NACE RP0391 is a standard developed by NACE International (the National Association of Corrosion Engineers), a globally recognized authority in corrosion prevention and control. The "RP" in its designation stands for , a class of NACE standards that provides procedures, guidelines, and methods for performing a specific task or selecting materials, without being as prescriptive as a code. The current and active version of this standard has been re-designated as NACE SP0391-2016 , where "SP" signifies Standard Practice , reflecting an update in NACE's nomenclature while retaining the same technical intent.
). In low-flow or stagnant conditions, hydrogen bubbles rise vertically along the walls of storage tanks or horizontal pipes. As these bubbles travel upward, they displace the protective passive film, creating vertical channels or "grooves" in the steel. NACE RP0391 dictates design practices to minimize stagnant zones and avoid hydrogen grooving. 3. Material Selection Matrix According to NACE RP0391
Concentrated sulfuric acid is a strong oxidizing agent, but its behavior changes dramatically depending on concentration, temperature, and fluid velocity. Concentration Range Passivation Effect on Carbon Steel Risks / Mechanisms Highly corrosive; breaks down protective films quickly. Rapid uniform thinning. 90% to 98% Forms a protective, passive ferrous sulfate ( FeSO4cap F e cap S cap O sub 4 Turbulence or high flow washes away the film. 99% to 100% nace rp 0391 pdf
A legitimate PDF of NACE RP 0391 is approximately 20–30 pages and organized into the following critical sections.
: All weldments must be free of slag, porosity, or mill scale, as these defects act as initiation points for localized attack. Where to Find the Official PDF NACE RP0391 is a standard developed by NACE
Because NACE RP0391 contains proprietary technical specifications, it is a copyrighted document. To obtain an official, up-to-date PDF copy, professionals should use authorized channels:
NACE RP 0391 is a widely adopted standard in the oil and gas industry, providing guidelines for the cathodic protection (CP) of internal corrosion in steel pipelines. The standard, titled "Cathodic Protection of Internal Corrosion in Steel Pipelines," offers a comprehensive framework for designing, operating, and maintaining CP systems to mitigate internal corrosion in pipelines. NACE RP0391 dictates design practices to minimize stagnant
You can find the document listed as NACE Standard RP0391-2001 on the ANSI Webstore.
The chemical reaction between steel and sulfuric acid produces hydrogen gas ( H2cap H sub 2