Addressing Material Discrepancies and Corrosion in Specialty Chemical Plants
In September 2025, a prominent industrial player in India's chemical sector, specifically in the fluorochemicals and refrigerants manufacturing plant experienced a major containment loss involving a pipeline rupture and the release of toxic gases. The incident occurred approximately six weeks after the facility converted its operations from producing a legacy refrigerant to a new product. This conversion utilized existing plant equipment and piping systems with minimal modifications. Following the accident, which led to a facility-wide shut down due to regulatory noncompliance, an independent assessment was mandated to ensure a safe restart.
About Case Study
1. The CorroSafe Approach
CorroSafe utilized a multi-disciplinary team of experts in corrosion engineering, metallurgy to conduct assessment:
- Internal Corrosion Assessment: Reviewed technical documentation (P&IDs, PFDs), utilized Non-Destructive Testing (NDT) such as Positive Material Identification (PMI) for material verification, and performed Ultrasonic Thickness (UT) measurements to assess wall loss.
- External Corrosion Assessment: Evaluated the integrity of structural steel and piping racks using international standards, specifically ISO 12944 for atmospheric corrosivity and ASTM D 610 for quantifying surface rusting.
- Failure Analysis: Conducted a metallurgical examination of the failed pipeline components to determine the root cause of the rapid "Time-to-Failure" (TTF).
2. Findings and Discoveries
The investigation revealed systemic failures in both material selection and maintenance culture:
- Critical Material Incompatibility: The legacy infrastructure, designed for R-22 service, was exposed to a far more aggressive chemical matrix in the R-32 process, which introduced Methylene Dichloride (MDC) and generated highly corrosive aqueous Hydrochloric Acid (HCl).
- Catastrophic Corrosion Mechanisms:
- Passivation Loss: New process chemicals stripped the stable iron fluoride (FeF2) layer that previously protected carbon steel, leading to exponential corrosion rates.
- Non-Metallic Failure: The new solvent (MDC) attacked legacy gaskets and seals, creating primary leak paths.
- Material Discrepancies: PMI testing identified that over 20% of the inspected points did not match design specifications. Specifically, high-nickel alloys were found to have been replaced by carbon steel in multiple high-risk locations.
- External Asset Neglect: Visual inspections revealed catastrophic rusting (ASTM Grade 0-G, >50% surface rust) in critical areas. Stack emission data confirmed a highly corrosive atmosphere (C4 High) that had been neglected for years.
3. Recommendations for Remediation
CorroSafe proposed a comprehensive remediation strategy required for the safe resumption of operations:
- Immediate MoC Upgrades: Mandatory re-verification of all Materials of Construction (MoC) for the new product process. All wetted parts (piping, valves, instrumentation) must be upgraded to high-performance materials like Alloy C-276 or PTFE-lined components, rather than "like-for-like" replacement.
- External Restoration: Implementation of a plant-wide coating remediation program based on the C4 corrosivity classification. This includes white-metal abrasive blasting (SSPC-SP5) and a qualified 3-coat protective system.
- Programmatic Overhaul: Transitioning from a reactive to a Risk-Based Inspection (RBI) model to proactively manage asset integrity.
4. Key Takeaways
- Management of Change (MOC) is Vital: Any change in process chemistry—no matter how minor it appears—must trigger a formal metallurgical review by a qualified corrosion engineer to identify new failure vectors.
- Legacy Data Reliability: Organizations cannot rely on old P&IDs for safety; "maintenance-induced" material downgrades over decades can create hidden "weak links" in the system.
- External Corrosion as a Cultural Indicator: Advanced external rusting is often a visible symptom of a deeper, systemic lapse in a company’s safety and integrity culture.
- Material-Specific Sensitivity: In specialized services (like HF or HCl), even minor trace elements in the metal (such as residual copper/nickel in carbon steel) can dictate the difference between a stable asset and a catastrophic failure