It is our understanding of NACE MR0175/ISO 15156 that provided ASTM A 995 Grade 4A (UNS J92205) 22 Cr duplex stainless steel complies with the material limits of Table A.24 of Annex A, it can be selected for use in H2S-containing environments provided the environmental limits given in Table A.24 are not exceeded.
Your understanding is correct.
Reference: ISO 15156 Maintenance Panel Inquiry #2006-04Q1
Question 2 It does not ALSO have to be listed in Annex D Table D7, which we believe is for information only and lists only SOME duplex stainless steels.
You are correct.
This is in relation to NACE MR0175/ISO 15156-3 Annex D
Reference: ISO 15156 Maintenance Panel Inquiry #2006-04Q2
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