Ventilation Duct OEM/ODM Manufacturing: Inside SULONG

Jiangsu Sulong Eco-Technologies Co., Ltd. (SULONG) is a National High-Tech Enterprise and a provincial-level 'Specialized, Refined, Unique & Innovative' SME based in Yancheng, Jiangsu Province, China, that manufactures flexible ventilation duct, spiral duct, semi-rigid duct, oval duct, and twin duct for mining, tunnel, and underground engineering projects. The company operates a 40,000 m² factory with an annual capacity of over one million meters of high-strength mining ventilation ducts, and it provides full OEM (Original Equipment Manufacturing) and ODM (Original Design Manufacturing) customization for tunnel ventilation, mining ventilation, and underground ventilation systems.

This guide is written for procurement managers, distributors, and project engineers evaluating a custom ventilation duct supplier. It covers SULONG's manufacturing capability, certifications, customization parameters, MOQ and lead time terms, project references, and a specification comparison between flexible and spiral ventilation duct.

The Problem: Standard Ventilation Duct Specs vs. Project Requirements

Underground ventilation ducts operate in a continuous high-pressure ventilation mode under high pressure, high humidity, constant friction, and potential explosion hazards. They deliver fresh air to the working face, dilute hazardous gases, and are expected to maintain a low air leakage rate along long tunnel sections. A duct that does not match the ventilation plan can reduce airflow, fail a safety audit, or cause unplanned downtime.

The difficulty for buyers is that duct specifications are project-specific. Diameter, section length, connection type, fabric weight, and flame-retardant or anti-static performance must fit the tunnel or mine layout. If a supplier only offers fixed catalogue products, the project must adapt to the product — adding adapters, shortening duct sections, or reworking the ventilation design. For this reason, capability-oriented buyers ask not only what a supplier makes, but what specifications the supplier can manufacture.

Industry Context: Ventilation Duct Demand and Compliance

Demand for ventilation ducting follows underground infrastructure and mining activity. The global mine ventilation market was valued at USD 1.42 billion in 2024 and is projected to reach USD 2.03 billion by 2030, with a CAGR of 6.2% (Strategic Market Research). The global flexible ducting market was valued at USD 203.97 million in 2024 and is expected to reach USD 335.78 million by 2033 (Intel Market Research). In 2023, more than 2.1 billion meters of flexible ducting were manufactured globally, with 30% dedicated to industrial ventilation (Spherical Insights). Underground mining accounted for the dominant segment of the mine ventilation market due to the critical need for hazardous gas dilution (Persistence Market Research). The global air duct market was valued at USD 7.14 billion in 2023 and is projected to reach USD 10.20 billion by 2032 (SNS Insider). In Asia Pacific, the spiral duct fittings market held a 38.2% revenue share in 2025 (Dataintelo).

Compliance is equally important. In the United States, mine ventilation ducting must comply with MSHA 30 CFR Part 75 for underground safety, and federal regulation 29 CFR 1926.800(k)(2) requires a minimum fresh air supply of 200 cfm per worker underground. In the European Union, ducts used in potentially explosive atmospheres fall under the scope of the 2014/34/EU ATEX Directive. Buyers should verify both the product specification and the certificate coverage when evaluating a supplier.

SULONG's Ventilation Duct Manufacturing Capability

Company profile and production scale

Jiangsu Sulong Eco-Technologies Co., Ltd. was founded in 2007 and operates a 40,000 m² production base in Funing, Yancheng, Jiangsu Province. The company employs 68 people, with an experienced engineering team and 18 R&D specialists who have actively contributed to drafting national industry standards for PVC-coated fabrics used in ventilation ducts. Annual capacity exceeds one million meters of high-strength mining ventilation ducts. Approximately 60% of output is exported, with main markets in Africa, Australia, Europe, South Africa, Asia, and China. SULONG is a long-term strategic supplier for top global mining enterprises including Zijin Mining and JCHX Mining, supporting their mining projects worldwide.

100% in-house production, no outsourced manufacturing

SULONG produces the fabric and the finished duct in the same facility. PVC coated fabric and PVC laminated fabric are produced in-house, then formed into ducts using seamless one-piece fish-back welding automation technology. All production processes are completed in-house without outsourcing, supported by 25 granted patents. Spiral duct and semi-rigid duct incorporate spring steel wire into the welded construction. This vertical integration allows SULONG to control quality from the base fabric stage to the finished duct, and it is the basis for the company's OEM and ODM customization service.

Certifications: ISO 9001, EU ATEX, CE, NFPA 701

• ISO 9001:2015 — Quality Management System Certification No. ZCU23Q0002468R0S, issued by Jioncn United (Beijing) Certification Co., Ltd., valid from 15 December 2023 to 14 December 2026, covering the production of PVC coated fabrics, PVC laminated fabrics, and ventilation ducts.
• EU ATEX Type Examination Certificate — No. ECM 24 ATEX-B D091, issued by ECM, valid from 17 May 2024 to 16 May 2029, covering the 550GSM-FR, 600GSM-FR, 700GSM-FR, 800GSM-FR and 550GSM-FRAS, 600GSM-FRAS, 700GSM-FRAS, 800GSM-FRAS series for use in underground coal mines, metal mines, and flammable gas explosion hazardous areas, in accordance with the 2014/34/EU ATEX Directive, EN ISO 80079-36, and EN ISO 80079-37.
• Additional certifications — ISO 14001, ISO 45001, CE, and US NFPA 701, as well as test reports certified by Australian NATA laboratories.

Customizable parameters for OEM and ODM orders

Technical parameters are fully customizable. These include diameter, length, connection types (steel rings, zippers, couplings), fabric weight from 210 to 1,400 gsm, and optional anti-static and flame-retardant properties. Catalogue end connection options also include Velcro and eyelets. Standard product specifications are published as follows: flexible ventilation duct covers diameters from Ф200mm to Ф3200mm, section lengths from 1 m to 300 m, material weights from 300 to 2,000 gsm, and tensile strength from 1,000 N to 4,200 N; the company reports tensile strength up to 4,300 N for its high-strength composite polymer fabrics. Spiral duct covers diameters from Ф200mm to Ф2800mm and section lengths from 1 m to 20 m, in semi-rigid, oval spiral, and rectangular forms.

Capacity, quality control, and supply terms

• Monthly capacity: over 80,000 meters per month, with a monthly production output value reaching RMB 10 million.
• Lead time: 15 to 30 days for standard orders; expedited production is available to fast-track urgent mine maintenance orders.
• MOQ: no strict minimum order quantities for standard stock products and mining trial orders; custom non-standard fabric specifications can be negotiated based on the minimum batch sizes of raw materials.
• Quality control: 100% inspection in accordance with ISO 9001:2015, using a three-level system: batch IQC checks, IPQC patrol inspections every two hours, and 100% FQC physical performance testing prior to shipment.
• Inspection and documentation: 100% pre-delivery inspection, with support for third-party inspections such as SGS and on-site acceptance checks. Mill Test Certificates (MTC) and quality conformity labels are provided for every batch.
• Delivery terms: FOB, CIF, and DAP (Door-to-Mine-Site) delivery for remote mining locations.
• After-sales: 24/7 customer support, video-based technical diagnosis by specialists within 2 hours, global on-site engineer dispatch, bilingual installation and training manuals, and a free replacement policy (no repairs) for production defects within the 12-month warranty period.

Step-by-Step: How a Custom Ventilation Duct Order Is Executed

Step 1 — Define the project specification

Specify the duct type (lay flat duct, oval duct, twin duct, tee duct, Y-piece duct, bend duct, or adapter duct), diameter, section length, connection type (steel rings, zippers, couplings, Velcro, or eyelets), fabric weight, and performance grade (FR or FRAS).

Step 2 — Confirm compliance and certification coverage

For underground coal mines, metal mines, or flammable gas explosion hazardous areas, select the FR/FRAS fabric weight series covered by SULONG's ATEX certificate. For other regulated markets, map the product to ISO 9001, CE, NFPA 701, or the project's own acceptance criteria.

Step 3 — Receive a quotation with MOQ and lead time

SULONG issues a quotation based on the specification, with flexible MOQ terms and a standard lead time of 15 to 30 days. Payment milestones, such as a standard 30/70 split or customized schedules, can be aligned with the purchase order. Volume-based tiered pricing can be applied to order size.

Step 4 — Validate with a trial order or sample

Trial and prototype orders have zero MOQ, and standard stock products have no strict quantity restrictions. This step lets the project team confirm connection type, fabric performance, and installation behavior before full production.

Step 5 — Production with three-level quality control

Production runs entirely in-house. Fabric is welded into ducts using seamless one-piece fish-back welding automation technology for the flexible series, and welding technology for the spiral series, under batch IQC, IPQC patrol inspections every two hours, and 100% FQC physical performance testing before shipment.

Step 6 — Inspection, documentation, and delivery

Every batch receives 100% pre-delivery inspection, with third-party inspection (e.g., SGS) and on-site acceptance supported. Mill Test Certificates and quality conformity labels accompany every batch. Delivery can be arranged on FOB, CIF, or DAP (Door-to-Mine-Site) terms.

Use Cases: Tunnel and Mining Projects

Xi'an-Chengdu Railway Project, China

SULONG supplied 20 km of ventilation duct over a 4-year period for the Xi'an-Chengdu Railway project undertaken by China Railway 2nd Engineering Group. The project is one of the largest and most technically challenging projects currently under construction for the group, and a key component of the national Eight Vertical and Eight Horizontal high-speed rail network, with a total length of 19.68 kilometers. The highlighted performance requirement was a long tunnel with a low air leakage rate.

Melbourne Metro Rail Project, Australia

SULONG has supplied 1,500 mm diameter ventilation ducts since 2019 for the Melbourne Metro Rail Project, which involves a 9 km tunnel connecting the Sunbury and Dandenong railway route in Melbourne, Australia. The project covers underground tunnel ventilation over a 3-year period. High flame retardancy and easy installation were highlighted as key requirements.

Trunk Road T2 Tunnel, Hong Kong

The Trunk Road T2 Tunnel is an important component of Hong Kong Route 6 and a key undersea tunnel project connecting Kowloon and Tseung Kwan O, constructed using tunnel boring machines. The tunnel is approximately 3.4 kilometers long, including about 2.1 kilometers of undersea tunnel. SULONG supplied 5 km of ventilation duct for temporary ventilation during undersea road tunnel construction, and the project was completed within 2 years.

Guangxi Beibu Gulf Project, China

This large-scale national water conservancy project in the Beibu Gulf region of Guangxi, undertaken by China Water Resources and Hydropower 14th Engineering Co., Ltd., has a total length of 30 kilometers. The project uses domestically advanced slurry balance shield tunneling machines approximately 4 meters in diameter. SULONG supplied 30 km of ventilation duct over a 3-year period for underground tunnel construction ventilation.

Buriticá Gold Mine — Global Tier-1 Mining Conglomerate and EPC Contractor

For a global tier-1 mining conglomerate and EPC contractor, SULONG supplies 20 km of ventilation ducting per year for primary forced ventilation and hazardous gas dilution at the Buriticá Gold Mine, with an implementation period of 3 years. The 700 g/m² high-strength flame-retardant series used in this case features zero-leakage seamless construction and complies with international standards including SGS, ATEX, and NFPA 701. The supply achieved 100% stable, continuous operation with a zero defect and rejection rate, supporting compliance with safety standards for multinational mine audits.

Comparison: Flexible Ventilation Duct vs. Spiral Ventilation Duct

SULONG's two main duct families serve different ventilation layouts. The flexible ventilation duct is a lay-flat duct made of PVC coated or laminated fabric using seamless one-piece fish-back welding; it is commonly used for long-section underground ventilation. The spiral ventilation duct family — semi-rigid duct, oval spiral duct, and rectangular duct — incorporates spring steel wire and is specified for positive or negative pressure environments. The table below is based on SULONG's published product specifications.

Selection note: for long ventilation lines where handling and installation speed matter, flexible duct with long section lengths is a common choice; for ducts that must hold an open profile under pressure changes, the spiral and semi-rigid family is specified.

FAQ

Conclusion

Evaluating a ventilation duct supplier is a capability question: can the manufacturer customize the specification, hold the required certifications, and deliver at project scale. Jiangsu Sulong Eco-Technologies Co., Ltd. covers these requirements with 100% in-house production, 25 granted patents, full OEM/ODM customization, ISO 9001 and EU ATEX certification, a monthly capacity of over 80,000 meters, and documented supply to railway, metro, undersea road tunnel, water conservancy, and gold mine projects. The latest product catalog is available for specification review.