) typically keeps standards in effect for several years; the 2018 version remains the active guidance for preventing Polythionic Acid (PTA) Stress Corrosion Cracking (SCC) during refinery shutdowns. ANSI Webstore Core Content & Mitigation Methods
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: Covers the entire shutdown process, including downtime and the periods immediately preceding and following it (start-up). Target Materials : Focuses on common refinery alloys like UNS S30400 (304 SS) S31600 (316 SS) , and stabilized grades like
NACE SP0170 PDF 2021 has significant implications for industries that use equipment and components in petroleum refining and petrochemical environments. Some key implications include: nace sp0170 pdf 2021
Uncertainty Quantification: SP0170 recognizes measurement uncertainties and variability in soil and coating properties. It encourages conservative thresholds for prioritizing excavations when data quality is poor and advocates sensitivity analysis in ranking outputs.
When implementing these procedures, rely strictly on verified, authentic copies of the standard to ensure safety compliance and engineering accuracy.
PTA typically results from the interaction of sulfide products with oxygen and moisture during periods when equipment is not in operation. ) typically keeps standards in effect for several
Indirectly, yes. While is the primary standard for materials used in sour service (sulfide stress cracking), SP0170 applies to the corrosion products resulting from those sulfides.
The following guide details the technical specifications, mechanics of PTA SCC, and mandatory mitigation procedures outlined in the NACE SP0170 PDF standard . What is NACE SP0170?
This standard provides technical procedures to prevent Stress Corrosion Cracking (SCC) caused by polythionic acids (PTA) that form when sulfide scales on equipment react with moisture and oxygen during refinery downtime. Key Aspects of the 2021 Revision PTA typically results from the interaction of sulfide
The standard emphasizes understanding if the material is sensitized. If not sensitized, the risk of PTA SCC is much lower, and the aggressive mitigation methods may not be necessary.
: Heavy-duty process units containing sulfur species operating at elevated temperatures, such as hydrocrackers, hydrotreaters, desulfurization units, coking units, and fluid catalytic cracking units (FCCUs).
The official active document for this designation is , which remains the current industry standard practice for protecting austenitic stainless steels from polythionic acid stress corrosion cracking (PTA SCC).