Applus+ successfully inspects Corrosion Under Pipe Support (CUPS) at a Czech refinery

This project was especially complex, as it involved the inspection of more than 50 carbon steel pipe supports with a wide variety of diameters (DN 50 – DN 700) and wall thicknesses (in range 2 – 20mm). The previous method employed, gamma ray RT, was not the best solution as it only works on small diameters (max. DN 100). To overcome this challenge, Applus+ suggested the use of EMAT MRUT. Using an Electro Magnetic Acoustic Transducer (EMAT), a medium range guided wave application that utilises ultrasonic waves without the need for liquid couplants, inspection of the pipe material volume can be done on difficult to inspect areas such as pipe supports.

Classification of the pipelines to ensure an efficient inspection

The severity of the corroded areas is interpreted based on three categories. The classification is based on the percentage of remaining wall thickness as measured with the ultrasound testing. Two EMAT sensors attached to both the pipe and the screen record the volume of the pipe at the location of the support, which gives an improved detection when compared with that provided by leakage testing.

To ensure a good inspection, the assets need to be sorted in three classes:

1. Pipeline without any defect
2. Pipeline with moderate corrosion loss
3. Pipeline with heavy corrosion loss

During every shift, the Applus+ team inspected up to 20 supports (depending on access and changing of coils, scanners and set-ups). Most pipelines on supports were evaluated as class A, several as class B.

After this efficient inspection, Applus+ is regarded as the NDT expert in the region, based on our work with EMAT MRUT inspections.