NDT,NDT,NDT? What is NDT?

I moved directly into the water Industry over 30 years ago as a Leakage Technician, then Supervisor and onto Leakage Manager. My career has unintentionally stayed connected to water/wastewater and pipeline markets.

I designed, validated and implemented the first ever district meter area (DMA) to have telemetry communication, many followed.

25 years ago, I decided I would move away from water network management and joined a company who offered NDT inspection services. I had absolutely no idea what that meant.

The reason I have provided the above information is that unbeknown to me I had been using Non-Destructive Testing (NDT) for many years. The industry language is different. A Leak Noise Correlator (LNC) and noise loggers would be considered NDT equipment. This then got me thinking about cross over knowledge sharing from the water utilities and their challenges to the Oil, Gas, COMAH and other industry challenges. Guess what? They are the same!

If we set aside budgets the issues are the same, the well-used historic equipment/technique in one market can be innovative in the other.

Introducing Phased Array and Automated Ultrasonics into the Utilities

The Challenge

An example of this occurred when WRc had an enquiry to inspect a Victorian water trunk main. The Water Company wanted to include a condition assessment of the pipe on either side of a burst.

The Solution

As the asset was over a hundred years old, we decided to try a range of inspection techniques to determine which could give the required report for the client. Our team utilised RMS corrosion mapping and Phased Array, using a wheel probe.

The Result

It was a good opportunity for our team to upskill in the techniques required for inspecting 19th-century pipes. Trialling the different techniques allowed us to determine which inspection worked best for the Victorian cast iron material. The combination of the two tests provided a high-quality result on the condition of the pipe.

This has provided WRc with a solution on cast iron trunk mains for any future inspections. This will reduce operational disruption and minimise costs for our clients in the water utility sector in the future.

Phased Array Ultrasonic Testing (PAUT), also known as phased array UT, is an advanced inspection technique that uses a set of ultrasonic testing (UT) probes made up of numerous small elements. The technique is very versatile and can be used on many material, pipelines and Storage Tanks.

Introducing Leak Noise Techniques into COMAH Sites

The Challenge

A client at COMAH Tier 2 status had issues within their water network including low pressure and high flow demand. Our Leakage Detection team who are CABWI accredited visited site.

The Solution

Our team using our Leak Noise Correlators (LNC), pipe tracing equipment and acoustic noise portable loggers surveyed the large site that had many differing pipe sizes and material inspected.

The Result

Three leaks were located, one was on a 200mm main, with the two others being valve leaks. During our investigation a cross connection valve was located between the water main and the fire main. Deployment of our acoustic logger resulted in a large leak being located on the fire main. The fire main would have not been fit for purpose in an emergency.

Correlation Leak Detection is a technique to find leaks in pressurised water pipes with pinpoint accuracy. A leaking pipe creates a sound which travels along the pipe wall material.

A Leak Noise Correlator works by attaching two sensors on the pipe.

The sensors emit and record a sound via radio to a separate processing unit. The correlator then calculates the location of the leak using a mathematical algorythm.

The calculation is composed of:

• Signal Delay
• Sensor Distance
• Sound Velocity

The calculation tells the operative how far along the pipe the leak is from each sensor

WRc NDTi provide an inspection service using many varied technologies. For further information, visit this page or contact us.