Professional Derouging Services for Pharmaceutical Systems
Remove Type I, II, and III rouge contamination from WFI loops, clean steam systems, and process vessels. EDTA and citric acid derouging with complete re-passivation per ASTM A967 and GMP documentation.
What Is Rouge & Why It Matters
Rouge is iron oxide contamination that forms on stainless steel when the protective chromium oxide passive layer is compromised—causing progressive system degradation and regulatory failures.
Rouge Is Not Rust—It's Complex Iron Oxide Contamination
Rouge is a mixture of iron oxides (Fe₂O₃, Fe₃O₄, FeO) that develops on stainless steel when the protective chromium oxide passive layer is compromised through heat exposure, aggressive CIP chemistry, contamination, or incomplete passivation.
Unlike surface rust, rouge is electrochemically generated from the stainless steel substrate itself. The iron content within 316L and 304 alloys oxidizes when protective chromium depletion occurs—creating adherent iron oxide deposits that shed particles into process streams.
Professional derouging requires understanding of ASTM A380 cleaning chemistry, iron chelation mechanisms, and proper ASTM A967 re-passivation to restore long-term corrosion resistance.
Three Types of Rouge Contamination
Understanding rouge type determines optimal derouging chemistry and process parameters. CXP assesses contamination severity with ferroxyl testing before recommending treatment protocols.
Type I Rouge
Black magnetic iron oxide formed under high-temperature conditions in clean steam systems, SIP cycles, and heat-exposed equipment. Most adherent and difficult to remove—requires aggressive EDTA chemistry.
Characteristics
- Black to dark gray appearance
- Magnetic properties
- Forms at 250-400°F (120-200°C)
- Tight adherence to substrate
- Requires EDTA-enhanced derouging
Type II Rouge
Dark brown to reddish-brown iron oxide formed in WFI/PW systems under moderate temperature and oxygen exposure. Most common rouge type in pharmaceutical water distribution systems.
Characteristics
- Dark reddish-brown color
- Non-magnetic
- Forms at 150-200°F (65-95°C)
- Moderate adherence
- Responds to citric or EDTA
Type III Rouge
Light red to orange-brown loose iron oxide formed under ambient conditions from contamination or failed passivation. Least adherent type—typically from external iron source contamination.
Characteristics
- Light red to orange appearance
- Loosely adhered
- Forms below 140°F (60°C)
- Easy mechanical removal
- Simple citric acid derouging
Ready to Eliminate Rouge From Your Systems?
CXP deploys nationwide with mobile derouging units, pharmaceutical-grade chemistry, and complete GMP documentation. Zero FDA findings across 200+ facilities.
What Causes Rouge Formation?
Rouge develops when multiple factors compromise the stainless steel passive layer. Understanding root causes helps prevent recurrence after derouging treatment.
Incomplete Passivation
Improper initial passivation leaves free iron embedded in the surface. Without complete iron removal and chromium oxide restoration, rouge begins forming immediately during system startup.
Aggressive CIP Chemistry
High-chloride cleaners (>25 ppm Cl⁻) and extreme pH solutions attack the passive layer, exposing underlying iron to oxidation. Review your CIP system protocols to prevent chemical damage.
Heat-Induced Oxidation
Clean steam, SIP cycles above 250°F, and hot WFI distribution accelerate iron oxide formation. Extended exposure converts protective chromium layers to rouge.
Carbon Steel Contamination
Contact with carbon steel tools, fittings, or contaminated water introduces free iron particles that nucleate rouge formation. Proper commissioning protocols prevent this.
Insufficient Rinsing
Inadequate rinse cycles after cleaning leave iron-bearing residues that oxidize. Conductivity spikes indicate incomplete rinse protocols.
Poor Water Quality
High iron content in makeup water (>0.3 ppm Fe), elevated chlorides, or poor pretreatment introduces contaminants that deposit on surfaces and oxidize to rouge over time.
Derouging Transformation
CXP derouging services completely remove rouge contamination and restore stainless steel to pristine, properly passivated condition with verified cleanliness documentation.
Heavy Type II Rouge
Dark reddish-brown deposits on electropolished surfaces. Particle counts exceeding 500/mL—well above USP acceptance limits.
Complete Restoration
Surface restored to original electropolished condition. Re-passivated per ASTM A967, particle counts <5/mL, conductivity <1.1 µS/cm.
CXP Derouging Process
Six-phase methodology ensuring complete rouge removal, surface restoration, and GMP-compliant passivation with full documentation.
Inspection & Testing
Visual assessment, ferroxyl testing, rouge type identification, surface documentation
Alkaline Degrease
Remove oils and organics per ASTM A380 for optimal acid contact
Derouging Cycle
EDTA or citric acid circulation at 140-160°F for iron oxide dissolution
Neutralization
pH adjustment and acid residue removal to prevent flash rusting
Re-Passivation
Citric passivation per ASTM A967 to restore chromium oxide layer
Verification
Ferroxyl test, conductivity, particle count, surface inspection, GMP documentation
Derouging Chemistry & Parameters
CXP uses pharmaceutical-grade chelating agents specifically formulated for iron oxide removal while protecting the stainless steel substrate.
Chemistry Selection Guide
Citric acid is preferred for Type II and Type III rouge due to excellent iron-chelating properties and safe handling. EDTA is used for stubborn Type I magnetite rouge requiring enhanced chelation strength.
| Chemistry | Concentration | Temperature | Best For |
|---|---|---|---|
| Citric Acid | 4-10% w/w | 140-150°F | Type II, III rouge |
| EDTA Enhanced | 2-5% EDTA | 150-160°F | Type I magnetite |
| Hybrid Citric/EDTA | 6% + 3% | 145-155°F | Mixed rouge types |
| Nitric Acid | 10-20% HNO₃ | 120-140°F | Severe cases only |
Derouging Verification & Testing
Multiple verification methods confirm complete rouge removal, proper passivation restoration, and system readiness for GMP operation.
Ferroxyl Test
Potassium ferricyanide detects free iron. Negative result confirms complete iron removal and proper passivation.
Water Break Test
Continuous water film indicates uniform passivation. Water beading signals incomplete treatment.
Conductivity
Final rinse must be <1.3 µS/cm per USP <645>. Elevated readings require additional rinsing.
Visual Inspection
White-light inspection confirms rouge removal, uniform surface, no discoloration on welds or HAZ.
pH Verification
Final rinse pH must stabilize 6.5-7.5 with no drift over 15 minutes indicating complete neutralization.
Particle Count
USP <788> testing: <10 particles/mL (≥10 µm), <2 particles/mL (≥25 µm) for pharmaceutical acceptance.
Complete Documentation Packages
FDA-compliant derouging documentation supporting validation, regulatory inspections, and quality system requirements.
Standard Deliverables
- Derouging protocol (approved & executed)
- Batch production records with signatures
- Chemical concentration verification
- Time/temperature logs
- pH and conductivity trending
- Ferroxyl test results with photos
- Particle count reports
- Chemical lot traceability
Optional IQ/OQ Packages
- Installation Qualification (IQ)
- Operational Qualification (OQ)
- Equipment calibration certificates
- Operator training records
- Deviation reports (if applicable)
- 21 CFR Part 11 electronic records
- Validation summary reports
- Final system turnover package
Industries We Serve
Derouging FAQs
Typical cycles range 24-72 hours depending on severity. Light Type III rouge: 24-36 hours with citric acid. Heavy Type I magnetite: 48-72 hours with EDTA. CXP provides detailed timeline estimates during project scoping.
Yes. Citric acid and EDTA selectively remove iron oxide while protecting the chromium-rich passive layer. CXP maintains strict temperature control and optimized chemistry to prevent etching. Post-derouging passivation often improves surface finish.
Rouge can return if root causes aren't addressed. After CXP derouging and re-passivation, systems remain rouge-free when proper protocols are maintained. CXP provides operating procedure recommendations to prevent recurrence.
Derouging removes existing rouge contamination using chelating agents. Passivation creates/restores the protective chromium oxide layer. Derouging is always followed by re-passivation. New equipment only needs passivation; contaminated equipment needs derouging first.
Yes, systems must be offline. CXP minimizes downtime through efficient planning, rapid mobilization, and parallel processing. Derouging is typically scheduled during maintenance shutdowns or validation campaigns.
Why CXP for Derouging
Owner-Led Execution
Direct owner involvement ensures technical precision and uncompromising quality on every project.
Chemistry Expertise
Deep understanding of rouge formation and iron chelation enables optimal process selection.
Mobile Rapid Response
Self-contained mobile units with integrated heating and monitoring for fast deployment nationwide.
GMP Documentation
FDA-compliant packages supporting pharmaceutical validation and regulatory inspections.
Zero-Compromise Safety
Perfect 10+ year safety record across 200+ facilities. Comprehensive risk assessment on every project.
Proven Results
Hundreds of successful derouging projects with zero FDA inspection findings related to our procedures.
Need Professional Derouging Services?
CXP Solutions provides complete derouging, rouge removal, and stainless steel restoration for pharmaceutical, biotech, and industrial facilities nationwide.
