316L BA Stainless Steel Coil Tube for Purified Water Systems
Product Overview
This precision-engineered 316L BA (Bore & Autopolished) stainless steel coil tube is specifically designed for Purified Water (PW) preparation and distribution systems in biopharmaceutical and pharmaceutical manufacturing facilities. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this coil tube delivers exceptional hygienic performance, meeting the stringent microbiological and chemical purity requirements mandated by global regulatory authorities including FDA, EMA, and WHO guidelines.
The coil tube format provides superior flexibility in system layout and installation, allowing for compact yet efficient routing of purified water through complex processing train configurations while maintaining the highest standards of sanitary design.
Material & Properties
The coil tube is fabricated from ASTM A270 Type 316L (UNS S31603) stainless steel, which offers superior corrosion resistance compared to standard 316 grade due to its reduced carbon content (≤0.03%), effectively eliminating intergranular corrosion risks during welding and heat exposure. The BA (Bore & Autopolished) surface treatment provides a passive oxide layer that resists microbial adhesion and biofilm formation, ensuring long-term sanitary integrity.
- Base Material: ASTM A270 / ASME SA-270 Type 316L (UNS S31603)
- Surface Treatment: Bore & Autopolished (BA) — Electrolytic polishing for enhanced passive film
- Surface Roughness: Ra ≤ 0.8 μm (meets BPE SF1–SF3 classification)
- Mechanical Properties: Tensile strength ≥ 515 MPa; Elongation ≥ 40%
- Corrosion Resistance: Excellent resistance to pitting, crevice, and intergranular corrosion in aqueous environments
- Temperature Range: Suitable for continuous operation from ambient to 120°C (with appropriate design considerations)
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Material Grade | 316L (UNS S31603) | ASTM A270 / ASME SA-270 |
| Surface Finish | BA (Bore & Autopolished) | BPE SF1–SF3 |
| Surface Roughness (Ra) | ≤ 0.8 μm | ISO 21920-2 |
| Microbial Limit | < 100 CFU/mL | USP <643> / EP 2.6.12 |
| Total Organic Carbon (TOC) | < 500 ppb | USP <643> / EP 2.2.44 |
| Welding Method | Orbital TIG / Automatic Welding | ASME BPE / ISO 15868 |
| End Preparation | Plain end, beveled, or custom | ASME B31.3 |
| Available Sizes | DN15 – DN100 (custom sizes available) | EN 10357 / ASTM A270 |
| Coil Diameter | Customizable (standard & large-diameter coils) | Project-specific |
| Compliance | ASME BPE, 3-A Sanitary, FDA 21 CFR | Multi-standard compliance |
Manufacturing Process
1. Raw Material Selection
Only certified 316L stainless steel coils conforming to ASTM A270 and EN 10357 standards are accepted. Each batch undergoes spectroscopic verification to confirm chemical composition, with full traceability documentation provided.
2. Forming & Coil Winding
The seamless tube is precision-formed into coil configurations using controlled bending equipment that maintains dimensional accuracy and surface integrity throughout the forming process. Cold-forming techniques are employed to preserve the metallurgical structure and surface finish.
3. Orbital TIG Welding
All welds are performed using orbital automatic TIG (Tungsten Inert Gas) welding with internal gas shielding (argon/helium), ensuring penetration-free, fully healed welds with a smooth internal contour. Weld parameters are monitored and documented in accordance with ASME BPE requirements.
4. Bore & Autopolish (BA) Treatment
The tube undergoes a multi-step cleaning and passivation process:
- Alkaline cleaning to remove organic contaminants and mill scale
- Acid pickling to restore uniform surface chemistry
- Electrolytic polishing (autopolishing) to achieve Ra ≤ 0.8 μm and enhance the passive chromium oxide layer
- Final rinse with deionized water and verification of surface roughness via profilometry
5. Inspection & Testing
Every coil tube lot undergoes rigorous quality verification including visual inspection, dimensional measurement, surface roughness profiling, weld radiographic or visual examination, and chemical analysis. Certificates of Conformance (CoC) and Material Test Reports (MTR) are provided with each shipment.
Applications
This 316L BA coil tube is purpose-built for the following critical applications within biopharmaceutical and pharmaceutical manufacturing:
- Purified Water (PW) Preparation: Water treatment trains including reverse osmosis (RO) feed and product lines, demineralization systems, and activated carbon filtration loops
- Purified Water Distribution: Closed-loop distribution piping networks delivering PW to points of use throughout the manufacturing facility
- Water for Injection (WFI) Systems: Upstream piping in distillation and membrane-based WFI generation systems
- CIP/SIP Loop Integration: Clean-in-Place and Steam-in-Place connection points requiring hygienic-grade tubing
- Pharmaceutical Processing: Product transfer lines for aqueous formulations where microbial control is critical
The coil format is particularly advantageous for compact installations where space is limited, providing efficient routing solutions for complex piping arrangements while maintaining sanitary design principles throughout.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring regulatory compliance across all product categories:
- ASME BPE: Bioprocessing Equipment standards for surface finish, welding, and design
- 3-A Sanitary Standards: Recognized by the 3-A Sanitary Standards Foundation for dairy and beverage-grade hygiene
- ISO 9001: Quality Management System certification
- ISO 14001: Environmental Management System certification
- USP <643>: Compliance with United States Pharmacopeia Water for Pharmaceutical Use standards
- EP 2.6.12: Compliance with European Pharmacopoeia Purified Water monograph
- FDA 21 CFR Part 11: Data integrity and traceability compliance
- CE Marking: Conformity with European regulatory requirements
Each shipment includes a full documentation package comprising Material Test Reports (MTR), Heat Number traceability, Weld Procedure Qualifications (WPQ), Non-Destructive Examination (NDE) reports, Surface Roughness certificates, and Certificate of Analysis confirming microbial and TOC compliance.
Key Selling Points
- Superior Hygienic Performance: Ra ≤ 0.8 μm surface finish ensures minimal microbial adhesion and facilitates effective CIP/SIP protocols
- Proven Material: 316L grade with low carbon content eliminates intergranular corrosion risks, ensuring long service life
- Regulatory Ready: Full compliance with ASME BPE, USP, EP, and FDA requirements — reduces audit risk and accelerates facility qualification
- Flexible Coil Configuration: Space-efficient installation solution for complex PW system layouts
- Complete Traceability: Full documentation from raw material to finished product for regulatory inspection readiness
- Custom Fabrication Capability: Tailored sizes, coil diameters, and end preparations to meet specific project requirements
Design Note: For optimal system performance, this coil tube should be installed in accordance with ASME BPE guidelines, ensuring proper slope, drainability, and sanitary fitting integration. System design should maintain turbulent flow (Reynolds number > 4,000) to prevent microbial stagnation.