Performing a diversion or tie-in without shutting down the pipeline requires welding a split tee connection into place then drilling, or hot tapping, through it so new pipeline or isolation tooling can be installed.

In many cases, pipeline operators have developed an internal specification to cover the split tee design. These specifications combine best practices from lessons learned, product and services providers, International standard (i.e. ASME, API), national design standards and local regulations. The new generation of pipeline engineers frequently raise questions regarding the origin of these requirements and can find it challenging to validate specification changes, deviations or improvements.

This paper explores the advantages and consequences of applying the European Standard EN-13480 to split tee design, manufacturing and inspection. It also identifies aspects that are not covered by the EN-13480. Finally, it highlights some of the conflicts and/or challenges involved in ensuring a consistent approach to such a unique product and its applications.