Corrosion Control Documents

The Hendrix Group offers proven expertise in developing corrosion-control documents for specific industry applications.

Corrosion-control documents have been referred to by different acronyms, including Material Operating Envelopes (MOEs); Critical Process Variables (CPVs); Corrosion Manuals; Corrosion Control Documents, Corrosion Circuits, Corrosion Reports, Corrosion Loops, etc. They can be combined in a risk-based inspection program implementation or can be stand-alone documents. 

“… a typical RBI assessment program is particularly ineffective in reducing risk … in the absence of expert input.”

What are corrosion-control documents?

Corrosion-control documents (CCD) provide essential input for effective mechanical integrity programs and risk-based inspection programs. They are particularly useful for capturing in one document the essential elements of a chemical or refining process that influences corrosion, i.e. materials of construction, process-stream chemistry, operating conditions and damage mechanisms.  The Hendrix Group, Inc. has developed Corrosion Control Documents (CCDs) for most refinery units and many chemical and petrochemical units.  We have functioned as the damage mechanism expert in workshop settings for clients implementing RBI software solutions using various software platforms, including Meridium, API RBI, Lloyds Capstone, Shell S-RBI and T-OCA.

The Hendrix Group Inc. has provided corrosion consulting, corrosion prevention, and corrosion-control services for more than 35 years. Our objectives are:

  • to provide a high quality of service at a reasonable price
  • to develop practical solutions to clients' corrosion problems
  • to work with our clients as a team.

Why corrosion-control documents are important

Semi-quantitative, risk-based inspection assessments and the various RBI software tools are very useful for capturing and presenting large amounts of equipment data, facilitating the structured assignment of risk to equipment, and setting inspection intervals. However, RBI programs and software are not particularly useful for identifying the damage mechanisms in a unit and do not address upset or startup/shutdown damage mechanisms at all. In fact, one could argue that a typical RBI assessment program is particularly ineffective in reducing risk - and largely a poor use of personnel and money - in the absence of expert input into a unit’s damage mechanism and where those mechanisms are likely to exist.

Download our CCD Presentation from the API Inspection Summit

Download the CCD presentation from the 2011 API Inspection Summit and Expo (PDF).

Corrosion control document contents

  • Describes the unit process
  • Provides rationale for materials of construction
  • Defines corrosion circuits
  • Defines damage mechanisms in each circuit:
  • Includes critical locations
  • Includes integrity operating windows
  • Provides start up, shut down and upset operation influences
  • Includes predicted (or actual) corrosion rates and environmental cracking tendencies

Uses of corrosion control documents

  • A training tool for new materials and corrosion engineers and unit inspectors
  • TML and CML placement tool
  • Input into RBI inspection programs
  • Inspection Planning
  • Optimizing inspection techniques
  • Establish integrity operating windows
  • The essential information for an individual corrosion circuit is typically summarized in a tabular, easy to understand format (PDF).

Related engineering services


Related Downloads

CCD Presentation

Download the CCD presentation from the 2011 API Inspection Summit and Expo (PDF).


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