Nafta Hydrotreating: Hydrogen Blistering in A106 GrB pipe?

[Lmarcano]

Hi, recently we carried out a thickness measurement of a PIPE by ultrasonics and find low values respect to the nominal, the problem, hidrogen blistering of a 12 months pipe, probably the pipe was inadecuate A53.
Now the question is, what is the better method or test in order to differentiate a A53 from A106 Gr.B pipes? if The chemical composition is the same.
By other side, you know about A106 Gr.B that has failed by blistering? where begin the critical range of H2S concentration that could be harmful for whatever of those materials?

 

[AndyG]

A106B has higher Si, though I do not think there is a nondestructive technique (portable fluorescence or spectroscopic PMI devices) that can differentiate. If you have NACE Refin*Cor database, there may be some data on Hydrogen Induced Damage of pipe. I believe I know of only one case reported by a Middle East refinery. It would be very rare but it could be possilbe in very severe hydrogen charging environment. A naphtha hydrofiner is not typically very severe though.