Which equipment pipelines in a pharmaceutical factory need to use 316L stainless steel?

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

I. Purified Water and Water for Injection Systems

1. Water for Injection (WFI) Preparation and Conveyance Pipelines

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

Equipment and Pipelines:

WFI preparation devices (such as multi-effect distillation water machines, reverse osmosis membrane modules, and connecting pipelines).

WFI storage tanks and circulation pipelines (must maintain a hot circulation above 70°C to prevent microbial growth).

WFI branch pipelines in the sterile preparation workshop (directly connected to the solution preparation tanks, bottle washers, etc.).

Requirements: Must comply with ASME BPE standards, with inner surfaces electrolytically polished (Ra ≤ 0.4 μm), and 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 humidification of cleanroom air.

Equipment and Pipelines:

Main and branch pipelines from the pure steam generator to various steam usage points (such as the steam inlet of freeze dryers, connection pipes of culture medium sterilization pots).

Steam condensate recovery pipelines (must withstand high temperatures and secondary steam corrosion). 

II. Sterile Preparation Production Equipment Pipelines

1. Solution Preparation and Filling System

Scenario: Used for preparing sterile injectable solutions, eye drops, and other drugs that are directly injected into the human body.

Equipment Pipelines:

Inlet and outlet pipelines of sterile solution preparation tanks (such as cephalosporin antibiotic solution preparation systems).

Connection pipelines of liquid filtration devices (such as pipelines before and after 0.22μm sterilizing filters).

Liquid delivery pipelines of filling lines (such as liquid pipelines of pre-filled syringe filling equipment).

Characteristics: Must pass USP Class VI certification, surface electrolytic polishing, and support online cleaning (CIP).

2. Freeze-Drying System

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

Equipment Pipelines:

Drug solution delivery pipelines within the freeze-drying chamber (direct contact with sterile drug solutions).

Silicone oil circulation pipelines (maintain uniform temperature of freeze-drying shelves, must withstand temperature differences from -40°C to +80°C).

Vacuum system pipelines (must prevent condensation water corrosion). 

III. Equipment and pipelines containing corrosive media

1. Acidic and alkaline solutions and solutions containing chloride ions

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

Equipment and pipelines:

Pipelines for sodium chloride injection preparation tanks and transportation (chloride ion concentration approximately 9g/L).

Pipelines for the preparation system of buffer solutions (such as phosphate buffer solution) (corrosion-resistant within pH range of 1-14).

Pipelines for transporting acidic or alkaline reaction solutions in the chemical synthesis raw material medicine workshop.

2. Disinfectants and cleaning systems

Scenarios: Strongly corrosive media such as hydrogen peroxide and formaldehyde solutions used for equipment disinfection.

Equipment and pipelines:

Pipelines for hydrogen peroxide spray in clean area space sterilization.

Pipelines for acid and alkali cleaning solutions in online cleaning (CIP) systems (such as 0.1M sodium hydroxide solution circulation pipes). 

IV. Key Cleanroom Areas and Sterilization Equipment Pipelines

1. A-Class Cleanroom Equipment Pipelines

Scenarios: Core areas such as aseptic filling lines and capping machines, which require the highest level of aseptic assurance.

Equipment Pipelines:

Medicine liquid delivery branch pipes within laminar flow hoods (directly exposed to aseptic environments).

Gas purging pipelines of aseptic isolators (to prevent external contamination from entering).

2. Sterilization Cabinet and Cleaning Equipment Pipelines

Scenarios: Equipment such as autoclaves and bottle washers that come into contact with high-temperature steam and cleaning agents.

Equipment Pipelines:

Steam inlet and condensate drainage pipelines of sterilization cabinets (able to withstand 134°C saturated steam).

Purified water / water for injection spray pipelines of bottle washers (resistant to corrosion from cleaning agent residues). 

V. Special Scenarios in Biopharmaceuticals

1. Fermentation and Medium Systems

Scenario: Bioreactors and medium preparation tanks come into contact with organic media such as proteins and amino acids.

Equipment and Pipelines:

The medium feed pipeline of the fermentation tank (which needs to prevent microbial contamination and medium corrosion).

The feeding pipeline of the bioreactor (such as glucose solution and defoamer delivery pipes).

2. Chromatography and Purification Systems

Scenario: Contact with high-salt solutions during the purification process of antibody drugs (such as sodium chloride gradient elution solution).

Equipment and Pipelines:

The feed and discharge pipelines of the chromatography column (able to withstand long-term flushing with 0.5M sodium chloride solution).

The circulation pipeline of the ultrafiltration membrane module (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

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

Compliance Bottom Line: In the production of sterile preparations subject to strict regulations by authorities such as the FDA and EMA, 316L is a mandatory requirement (for instance, ASME BPE standards explicitly stipulate the core material for pipelines).

Cost and Risk Balance: Although 316L is approximately 30% more expensive than 304, using 304 in critical areas such as freeze dryers and filling machines may lead to drug contamination and recall risks, thus cost cannot be compromised.

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