What to expect from the upcoming API-970 Corrosion Control Document/Manual

By Marc McConnell, P.E., Metallurgy and Fixed Equipment Engineering Coordinator at Pro-Surve Technical Services. December 30, 2013

On November 19, 2013, API issued project/document number 970 for an entirely new Recommended Practice (RP).  The scope of this project will be to develop a work process and a standardized approach to the development of Corrosion Control Documents (CCDs) that will apply to the most common refinery process units.  It will provide guidance and basic requirements for preparing a Corrosion Control Document (CCD) on a given unit.


In order to maintain the integrity and reliability of pressure equipment in the refining and petrochemical industry, several process safety management systems are necessary.  A CCD is another tool to aid in the continuing improvement process of process safety management.  A CCD is developed on a process unit in order to identify known and possible damage mechanisms of equipment and piping, and to recommend additional inspections outside of API 510 Pressure Vessel Inspection Code.  The need for this document was identified by the Inspection and Corrosion/Materials Subcommittees of the API Committee on Refinery Equipment.  The CCD should dive deep into the fundamental understanding of the process/operating conditions and resulting damage mechanisms.

The Corrosion Control Document Process

A CCD will be developed on individual corrosion systems or loops one at a time.  Each loop will be evaluated with the same sections/topics.  We haven’t started discussing the details that will be in this SP, but some of the sections commonly included in existing CCD are as follows:

  1. Process conditions (main stream composition, temperature, pressure, contaminants)
  2. Materials of Construction
  3. Reason for the materials of construction, expected corrosion rates and possible alternative construction materials
  4. Damage mechanisms - corrosion precursors
  5. Injection/mix points, configuration, purpose, and risk ranking
  6. Inspection history and highlights
  7. Any process operation problem history
  8. Operating envelope limits, reason for monitoring, and consequence of deviation
  9. Special inspection considerations beyond API 510 and API 570
  10. Start-up and shutdown considerations
  11. Findings and recommendations

CCDs should be dynamic and account for changing process conditions and current equipment conditions.  In order to develop the necessary information, identify potential degradation mechanisms and failure scenarios along with consideration for future operating conditions, the combined efforts of a multi-disciplinary team of SMEs is recommended.  Typically this team would consist of:

  • Site corrosion engineer/specialist,
  • Unit process engineer/technologist,
  • Unit inspector,
  • Experienced unit operations representative(s),
  • Unit Maintenance / Reliability Engineer (as needed, ad hoc),
  • License Technology Specialists, as needed,
  • Process Chemical Treatment Vendor (as needed, ad hoc), and
  • Process Chemist.

Our first meeting on this new RP will be at the API Spring Refining and Equipment Standards Meeting in Orlando, Florida the week of May 19th.  Join us at that time, or send your comments and suggestions for us to incorporate.

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