Halting hot hydrogen attack

London - Hot hydrogen attack (HHA) is a form of degradation brought about by hydrogen reacting with carbon which in turn can cause cracks and loss of strength in steel. For this reason, the presence of hydrogen in industrial plants is a potential source of damage that can cause unsafe situations. In weld material, HHA can lead to a leak but when the damage is in the parent material, the result can be catastrophic. Therefore, it is both crucial and required to precisely and adequately monitor HHA.

To support owners of industrial facilities, SGS Pakistan, in cooperation with SGS Netherlands, conducted a seminar on Hot Hydrogen Attack and the most efficient Advanced Non-Destructive Testing (NDT) techniques to detect it. Held back in Marchl in Karachi, Pakistan, the seminar aimed to provide industrial facility owners a platform to better understand the process of HHA. For the very first time, attendees from different industrial fields had the chance to share their views and insights on the various ways that advanced inspection techniques can work for them.

The seminar was presented by NDT specialist Norbert Trimborn from SGS Netherlands, as well as director of operations Abdul Razzak Lakhani and operations manager Muhammad Aqeel, both from SGS Pakistan. Attendees were taught about the formation of HHA in steel and welds and its destructive effects on industrial plants, and about efficient inspection techniques for the detection of HHA.

The seminar especially highlighted advanced ultrasonic inspection methods like time of flight diffraction (TOFD), automated backscatter and velocity ratio measurements. By combining these three NDT techniques, SGS Industrial Services has developed a specific procedure and approach to sufficiently identify and monitor HHA.

To detect the possible occurrence of HHA, SGS sets up a precise inspection plan with the backscatter technique using Corroscan for the most critical areas. In order to distinguish between HHA and small inclusions and to verify the attack, additional measurements are taken using the velocity ratio technique. For the inspection of weld material, the scanning of all welds with TOFD and manual or automated pulse echo is required.