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Bury, Lancashire, United Kingdom, 2011/01/06 - A network of two inch gas pipes, water pipes and old steam pipes were found during preparation of the new-build site.
Extensions, redevelopments and renovations to historic properties are rarely straightforward. North West based contractors Barnfield Construction can confirm this having encountered problems with ‘ghost’ gas mains, water and steam pipes in a contract for a private client. Fortunately, they were partnered with multi-utility connections specialists Crown Energy who were able to resolve potentially explosive difficulties with these legacy services and bring new gas mains into the site.
Barnfield Construction were contracted to add an extension to a historic house. Many years in the past this had outbuildings – possibly stables, workshops, glasshouses and other structures that had long since been demolished. A new vicarage had been built over part of this site in the 1960’s and this was demolished to make way for the new works.
The first part of the project was relatively straightforward. This included the disconnection of the old gas service and installation of a new main. The disconnection of the old service was coordinated by Crown Energy.
The new main required a four inch cast low-pressure main reducing to a two inch riser in MDPE (medium density poly ethylene) and termination in a steel pipe to the meter. This finally required purging and commissioning. These works were undertaken without difficulty. The new services were then reconnected.
Problems arose elsewhere on the extension. It was necessary to drive steel piles to establish a solid base for the new building and so, as a preliminary to this, the surface was excavated and a piling mat of aggregate laid down for the heavy piling plant. It was during this phase of the works that an extensive network of two inch gas pipes, water pipes and old steam pipes were discovered covering a large part of the new-build site. None of these pipes were shown on service drawings and it was clear that gas services were still connected to mains at an unknown point.
Metal detectors revealed the full extent of the hidden network so that it could be removed. Crown Energy arranged disconnection of the un-recorded mains connection. Piling works then proceeded in the expectation that there was no further danger of striking hidden gas services that might cause an explosion. However, as works began an excavation revealed another pipe in the side of the trench – again not shown on service drawings and at least eight metres away from the main. Crown Energy arranged the disconnection to make the site safe.
“We were fortunate to have Crown Energy working with us on this project,” explained Barnfield’s site manager Darren Mackenzie. “Not only were they able to liaise with the utility suppliers allowing us to make trench preparations in a timely way, but they were invaluable when we encountered the ghost mains bringing the emergency team to site so quickly.”
Speaking for Crown Energy, Keeley Downing explained, “The problem with many brownfield sites is that official service drawings do not reveal the full extent of the private service networks installed. Sometimes, as in this case, these are not fully decommissioned when buildings are demolished and this can give rise to potentially explosive problems for contractors and their clients.”
Crown Energy (crownenergy.co.uk) specialise in the co-ordinated and timely delivery of multi-service utility connections. This includes removal and disconnection of redundant services, evaluation of new service needs and liaison between gas, electricity and water utility companies to ensure synchronised completion to keep building handover on track.
Keeley Downing, Head of Energy and Utilities, Crown Energy
T: +44 (0) 161 762 7744 F:+44 (0) 161 761 2957
Crown Energy, Crown House, Heap Brow, Bury, Lancashire, BL9 7JR, UK