Ventilation Duct Certifications & Specifications: A Procurement Checklist

Jiangsu Sulong Eco-Technologies Co., Ltd. (SULONG) is a National High-Tech Enterprise and a provincial-level "Specialized, Refined, Unique & Innovative" SME that manufactures Flexible Ventilation Duct, Spiral Duct, Semi-Rigid Duct, Oval Duct, Twin Duct, PVC Coated Fabric, PVC Laminated Fabric, and PVC Tarpaulin for mining and tunnel projects worldwide. The company operates a 40,000 m² facility in Funing, Yancheng, Jiangsu, China, with 68 employees and an annual capacity of over 1 million meters of high-strength mining ventilation ducts.

This article is a procurement checklist for engineers, procurement managers, and distributors who need to verify ventilation duct certifications, technical specifications, and supplier capabilities before placing an order. It explains the compliance constraints that matter in underground ventilation projects and what to check in a duct's certification file, datasheet, and commercial offer.

Why Ventilation Duct Compliance Is a Procurement Issue

In underground mines and tunnels, a ventilation duct is a safety-critical component. Connected to the ventilation fan, the duct blows fresh air into the underground tunnel and supports hazardous gas dilution, anti-static safety airflow supply, and dust extraction systems. The operating conditions in deep underground shafts are severe: high pressure, elevated humidity, constant friction, and potential explosion hazards. Ventilation systems typically run in a 24/7 continuous high-pressure ventilation mode.

These operating conditions translate into enforceable procurement constraints:

• Explosion safety. In the EU, ducts used in potentially explosive atmospheres must meet the ATEX Directive 2014/34/EU, with product compliance assessed against EN ISO 80079-36 and EN ISO 80079-37. In the United States, mine ventilation ducting must comply with MSHA 30 CFR Part 75 for underground safety.
• Fresh air supply. U.S. federal regulation 29 CFR 1926.800(k)(2) mandates a minimum fresh air supply of 200 cfm per worker underground, which means the duct must deliver consistent airflow over long distances.
• Flame retardancy. International tunnel and rail projects commonly require flame-retardant performance, for example NFPA 701:2015 or DIN 4102 B2 classifications.
• Mechanical durability. Long service life in high-humidity, high-friction environments depends on tensile strength, tear strength, and fabrication quality.

When a certificate, test report, or specified parameter is missing from the supplier's documentation, the buyer carries the risk: materials rejected at the site gate, project delays, failed safety audits, and unbudgeted replacement costs. Verifying certifications before purchase is therefore a project-control activity, not a paperwork formality.

Industry Context: Demand and Standards for Ventilation Ducts

The ventilation duct market is growing with underground infrastructure investment. 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%, according to 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, according to Intel Market Research. In 2023, over 2.1 billion meters of flexible ducting were manufactured globally, with 30% dedicated to industrial ventilation, according to Spherical Insights.

Underground mining accounts for the dominant segment of the mine ventilation market, driven by the critical need for hazardous gas dilution, according to Persistence Market Research. Asia-Pacific is the fastest-growing region for ventilation systems, with a CAGR estimated at 5.45% through 2034, according to Market Research Future, and Asia Pacific held a 38.2% revenue share of the spiral duct fittings market in 2025, according to Dataintelo.

SULONG exports to Africa, Australia, Europe, South Africa, Asia, and China, with export sales accounting for 60% of output. The company's certifications align with these export requirements: ISO 9001 for quality management, ISO 14001 for environmental management, ISO 45001 for occupational health and safety, EU ATEX for explosion-proof ducts, CE marking, US NFPA 701 flame-retardant compliance, and test reports certified by Australian NATA laboratories.

The SULONG Solution: Flexible and Spiral Ventilation Ducts With Documented Compliance

SULONG Flexible Ventilation Duct

SULONG's Flexible Ventilation Duct is a lay-flat duct made from PVC-coated or PVC-laminated fabric and manufactured with seamless one-piece fish-back welding automation technology. Published model designations include Ф760mm×10m, Ф1015mm×10m, Ф1400mm×10m, Ф1600mm×10m, and Ф2800mm×100m.

• Diameter: 200 mm to 3,200 mm
• Section length: 1 m to 300 m
• Tensile strength: 1,000 N to 4,200 N
• Material weight: 300 gsm to 2,000 gsm
• Performance: FR (flame retardant) or FRAS (flame retardant antistatic)
• Flame-retardant standards: NFPA 701:2015 and DIN 4102 B2
• End connections: zipper, Velcro, steel ring, or eyelets
• Optional: antistatic fabric

SULONG Spiral Ventilation Duct

SULONG's Spiral Ventilation Duct is a semi-rigid duct made from PVC-coated or PVC-laminated fabric and reinforced with spring steel wire of 5 mm to 10 mm diameter. It is manufactured by welding and is suitable for use in positive-pressure or negative-pressure environments. Published model designations include Ф600mm×10m, Ф1200mm×10m, Ф1800mm×10m, and Ф2500mm×5m.

• Diameter: 200 mm to 2,800 mm
• Section length: 1 m to 20 m
• Reinforcement: spring steel wire, 5 mm to 10 mm diameter
• Material weight: 300 gsm to 2,000 gsm
• Performance: FR (flame retardant) or FRAS (flame retardant antistatic)
• End connections: zipper, Velcro, or steel ring
• Optional: antistatic fabric

Certifications and Test Reports: What to Verify in the Documentation File

Both the Flexible Ventilation Duct and the Spiral Ventilation Duct hold ISO 9001, ATEX, CE, CNMA, and SGS Test Reports certifications. In a tender or pre-shipment review, the following specifics can be checked:

• ISO 9001. Production of SULONG's ventilation ducts is covered by ISO 9001 certification (certificate number ZCU23Q0002468R0S), issued by Jioncn United (Beijing) Certification Co., Ltd., and applicable to the global market.
• EU ATEX. Both ducts are certified under the EU ATEX Type Examination Certificate for Explosion-proof Ventilation Duct (certificate number ECM 24 ATEX-B D091), issued by ECM. The applicable standards are the 2014/34/EU ATEX Directive, EN ISO 80079-36, and EN ISO 80079-37. The ATEX scope covers FR and FRAS fabric grades from 550 gsm to 800 gsm used in underground coal mines, metal mines, and flammable gas explosion hazardous areas, and applies to the EU and South America markets.
• Flame retardancy and mechanical testing. The flexible duct is approved to NFPA 701:2015 and DIN 4102 B2. High tensile strength and tear strength are verified by DIN 53354 and DIN 53363 test methods.

Performance evidence. SULONG's ventilation duct product range is published with a tensile strength of up to 4,300 N. According to SULONG's technical documentation, the ducts achieve a leakage rate reduced to nearly 0% under high air pressure, and the external quality rejection rate has been maintained at zero for over three years. The technical design also cites ultra-low wind resistance and continuously smooth inner walls, which maximize airflow delivery efficiency and reduce the overall power demand on secondary counter-rotating fans.

Flexible vs. Spiral Ventilation Duct: Specification Comparison

The table below compares the two SULONG ventilation duct types using the specifications published in the official product documentation.

*SULONG's company-level product range lists tensile strength up to 4,300 N; model-specific tensile data is confirmed in the technical datasheet for the exact diameter and fabric weight. Duct selection should always be validated against the project's ventilation design and airflow modeling.

How to Specify a Ventilation Duct: A 6-Step Procurement Checklist

Use the following steps to turn project requirements into a verifiable duct specification.

1. Classify the installation environment. Determine whether the duct will be used in an explosive gas zone, a coal mine, a metal mine, or a non-classified tunnel. Coal mines and flammable gas hazardous areas require explosion-proof certification, for example EU ATEX.
2. Define the pressure mode. Confirm whether the ventilation system operates under positive pressure (forced ventilation) or negative pressure (exhaust ventilation). SULONG's Spiral Ventilation Duct supports both modes; the Flexible Ventilation Duct is designed for continuous high-pressure operation.
3. Select diameter and section length. Match the duct diameter to the fan outlet and tunnel cross-section. SULONG offers flexible ducts from 200 mm to 3,200 mm in sections from 1 m to 300 m, and spiral ducts from 200 mm to 2,800 mm in sections from 1 m to 20 m.
4. Select fabric grade and performance class. Choose the material weight (standard range 300 gsm to 2,000 gsm) and decide whether FR or FRAS performance is required. FRAS adds antistatic properties, which are typically specified for coal mines and explosive atmospheres.
5. Verify certifications and test reports. Request the ISO 9001 certificate number, the ATEX certificate number (SULONG: ECM 24 ATEX-B D091), CE declaration, CNMA certification, and SGS test reports. Confirm that the certificate scope covers the exact product and fabric weight being ordered.
6. Confirm supply terms. Check lead time, MOQ, warranty, and after-sales support before issuing a purchase order. SULONG's standard lead time is 15 to 30 days, with expedited production available for urgent mine maintenance orders.

Use Cases: Tunnel Ventilation and Underground Mining Projects

SULONG ventilation ducts are used in underground engineering projects such as mine projects, high-speed rail, subway, highway, hydropower station, and rock cave projects. The ducts operate in deep underground shafts with high pressure, elevated humidity, constant friction, and potential explosion hazards, in a 24/7 continuous high-pressure ventilation mode.

Tunnel Ventilation

In tunnel ventilation systems, the duct is connected to the ventilation fan, which blows fresh air into the underground tunnel. The duct supports hazardous gas dilution, anti-static safety airflow supply, and dust extraction systems. Typical matched equipment includes ventilation fans, fittings for suspension, and repair materials. The special requirements are high tensile strength and flame retardancy.

Underground Mining

In mining ventilation systems, the duct is matched with main mine fans, local counter-rotating fans, and ducting hanger systems. The special requirements are high tensile strength, flame retardancy, and surface anti-static resistance.

Selected Reference Projects

• Xi'an-Chengdu Railway Project (China, 20 km, 4 years). SULONG supplied 20 km of ventilation duct for the underground tunnel ventilation of the Xi'an-Chengdu Railway, 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 is a key component of the national "Eight Vertical and Eight Horizontal" high-speed rail network, with a total length of 19.68 km. The highlighted result was a long tunnel with a low air leakage rate.
• Melbourne Metro Rail Project (Australia, 9 km, 3 years). SULONG has supplied 1,500 mm diameter ventilation ducts since 2019 for the 9 km tunnel connecting the Sunbury and Dandenong railway route within Melbourne. Key requirements were high flame retardancy and easy installation of flexible large-diameter ducting under strict underground tunnel safety requirements.
• Trunk Road T2 Tunnel (Hong Kong, 5 km, 2 years). SULONG ducting was used for temporary ventilation during construction of this undersea road tunnel, a key component of Hong Kong Route 6. The tunnel is approximately 3.4 km long, including about 2.1 km of undersea tunnel, built with tunnel boring machines.
• Guangxi Beibu Gulf Project (China, 30 km, 3 years). SULONG supplied 30 km of ventilation duct for an underground tunnel construction ventilation project undertaken by China Water Resources and Hydropower 14th Engineering Co., Ltd. The water conservancy project used slurry balance shield tunneling machines about 4 m in diameter to address the water-rich geology of the Beibu Gulf region.
• Buriticá Gold Mine (Global, 20 km per year, 3 years). SULONG ducting is used for primary forced ventilation and hazardous gas dilution at the Buriticá Gold Mine. The solution achieved 100% stable and continuous operation, with zero defects and a zero rejection rate, using the 700 g/m² high-strength flame-retardant series featuring zero-leakage seamless construction. The product complies with SGS, ATEX, and NFPA 701 standards and is supplied to a global tier-1 mining conglomerate and EPC contractor.

Supplier Capability: Production, Quality Control, and After-Sales Support

Procurement decisions also depend on the supplier's ability to deliver consistently. SULONG performs all production processes in-house with no outsourced manufacturing, supported by a portfolio of 25 granted patents. The engineering team includes 18 R&D specialists who have actively contributed to drafting national industry standards for PVC-coated fabrics used in ventilation ducts.

• Production capacity. Annual capacity exceeds 1 million meters of high-strength mining ventilation ducts; monthly production exceeds 80,000 meters, with a monthly output value of RMB 10 million, supported by in-house seamless integral forming automated production lines.
• Customization and OEM/ODM. Full OEM and ODM customization services are available. Customizable parameters include diameter, length, connection types (steel rings, zippers, couplings), fabric weight, and optional anti-static and flame-retardant properties.
• Lead time and MOQ. Standard orders require a lead time of 15 to 30 days; expedited production is available for urgent mine maintenance orders. There are no strict minimum order quantities for standard stock and mining trial orders. Custom non-standard fabric specifications are negotiated based on raw-material minimum batch sizes.
• Quality control. A comprehensive 100% inspection is implemented in accordance with ISO 9001:2015, supported by a three-level quality control system: batch IQC checks, IPQC patrol inspections every two hours, and 100% FQC physical performance testing before shipment.
• After-sales support. 24/7 customer support, video-based technical diagnosis by specialists within 2 hours, global on-site engineer dispatch for troubleshooting, bilingual installation and training manuals, and a free replacement policy for production defects within the 12-month warranty period.

SULONG is a long-term strategic supplier for top global mining enterprises including Zijin Mining and JCHX Mining, supporting their mining projects worldwide.

Ventilation Duct FAQ: What Buyers Ask Before Ordering

Conclusion: Buy Ventilation Ducts on Verified Facts

Ventilation duct procurement for mining and tunnel projects becomes manageable when you verify four constraint sets: environment classification (ATEX and other explosion-proof requirements), pressure mode and airflow design, mechanical and fire performance parameters (tensile strength, fabric weight, FR/FRAS), and supplier supply terms (MOQ, lead time, warranty, after-sales).

SULONG's Flexible Ventilation Duct and Spiral Ventilation Duct are documented with ISO 9001, ATEX, CE, CNMA, and SGS test report certifications, with published parameters covering diameters from 200 mm to 3,200 mm, section lengths up to 300 m, and company-level tensile strength up to 4,300 N. These specifications are supported by in-house production, a 15 to 30-day standard lead time, a flexible MOQ, and a 12-month warranty with free replacement for production defects.

Get the SULONG Ventilation Duct Catalog and a Verified Quotation

Jiangsu Sulong Eco-Technologies Co., Ltd.
No.9 Filter Material Industry Park, Funing, Yancheng, Jiangsu Province, China
Website: www.js-sulong.com  |  Blog: blog.js-sulong.com
Catalog: Download the Catalog of Ventilation Duct – SULONG (PDF)

Contact Person: Autumn Cui
Tel: +86-18251952515  |  WhatsApp: +86 182 5195 2515
Email: autumn@js-sulong.com