Provides guidance on using carbon steel, stainless steels, and various alloys. Corrosion Phenomena: Addresses specific risks like hydrogen grooving
While many NACE standards focus solely on chemical resistance (like RP 0188), RP 0391 addresses the specific niche of . It serves as a comprehensive guide for selecting, specifying, and applying organic linings designed to protect concrete and steel substrates from wear and tear. nace rp 0391 pdf
| | Fact (per RP0391) | | :--- | :--- | | "Carbon steel is fine for any concentration of sulfuric acid." | False. RP0391 limits carbon steel to above 90% concentration and ambient temperatures. Below that, corrosion rates skyrocket. | | "Stainless steel is always better." | False. Standard 304/316 stainless can suffer from active corrosion in stagnant concentrated acid. The standard specifies passive alloys only under specific flow conditions. | | "The standard ignores temperature." | False. RP0391 is explicit about the 32°F to 120°F range. Above 120°F, different materials (e.g., high-silicon iron, tantalum) are required. | | "Old copies are fine." | False. The standard has been reaffirmed and revised. Always use the "SP" version to get the latest data on alloy availability. | Provides guidance on using carbon steel, stainless steels,
: Focuses on alloys and construction materials (like carbon steel) suitable for storage tanks and piping systems in the chemical process industry (CPI). Limitations | | Fact (per RP0391) | | :---
: When carbon steel contacts concentrated acid, it initially corrodes but quickly forms an insoluble sulfate layer that limits further attack.