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PRCI PR-205-017
- Underwater Branch Connections
- Report / Survey by Pipeline Research Council International, 06/01/1992
- Publisher: PRCI
$148.00$295.00
L51670e
R.J. Brown and Associates of America, Inc.
Need: During the installation of a gas main line, tap valve assemblies can be provided at strategic locations along the pipeline to allow lateral lines to be tied-in. In existing main lines that do not have a tap valve assembly, a lateral tie-in can be made with a hot tap to the main line. The underwater branch connection then consists of the tee or hot tap fitting on the main line plus valves and other fittings as required. The design of underwater branch connections for gas transmission pipelines must comply with the requirements set out in the applicable design codes and regulations. This information can be obtained from the design basis relevant to the main line and the lateral line.
Benefit: The design guidelines presented in this report cover the physical connection of a branch line to a main line. It is assumed that the branch line itself has already been designed. Branch pipelines can feed from or to a main line, but in this study the trunk line is considered to be a part of a gas gathering system which is fed by lateral lines. The maximum lateral line size considered in this report is 12 inch nominal pipe diameter, but much of the material presented here can be applied to larger diameter lateral lines. The design guidelines provided in this report are applicable to diver accessible water depths, which presently exceed 1000 feet.
Result: The report summarizes, and draws from, the results of a survey of the relevant practice and experience of fifteen gas pipeline operating companies. The survey indicates that most existing branch connections do not provide for pigging of the lateral lines, but that there is a growing consensus that cleaning and inspection pigging of lateral lines is desirable or necessary.
R.J. Brown and Associates of America, Inc.
Need: During the installation of a gas main line, tap valve assemblies can be provided at strategic locations along the pipeline to allow lateral lines to be tied-in. In existing main lines that do not have a tap valve assembly, a lateral tie-in can be made with a hot tap to the main line. The underwater branch connection then consists of the tee or hot tap fitting on the main line plus valves and other fittings as required. The design of underwater branch connections for gas transmission pipelines must comply with the requirements set out in the applicable design codes and regulations. This information can be obtained from the design basis relevant to the main line and the lateral line.
Benefit: The design guidelines presented in this report cover the physical connection of a branch line to a main line. It is assumed that the branch line itself has already been designed. Branch pipelines can feed from or to a main line, but in this study the trunk line is considered to be a part of a gas gathering system which is fed by lateral lines. The maximum lateral line size considered in this report is 12 inch nominal pipe diameter, but much of the material presented here can be applied to larger diameter lateral lines. The design guidelines provided in this report are applicable to diver accessible water depths, which presently exceed 1000 feet.
Result: The report summarizes, and draws from, the results of a survey of the relevant practice and experience of fifteen gas pipeline operating companies. The survey indicates that most existing branch connections do not provide for pigging of the lateral lines, but that there is a growing consensus that cleaning and inspection pigging of lateral lines is desirable or necessary.