Stainless Steel Coil Tube for Fan Coil Unit (FCU) HVAC Systems
Product Overview
The Stainless Steel Coil Tube (盘管) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered heat exchange component specifically designed for Fan Coil Unit (FCU) air conditioning systems. This product represents a critical element within Building Information Modeling (BIM) compatible HVAC architectures, enabling efficient thermal transfer between refrigerant circuits and ambient air. The coil tube is fabricated from high-grade stainless steel, ensuring superior corrosion resistance, mechanical integrity, and long-term service reliability in demanding indoor climate control environments.
Unlike conventional carbon steel or copper alternatives, the stainless steel coil tube offers exceptional resistance to condensation-induced corrosion, making it particularly suitable for humid climates and high-moisture applications. The product is manufactured to strict dimensional tolerances to ensure seamless integration within modular fan coil assemblies and automated BIM-based system generation workflows.
Material & Properties
The coil tube is fabricated from austenitic stainless steel grades, selected for their optimal balance of thermal conductivity, mechanical strength, and corrosion resistance.
- Base Material: Austenitic Stainless Steel (e.g., SUS304 / SUS316L equivalent to ASTM A240)
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and general atmospheric corrosion; Cl- resistance up to 1000 ppm (SUS316L)
- Thermal Conductivity: 14–16 W/(m·K) at 20°C, ensuring efficient heat exchange performance
- Tensile Strength: ≥ 520 MPa (minimum), providing structural durability under pressure cycling
- Operating Temperature Range: −40°C to +200°C continuous service
- Surface Finish: Mirror polish or matte finish (Ra ≤ 0.8 μm) to minimize fouling and optimize heat transfer coefficients
- Non-Magnetic: Austenitic structure ensures non-magnetic properties for compatibility with sensitive instrumentation
Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Tube Outer Diameter (OD) | 6.35 mm / 9.53 mm / 12.70 mm (1/4" / 3/8" / 1/2") | ASME B8.19 / ISO 65 |
| Wall Thickness | 0.5 mm – 1.2 mm (configurable) | ASTM A213 / ASTM A269 |
| Coil Diameter | 150 mm – 600 mm (adjustable per FCU design) | Custom / OEM specification |
| Number of Rows | 2 – 6 rows (heat exchanger configuration) | ASHRAE Standard 15 |
| Fin Pitch | 2.0 mm – 3.5 mm | ISO 13711 |
| Maximum Working Pressure | 2.5 MPa (363 psi) | EN 12828 / GB 50015 |
| Hydrostatic Test Pressure | 3.75 MPa (544 psi) | ASME BPV Section I |
| Refrigerant Compatibility | R-410A, R-32, R-22, R-134a, R-407C | ASHRAE Standard 34 |
| Cooling Capacity Range | 2.0 kW – 15.0 kW | ARI Standard 400 / ISO 13246 |
| Weight | 0.8 kg – 8.5 kg (depending on configuration) | — |
| Surface Treatment | Electro-polished / Passivated / Coated (optional) | ASTM A967 |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, surface quality, and metallurgical integrity:
- Material Procurement & Inspection: Stainless steel strip or tubing is sourced from certified mills with full mill test certificates (MTC). Incoming material undergoes spectroscopic analysis to verify chemical composition compliance with ASTM A240 / JIS G4305 specifications.
- Tube Forming: Precision drawing or cold-rolling processes form the base tube to exact OD and wall thickness tolerances (±0.05 mm). Seamless tube options are available for high-pressure applications.
- Coil Winding: The formed tube is wound into the specified coil geometry using CNC-controlled coiling machinery, ensuring uniform pitch, consistent turn-to-turn spacing, and accurate overall coil dimensions compatible with BIM model parameters.
- Fin Attachment (if applicable): Aluminum or stainless steel fins are mechanically or brazed onto the tube surface to maximize heat transfer area. Fin bonding integrity is verified through pull-force testing (≥ 15 N per fin).
- Welding & Brazing: Header connections and U-bends are joined using TIG (Tungsten Inert Gas) welding or high-temperature brazing with silver-based filler alloys. All welds undergo visual and radiographic inspection.
- Surface Treatment: Electro-polishing removes surface contaminants and creates a smooth, corrosion-resistant finish. Passivation treatment (nitric acid or citric acid) restores full passive film integrity.
- Pressure Testing: Each coil tube undergoes 100% hydrostatic pressure testing at 1.5× the maximum working pressure for a minimum of 30 seconds to verify leak-tightness and structural soundness.
- Final Inspection & Packaging: Dimensional verification, surface quality assessment, and material traceability documentation are completed. Products are packaged with desiccants and protective wrapping to prevent transport damage.
Applications
The stainless steel coil tube is designed for integration into a broad spectrum of HVAC and thermal management systems:
- Commercial Fan Coil Units (FCU): Primary heat exchange element in ceiling-mounted, floor-standing, and concealed ducted FCUs for office buildings, hotels, and retail spaces.
- Residential HVAC Systems: High-performance coil tubes for premium residential air conditioning and heating applications requiring long service life and low maintenance.
- Medical & Pharmaceutical Facilities: Corrosion-resistant coil tubes for cleanroom environments, hospital operating theaters, and pharmaceutical manufacturing plants where hygienic standards are paramount.
- Food & Beverage Processing: Suitable for applications involving condensate exposure, acidic environments, and frequent sanitization cycles.
- BIM-Integrated Smart Buildings: Designed with standardized dimensional interfaces to facilitate automated system generation within BIM (Building Information Modeling) environments, enabling rapid design-to-construction workflows.
- Marine & Coastal Environments: SUS316L grade coil tubes offer enhanced chloride resistance for HVAC installations in coastal regions and marine vessels.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System certification for consistent manufacturing excellence
- ISO 14001:2015 — Environmental Management System for sustainable production practices
- ISO 45001:2018 — Occupational Health & Safety Management System
- CE Marking — Compliance with European Union machinery and pressure equipment directives
- EN 12828 — Conformity with European standard for water-based components for heating systems
- ASME / PED — Pressure Equipment Directive compliance for applicable pressure ratings
- GB/T 14976 — Chinese national standard for seamless stainless steel tubes
- Mill Test Certificate (MTC) — Full traceability documentation provided with each shipment
- Third-Party Inspection — Available upon request (SGS, Bureau Veritas, TÜV)
Unique Selling Points
- BIM-Compatible Design: Pre-parameterized dimensional data enables seamless integration into BIM-based automatic system generation workflows, reducing design errors and accelerating project timelines.
- Superior Corrosion Resistance: Austenitic stainless steel construction eliminates the need for internal coatings or inhibitors, reducing lifecycle maintenance costs by up to 40% compared to carbon steel alternatives.
- Extended Service Life: Demonstrated operational lifespan exceeding 25 years under continuous duty, significantly outperforming conventional copper or aluminum coil tubes in corrosive environments.
- Hygienic Surface Finish: Electro-polished surfaces with Ra ≤ 0.8 μm inhibit bacterial adhesion and facilitate easy cleaning, meeting FDA and EHEDG guidelines for food-grade applications.
- Customizable Configurations: Flexible manufacturing capability supports OEM-specific coil geometries, fin patterns, and connection interfaces tailored to individual project requirements.
- Environmental Sustainability: 100% recyclable stainless steel construction supports circular economy principles; production process incorporates energy-efficient practices aligned with ISO 14001 standards.
Note: All specifications are subject to change without prior notice as Wenzhou Jixing Metal Materials Co., Ltd continuously improves product performance through ongoing R&D investment. For project-specific requirements, consult the technical sales engineering team for customized solutions and detailed compliance documentation.