When writing procurement specifications for concentrated sulfuric acid handling equipment, engineers should cite the standard as follows:
The NACE (National Association of Corrosion Engineers), which is now part of AMPP, revised its naming convention, so what was once a "Recommended Practice" (RP) is now called a "Standard Practice" (SP).
NACE standards, including RP0391 and SP0391, are not freely available to the general public. Some university libraries or corporate technical libraries may provide access via subscription services. However, no legitimate "free download" sites exist for the complete, unwatermarked PDF. Engineers should avoid illegal download sites that offer the document without payment, as these versions are often incomplete, outdated, or watermarked for legal action.
Materials for the Handling and Storage of Commercial Concentrated Sulfuric Acid at Ambient Temperatures ANSI Webstore
The document details how to evaluate materials against various forms of environmental degradation: nace rp 0391 pdf
for carbon steel in sulphuric acid.
The confusion likely arises from the fact that both standards address corrosion control in refineries—RP0391 for acid service (sulfuric acid) and MR0175 for sour service (H₂S). However, the material requirements and environmental conditions covered are completely distinct. .
NACE SP0391 also addresses non-metallic materials. It explicitly warns that PE and PP are prone to in concentrated sulfuric acid. The standard emphasizes that the likelihood of cracking increases with higher acid concentrations and temperature, and mandates a careful review of the long-term performance of these materials before any application.
The term "NACE RP0391" is one of the most searched keywords among corrosion and process engineers, particularly those dealing with highly corrosive industrial chemicals. However, a common misconception exists in the engineering community: many assume NACE RP0391 is a refinery piping standard covering wet H₂S cracking resistance. In reality, at ambient temperatures. However, no legitimate "free download" sites exist for
NACE (now often referred to as SP0391 ) is a technical standard titled " Materials for the Handling and Storage of Commercial Concentrated (90 to 100%) Sulfuric Acid at Ambient Temperatures ". Accessing the Full Text
A common point of confusion is how NACE RP0391 relates to (the global standard for materials in H2Scap H sub 2 cap S -containing environments). NACE MR0175/ISO 15156 focuses broadly on sour service ( H2Scap H sub 2 cap S
It is suitable for static or low-velocity ( ) conditions.
The keyword refers to a critical industrial standard practice published by NACE International (now part of AMPP ) titled "Materials for the Handling and Storage of Commercial Concentrated (90 to 100%) Sulfuric Acid at Ambient Temperatures." The confusion likely arises from the fact that
To simulate long-term subsea exposure under operational loads. NACE RP0391 vs. NACE MR0175 / ISO 15156
| Document | Format | Year | Publisher | Key Page Details | | :--- | :--- | :--- | :--- | :--- | | | PDF (16 pages) | 2016 | NACE International / NORMADOC | 19 | | NACE RP0391-2001 | PDF (13 pages, 77 KB) | 2001 | NACE International / Norm Library | 20 | | NACE RP0391-2001 | PDF (13 pages, 77 KB) | 2001 | NACE International / Standards Global | 9 |
The standard focuses on concentrated sulfuric acid within the 90 to 100% weight range at ambient temperatures (up to ). It is crucial to note that NACE SP0391 does cover: Sulfuric acid concentrations below 90%. Oleum concentrations above 65%. Transportation vessels such as railcars or tank trailers. Key Material Selection Guidelines