Is your risk-based inspection (RBI) implementation 3rd party really qualified to do the job?

Many RBI programs fail quietly, not because the methodology is flawed, but because the 3rd-party implementer lacks the depth to apply it correctly. When that happens, RBI becomes a paperwork exercise that appears compliant while subtly increasing operational risk.

Here’s how to tell whether your RBI contractor is truly qualified, or just proficient with software.

1. RBI is an integrity decision process, not a modeling service

A qualified 3rd party understands that RBI exists to inform inspection and maintenance decisions, not to generate intervals as an end product.

Warning signs:

• • Default corrosion rates are used with little justification, i.e. heavy reliance on default inputs and generic corrosion rates.
  • Minimal challenge to legacy inspection data, i.e. minimal questioning to historical inspection data quality.
  • Software outputs accepted without technical defense, i.e. the software doesn’t have a documented algorithm that steps you through the probability of failure (POF) and consequence of failure (COF).

Competent practitioners can clearly explain why a damage mechanism applies, why an inspection method is effective (or not), and how uncertainty is managed.

2. Damage mechanisms require expertise, not dropdown selection

Selecting damage mechanisms from a predefined list is not engineering judgment.

A qualified RBI implementer does not ask “Is this mechanism available in the software?”
They ask, “Are the necessary conditions for this mechanism present?”

This requires explicit confirmation of:

• • Material susceptibility (alloy chemistry, heat treatment, fabrication history)
  • Environmental drivers (water phase, contaminants, pH, partial pressures)
  • Thermal and mechanical thresholds (temperature windows, cyclic stress, pressure excursions)

Example:

• • Assigning high temperature sulfidation without verifying sulfur activity and metal temperature range is a modeling error, not a conservative assumption.
  • Assigning chloride SCC without confirming chloride concentration and tensile stress state is indefensible.

3. Inspection effectiveness is where most RBI programs break down

Post-incident investigations consistently show that inspection effectiveness is overstated, not that RBI models were mathematically wrong. A credible 3rd party:

• • Coverage (what percentage of the susceptible area was examined)
  • Resolution (smallest flaw size realistically detectable)
  • Access limitations (supports, deadlegs, insulation, coatings)
  • Human factors (technique variability, interpretation uncertainty)

Example:

• • A CUI circuit credited with “external VT” has effectively no detection capability unless insulation was removed in the susceptible temperature band.
  • A piping circuit inspected with sparse UT points does not have meaningful coverage for localized corrosion.

If the degradation could physically exist outside the inspected volume, inspection effectiveness is overstated.

4. Can they defend the RBI to regulators, auditors, or investigators?

Ask yourself:

Could this RBI analysis be technically defended under regulatory review or in a deposition? What does “Defensible” actually mean in practice?

A qualified 3rd party makes RBI defensible by:

• • Documenting any assumptions, every assumption must be:
    • Explicitly stated and traceable to a source.
    • Technically reasonable for the specific equipment and damage mechanisms.
    • Why default values were accepted or why they were overridden.
    • Who approved each assumption and when.
  • Documented basis for corrosion rates, initial damage potentials, and credit for inspection effectiveness.
  • Alignment with industry-recognized practices, such as those from the American Petroleum Institute

If the defense relies on “that’s what the software calculated,” you already have exposure.

5. Independence matters more than most owners realize

RBI is only as credible as the freedom to make unpopular conclusions. When the same party that performs the RBI also benefits from its outcomes, the technical integrity of the analysis is immediately suspect under external review.

Regulators, auditors, and investigators do not need to prove bias. They only need to show that bias was possible.

Be cautious when:

• • The same firm recommends extended intervals and benefits from reduced inspection scope.
  • RBI is framed primarily as a cost-reduction tool.
  • Assumptions just happen to lower cost.

Credible RBI practitioners prioritize risk transparency, even when it leads to increased inspection or maintenance scope.

6. The single most revealing question to ask a 3rd party

Before awarding work, ask:

“What RBI recommendations have you made that increased inspection or maintenance scope and why?”

This question works because it forces the consultant to demonstrate judgment, independence, and technical courage, not software proficiency. Why is this question so powerful? RBI, when applied correctly, does not trend in one direction. Some outcomes reduce inspection. Others increase it. If a practitioner has never recommended:

• • Shorter inspection intervals
  • More intrusive inspections
  • Expanded coverage
  • Costly repairs or replacements

then they are not managing risk; they are managing optics. Regulators know this. Experienced auditors know this. And in depositions, this pattern is unmistakable.

Bottom line

RBI done well improves safety and reliability, but RBI done superficially hides risk behind calculations.

If your 3rd-party RBI implementer:

• Treats RBI as a software deliverable
• Overstates inspection effectiveness
• Avoids uncomfortable conclusions
• Cannot technically defend assumptions

then you don’t have a risk-based inspection program, you have risk-based paperwork.

Source Bibliography

1. American Petroleum Institute
   API RP 580 – Risk-Based Inspection
   Establishes the principles, requirements, and expectations for RBI programs, including data quality, damage mechanism identification, inspection effectiveness, and management of uncertainty.
2. American Petroleum Institute
   API RP 581 – Risk-Based Inspection Methodology
   Provides the quantitative and semi-quantitative methodology commonly implemented via RBI software, including consequence modeling, probability calculations, and inspection credit assumptions.
3. Center for Chemical Process Safety (CCPS)
   Guidelines for Risk-Based Process Safety
   Emphasizes that risk tools are decision-support mechanisms and highlights common organizational and human-factor failures that undermine technical risk assessments.
4. S. Chemical Safety and Hazard Investigation Board (CSB)
   Refinery and Chemical Plant Incident Investigation Reports
   Multiple investigations identify failures in inspection execution, inspection effectiveness assumptions, and deferred maintenance—not mathematical RBI errors—as leading contributors to loss-of-containment events.
5. DNV
   Recommended Practices and Technical Papers on RBI and Inspection Effectiveness
   Industry guidance addressing inspection reliability, probability of detection (POD), and the limitations of non-intrusive inspection methods.
6. Health and Safety Executive (HSE)
   Best Practice Guidance on Risk-Based Inspection
   Regulatory perspective emphasizing that RBI must be demonstrably conservative, auditable, and defensible—not solely software-driven.
7. Materials Technology Institute (MTI)
   Corrosion, Damage Mechanism, and Inspection Reliability Publications
   Technical studies supporting realistic corrosion rate development and inspection method limitations.

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