Published on 01-Dec-2021

Managing Corrosion Under Insulation with ALS

Managing Corrosion Under Insulation with ALS

CUI is one of the greatest concerns for the integrity of insulated piping. Yet, when detecting, managing and mitigating CUI there is no silver bullet approach. There are however advanced inspection technologies which are enhancing CUI mitigation approaches and rendering traditional techniques obsolete.

Traditional inspection approaches have required the removal of lagging or sections of lagging, and a combination of visual and manual ultrasonic testing or conventional profile radiography in order to detect for the presence of CUI. The removal of this lagging is a major disruptor to operations and when combined with the scaffolding requirements, creates a financially burdensome inspection.

These disruptions extend to radiographic inspections, given the hazards associated with the procedure. In some cases, this rolling CUI inspection program mandates restricted access or a plant shutdown, and the substrate can often be found in good condition. All-in-all, this manual approach is financially intensive and brings significant production disruptions. Advanced inspection methods have created superior CUI inspection approaches. At ALS, advanced inspection tools such as Real-Time Radiography (RTR) and Pulsed Eddy Current Testing (PECT) are the preferred CUI approaches for through-lagging screening for a myriad of reasons.

Download Our Managing Corrosion Under Insulation Approach here.

The Solutions

Real-Time Radiography (RTR)

Real-Time Radiography (RTR) is a radiographic approach that can produce instant digital images. RTR eliminates processing timeframes, drastically improves cycle times and elevates safety due to the reduced radiation requirements. Unlike film radiography, RTR solutions uses digital x-ray systems with live video output for real-time inspection and reporting. This real-time reporting enables the inspection of many meters of insulated piping and the quick identification of corrosion indicators or corrosion precursors such as scaling, external wall loss, and wet insulation.

RTR can be used on various insulation and cladding combinations, including mineral wool and calcium silicate with galvanized steel, stainless steel and aluminum cladding.

RTR is recognised by the HOIS/OGTC Guidelines for in-situ inspection of corrosion under insulation (CUI) as an inspection approach that maximises in-situ inspection strategies and improves the effectiveness of CUI detection. RTR is mostly suited to the inspection of piping systems.

OpenVisionTM DX, developed by QSA Global, is the handheld, real-time imaging device used at ALS. It features a three-hour battery life and allows pictures and real-time videos to be recorded and downloaded for rapid review and reporting.

Pulsed Eddy Current Testing (PECT)

Alongside RTR, Pulsed Eddy Current Testing (PECT) is another CUI approach which has been uniquely developed to detect corrosion hidden under insulation. PECT is an electromagnetic technique which detects for the remaining thickness of piping, along with other assets, without requiring insulation or lagging removal.

Maxwell NDT is the world leader of PECT technology and is the State-of-the-Art Equipment used at ALS. Designed by experts with 20 years of hands-on experience, the PECT instrument has been uniquely designed to detect CUI using the latest battery technology. This battery technology and power allows for higher energy pulsing as wells as full shift field scanning.

Each system also has four probes to cover a range of material thickness and insulation thickness. PECT can also be used on insulated vessels and tanks, as well as piping systems.

Both RTR and PEC are ALS’s preferred screening approaches that deliver “best practice” inspection outcomes when detecting for CUI. They both support substantially lower financial outputs whilst reducing inspection timeframes. Beyond this, both approaches can be performed via rope access deployment, which fraction the construction and cost demands of traditional methods without safety tradeoffs.

Discover more about ALS's Corrosion Investigation services here.



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