Northern Gas Networks currently abandon metallic stubs using a mixture of ESEAL and traditional tee piece cut out techniques.
The ESEAL system and ESEAL 2 system can be employed on metallic Tier 1 and Tier 2 pipes currently up to 14”, beyond this there is difficulties and inconsistencies in applying the current methods available. Northern Gas Networks, and all other Gas Distribution Networks, have a vast array of larger diameter pipes that could benefit from the ESeal system, which was proven successful through previous NIA funded projects, and still to date delivers benefits.
The cost for cutting out tier 2 diameter tees using standard techniques is substantial. There is a large impact on the environment due to excavation size and the resulting traffic management to accompany this.
Standard cut out practices also introduces further risks to our own gas engineers and members of the public. The majority of Tier 2 tees and stubs will require deep excavations in highways in order to cut them out, bringing with it further risks.

Objectives

Design - Tier 2 ESEAL sealing system for abandoning 15” stubs

Measured using pressure testing, installation validation testing and data collection via the Project Log document. Phase success measured at the stage gate meeting. Overall success measured with Field Trials and reporting to be assessed at the project closeout phase.

Phases - Tier 2 ESEAL sealing system for abandoning 15” stubs

The project must meet the requirement of each phase stage gate in order for it to progress onto the next phase. All documentation must be published and approved to G23 standards by SVI and NGN

Preparation to enable – 15” system

The project will be measured using all of the published and presented data and reports.