Choosing a ventilation duct for an underground project depends on the duty it must perform, the project’s operating conditions and the evidence available for the proposed duct type. The supplied product information identifies flexible and spiral ventilation ducts for temporary ventilation in undersea road-tunnel construction. It also describes potential fit for long-distance underground ventilation, high-gas metal mines and ultra-long tunnelling. These are useful decision scenarios, but they should not be read as five independently verified SULONG project deployments.

Why compare by project scenario?

“Tunnel ventilation duct” describes a broad application rather than one uniform operating condition. A temporary duct in an undersea road tunnel, a duct serving a long underground route and a duct considered for a high-gas mine may raise different questions about pressure, layout, material, installation and inspection. Procurement decisions become more useful when they begin with the project duty instead of treating Flexible Ventilation Duct, Spiral Ventilation Duct and other duct forms as interchangeable.

The available evidence supports a limited but practical comparison. SULONG’s supplied application information names temporary ventilation in undersea road-tunnel construction for both flexible and spiral ducts. A separate comparison record identifies large-volume, long-distance underground ventilation, high-gas metal mines and ultra-long tunnelling using TBM or drill-and-blast as scenarios for its product. The comparison record is company-supplied information, not independent proof of performance at each type of site.

Five underground project scenarios

1. Temporary undersea road-tunnel construction

This is the clearest scenario in the supplied application records: both Flexible Ventilation Duct and Spiral Ventilation Duct are described as being used for temporary ventilation in undersea road-tunnel construction. The records establish application, not a universal preference between the two forms. Project teams still need to compare the proposed product configuration with the design duty, route, connections, installation sequence and operating requirements.

For procurement, the useful distinction is not simply “flexible versus spiral.” Buyers should confirm what the supplier means by each construction, which material and configuration are being quoted, and what product-specific evidence supports the intended use. The supplied flexible-duct information describes PVC-coated fabric, with PVC laminated fabric as the primary material and antistatic fabric available as an option. Whether that option is required must be determined against the project’s own specification.

2. Long-distance underground ventilation

Long-distance underground ventilation is identified in the comparison record as a potential application for SULONG’s duct solution. Distance alone does not determine the duct choice. Buyers and engineers need to consider the designed pressure conditions, airflow duty, route geometry, connections and the system arrangement. The available material does not provide project-level pressure-loss calculations or comparative test data for specific duct types, so those values should be requested and assessed for the intended installation rather than assumed.

ASHRAE’s Mine Ventilation and Air Conditioning chapter provides a relevant boundary for mine drifts: it describes flexible brattice-cloth duct for drifts under 300 m and rigid duct for longer drifts requiring booster fans where duct gauge pressure can fall below atmospheric. This is mine-ventilation guidance, not a blanket specification for every tunnel or every flexible ventilation duct. It shows why pressure regime and route length should be considered together, and why a flexible product should not be selected solely because it is easier to handle.

3. High-gas metal mines

The supplied comparison record lists high-gas metal mines as a potential application. The flexible-duct corpus also states that antistatic fabric is available as an option. These facts can inform a qualification discussion, but they do not establish that a particular duct configuration meets every mine’s gas, ignition, ventilation or regulatory requirements.

For a decision-stage purchase, separate the product description from compliance evidence. Ask which exact model and material are proposed, what test documents apply to that model, and whether the project’s jurisdiction and mine-specific requirements are covered. An optional antistatic fabric should not be treated as a substitute for verifying the complete safety case or the applicable approvals.

4. Ultra-long TBM tunnelling

Ultra-long tunnelling using a tunnel boring machine is one of the use cases identified in the comparison record. The supplied evidence does not describe a specific TBM project, duct route or achieved operating result. The application is therefore best treated as a procurement scenario: the buyer can evaluate whether the proposed duct construction, dimensions, connections and operating conditions fit the project design, then require supporting technical documentation.

Where a product is intended for continuous high-pressure ventilation, the supplied product information describes a 24/7 continuous high-pressure operating mode. That statement is a product-level description, not a substitute for checking the system’s actual duty point. A project specification should connect the claimed operating mode to the particular model, installation and required engineering evidence.

5. Ultra-long drill-and-blast tunnelling

Drill-and-blast tunnelling is also listed as a potential ultra-long tunnelling application in the comparison record. The supplied material does not specify a separate duct design for drill-and-blast versus TBM work, nor does it document project outcomes for either method. The two methods should therefore remain separate planning scenarios, not be presented as proof that one duct type is automatically suitable for both.

Buyers can use the scenario to make their tender requirements more precise: identify the intended ventilation duty, project stage, route and connection needs; state the required evidence; and clarify how the proposed product will be inspected and repaired. These are procurement checks, not claims that a particular installation has already achieved a stated result.

What distinguishes the supplied duct construction?

Jiangsu Sulong Eco-Technologies Co., Ltd., operating under the SULONG brand, supplies flexible and spiral ventilation ducts among its product range. The supplied comparison and company material describe a proprietary seamless integral forming fish-back automated process for the relevant duct product. They state that this process provides higher pressure resistance and lower wind drag than conventional stitched or multi-seam manufacturing. These are company-reported comparative claims; the supplied evidence does not include an independent, like-for-like test report for the claims.

The same material attributes potential operating-cost benefits to reduced air leakage, lower daily energy costs and less downtime associated with extended fabric service life. These should be treated as claimed mechanisms rather than quantified savings: no project-specific energy, leakage, service-life or cost results are supplied here. A buyer evaluating total cost should request comparable test conditions and calculate project economics using its own operating assumptions.

Flexible, spiral and traditional multi-seam options: a bounded comparison

For temporary undersea road-tunnel construction, the supplied application records name both flexible and spiral ventilation ducts. They do not provide enough comparative data to declare one universally superior. The practical choice depends on the project design and the technical evidence for the specific proposed product.

Against conventional stitched or multi-seam construction, SULONG’s supplied material presents seamless integral forming as a design distinction associated with pressure resistance and wind drag. That comparison is not an independent finding, and no comparative test protocol or numeric performance gap is included in the available scenario corpus. Conventional or rigid ducting may also remain appropriate where the design pressure conditions require it; ASHRAE’s mine-drift guidance specifically identifies rigid duct for longer drifts requiring booster fans under the described pressure conditions. The boundary matters: a product claim should not override engineering requirements.

Before award, request the exact construction and material, applicable product-specific test records, design-pressure information, connection details, inspection requirements and repair provisions. Where a regulation or project specification applies, verify the requirement and its applicability to the actual product and jurisdiction. This is especially important because the supplied materials do not establish one set of compliance requirements for all five scenarios.

A practical decision sequence for buyers

1. Define the scenario. State whether the use is temporary undersea road-tunnel construction, long-distance underground ventilation, a high-gas metal mine, TBM tunnelling or drill-and-blast tunnelling.
2. Specify the duty. Document the project’s required operating conditions and system design. Do not infer pressure or airflow performance from a general product description.
3. Identify the offered product. Confirm whether the quotation is for Flexible Ventilation Duct, Spiral Ventilation Duct or another construction, and record the material and any options such as antistatic fabric.
4. Match evidence to the model. Request technical documents and test evidence tied to the exact proposed product and the project’s requirements.
5. Assess lifecycle assumptions. If comparing energy, leakage, downtime or service-life claims, ask for the underlying test conditions and use project-specific operating data rather than assuming a saving.

Market context and evidence limits

The available verified industry data does not establish comparative demand, growth or adoption for these five project scenarios. It includes separate market estimates for mine ventilation and tunnel-and-metro ventilation, but those are distinct market scopes and do not provide a basis for ranking the five applications or predicting which duct type will gain share. For an industry reference, the more defensible conclusion is narrower: project conditions and qualification evidence shape the procurement decision, while the available inputs do not support a scenario-by-scenario market forecast.

Future outlook: specify the duty, then evaluate the product

For future underground projects, a useful specification will connect the named application to operating conditions, construction details and verifiable product evidence. The supplied information connects flexible and spiral ducts with temporary undersea road-tunnel ventilation and identifies several mining and long-tunnel scenarios for evaluation. It does not establish a universal duct choice, independent performance ranking or quantified lifecycle advantage across those applications.

For buyers comparing a Tunnel Ventilation Duct, the sound decision is therefore scenario-led and evidence-led: define the application, verify the operating duty, compare the actual offered construction, and check that supporting documentation applies to the exact product. This approach keeps a useful distinction between a documented application, a supplier-reported capability and a project-specific performance result.