Burst on 40” Cement Lined Raw Water Gravity Main

PMP received an emergency request for assistance from United Utilities following a serious burst on a 40” Ø pipeline transferring Raw Water from Prescott Reservoir. The pipeline is one of three (the others being 44 and 36”Ø) of which at least two are required at all times to avoid any interruptions in supply.

It was immediately apparent that this was a very serious incident potentially impacting on 170,000 customers in the Toxteth area of Liverpool. In addition a significant number of properties in Huyton, the location of the burst, had been seriously affected by flooding due to the burst.

Project duration was deemed as critical by United Utilities as they were of the opinion the condition of the adjacent 36” main was suspect and their risk exposure to further bursts was significant.

In total we surveyed 4.5km of pipeline in approximately 500m sections. A survey report for each section of pipeline was produced within 2 days for United Utilities including an assessment of the number of AMEX-10 seals required.

United Utilities’ Framework contractor, Enterprise, was responsible for exposing the pipe at 11 locations both East and West of the burst. This allowed an access point for PMP to undertake the surveys and install the AMEX-10 seals. The surveys and installations were undertaken under Confined Space Regulations and as such a seven man team was required.

In total 139 AMEX-10 seals were installed along the 4.5km pipeline. This was successfully achieved without causing any other adverse impacts. As it was also delivered within the required project timescale United Utilities were able to return this pipeline to service without any interruptions in supply.