The scope of the project entailed the inspection of over 50 carbon steel pipeline supports with various diameters and wall thicknesses (ranging from DN 50 to DN 300 and wt. 2,9 – 7,1mm). The previous method employed, gamma rays, only works on small diameters (max. DN 100).
Due to the complexity of the project caused by the wide variety of diameters (DN 50 – DN 700) and wall thicknesses (in range 2 – 20mm), Applus+ suggested EMAT MRUT. Thanks to a medium range guided wave application, an Electro Magnetic Acoustic Transducer (EMAT) 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.
Three classes of pipeline to ensure a good inspection
The severity of the corroded areas will be interpreted based on categories. The result is a percentage of remaining wall thickness based on the attenuation of the ultrasound. Two EMAT sensors attached to both the pipe and the screen record the volume of the pipe at the location of the support, 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:
- Pipeline without any defect
- Pipeline with moderate corrosion loss
- 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, the client regards Applus+ as the NDT expert in the region, based on our references of EMAT MRUT inspections. This is an example of a good implementation of NDT: repeated job opportunities after a successful execution carried out at the client’s request.