Gas Leak

Another day, and another news story of disruption caused by a water or gas leak.  This time in central London.  Most of the failures just result in disruption to water supplies, or maybe some road works delaying your commute, but now and again they lead to massive disruption (as in London today), or even deaths as happened in New York in 2014 (

The failures seen by utilities such as water and gas are most often not as a result of the pipe failing but actually the joint between pipes.  This is a well-known problem within the industry with defects in joints often arising due to poor welding of joints which are hidden from sight until pipeline finally fails.  In fact studies show that as many as 20% of joints fail prematurely, causing a water leak or gas leak.

This is an extremely high failure rate and so there is a clear need for a system which can carry out infield non-destructive testing of joints before they’re put in the ground.   After looking at what currently existed on the market, the only devices available to identify these poor joints were extremely expensive, required a highly trained operator or could only assess certain joints.  Obviously, these cannot be used on the scale needed to address the problem, so Impact decided to develop a simple, accurate, low cost method of testing any joint.

What Impact have developed is an easily portable, probe and laptop device, which in combination with proprietary software assesses electrofusion joints for voids, mud and other common flaws which can lead to failures. The system has been correlated with destructive testing over a two-year period with trials conducted across the UK and blind trials conducted in the US with a 93% success rate.  By developing the NDT system to marry up with industry destructive testing standards, it becomes possible for the first time to make in situ assessments of welds as they are installed, that are indicative of how the weld would perform in a laboratory testing.

The system is developed to be as simple as possible giving the operators a green, red or yellow signal at each point around the joint to indicate whether the location shows good fusion or not.  Once a joint has been tested, a report is produced automatically allowing the operator to make an assessment of the overall weld quality and whether or not it should be removed.  These reports can be inputted into any QC/QA process to aid in tracking failures across the network or the quality of welding by different teams.

By deploying this system in the field we hope to drastically reduce the number of failures seen across our infrastructure over time, be it a gas leak or water leak.  Thus, reducing the cost on utility companies and contractors whilst also reducing the impact on customers and commuters through outages and excavation works.

Ultimately this system will allow for the first time a rigorous method for checking quality and tracking asset integrity across our network.   It will improve the quality and training of welders and allow us to catch any issues before they become serious or a public safety hazard.

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