Whether it’s a dairy farm or geothermal site, the main challenge for running ageing facilities operating beyond their original life span is ensuring safety and reliability.

“With updated Worksafe regulations in force across New Zealand, adhering to asset integrity requirements has become ever more critical,” says Rhys Humphries, general manager of EnerMech.

He says a focus area is the central issue of insulated piping made of carbon or low alloy steel and stainless steel (under the right conditions) and the prevalence of corrosion under insulation (CUI). Left undetected, it can cause loss of containment/environmental risk, and cause financial and reputational damage.

“With over 35 years’ experience in the region, EnerMech specialises in world-class non-destructive testing (NDT) inspection services… keeping assets running,” says Humphries.

CUI is typically caused when moisture becomes trapped in the insulation material and worsens corrosion taking place on the outer surface of the piping.

A tailored CUI programme using the most appropriate NDT solutions help identify potential problem areas for insulated piping – such as leaks – in advance, as well as gaining greater insight into the condition of the insulated piping itself.

“We employ a variety of techniques to detect and/ prevent CUI including our digital radiography system DigitRT, Open Vision solution and pulsed eddy current screening tools.”

Digital radiography is widely used for detecting defects, cracks, corrosion, corrosion under insulation, erosion and loss of wall thickness.  DigitRT accurately assesses piping, pressure vessels and valves, and can detect discontinuities in a range of materials including aluminium, steel, plastics and composites.

Humphries compares DigiRT to conventional radiography: “Less operator dependent, it deliver more accurate results 71% faster. Images are captured using a flat panel detector then sent wirelessly or via cable to our mobile unit on-site for instant interpretation. It can use weaker radiation sources, requiring a smaller containment area to control, which has less impact on day-to-day activity.”

Open Vision work provides a live-video x-ray inspection of insulated piping circuits to identify targeted areas prior to removal of insulation.

“It uses an ultra-weak x-ray source, requiring no exclusion zone to control, resulting in large quantities of pipework being completed screening relatively quickly without causing any disruption to production. Still and video recordings are captured for inspection reports and archives.”

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