Learnings

Outcomes

The primary results can be summarised as follows:

• The tools did not perform well enough during this testing to provide confidence that they would be suitable for use on the UK gas network without modification or limitation
• Quality control issues were noted

The challenges encountered during testing can be loosely grouped into quality control issues, and tool performance issues, although there is some overlap. The issues noted are listed below:

Initial use quality control issues:

• No stopper bag wires were provided
• No plugs were provided
• The saddle clamp seals were not effective
• PTFE thread sealant tape obstructing the pipe
• Leakage in the stopper bag inflation tubes

Tool performance issues

• Thread taping failure
• Clamp sealing
• Bottled gas leakage
• Hole saw failure and inadequate design
• Drill tool design
• Pressure spikes
• Tool leakage
• Stopper bag deflation
• Leaking plugs
• Debris remaining in pipes
• Plug insertion tool failure (reconnection)

General tool issues

• Use of an o-ring to secure plug onto insertion tool seems inappropriate
• Scratching of the control chamber ball valve ball
• US standard (NPT) threads
• Use of Cyanoacrylate adhesive for stopper bags
• Stopper bag vent screw works loose
• Direction arrow / compression gland bolts work loose
• Stopper bag inflation tube rotation
• No mechanism to prevent early removal of tools without closing control chamber valve

In addition to this, whilst the business case was not fully explored within this project, the requirement for a solution to avoid entering customer homes due to COVID-19 has reduced since this work began.  

The TRL of the project moved from 6 – 7 

Lessons Learnt

The proposed project originally encompassed both Phases 1 and 2. However, in a way to mitigate risk and cost, it was spilt into separate phases. This worked well and allowed the GDNs to observe the challenges with the tool prior to committing further resources. We also ensured that the majority of the initial work was carried out by Steer to ensure that the full personnel resources from both GDNs were only engaged at an appropriate time. 

It is noted that Steer expended more time and resources than they anticipated or budgeted for both in engaging with the stakeholders (specifically the suppliers), and assessment of the product. This was beneficial in facilitating an early decision regarding the outcome of the project.

The project utilised comms systems provide real time updates and footage of testing to the GDNs. The steering group agreed that this increased engagement within the project. While we feel it was appropriate in this project, Steer were aware of the risk of providing information that was not fully balanced, and adversely influencing stakeholder views. It was also noted that there was additional time required to ensure videos were of a suitable level of information (requiring some editing of the work to ensure the information was appropriate).