20 Apr 2005 Gas pipeline activiity

The new gas pipeline from Barton Stacey to Humbly Grove makes good progress with preparation, welding and trench digging.

The 17 mile (27 kilometre) pipeline is a major investment by UK based Star Energy, an important company in the integrated energy business, and connects to their new gas storage facility at Humbly Grove (just north of Alton).

Although Barton Stacey contains very little of the actual pipeline - less than a mile - it is the site of the important connection to the national gas transmission network and the focus of much project activity, with key activities including preparing the route, digging the trench, preparing the pipe, laying the pipe, and reinstating the ground.

During the preparation stages the Star Energy land agent contacts landowners and makes arrangements for access along the route, site preparation and reinstatement, and then keeps a careful eye on how the work progresses to make sure that it progresses as agreed.

The pipe dump just off the A303 at Barton Stacey has been busy for over 6 months, and serves as a base for around 200 workers involved in project. This dump is the initial home for the 12 metre sections of 24 inch diameter pipe, which were made in Greece, shipped to Southampton, then trucked to the site.

The pipe sections have already been laid along the precision measured route, and are being welded into longer sections ready for being lowered into the trench. There are six welding teams who complete over 100 joins a day. Each join is made in stages with a carefully structured process of preparation, joining, testing, and covering to ensure that it makes a secure and durable closing which will contain the gas at high pressure.

The trench is dug through the soft chalk of Hampshire using a huge digger specially imported from Italy, with the depth carefully measured to ensure that the top of the pipe will lay at least 1.2 metres below ground level.

To avoid disrupting traffic, where the pipeline meets a road - such as the busy A34, a tunnel is bored under the road and the pipe is pushed through with hydraulic rams (pictured right).

Occasionally the digging encounters problems which cause delays. One such instance was the discovery of a large amount - possibly several tons - of household rubbish buried three feet below the surface on the site of the old Great Western Railway line from Newbury to Winchester. The area will need to be excavated much wider and deeper than expected in order to remove the rubbish, which then has to be properly disposed of, then the excavation will need to be backfilled with clean chalk and compacted to provide a firm base for the pipeline.

The Star Energy pipeline will terminate in the old Army camp just north of the A303 close to the existing Transco compound which forms part of the national gas network.

The final stage will involve the connection of these two using a 'hot tap' technique, with the somewhat scary thought that this involves welding onto the existing 36 inch diameter pipeline which contains gas at high pressure.

The project is on schedule, with pipe laying about to start, closely followed by reinstatement so that the land will be ready for replanting crops in autumn 2005, and the pipe dump will disappear soon afterwards.

In a few years, there will be no trace of the work, just as today the only clues to the national gas pipeline laid in 1975-77 are the occasional marker posts in verges and hedges.

Star Energy have published a community briefing document and set up a telephone information line on 01491 414 496. Additional information is also available from their web site at www.starenergy.co.uk

Date: Wednesday 20 Apr 2005

Website news from Andy Glenister of Barton Stacey, Hampshire

Posted on 20 Apr 2005 at 04:50 pm