Construction work for gas pipelines

Tender description

Highways England have requested that NGN divert their pipelines in order to facilitate the improvement and widening of the A1 Birtley to Coal House main road and the replacement of Allerdene railway bridge. The scheme requires NGN to divert their assets and relocate to the south of the existing A1. This includes diverting four existing gas pipelines: 450NB High Pressure (HP) steel main, 450NB Intermediate Pressure (IP) steel main, 355NB Medium Pressure (MP) steel main, 150NB Low Pressure (LP) spun iron main. Highways England have requested that NGN divert their pipelines in order to facilitate the improvement and widening of the A1 Birtley to Coal House main road and the replacement of Allerdene railway bridge. The scheme requires NGN to divert their assets and relocate to the south of the existing A1. This includes diverting four existing gas pipelines: 450NB High Pressure (HP) steel main, 450NB Intermediate Pressure (IP) steel main, 355NB Medium Pressure (MP) steel main, 150NB Low Pressure (LP) spun iron main. A new Above Ground Installation (AGI) shall be constructed to the south of the A1. The AGI will comprise of two sets of regulators to carry out pressure reduction across two tiers, new filters, new metering skid, a boiler house package, new heat exchangers, a back-up generator and an electrical and instrumentation kiosk. The new AGI will also have a connection to facilitate a future CNG filling station. Two new District Governors shall be installed within the existing AGI compound to the north of the scheme in order to provide gas to the Team Valley Trading Estate and the Low Fell area of Gateshead. A new IP pipeline will be diverted underneath the A1 via a micro tunnel which will include reception/receiving shafts and will be routed between the new foundations of the new road bridge. Once the tunnel has been constructed and the two new AGIs commissioned, work involving the abandonment and diversions of the HP, IP, MP and LP pipelines. The scheme also involves the decommissioning and disinvestment of the existing AGI at Lamesley.