As of 2021, NACE International merged with SSPC to form AMPP. The standard is available for purchase and download through: (formerly NACE Store) ANSI Webstore GlobalSpec/Accuris
): Atmospheric oxygen entering the system when equipment is opened for inspection or catalyst dumping.
NACE changed its naming convention years ago. stood for "Recommended Practice," while "SP" stands for "Standard Practice." SP0170 implies a higher level of consensus and mandatory language than the previous RP designation. Historical versions are often listed as RP0170-93, RP0170-2004, and so on. nace sp0170 pdf 2021
NACE SP0170 is the definitive from a specific danger known as polythionic acid stress corrosion cracking (PTA SCC). This aggressive cracking typically initiates when high-temperature refinery equipment is taken offline and exposed to air and moisture. The standard provides essential mitigation methods to prevent PTA SCC in these vulnerable environments.
The standard focuses on austenitic stainless steels and high-nickel alloys that may be susceptible to specific forms of corrosion after exposure to high temperatures. As of 2021, NACE International merged with SSPC to form AMPP
Often applied as an internal wash or spray to all surfaces, including piping, reactors, and exchangers.
This includes residual stresses introduced during fabrication and welding, as well as operational or structural loads. Corrosive Environment (PTA): Polythionic acids ( stood for "Recommended Practice," while "SP" stands for
The new edition provides updated charts for maximum H₂S partial pressure versus pH. Carbon steels that passed in 2015 may now be disqualified under the 2021 thresholds, especially in low-pH (acidic) environments.
Corrosion is a massive economic burden. NACE estimates the total annual cost of corrosion in petroleum refining to be approximately in the US alone. Without strict adherence to standards like SP0170, the financial and safety consequences are severe.