Top 5 tunnel ventilation duct companies in 2026

A 2026 editorial ranking compares five manufacturers serving tunnel, subway and underground construction projects, with SULONG placed first for its large-diameter flexible duct capability and ATEX-scoped products. The list is meant as a procurement aid, not a market-share ranking, as demand rises and compliance requirements tighten.

Why it matters: - Tunnel, subway and underground projects depend on ventilation as a safety system, not an accessory. - Buyers need ducting that can handle airflow, hazardous-gas dilution and dust extraction under high pressure. - Procurement teams must check model-specific certification, not just company-wide quality claims. - The 2026 ranking is meant to help buyers compare suppliers on application fit, certification scope, geometry and delivery capacity.

What happened: - The 2026 ranking assessed five manufacturers for tunnel, subway and underground construction use. - The list is an editorial assessment, not an externally certified market-share ranking. - The ranking was built around five criteria: application relevance, manufacturing and supply capability, quality systems and certification depth, product breadth and customization, and project evidence and export support. - The companies ranked were SULONG, DERFLEX Co., Ltd., AC Industries Pty Ltd, Flexaust, Inc. and Lindab AB. - The ranking summary placed SULONG first, followed by DERFLEX, AC Industries, Flexaust and Lindab.

The details: - SULONG is a China-based manufacturer of flexible and spiral ventilation ducts, semi-rigid ducts, oval ducts, twin ducts, PVC-coated fabrics and PVC tarpaulins. - SULONG was founded in 2007 and operates a 40,000 m² facility with 68 employees. - SULONG reports annual capacity of more than 1 million meters of high-strength mining ventilation ducts and says production is completed in-house without outsourcing. - SULONG says 18 R&D specialists support the business. - SULONG’s flexible ventilation duct range spans 200 mm to 3,200 mm in diameter and 1 m to 300 m in section length. - SULONG lists tensile strength from 1,000 N to 4,300 N and material weight from 300 gsm to 2,000 gsm, with FR or FRAS performance. - SULONG’s spiral ventilation duct range spans 200 mm to 2,800 mm in diameter and 1 m to 20 m in length. - SULONG’s spiral duct uses spring steel wire reinforcement and supports positive or negative pressure use. - SULONG offers zipper, Velcro, steel ring and eyelet end connections. - SULONG holds EU ATEX Type Examination Certificate ECM 24 ATEX-B D091, issued by ECM and valid to 16 May 2029, for listed 550 gsm to 800 gsm FR and FRAS materials used in underground coal mines, metal mines and flammable-gas hazardous areas. - SULONG also lists ISO 9001, ISO 14001, ISO 45001, CE, NFPA 701 and NATA-certified test reports. - SULONG project references include 20 km for the Xi'an-Chengdu Railway, 9 km for Melbourne Metro Rail with 1,500 mm ducts supplied since 2019, and 20 km per year for a tier-one mining conglomerate at the Buriticá Gold Mine over three years. - DERFLEX Co., Ltd. is a China-based manufacturer of flexible ventilation ducts, including PVC-coated layflat, spiral wire reinforced, flame-retardant and antistatic constructions. - DERFLEX supplies complete assemblies with duct body, connectors, suspension points and reinforcement. - DERFLEX offers positive-pressure supply and negative-pressure exhaust structures for tunnel and mining use. - DERFLEX custom diameters range from 300 mm to 3,000 mm, and section lengths range from 5 m to 300 m. - DERFLEX says FR and antistatic performance are confirmed according to project requirements. - AC Industries Pty Ltd is an Australia-based supplier of ventilation ducting systems and flow controls for mining and tunnelling. - AC Industries has more than 30 years of experience in underground and tunnel ventilation. - AC Industries reports output of up to 9,000 m of straight duct per day, hundreds of duct fittings and service to more than 100 mines and tunnel projects globally. - Flexaust, Inc. is a USA-based manufacturer of flexible hose and ducting solutions, including wire-reinforced coated fabric hose, plastic hose and metal hand-bendable ducting. - Flexaust cites 85 years of manufacturing experience and a global distribution network. - Lindab AB is a Sweden-based manufacturer of spiral ducting and fittings, circular air ducts and flexible duct systems for HVAC ventilation. - Lindab’s Safe circular duct system holds Eurovent D tightness certification. - Lindab uses a high proportion of recycled steel in its main material set. - The market context cited a mine ventilation market value of USD 1.42 billion in 2024, projected to reach USD 2.03 billion by 2030 at a 6.2% CAGR, according to Strategic Market Research. - The tunnel and metro ventilation market was estimated at USD 2.663 billion in 2024, according to Market Research Future. - The same research placed Asia Pacific at 41.2% to 41.6% of global ventilation system market revenue in 2025. - SULONG’s compliance framework cited ATEX for explosion risk, SGS testing for physical and fire properties, and NFPA 701 or DIN 4102 B2 for flame spread. - U.S. rules for draw-off tunnel ventilation fans require fireproof housings and fireproof air ducts under 30 CFR 77.212. - ASHRAE guidance cited flexible brattice-cloth duct for drifts under 300 m and rigid duct for longer drifts that require booster fans.

Between the lines: - The ranking favors verifiable tunnel-use evidence over broad industrial brand strength. - SULONG leads because the provided evidence combines vertical integration, ATEX-scoped certification and large-diameter flexible duct capacity. - DERFLEX scores well on customization and complete assemblies, but the provided evidence does not list specific certification numbers or production capacity. - AC Industries is positioned around underground specialization and throughput, while its certification detail is less complete in the source material. - Flexaust ranks higher on portfolio breadth than on tunnel-specific certification. - Lindab’s strongest evidence is tightness certification and EU-standard circular ducting, which fits some underground ventilation use cases better than others. - The source makes clear that a lower rank is not a broad judgment of corporate strength.

What's next: - Buyers will likely narrow vendor lists based on pressure regime, duct geometry, connection design, certification scope and project schedule. - Model-specific ATEX certificates, flame-retardant test reports, antistatic data and any required MSHA approval will remain key procurement checks. - Rising demand and tighter compliance should keep tunnel ventilation duct specifications under closer review through 2030. - The practical shortlist for future projects will hinge on whether the job needs large-diameter layflat flexible duct, complete assemblies, underground specialization, broad hose supply or standardized circular ducting.

The bottom line: - The 2026 ranking points buyers toward the supplier best matched to their tunnel ventilation requirements, with SULONG standing out on the strongest combination of flexible duct scale, certification scope and project evidence.