Steve Vick International and Northern Gas Networks take an innovative approach to reducing disruption in the street

Steve Vick International (SVI) and Northern Gas Networks (NGN), have joined forces and developed the Enhanced S.E.A.L. system; an innovative new method that allows 100% of Tier 1 (T1) gas mains, including the last joint before entering the T2 or T3 main, to be sealed and abandoned.

Gas Distribution Networks are required to abandon or replace all cast iron and ductile T1 pipes within 30m of a building by 2032. This is part of a gas mains replacement program that will improve the safety and reliability of the UK gas network.

The Original S.E.A.L. System

20 years ago SVI developed a S.E.A.L. (Stub End Abandonment Live) system that uses expanding foam to remotely seal a T1 main within 1m of the parent main, that does not require the removal of the tee piece.

Alternative methods involve digging deep excavations, often in highways, in order for the tee piece to be completely removed. Whereas the S.E.A.L. method negates the need to dig in the carriageway directly above the tee; avoiding costly road closures, traffic management and expensive reinstatement costs together with any associated risks.

The Enhanced S.E.A.L. System

NGN recognised that recent technologies could further develop the existing S.E.A.L. system and approached SVI to design an enhanced technique, to include all the associated benefits but that would allow for 100% of the T1 pipe to be abandoned.

In collaboration with SVI, NGN conducted the NIA funded project to create the Enhanced S.E.A.L. system: an innovation of the original S.E.A.L. technique.
Peter Christie, NGN Quality Assurance Manager, commented that ‘The development demanded innovative thinking and collaborative working to ensure NGN get it right first time, every time’.

The key benefits of using the Enhanced S.E.A.L technique are:

•  A significant reduction in the risks associated with excavating in highways – the entrance pit is dug up to 60m away in a non-sensitive area.
•  Reduced environmental impact – excavations are 80% smaller than those dug using alternative methods, which in turn reduces the amount of spoil sent to landfill.
• Substantial cost savings – made through reduced traffic management, time on site, materials and reinstatement materials.
• Reduction in disruption to customers – the technique ensures that the need for future repair work associated with leaks is eradicated.
• Reduction in disruption to the public – the need for traffic management and road closures is significantly reduced using this method.

As with all NIA projects the resulting technology is shared amongst all the Gas Distribution Networks. Richie Read, NGN Programme Manager said that ‘By adopting the technique NGN anticipate a saving of £4m in the current RIIO period’. Similar savings could be experienced by all the GDN’s if this technique is adopted.

NGN approved the Enhanced S.E.A.L. technique in December 2015 and have since carried out approximately 4 operations per week across the NGN network.

SVI and NGN believe that the Enhanced S.E.A.L. Technique will contribute to providing a safe and efficient gas network for the future; with fewer gas leaks and less disruptions to customers gas supplies.