The UK’s biggest-ever under-pressure gas branch connection has been completed at the University of Liverpool’s Energy Centre.

The GIRS-accredited design team at Energy Assets gained National Grid approval to design a 500mm by 315mm branch saddle fitting to support the high volume of gas required for the University’s second Combined Heat & Power unit.

As Richard Collinson, Energy Assets’ Technical Account Manager explains: “Initially we were looking at a 250mm PE pipework branch saddle connection to the 500mm LP main, but then the customer advised that they wanted to install a booster downline of the meter installation.

The consumption curve of the new CHP unit required an initial step of 1322kW and could not be reduced, so using a 250mm connection was not an option – so we investigated increasing the new service size from 250mm to 315mm to help counteract the impact of the booster.”

However, the only approved method of connecting a 315mm PE service to a 500mm main on National Grid’s network would have meant taking a 500mm x 500mm cut out and inserting a tee connection – a process that would have also required a deep excavation in excess of 10m in length. This would also have involved considerable additional cost to the customer.

“We were aware that a 500mm x 315mm branch saddle was available but had not been approved by National Grid – we therefore approached the manufacturer and National Grid and arranged for this project to be used as a field trial to allow this size of fitting to be used on this and future projects of this scale,” says Richard.

Energy Assets and the project team completed the work ahead of schedule, along with the installation of a large rotary meter sited externally in a secure external compound because of access issues around the location of the new CHP at Liverpool University.

University Project Consultant Ian Murray said: “It was impressive how Energy Assets was able to overcome some quite significant gas infrastructure challenges when they brought in the new energy supply.”

The additional CHP will enable the University’s Energy Centre to deliver around 90% of its electrical load requirement and virtually all its heating and hot water needs via the integrated district heating scheme.

Energy Assets

www.energyassets.co.uk