Nace Sp0170 Pdf

: The primary source for the most recent version (2018) is the AMPP Standards Store .

If liquid washing is impractical, keeping the internal environment completely dry is an alternative. By introducing dehumidified air with a relative humidity (RH) below 20%, moisture is eliminated from the equation, preventing the chemical reaction that yields polythionic acid. Evolving Material Selection to Complement SP0170

Successfully executing NACE SP0170 prevents catastrophic metallurgical failures that can delay turnarounds by weeks and cost millions in unbudgeted repairs. The standard proves that proper chemistry management during a shutdown is just as critical as mechanical engineering controls during active production. nace sp0170 pdf

What is Polythionic Acid Stress Corrosion Cracking (PTA-SCC)?

The 2018 version of the standard (NACE SP0170-2018) is the most recent and supersedes all previous versions, including the 2012 edition . The current version has a page count of 16 pages . : The primary source for the most recent

This method involves purging the equipment with an inert gas, most commonly dry nitrogen gas (N₂). According to the standard, purging is defined as a continuous or intermittent flow of dry nitrogen to free the system of corrosive impurities, particularly oxygen (O₂) . By displacing oxygen, nitrogen purging prevents the chemical reaction that forms polythionic acid from the existing iron sulfide scale. The standard specifies that the nitrogen must be dry to prevent the introduction of moisture, which is also a critical ingredient for PTA formation.

Understanding NACE SP0170: Protection of Austenitic Stainless Steels from Polythionic Acid Stress Corrosion Cracking The 2018 version of the standard (NACE SP0170-2018)

During a shutdown where PTA SCC mitigation is performed, other integrity activities, such as an internal visual inspection or Non-Destructive Examination (NDE), are also typically carried out. The team responsible for implementing NACE SP0170 (e.g., the nitrogen purging crew) must coordinate with the inspection team to ensure that the inert atmosphere is maintained or that surfaces remain neutralized for the required duration.

This guide explains the technical scope of NACE SP0170, the mechanisms of the corrosion it prevents, and how to access the official PDF documentation. What is NACE SP0170?