NACE SP0170 PDF: Protecting Refinery Equipment from Polythionic Acid Stress Corrosion Cracking
Refinery heaters, heat exchangers, piping, and pressure vessels. Standard austenitic stainless steels (300 series).
You need both standards. MR0175 tells you which material to buy. SP0170 tells you how to protect that material when you shut down the unit.
The most reliable way to obtain the correct and most current version is through NACE/AMPP's authorized distribution network. Several online standards retailers, such as Accuris (formerly Techstreet), ANSI Webstore, and GlobalSpec, are official partners. nace sp0170 pdf
If a wet chemical wash is undesirable (for example, in catalyst-filled reactors or systems sensitive to water retention), NACE SP0170 allows for the exclusion of moisture.
To effectively implement NACE SP0170, one must first grasp the three components required for PTA-SCC to occur:
The consequences can be severe, leading to: MR0175 tells you which material to buy
The NACE SP0170 standard establishes mandatory practices and recommended procedures to protect both sensitized austenitic stainless steels and other austenitic alloys (such as Alloy 800 or Alloy 825) from PTA-SCC.
Understanding NACE SP0170: Protection of Austenitic Stainless Steels from Polythionic Acid Stress Corrosion Cracking
The document (now managed by AMPP ) is a Standard Practice rather than a single academic paper. It provides critical procedures for protecting austenitic stainless steels from Polythionic Acid Stress Corrosion Cracking (PTA SCC) during refinery shutdowns. Core Focus of NACE SP0170 Document Scope & Contents
A critical caveat in SP0170 is chloride stress corrosion cracking (Cl-SCC). To prevent introducing a secondary cracking mechanism, the water used to mix the soda ash solution must have strictly controlled, ultra-low chloride levels (typically less than 50 ppm, and ideally less than 20 ppm). 3. Dehumidification (Dry Air Blanketing)
: Provides both the PDF and printed editions . Document Scope & Contents