What is the difference between the NACE MR 01-75 and NACE MR 01-03.
The new version of the standard NACE MR 01-75 doesn't specify classes (Class I, II, III) as it was before. To what those classes refer ?
MR0175-03: There are four classes (Region 0, 1, 2, and 3 in Fig.1) per sour severity.
Region 0 (PH2S<0.05psi)- No precaution. But may be considerable tensile strength limit, geometry effect (avoid stress concentration structure), etc.(seepara 7.2.1.3)
Region 1 - apply para A.2, A.3, or A.4
Region 2 - apply para A.2 or A.3
Region 3 - apply para A.2
MR0103-03: Find below article (Hydrocarbon Processing, p73-77, November 2004)- summarized paper