The Project
As a result of the Asset Health Survey Programme carried out by Northern Gas Networks under the RIIO price control period, it was identified that the existing plant and equipment at Chopwell PRS site was obsolete, approaching end of service life and in need of replacement.

The project comprised installation of a new E&I kiosk, replacement governor building, general site civil improvements, electrical and instrument rebuild to bring the site in line with current Northern Gas Networks standards and compliant with British and European legislation. The project posed a challenge as it could not be isolated during the works resulting in an extensive crash deck being installed to protect the live gas equipment prior to the old building being dismantled. A new modular GRP building was constructed in its place meaning the supply of gas was uninterrupted.

Employed directly by Northern Gas Networks as MWC, key deliverables were achieved to the satisfaction of and the end user (Northern Gas Networks) utilising the expertise of approved civil framework partners.

A new E&I kiosk was constructed to house an all new electrical distribution system allowing the existing installation to continue to operate in parallel the new installation. A new electrical system was installed comprising incoming switchgear, overcurrent and earth leakage protection and small power distribution system servicing new interior and exterior site lighting, E&I room lighting and heating and telemetry power supply unit. The installation was delivered in accordance with the clients G17 detailed design documentation and inspected and tested to BS7671.

A new E&I kiosk was constructed to house an all new remote telemetered instrument monitoring and control system. The scope included the manufacture and installation of new RTU, I.S barrier, Non-I.S and PSU control panels. Pneumatic hook-up and cabling of Inlet Pressure Transmitter HP1, Outlet Pressure Transmitter MP1 and Filter Differential Pressure FLT-DP1 and FLT-DP2. Installation of switches and cabling associated with Slam Shut and Intruder Alarm equipment. Pneumatic Pressure Testing of new small bore stainless steel impulse pipe and instrument loop checks. Isolation, disconnection and removal of redundant, obsolete equipment following instrument changeover.

DSEAR Inspection
All ATEX certified equipment supplied and installed under the contract scope was subject to detailed inspection in accordance with DSEAR Regulations BS EN 60079-17.

SONAE were responsible for supplying both the NRO documentation and competent persons to control and execute the changeover in line with the networks SCO 5 requirements. Commissioning was phased to allow the existing and new E&I systems to operate in parallel before isolating and de-commissioning the old equipment ensuring continuity of supply throughout the procedure.

Test Records and red-line marked as-built drawings were produced and submitted at key stages as identified by Northern Gas Networks for pre-commissioning purposes in accordance with management procedure NGN/PM/RE/18.

Databook records were compiled in accordance with MPTF-001 Databook Framework document.
All final handover records were submitted to the Northern Gas Networks in both electronic format via A-site media document control system and hard copy format.

Health & Safety
Sonae (UK) were appointed Principal Contractor to manage the health and safety during the construction phase including the coordination and management of all subcontractors.
All works were carried out under a controlled PTW in accordance with Northern Gas Networks SCO (Safe Control of Operations) management procedures.


December 2018
Northern Gas Networks