Pipeline Construction

The construction process for different pipelines is largely similar. It begins with the pipeline easement being cleared and graded to ensure that there is an unobstructed path for the pipeline. This is followed by trenching, which involves ploughing a ditch in the earth into which the pipeline will be laid. 

Lengths of pipe are organised alongside the trench in a process called ‘stringing’. This is in preparation for welding, which needs to be both fast and accurate. 

The freshly welded joint is ground down to ensure a smooth surface and blasted with sand to facilitate coating adhesion before the field joint coating is applied. This acts as a protective barrier between the pipeline and its surrounding environment, preventing corrosion and extending the asset’s lifespan. 

The pipeline undergoes weld testing and inspection before being carefully lowered into the trench. Rollers are used to protect the freshly applied coating and a padding machine prevents damage to the pipeline by sifting rocks out of the soft soil which is used to cushion and cover the pipeline. After the pipeline has been adequately covered with soft soil, backfilling occurs, with regular soil pushed back in to fill the trench. 

Once the pipeline is installed, hydrotesting is performed, pumping water through the pipeline’s length at a higher pressure than the product in order to test its durability and to ensure there are no leaks. After this has been successfully completed, the pipeline can be placed into service. 

Finally, environmental consultants step in to direct resinstatement, restoring the environment along the easement to its original state prior to pipeline construction.

Source : http://pipelinesinternational.com/resource/category/pipeline_construction/1244#news