Nace Sp0170 Pdf May 2026
NACE SP0170 provides essential protocols for protecting austenitic stainless steels from polythionic acid stress corrosion cracking (PTA-SCC) during refinery shutdowns. The standard details mitigation strategies, including nitrogen purging, alkaline washing, and dehumidification to prevent catastrophic equipment failure caused by acid formation. The official, copyrighted PDF can be purchased through the AMPP store.
- Product Number: 21019 (for the current version).
- Cost: Approximately $150–$250 for members; $200–$350 for non-members (prices vary by revision and membership status).
- Format: DRM-protected PDF or watermarked downloadable file.
Subscription Services: Certain subscription-based services may provide access to NACE standards, including the SP0170 document. nace sp0170 pdf
Nitrogen Purging: Using dry nitrogen to exclude oxygen from the equipment's internal surfaces. Product Number: 21019 (for the current version)
In a refinery environment, equipment made from austenitic stainless steels (like 300-series alloys) often develops sulfide scales on internal surfaces during operation. When the unit is shut down and opened, these sulfides react with moisture and oxygen in the air to form polythionic acids (PTA). These acids can cause rapid, catastrophic cracking in sensitized metals—sometimes within hours of exposure. Key Mitigation Strategies in SP0170 including nitrogen purging
“With a set of SP0170-compliant isolation pads. They’re in the warehouse. Red box, top shelf. They’re fiberglass-reinforced with a 500°F rating. Slide them between the pipe and the saddle. No clamp. No metal-to-metal contact. No galvanic corrosion.”
This cracking typically occurs during refinery equipment shutdowns when sulfide scale on the metal reacts with air (oxygen) and moisture (water) to form polythionic acids. Scope and Application