Which equipment and pipelines in the pharmaceutical factory need to be made of 316L stainless steel?

In pharmaceutical factories, 316L stainless steel is widely used due to its excellent corrosion resistance, compliance, and biocompatibility in key equipment pipelines that directly come into contact with high-purity media, sterile drugs, or corrosive environments. The following are typical scenarios where 316L stainless steel is required and the classification of equipment pipelines: 

I. Purified Water and Injection Water System

1. Injection Water (WFI) Preparation and Delivery Pipelines

Scenario: WFI is the highest purity water in the pharmaceutical industry, used for preparing injections, cleaning sterile equipment, etc.

Equipment Pipelines:

WFI preparation device (such as multi-effect distillation water machine, connection pipes of reverse osmosis membrane components).

WFI storage tank and circulation delivery pipelines (need to maintain a heat circulation above 70°C to prevent microbial growth).

WFI branch pipes in the sterile formulation workshop (directly connected to the mixing tank, bottle washing machine, etc.).

Requirements: Must comply with ASME BPE standards, inner surface electrolytic polishing (Ra ≤ 0.4 μm), support online sterilization (SIP).

2. Pure Steam System Pipelines

Scenario: Pure steam is used for equipment sterilization (such as sterilization cabinets), pipeline disinfection (SIP), and air humidification in clean areas.

Equipment Pipelines:

Main pipelines and branch pipes from the pure steam generator to each steam-using point (such as steam inlet of freeze-drying machines, connection pipes of culture medium sterilization pots).

Steam condensate recovery pipelines (need to withstand high temperature and secondary steam corrosion). 

II. Sterile Preparation Equipment Pipelines

1. Mixing and Filling System

Scenario: Used for preparing sterile injectables, eye drops, etc. that are directly administered to the human body.

Equipment Pipelines:

Inlet and outlet pipelines of the sterile mixing tanks (such as the cephalosporin antibiotic mixing system).

Pipelines connecting the drug liquid filtration devices (such as the 0.22μm sterilization filters before and after the front and rear ends) for drug liquid filtration.

Material liquid conveying pipelines of the filling line (such as the material liquid pipes of the pre-filled syringe filling equipment).

Features: Must be certified by USP Class VI, have surface electrolytic polishing, and support online cleaning (CIP).

2. Freeze-Drying System

Scenario: Freeze-dryers are used for the freeze-drying of sterile drugs, with pipelines in contact with low-temperature drug liquids and high-temperature steam.

Equipment Pipelines:

Drug liquid conveying pipelines in the freeze-drying box (directly in contact with sterile drug liquids).

Silicone oil circulation pipelines (maintaining uniform temperature of the freeze-drying plate layers, capable of withstanding a temperature difference of -40°C to +80°C) and vacuum system pipelines (required to prevent condensation water from corroding). 

III. Equipment and Pipelines Containing Corrosive Media

1. Acid, Alkali and Chloride-Ion Containing Solution Pipelines

Scenario: Such as sodium chloride injection solution (containing chloride ions), amantadine hydrochloride solution (acidic) etc.

Equipment Pipelines:

Sodium chloride injection solution preparation tank and transportation pipeline (chloride ion concentration approximately 9g/L).

Buffer solution (such as phosphate buffer solution) preparation system pipeline (resistant to corrosion within the pH range of 1-14).

Acidic/Alkaline reaction liquid transportation pipeline in the chemical synthesis raw material drug workshop.

2. Disinfectants and Cleaning System

Scenario: Strong corrosive media used for equipment disinfection such as hydrogen peroxide, formaldehyde solution, etc.

Equipment Pipelines:

Hydrogen peroxide spray pipeline for sterilization in the clean area space.

Acid and alkali cleaning liquid pipeline of the online cleaning (CIP) system (such as 0.1M sodium hydroxide solution circulation pipe). 

IV. Key Clean Areas and Sterilization Equipment Pipelines

1. Equipment Pipelines for Class A Clean Areas

Scenario: Core areas such as sterile filling lines and capping machines require the highest level of aseptic protection.

Equipment Pipelines:

Branch pipes for liquid transportation within laminar flow hoods (directly exposed to an aseptic environment).

Gas blow-off pipelines for the aseptic isolators (to prevent external contamination from entering).

2. Sterilization Cabinets and Cleaning Equipment Pipelines

Scenario: Equipment such as wet heat sterilization cabinets and bottle washing machines come into contact with high-temperature steam and cleaning agents.

Equipment Pipelines:

Steam inlet and condensate discharge pipes for sterilization cabinets (able to withstand 134℃ saturated steam).

Piping for purified water / injection water spray of the bottle washing machine (required to resist corrosion from cleaning agent residues). 

V. Special Scenarios in Biopharmaceuticals

1. Fermentation and Culture Medium System

Scene: Contacting proteins, amino acids, and other organic media in bioreactors and culture medium preparation tanks.

Equipment Pipelines:

Feed pipelines for the culture medium in fermentation tanks (to prevent microbial contamination and medium corrosion).

Feed pipelines for the bioreactors (such as glucose solutions, defoamer delivery pipes).

2. Chromatography and Purification System

Scene: During the purification of antibody drugs, contact with high-salt solutions (such as sodium chloride gradient elution solutions).

Equipment Pipelines:

Inlet and outlet pipelines for the chromatography column (able to withstand long-term flushing with 0.5M sodium chloride solution).

Circulation pipelines for ultrafiltration membrane modules (to prevent protein deposition and bacterial growth). 

VI. Compliance and Material Selection Basis

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Summary: Core Application Principles of 316L Stainless Steel

Preferred Scenarios: Equipment and pipelines that come into contact with purified water for injection, sterile solutions, media containing chloride ions, high-temperature steam, or highly corrosive reagents must be made of 316L stainless steel.

Compliance Bottom Line: For sterile drug production subject to strict regulations such as FDA and EMA, 316L is mandatory (as specified in ASME BPE standards regarding the core pipe material).

Cost and Risk Balance: Although the cost of 316L is approximately 30% higher than that of 304, in critical areas (such as freeze-drying machines and filling machines), using 304 may lead to drug contamination and trigger recall risks. Therefore, one should not compromise on cost.

By precisely differentiating the corrosiveness of the medium, the cleanliness level, and regulatory requirements, 316L stainless steel can be ensured to be applied in the truly high-risk scenarios that require it in pharmaceutical factories, while avoiding excessive selection that leads to cost waste.