Blistering, corrosion undercoating and peeling are silent threats to industrial coatings on critical assets. When an oil refinery coating fails, the consequences ripple from costly repairs to environmental hazards and safety risks.
Industrial coatings protect metal surfaces from chemical attack, abrasion and weathering. This article examines real warning signs—blistering and corrosion undercoating—using an oil refinery failure to show what goes wrong and how to act.
Why industrial coatings matter for heavy industry
Protection beyond paint
Coatings act as the first line of defense, preventing chemical attack and moisture ingress on steel structures. They extend service life and reduce maintenance frequency.
Choosing the right system influences corrosion resistance, adhesion and long-term performance under extreme conditions and chemical exposure.
Economic and safety stakes
Failure leads to shutdowns, expensive repairs and regulatory fines. Effective industrial coatings preserve uptime and avoid costly environmental remediation.
Insurance costs and workplace safety metrics also improve when protective coatings perform reliably over years of service.
Common failure modes: blistering and underlying corrosion
What causes blistering
Blisters form when moisture, solvent or gases become trapped beneath the film, lifting the coating from the substrate. Heat, contamination and poor drying accelerate the process.
Early blister detection is critical—small bubbles often signal bigger adhesion or surface preparation issues that can cascade into structural damage.
Corrosion undercoating explained
Corrosion undercoating is hidden decay—rust forms beneath intact-looking paint due to permeation of salts, moisture or inadequate priming. It undermines structural integrity quietly.
Left unchecked, underfilm corrosion expands, causing flaking, pinholing and eventual loss of load-bearing capacity in pipework and tanks.
Case study: oil refinery coating failure that escalated
Initial signs and missteps
At a coastal refinery, technicians noted scattered blistering on a crude feed tank but delayed investigation. Salt contamination and poor surface prep were later identified as triggers.
Short-term touch-ups masked the issue, allowing corrosion to propagate beneath the coating, compromising valves and fittings connected to the tank.
Consequences and lessons
A controlled shutdown revealed extensive underfilm corrosion requiring selective plate replacement. The plant faced weeks of lost production and regulatory scrutiny.
The incident showed that rapid diagnostics, correct substrate prep and cathodic protection coordination are non-negotiable for hydrocarbon facilities.
Detecting warning signs early
Visual and tactile inspection routines
Train teams to spot odourless paint bubbling, edge lifting and subtle color changes. Use knifing tests and adhesion assessments to confirm compromises.
Regular walkdowns, especially post-rain or post-shutdown, reveal blister clusters and weeping joints before failures escalate into leaks.
Instrumental checks and monitoring
Use holiday detectors, ultrasonic thickness gauges and corrosion coupons to measure coating integrity and substrate loss without full strip-downs.
Combine sensor data with maintenance logs to detect trends—rising pinhole counts or thinning areas predict imminent problems.
Practical response plan (step-by-step)
Immediate containment and assessment
Stop the spread: isolate the area, reduce mechanical loads and prevent exposure to chemicals. Safety first—ensure permit-to-work and hot-work controls.
Document photos, map blistering patterns and sample coatings for lab analysis to determine root cause and repair scope.
Repair and remediation steps
- Stop operations in that zone and secure isolation valves.
- Remove failed coating down to sound metal with abrasives or hand tools.
- Perform solvent wipe and grit blast to specified cleanliness.
- Apply compatible primer under controlled humidity and temperature.
- Topcoat with specified industrial coatings meeting chemical exposure profile.
Follow manufacturer cure times and apply holiday testing before returning to service to ensure coating continuity and adhesion.
Choosing the right industrial coatings and system design
Match chemistry to environment
Select coatings resistant to the refinery’s specific chemicals—acids, alkalis, hydrocarbons—and account for temperature cycles and UV exposure.
Epoxies, polyurethanes and specialized fluoropolymers offer different balances of chemical resistance, abrasion protection and color stability.
System components and compatibility
Successful systems pair surface preparation, primer, mid-coat and topcoat engineered to work together and bond to the substrate reliably.
Include corrosion inhibitors, proper film thickness, and consider sacrificial or impressed-current cathodic protection where applicable.
Maintenance strategies that prevent failures
Routine inspections and predictive maintenance
Implement scheduled inspections with photographic records and threshold criteria triggering remediation. Integrate coating condition into CMMS workflows.
Predictive analytics on sensor and inspection data helps prioritize repairs, budget accurately and avoid crisis-driven interventions.
Training, procurement and quality assurance
Invest in applicator training, specify SSPC/NACE surface prep standards, and enforce quality checks during application to prevent workmanship defects.
Procure coatings from trusted manufacturers and insist on certified test reports, ensuring materials meet exposure and adhesion requirements.
Conclusion
Blistering and corrosion undercoating are early alarms—neglect them and a small defect can become an operational catastrophe. The oil refinery example shows how quick detection, correct materials and disciplined maintenance stop failures before they spread.
Act early, use the right industrial coatings, and treat coating integrity as essential infrastructure protection, not cosmetic upkeep.
FAQ
What are the first signs that industrial coatings are failing?
Initial signs include small blisters, discoloration, soft spots, and edge lifting. You may notice rust stains at seams or slight bubbling after rain. Early action—inspection and testing—prevents hidden corrosion and expensive repairs when these indicators appear.
How does corrosion undercoating develop despite intact paint?
Corrosion undercoating starts from moisture, salts or contaminants trapped during application or later penetration through micro-defects. The coating can look intact while rust forms beneath, progressively undermining adhesion and structural strength until visible failure occurs.
Can blistering be repaired without full stripping?
Minor localized blistering sometimes allows spot repair: cut out the blister, clean to bare metal, apply primer and topcoat. Larger or widespread blistering requires full removal and reapplication under proper surface preparation to ensure long-term performance.
Which inspections best detect hidden underfilm corrosion?
Holiday detection, ultrasonic thickness measurement and borescope inspection reveal hidden corrosion without total stripping. Corrosion coupons and electrical monitoring add long-term trend data, enabling proactive maintenance planning and targeted remediation.
How do I choose the best industrial coatings for a refinery environment?
Assess chemical exposure, temperature, abrasion and UV conditions, then choose compatible primers, mid-coats and topcoats rated for those hazards. Consult manufacturers’ datasheets, third-party tests and experienced coatings engineers to specify a proven system.
References: For technical guidance consult ASTM and NACE standards, and manufacturers’ technical data sheets such as those from Sherwin-Williams and AkzoNobel for coatings performance and application best practices. Additional reading at NACE/AMPP and ASTM International.