Tee Connection To A Pipeline

摘要

A method is provided for securing a branch assembly 1 to a "live" pipeline 6. An upper part 2 of the assembly incorporating the branch 13 is positioned on the pipeline over a first containment ring/annular seal arrangement 16/17 and a second containment ring/annular seal arrangement 116/117 spaced from the first arrangement to leave an annular gap 118 therebetween. A lower part 3 of the assembly is positioned on the pipeline beneath the upper part and the two parts are secured together so that the seals are compressed. An access point 119 allows the monitoring of the pressure in the annular gap 118 to check for seal integrity of the inner seal 17. If pressure is detected, as a result of leakage of fluid via the branch 13 past the seal 17 the vent can be closed so that the second seal 117 becomes effective.