Steve Vick International assisted JDT Utilities in decommissioning a 180 m stretch of 18 in (460 mm) diameter intermediate pressure steel gas pipeline (running at 7 Bar pressure). The abandoned main, prior to diversion and decommissioning, supplied the whole of Surrey Quays.
Part of a larger fifteen-year regeneration project, of a five-acre site, the pipe was required to be decommissioned following commission of the new main in October 2020, which now runs around the perimeter.
SVI grout filling operations offered the ideal solution for abandoning the main because it enables the void to be filled. This helps maintain the pipes strength and prevents cracking in the future which can lead to surface slump. The alternatives for JDT, were to completely remove the pipe or continue to protect the integrity of the pipe by a Cathodic Protect method, both of which are costly options when compared to void filling.
SVI provided the Endseals which JDT Utilities engineers installed prior to commencement of the grouting operation. The SVI Contract Service team then installed two 63 mm diameter fill tubes which were pushed each way, 70 m up the main from the centre. Grout was then gravity fed into the void to ensure 100% abandonment of the main. The entire process took just 8 hours. The cost benefits over traditional methods are quite significant.
Craig French, Operations Director at JDT Utilities commented: “The Steve Vick International team were extremely knowledgeable and provided us with a competitive quote which offered good value for money. SVI operatives and plant attended site on various occasions to complete the grouting. The work they carried out was done in a professional manner and to a high standard.”
The quick cure grout was mixed on site in a purpose-built machine and pumped into the main via fill tubes in the ENDSEALSTM. The grouting machine can be sited up to 30 m away depending on site conditions. As the grout is gravity fed, rather than pumped under pressure, this helps safety compliance as there are no issues with pressurisation.
With large quantities of water being required to mix the grout, SVI use tankers and, if necessary, transport water to the fill site in bowsers. For this project we supplied two 19,000 l water tankers, a total of 29,000 l was used.
“Having a supply of water, and a portable-powered rig means that we are self-sufficient on site.” said Mike Hall, SVI’s Contract Development Manager. “Furthermore, because the rig is compact enough to be operated from the back of our vehicles, we are able to continue working even when it rains.” he added.