316L EP Pure Steam (PS) Sterilization Coil Tube for Biopharmaceutical Applications

Product Overview

Wenzhou Jixing Metal Materials Co., Ltd. presents a precision-engineered coiled stainless steel tube system specifically designed for pure steam (PS) sterilization circuits in biopharmaceutical manufacturing environments. This product is engineered to deliver saturated steam at temperatures ranging from 121°C to 140°C, with condensate quality equivalent to Water for Injection (WFI) standards. The system is purpose-built for the most demanding aseptic processing and terminal sterilization applications where absolute purity, reliability, and regulatory compliance are non-negotiable.

The coiled tube design eliminates dead-legs and stagnant zones inherent in straight-pipe runs, ensuring uniform steam distribution, rapid heat transfer, and complete condensate drainage — critical factors in preventing microbial proliferation and maintaining sterility assurance levels (SAL) of 10⁻⁶ or better.

Material & Properties

The coil tube is fabricated from AISI 316L (UNS S31603) Electropolished (EP) stainless steel, the gold standard for pharmaceutical-grade piping systems. This ultra-low carbon austenitic alloy offers exceptional resistance to pitting, crevice corrosion, and stress-corrosion cracking in the presence of chlorides, peroxides, and other aggressive pharmaceutical process fluids.

• Surface Finish: Electropolished to Ra ≤ 0.4 µm (inner surface), providing a smooth, non-reactive barrier that resists biofilm attachment and facilitates CIP/SIP processes.
• Chemical Composition: Minimum 16% Cr, 10–14% Ni, 2–3% Mo, with carbon content ≤ 0.03% to prevent sensitization during welding.
• Mechanical Strength: Tensile strength ≥ 485 MPa; yield strength ≥ 170 MPa; elongation ≥ 40%.
• Operating Temperature Range: –196°C to +425°C, with sustained performance validated at 121–140°C saturated steam conditions.
• Corrosion Resistance: Excellent resistance to dilute acids, alkalis, and halide-containing environments typical of steam sterilization systems.

Specifications

Parameter	Specification
Material Grade	AISI 316L (UNS S31603) Electropolished
Tube Form	Coiled (Coiltube) — Seamless
Operating Steam Temperature	121°C – 140°C (Saturated)
Condensate Quality	WFI (Water for Injection) Grade
Surface Roughness (ID)	Ra ≤ 0.4 µm (Electropolished)
Design Drainage	Slope Drain Configuration — Continuous Gradient
Steam Trap Compatibility	Pre-Matched Thermostatic / Dynamic Pressure Disc Type
Welding Method	Orbital TIG (GTAW) — Back Purged with Argon
Applicable Standards	ASME BPE, ISO 15002-2, ASTM A269/A270, EN 10217
Sterilization Method	SIP (Steam-in-Place) at 121–140°C
Available OD × Wall	Custom (Typical: 12–50.8 mm OD × 1.5–3.0 mm WT)
Coil Diameter	Custom — Engineered per Layout Requirements

Manufacturing Process

Every coil tube assembly is manufactured under strict Good Manufacturing Practice (GMP) protocols within a controlled, dust-free production environment. The process flow is as follows:

1. Material Verification: Incoming 316L seamless tube stock is verified against mill test certificates (MTC) conforming to EN 10204 3.1, with full chemical analysis and mechanical testing.
2. Cutting & Preparation: Precision laser or mechanical cutting to specified lengths, followed by end deburring and internal cleaning to remove all particulate contamination.
3. Forming & Coiling: Cold-forming techniques are employed to shape the tube into the required coil geometry while maintaining dimensional accuracy and avoiding work-hardening or surface defects.
4. Orbital TIG Welding: All joints are welded using automated orbital TIG (GTAW) with continuous argon back-purging to prevent internal oxidation. Weld parameters are documented and traceable.
5. Electropolishing: The entire internal surface is electropolished to achieve Ra ≤ 0.4 µm, removing surface contaminants, micro-pores, and any welding residue.
6. Slope Drain Configuration: The coil assembly is engineered with a continuous slope gradient (typically ≥ 1:100) to ensure complete condensate drainage without pooling or trapping.
7. Steam Trap Integration: Pre-selected steam traps (thermostatic or dynamic pressure disc type) are matched to the system's steam pressure differential and condensate load for optimal performance and energy efficiency.
8. Hydrostatic Testing: Each assembly undergoes hydrostatic pressure testing at 1.5× the maximum operating pressure to verify integrity and leak-tightness.
9. Final Cleaning & Passivation: Citric acid cleaning followed by passivation treatment to restore and enhance the passive chromium oxide film.
10. End-to-End Traceability: Full batch traceability from raw material through final delivery, with all test and inspection records archived.

Applications

This pure steam sterilization coil tube system is specifically engineered for the following biopharmaceutical and related applications:

• Terminal Sterilization Circuits: Saturated steam distribution to autoclaves, tunnel sterilizers, and batch sterilization vessels for pharmaceutical products, medical devices, and packaging materials.
• Sterile Filling Line Steam Supply: Clean steam delivery to isolators, RABS (Restricted Access Barrier Systems), and filling equipment where WFI-grade condensate is mandatory.
• SIP (Sterilization-in-Place) Systems: Steam injection and circulation loops for process equipment, piping, and bioreactors requiring in-situ sterilization validation.
• Water for Injection (WFI) Systems: Steam distillation columns and condensate collection systems where the condensate itself constitutes the WFI product stream.
• Pure Steam Generation & Distribution: Main steam headers, branch lines, and terminal points within pharmaceutical cleanroom environments (ISO Class 5/7/8).
• Medical Device Manufacturing: Steam sterilization circuits for implantable devices, syringes, needles, and other single-use pharmaceutical products.

Unique Selling Points

• WFI-Grade Condensate Assurance: The 316L EP material, combined with the slope drain design, ensures that all condensate meets Water for Injection quality standards — eliminating the need for additional polishing or treatment steps.
• Optimized Slope Drain Architecture: Continuous gradient design guarantees 100% condensate removal, preventing water hammer, thermal stress, and microbial harborage — a common failure mode in conventional steam piping.
• Steam Trap Pre-Matching: Each coil assembly is delivered with a steam trap type and sizing pre-calculated for the specific system pressure and condensate load, ensuring efficient steam utilization and minimal energy waste.
• Biopharmaceutical-Grade Surface: Ra ≤ 0.4 µm electropolished interior provides a biologically inert surface that resists biofilm formation and supports validated CIP/SIP cycles.
• Regulatory Compliance: Manufactured in accordance with ASME BPE guidelines and fully traceable documentation supports FDA, EMA, and MHRA audit readiness.

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and regulatory compliance framework:

• ISO 9001:2015 — Quality Management System Certification
• ISO 14001:2015 — Environmental Management System Certification
• ISO 22000 — Food Safety Management (where applicable to steam systems)
• ASME BPE — Bioprocessing Equipment Standards (Design & Fabrication)
• ISO 15002-2 — Welding Procedure Qualification for ASME BPE Piping
• CE Marking — European Conformity for pressure equipment (PED 2014/68/EU)
• GMP-Compliant Manufacturing — Production facilities designed and operated in accordance with pharmaceutical GMP principles
• Full Traceability: EN 10204 Type 3.1 material certificates, weld log records, hydrostatic test reports, and electropolishing verification documentation provided with every delivery

Wenzhou Jixing Metal Materials Co., Ltd. — Delivering pharmaceutical-grade stainless steel coiled tube solutions engineered for absolute purity, regulatory compliance, and uncompromising performance in biopharmaceutical clean steam systems.