# Fermentation Heating Tube Anti-Corrosion Explosion-Proof & Hazardous Area Corrosion Prevention Specification ## Preface This specification (Doc.164) is a special safety supplementary document for the existing anti-corrosion management system from Doc.15 to Doc.161. It standardizes anti-corrosion construction, equipment layout, electrical protection, material selection and on-site operation management for heating pipelines located in flammable, explosive hazardous production areas. Corrosion damage to pipelines and supporting electrical facilities in hazardous areas may not only cause medium leakage, fire and explosion accidents, but also easily induce stray current corrosion, external atmospheric corrosion and grounding failure corrosion. This specification combines explosion-proof safety requirements with equipment anti-corrosion control, eliminates dual risks of explosion and pipeline corrosion in hazardous areas, and realizes the unified governance of safety production and equipment anti-corrosion. ## 1. Hazardous Area Classification and Corrosion Risk Regional Division According to the concentration of flammable gas, vapor and dust in the workshop, hazardous areas are divided into different explosion-proof zones. All heating pipelines, valves, monitoring instruments, wiring and auxiliary facilities within the hazardous boundary are included in the scope of this specification. Combined with atmospheric humidity, volatile corrosive gas and splash of acidic/alkaline cleaning agents, secondary corrosion risk grading is carried out. High humidity plus flammable volatile medium areas are defined as double high-risk regions, requiring both explosion-proof grade compliance and enhanced external anti-corrosion coating protection. Cross-regional pipeline penetration points between hazardous and non-hazardous areas are set as key inspection positions to prevent external corrosion and sealing failure. ## 2. Explosion-Proof Equipment Material Selection & External Anti-Corrosion Design All electrical equipment, sensors, junction boxes and actuators used in hazardous areas must pass the corresponding explosion-proof certification, and their shell materials shall adopt corrosion-resistant cast aluminum, stainless steel or coated alloy to resist atmospheric salt mist, acid and alkali volatile corrosion. The outer surface of heating pipelines in hazardous areas shall be coated with explosion-proof anti-corrosion and fire-retardant protective paint; flange, bolt and grounding parts are treated with hot-dip galvanizing or stainless steel upgrading to avoid rusting, jamming and poor contact caused by atmospheric corrosion. Ordinary carbon steel materials without anti-corrosion treatment are prohibited from being used for pipeline supports, brackets and fixed frames in hazardous areas. ## 3. Stray Current Control & Equipotential Anti-Corrosion Grounding Management Unstable grounding and stray current are important inducements for electrochemical corrosion of metal pipelines in hazardous areas. All heating pipelines, equipment supports, explosion-proof electrical casings and metal wire grooves must implement unified equipotential grounding. Regular inspection of grounding resistance is conducted every six months to ensure it meets safety standards; rusted, loose or corroded grounding connectors shall be polished, replaced and reconnected in a timely manner. Electrical overhaul, pipeline welding and temporary wiring operations in hazardous areas must strictly avoid disorderly grounding, prevent potential difference formation between metal facilities, and eliminate stray current corrosion while preventing electric spark explosion hazards. ## 4. Explosion-Proof Area Anti-Corrosion Operation & Hot Work Special Control CIP cleaning, passivation, reagent dosing and pipeline maintenance carried out in hazardous areas shall adopt explosion-proof type circulating pumps, sealed delivery equipment and intrinsically safe monitoring instruments. Volatile acidic and alkaline anti-corrosion chemicals shall be stored in sealed corrosion-resistant explosion-proof cabinets, with leakage trays and ventilation facilities to prevent volatile gas corrosion on surrounding equipment and fire risks. Any welding, cutting, polishing and hot work must complete explosion-proof hot work approval, gas detection, isolation blocking and on-site fire protection preparation; post-weld oxide cleaning and enhanced anti-corrosion coating shall be implemented immediately to avoid local pitting corrosion in high-temperature oxidation areas. ## 5. Regular Combined Inspection of Explosion-Proof Performance and Corrosion Status Daily patrol simultaneously checks two core items: explosion-proof sealing integrity of electrical equipment and pipeline external anti-corrosion coating integrity. Quarterly special inspection verifies grounding system corrosion, bolt rusting, wire sheath aging and sealing interface corrosion failure. Ultrasonic wall thickness measurement and internal corrosion inspection of heating pipelines in hazardous areas shall adopt intrinsically safe detection tools. Once coating peeling, shell rust leakage, sealing aging or grounding resistance exceeds the standard, operation shall be restricted immediately, and rectification shall be completed before resuming production to avoid simultaneous occurrence of corrosion leakage and explosion safety accidents. ## 6. System Value This specification realizes the deep integration of explosion-proof safety management and equipment anti-corrosion technical control in hazardous production areas, avoids secondary safety accidents caused by corrosion failure of explosion-proof facilities and heating pipelines, forms a dual safety defense line against explosion risks and various corrosion types, supplements the anti-corrosion control requirements under special safety scenarios, and further improves the full-scenario, safety-oriented closed-loop anti-c
orrosion management system of fermentation heating tubes.
