Update on ANSI/NACE MR0175/ISO 15156

This page provides an update dated 2017-12-22 about ANSI/NACE MR0175/ISO 15156. A Technical Circular has been published which is relevant to external bolts. The page recommends following a link related to part 2 A.2.2.4 Bolting and Fasteners, available at https://ogcenergy.com/nace-mr0175-iso-15156-technical-circulars-for-part-1-and-2-published-2017-12-22/.

Bolt Compliance to NACE MR0175

The page clarifies that bolt compliance to NACE MR0175 can sometimes lead to confusion, particularly as flange bolts may not be in direct contact with transport fluids. However, a leak may expose them to H₂S. NACE MR0175/ISO 15156-2 section A.2.2.4 addresses this matter.

Identifying the Sour Environment for Bolting Alloy Conformance

In 2011, an inquiry was sent to the maintenance panel, which the page also cites for reference. The question was about identifying the sour environment for deciding whether a bolting alloy conforms to the general requirements of A.2.1 as required by A.2.2.4 when the bolting material is denied direct atmosphere exposure. The answer reinforces the fact that the equipment user is responsible for NACE MR0175 compliance and for defining the intended service environment and selecting materials in accordance with this standard.

This question relates to NACE MR0175/ISO 15156.