Bespoke engineering solutions

How PMC avoided the close down of Peterborough Compressor Station by developing a bespoke engineering solution

The challenge 

PMC were called out to a suspected gas leak at Peterborough compressor station. Non-destructive testing showed that 50% of the weld on the flange connection was defective. 

If left, this could lead to the fitting detaching itself from the pipe. 

Removing this section of pipe would have involved a complete re-design of the compressor pipework, impossible in the timescales. For one, the materials would have had a minimum 20 week lead time. An outage of this magnitude would cause serious issues across the whole of the NTS along with a high risk that replacing this section of pipe could cause the compressor and gas turbine to move out of alignment. 

PMC and the National Grid integrity team had to come up with a solution to fix the defect without removing the entire section of pipe. 

The solution 

Utilising a solid coupon taken from a piece of pipe that could be welded in place. 

To enable this to happen, PMC had to manufacture and design a series of bespoke cutters to facilitate the adaption of drilling machines and metal cutters. 


We had to ensure that the fitting and surrounding pipe was removed in one piece and also to ensure the fitting was removed when the drill retracted rather than falling into the pipe. 

Once the coupon was in place and welded, inspection of the coupon was restricted. We had to arrange a special variation of Phased Array. 

Every step of the process was mocked up and proven at PMC’s depot in Ambergate prior to being used on-site. 

The coupon was a success. 

Watch the video by clicking below.