Frequently-Asked Question FAQ #223

FAQ-223: Data Gathering to support SCCDA

Question: What kind of data must I collect and evaluate to use stress corrosion cracking direct assessment (SCCDA)?

Answer: Section 192.929(b)(1) requires that operators planning to use SCCDA must gather and evaluate "data related to SCC at all sites an operator excavates during the conduct of its pipeline operations where the criteria in ASME/ANSI B31.8S, appendix A3...indicate the potential for SCC." This is because information from actual examinations of pipe in service are the most reliable indicator of problems and are the key data relied upon in the SCCDA method. Operators may not have heretofore gathered such information.

NACE International has recently published recommended practice RP0204-2004. While OPS has not yet reviewed this recommended practice for possible incorporation into the integrity management rules, it does provide current guidance concerning stress corrosion cracking and the use of DA processes in its assessment.

Operators who find they are subject to the threat of SCC, and who intend to use SCCDA to conduct assessments, should revise their O&M procedures to assure that relevant data is collected that will allow the SCCDA process to be used. Data collected should include magnetic particle NDE, which is vital to detecting stress corrosion cracking, as well as data on soil conditions, coating condition, etc.

Operators should note that the criteria for susceptible segments in ASME/ANSI B31.8S, Appendix A, Section 3.3 (a)-(e) relate to classical, high-pH SCC. These same factors, except for those relating to temperature [factors (b) and (c)], should be referred to regarding the susceptibility of near-neutral SCC as specified in the NACE recommended practice RP0204-2004.

At this time, use of DA for near-neutral SCC is considered "other technology" and operators must notify OPS at least 180 days before conducting an assessment using such a method. This could change if OPS adopts the new recommended practice, but rulemaking will be required to do so.