Corrology®-IRI: H2SO4 User Manual
Production-grade operating guide for sulfuric-acid systems integrity screening, driver diagnosis, and staged remediation decisions.
| Manual Focus | Description |
|---|---|
| Primary objective | Support robust integrity prioritization and action planning |
| Decision style | Comparative risk signal with engineering judgment |
| Recommended workflow | Baseline -> driver diagnosis -> staged remediation -> documented action |
Use this page as your standard runbook during live H2SO4 analysis.
Designed for fast, reliable execution in sulfuric-acid workflows. Keep one baseline pinned, change one lever group at a time, and document each remediation decision with residual uncertainty.
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Purpose
This manual explains how to use Corrology®-IRI: H2SO4 for practical integrity screening and how to interpret outputs with confidence.
It is written for day-to-day engineering use: run setup, result interpretation, staged remediation usage, and reporting.
At a Glance
- Primary purpose: Prioritize sulfuric-acid corrosion risk and support integrity action planning.
- Output: A comparative risk indicator that supports engineering judgment. It is not a standalone fitness-for-service (FFS) assessment.
- Recommended workflow: Establish a baseline case, then evaluate the impact of controlled what-if scenarios to understand how potential changes influence the predicted risk.
Quick Start
Run Flow
- Open Corrology®-IRI: H2SO4.
- Choose Predictive or Inspection mode.
- Enter required inputs.
- Click Analyze.
- Review susceptibility score, corrosion-rate context, and susceptibility drivers.
- Activate remediation mode only after baseline review, then stage and validate selected paths.
Recommended Operating Practice
- Define a single objective for each analysis set.
- Change only one variable or variable group in each what-if scenario.
- Record one clear engineering conclusion for each analysis set.
Critical Mode Warning
Predictive and Inspection modes are not directly comparable without context translation.
When switching modes, treat the next run as a new analytical context and re-establish baseline before drawing conclusions.
Before You Run
Complete the following checks to ensure reliable results and meaningful comparisons.
✔ Confirm that the intended analysis mode (Predictive or Inspection) is selected.
✔ Verify that temperature, acid concentration, and velocity represent the actual operating case.
✔ Confirm that thickness and t_min context are realistic for the assessed component.
✔ Check inspection dates and effectiveness before entering Inspection mode.
✔ Ensure that all units and operating ranges are consistent with site records.
Understanding the Model Outputs
- Susceptibility Score: summarized integrity indicator for screening and prioritization.
- Corrosion-Rate Context: modeled or inspection-derived corrosion basis used by the run.
- Susceptibility Drivers: relative contribution from Severity, Uncertainty, and Detection factors.
- Baseline Comparison: directional change relative to prior or pinned baseline case.
Interpretation Guidance
Treat the Susceptibility Score as a decision-support indicator rather than a standalone acceptance criterion.
Use the Susceptibility Drivers to determine whether improvement is best achieved through process severity reduction, improved inspection confidence, better detectability, or a combination of these elements.
Reading the Results
- Review the overall trend before focusing on the absolute score.
- Identify the dominant driver family.
- Determine whether the dominant contribution is operational (Severity) or related to data quality (Uncertainty or Detection).
- Select the most appropriate response:
- operational changes,
- inspection improvements, or
- a combination of both.
Decision Ladder
- Is the risk increasing compared with the baseline?
- Which driver family contributes most to the result?
- Is the available evidence sufficient to support a decision?
- Select the appropriate response:
- operational adjustment,
- improved inspection or data quality,
- or a combined mitigation strategy.
Decision Flowchart
Decision intent: Move from diagnostic output → one explicit action path → verify impact against baseline.
Short Interpretation Examples
Example A: Severity Dominant
Pattern: severity dominates, uncertainty is secondary.
Interpretation: the operating envelope is likely the main risk lever.
Action focus: temperature, concentration, or velocity changes, then re-check score shift.
Example B: Uncertainty Dominant
Pattern: uncertainty or detection contributions exceed severity.
Interpretation: current confidence is weak; risk may be conservatively elevated.
Action focus: inspection evidence quality, timing, and monitoring improvements.
Decision Guidance by Driver Dominance
Driver-to-Action Matrix
| Dominant Driver Pattern | Typical Meaning | First Recommended Move | Expected Direction |
|---|---|---|---|
| Severity > Uncertainty/Detection | Real operating stress likely drives risk | Stabilize process window and reassess | Score reduction |
| Uncertainty high | Data quality or age limits confidence | Improve inspection evidence and data quality | Confidence increase |
| Detection high | Detectability limitation risk | Adjust inspection method, interval, monitoring, or coverage | Detectability improvement ↑ |
| Mixed profile | Multiple coupled mechanisms | Stage actions and validate after each step | Controlled convergence |
Remediation Paths (Advanced Users)
What Remediation Paths Do
Remediation Paths mode converts ranked-driver outputs into actionable pathways and projects scenario impact.
Typical pathway families:
- Defend Asset Life: operating-envelope changes such as temperature, concentration, or velocity adjustments.
- Inspection Evidence Refresh: inspection-evidence changes such as better effectiveness or shorter uncertainty horizon.
- Monitoring and Inspection Upgrade: monitoring and conservative-control changes that stabilize decision confidence.
Remediation Quick Reference (Example)
Pathway Families
| Pathway Family | Typical Trigger | Typical Action | Expected Direction |
|---|---|---|---|
| Defend Asset Life | Severity-dominant risk | Adjust temperature, acid concentration, or velocity | Score reduction |
| Eliminate Uncertainty | Uncertainty or detection drivers dominate | Upgrade inspection quality, timing, or evidence | Confidence increase |
| Strengthen Monitoring | Trend instability or hidden acceleration concern | Enable monitoring and retain conservative controls | Variability reduction |
How to Use Remediation Paths
- Run Analyze first and review the baseline score.
- Click Activate Remediation Paths.
- Wait until the status changes to Remediation Paths Mode Active.
- Review ranked pathways for the selected material.
- Select one or more pathway checkboxes.
- Preview projected impact.
- Apply the practical paths, then rerun Analyze.
What to Read in Each Pathway Card
- Action: what operational or inspection step is proposed.
- Result: expected outcome and projected score direction.
- Engineering intent: why that path addresses the dominant driver.
- Material scope: the currently selected material only.
- Validation requirement: rerun Analyze after applying.
Report Integration
After evaluating pathways, click Append Engineering Justification to Report to include selected pathway rationale in generated reporting output.
Practical Selection Guidance
- Pick pathways that are implementable within outage, access, and budget constraints.
- Prefer pathways that reduce score and improve evidence quality together.
- Do not select conflicting pathways only because each looks good in isolation.
- Re-run Analyze after implementing real field changes to verify actual effect.
What Good Looks Like
- Selected actions are technically feasible and operationally acceptable.
- Projected reduction is meaningful and not achieved by unrealistic assumptions.
- Data confidence improves, not just the score.
- Follow-up inspection and monitoring steps are explicitly scheduled.
Important Limitations
- Pathway projection is a decision-support estimate, not a guaranteed field outcome.
- If no prior analysis exists, remediation evaluation cannot run.
- Pathway logic is based on configured rule sets and model assumptions; engineering review is still mandatory.
Best practice: apply one practical pathway set at a time, then re-run and validate the real effect against baseline.
Common Mistakes to Avoid
- Switching between Predictive and Inspection modes and interpreting values as directly equivalent.
- Comparing Predictive and Inspection runs as if equivalent.
- Changing many inputs at once, then over-interpreting ranking order.
- Treating one score as pass/fail without context.
- Ignoring data quality warnings when uncertainty is dominant.
Troubleshooting
Open Troubleshooting Checklist
- No result: verify required fields, ranges, and inspection date validity.
- Unexpected ranking: verify mode, baseline, monitoring state, and intended variable changes only.
- Counter-intuitive trend: verify corrosion-rate basis, inspection context, and whether the staged pathway actually addressed the dominant driver.
Reporting Template (Short)
When documenting a run, include:
- Run mode and context (asset, date, operating window).
- Baseline score and dominant drivers.
- Selected remediation pathway(s) and why.
- Expected outcome and residual uncertainty.
- Planned validation step (next inspection/monitoring check).
Report Quality Gate
- What changed is explicitly identified.
- Why it changed is technically justified.
- Residual uncertainty is stated.
- Verification step and timing are scheduled.
Status rule: mark Ready for Approval only when all items are checked.
Key Terms
Open Key Terms
Severity
How damaging current sulfuric-acid service conditions are expected to be.
Uncertainty
How much confidence is limited by data quality and time context.
Detection Limitation
How limited damage detectability is due to inspection effectiveness and monitoring context.
Low Confidence in Historical Data
Data quality issue (trustworthiness/completeness).
Outdated Inspection Data
Data age issue (staleness over time).
Monitoring Credit
Risk-reduction credit when credible online monitoring is active.
Staged Remediation Change
A selected remediation path that has been previewed but not yet validated by rerunning Analyze.
Need Deeper Technical Detail?
For more details on IRI functionality, please contact Corrology Engineering Team.