Issues with pipeline design specifications in pharmaceutical factories

For clean pipes and fittings in pharmaceutical plants, the ASME A270-BPE standard can be selected.

It is necessary to determine whether it is the active pharmaceutical ingredient or something else, as different purity requirements lead to different selection outcomes

For flammable and explosive media, plastic pipes definitely cannot be used; in clean areas, carbon steel should not be employed – galvanized steel pipes are the minimum acceptable option. For other types of media, 300-series stainless steel is generally used, depending on the specific medium involved

The piping design in pharmaceutical factories is an important aspect of Good Manufacturing Practices (GMP), as it has a direct impact on product quality, the risk of cross-contamination, and production efficiency. The following are the key specifications and requirements for pipeline design in pharmaceutical factories, for reference:  1. Material selection • Material requirements: ◦ 316L stainless steel (low carbon, corrosion-resistant) should be preferred, especially in systems for sterile preparations or high-purity water. ◦ 304 stainless steel can be considered for non-critical systems, but it should be avoided in corrosive environments. ◦ Plastic pipes (such as PTFE, PP) can be used for corrosive chemicals, but their compatibility must be verified. • Surface treatment: ◦ The inner wall must be electropolished (Ra≤0.6μm) to ensure smoothness and reduce the growth of microorganisms and residues. ◦ The welded area needs to be passivated to remove the oxide layer. 2. Pipeline Layout and Installation • Slope Design: ◦ Pipelines for systems such as purified water and water for injection should maintain a slope of 0.5%~1% to ensure complete drainage and prevent the accumulation of stagnant water. • Avoid dead zones: ◦ Follow the 3D principle (Dead Leg Rule): the length of branch pipes should be ≤ 3 times the pipe diameter (as per ASME BPE standards). • Oblique connection: ◦ Branch pipes should be connected to the main pipe at a 45° angle to minimize turbulence and residue. • Support and labeling: ◦ Pipes must be securely fixed to prevent vibration, with labels indicating the contents, flow direction, and cleaning status. 3. Cleaning and sterilization requirements • CIP/SIP design: ◦ The piping system must support online cleaning (CIP) and online sterilization (SIP), especially in aseptic production lines. ◦ Sterilization steam must reach above 121°C (for 30 minutes) or higher temperatures (such as superheated water sterilization). • Drainage design: ◦ A drain valve is installed at the lowest point to ensure no water accumulation. 4. Prevent cross-contamination • Dedicated pipelines: ◦ Products with high activity and high sensitization potential require an independent pipeline system. • Gas lock/barrier design: ◦ Pipelines passing through walls between areas with different cleanliness levels must be sealed (e.g., by using sanitary sleeves). 5. Fluid property considerations • Flow rate control: ◦ The flow rate in the water for injection pipelines must be ≥1.5 m/s (turbulent flow to reduce the risk of biofilms). ◦ For high-viscosity liquids, the pipe diameter must be adjusted to prevent clogging. • Filtration and venting: ◦ Key points: Install filters (such as 0.22μm sterilizing filters) and vent valves. 6. Compliance and Verification • Documentation requirements: ◦ The design must comply with regulations such as GMP, FDA 21 CFR Part 211, and EU GMP Annex 1. ◦ Provide pipeline material certificates and welding records (such as weld map). • Verification steps: ◦ Conduct DQ (Design Qualification), IQ (Installation Qualification), OQ (Operational Qualification), PQ (Performance Qualification). ◦ This includes slope testing, dead corner inspection, pressure testing, and cleaning validation. 7. Special system requirements • Purified water/injection water system: ◦ Use a circulation loop + ultraviolet disinfection to avoid dead ends in the pipes. • Process gas system: ◦ Sterilizing filters must be installed on compressed air/nitrogen pipelines; the material must be pressure-resistant and oil-free. Common Issues and Risks • Microbial Contamination: Biofilm formation due to dead zones or low flow rates. • Residual risk: Inadequate cleaning due to unreasonable design. • Material corrosion: Improper material selection affects product safety. Reference standards • ASME BPE (Standard for Bioprocessing Equipment) • ISPE guidelines (International Society for Pharmaceutical Engineering) • Appendix to China’s GMP: Sterile pharmaceuticals. It is recommended to collaborate with a professional engineering firm during the design phase and to conduct a risk assessment (such as FMEA) based on the specific product processes.