At the meeting held in the Park Lane Village Centre on the evening of 20th April, we were given a very informative update presentation by National Grid on their plans for the new 19km-long 1220mm-diameter gas pipeline between Harefield and Southall. We would like to note our thanks to the team for taking the time to come and present to the Village on this major project that will have an impact on the area during 2007-2008. The Association will continue to work with National Grid and to monitor the plans for the pipeline. The following is a summary of the information that was presented:
Why?The pipeline is needed to maintain gas supplies safely and reliably following significant increases in the demand for gas in the West London area.
When?Construction of special engineering sections, such as major crossings under the A40 and the A312 will be carried out from April 2007. The majority of the pipeline will be constructed between April 2008 and October 2008. Construction during this period gives the best condition for working and restoration of the land.
How is the route decided?The pipeline needs to be constructed between two particular points on the existing gas supply network -Harefield and Southall - to enable more gas to be supplied to West London.
Potential route corridors have been considered, in an area of 196 km square, based on:
1. The start and finish of the pipeline.
2. The reasonable avoidance of centres of population.
3. The reasonable avoidance of significant environmental features and sites of archaeological significance.
4. The reasonable avoidance of potentially difficult construction areas, such as steep slopes, peat and complex river crossings.
5. The shortest distance (taking into consideration points 1-4)
A map of the proposed route is available from National Grid (or Association Committee Members) - We have been asked not to post a copy onto this website.
Construction Methods:The pipeline will be tunneled beneath roads, railway crossings and major watercourses. The remainder will be placed in a covered trench.
Working Hours:For the main pipeline construction, from April 2008 - October 2009, planned working hours are 7am-7pm Monday to Friday and 7am-4pm on Saturdays - Sunday working may be necessary, but this will be kept to a minimum.
During tunnel construction, which is expected to start in April 2007, there will be periods when 24-hour working is necessary. Any construction activity above ground will be kept to a minimum outside of normal working hours.
Working Area:One of the first activities is to mark out the centre line for the pipeline and then to peg out the working width (generally 44 meters). Pre-construction drainage is installed and topsoil is then carefully removed and stored within this working width.
Construction Progress:Pipeline construction is carried out in a series of phases that will run concurrently along the length of the pipeline. These activities are as follows:
1. Lay out the pipeline above ground.
2. Weld the pipe above ground with breaks for road crossings etc. The welds are then tested to check for soundness and coated to provide additional protection.
3. Excavate a 2 meters-wide by 2.5 meters deep trench. It is normal practice to have this open for the minimum amount of time for safety and to reduce the likelihood of it being affected by adverse weather conditions.
4. Place the pipe in the trench.
5. Reinstate the land in the original layers that were removed - this includes the replacement of any hedges or similar landmarks that have to be removed during the construction process.
Summary:It is the aim of National Grid to construct the pipeline with the minimum amount of inconvenience and to work with all those who may be affected to achieve this.
Care for the environment is a prime concern during the pipeline construction and we work very closely with environmentalists throughout the process. All land will be fully reinstated and the only permanent reminder of the pipeline will be its marker posts. National Grid maintains responsibility for returning the land to its original condition.
For further information please contact: National Grid Community Relations Team 0800 731 1231
You may also contact any members of the Committee with any questions and feedback on this project.
