the chamber wall (10) and further adapted to allow the pipe (4) to pass through the sleeve (22); (ii) a flange (24), extending radially outwardly from the sleeve (22), a first surface (26) of the flange (24) being configured to contact the chamber wall (10) around substantially the whole circumference of the opening; characterised in that the flange (24) incorporates an energy transfer means at or near the first surface (26), said energy transfer means enabling the first surface (26) and/or the wall of chamber (6) in the vicinity of the flange (24) to be heated to cause the flange (24) and the wall (10) to fuse or bond together in order to form a substantially fluid tight seal.
