FAQ's

NACE MR0175 requirements for Gr. 660 flange bolting materials

NACE MR0175/ISO 15156-2 and NACE MR0175/ISO 15156-3 Questions and Answers

Does NACE MR0175/ISO 15156-2, Paragraph A.2.2.4 Apply to Gr. 660 Flange Bolting Materials?

The first question on this page addresses whether NACE MR0175/ISO 15156-2, Paragraph A.2.2.4 applies to Gr. 660 flange bolting materials or only to carbon and low alloy steel bolting materials in Part 2. The answer to this question is that Paragraph A.2.2.4 only applies to materials in Part 2.

ISO 15156-3, Table A.2 and Operator Responsibility

The answer to the first question also discusses ISO 15156-3, Table A.2, which assumes a mixed-phase environment with both a gas and a liquid phase. However, it is the operator’s responsibility to determine the service conditions, including chloride content. If the user feels that Table A.2 does not address the expected field conditions, they have the freedom to test materials under alternative environmental limits and use the outcome of successful tests to justify the use of a material outside the limits set in the standard.

Does NACE MR0175/ISO 15156-3 Table A.26 Apply to Gr. 660 Material Used in Subsea Bolting Applications External to the Production Wellbore Environment?

The second question on this page asks whether NACE MR0175/ISO 15156-3 Table A.26 applies to Gr. 660 material used in subsea bolting applications external to the production wellbore environment when it is indirectly heated above 150°F. The answer to this question is that Table A.26 does not apply to Grade 660 material used in subsea bolting applications external to the production wellbore environment. This question is in relation to NACE MR0175/ISO 15156-2 Annex A.2.2.4, and the reference cited is ISO 15156 Maintenance Panel Inquiry #2005-09Q1 and Q2.

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