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#Condensation #Metal ducts #Washing #Lead time
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#Air Dispersion Principle
FlowSox® is an air dispersion system that uses internal static pressure to inflate the fabric duct and distribute supply air to the target zone. Laser-engineered perforations are sized, spaced and oriented to deliver the required airflow rate and air velocity along the duct.
Micro Flow and Wide Flow provide low-velocity, diffused air distribution. Direct Flow concentrates air toward a defined work zone, while Jet Flow uses nozzles for longer throw distances. The airflow model is selected for the mounting height, available static pressure and required target-zone velocity.
CFD design validation is used to review air velocity, temperature distribution and stagnant zones before installation. The objective is to distribute conditioned air where it is needed, rather than simply convey it through a duct.
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#Metal duct comparison
Compared with conventional metal ductwork, FlowSox® offers lightweight construction, uniform air distribution and easier installation. The system can reduce dead zones and concentrated drafts, while removable modules simplify washing, reinstallation and partial replacement.
The perforation pattern must be engineered for the available static pressure and required air velocity. The maximum allowable static pressure specified for this FAQ is 500 Pa; the final operating conditions are confirmed during design.
Installed cost depends on the comparison material, insulation, suspension system and installation scope. Cost savings of up to 70% compared with stainless-steel (STS) ductwork may be achievable, subject to project conditions.
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#Applications
FlowSox® fabric duct systems are used in manufacturing facilities, logistics centers, smart farms and vertical farms, cold storage facilities, food processing plants, indoor sports facilities, swimming pools, cleanrooms and commercial facilities.
They are particularly useful where high ceilings, process heat loads, non-uniform air distribution or direct drafts affect the occupied zone. The duct layout and airflow model are designed around the building use and required target-zone air velocity.
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#Diameter and sizes
Fabric duct diameter is selected from the air-handling unit (AHU) airflow rate. As a general design reference, the inlet air velocity is kept at or below 9.5 m/s. Available diameters range from 100 to 2,500 mm, subject to design review.
The final diameter also depends on internal static pressure, mounting height, available clearance, duct layout and structural obstructions. It must provide the required flow area while allowing the fabric duct to inflate and maintain a stable cross-section.
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#Fabric selection
FlowSox® fabric is selected according to the airflow model and operating environment. Permeable fabric allows a controlled amount of supply air through the fabric surface, supporting gentle air dispersion and condensation control. Impermeable fabric directs supply air through the engineered perforations or nozzles for precise, directional air distribution.
Flame retardancy, antibacterial performance, cleanroom requirements and maintenance conditions are reviewed together. Antistatic fabric with woven conductive yarn is available for applications where static buildup must be controlled.
Fabric selection is part of the system design. The final specification is confirmed against the AHU airflow rate, static pressure, installation conditions and the intended application.
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#Shape Retention System
Fabric ducts maintain their inflated shape through internal static pressure. When the air supply stops, an unsupported duct naturally relaxes. In larger systems, sudden inflation at fan startup may also cause movement, noise or mechanical shock.
The FlowSox® shape retention system uses internal plastic rings or external aluminum rings to limit sagging and reduce startup movement. Internal rings provide a compact, economical solution; external rings keep the internal airflow path unobstructed and support larger diameters.
The ring arrangement is selected for duct diameter, suspension type, appearance and maintenance access. Rings and other fittings may need to be removed before washing.
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#High-ceiling spaces
Yes. FlowSox® can be engineered for high-ceiling and large-volume spaces by selecting an airflow model with the required throw distance and target-zone air velocity.
Jet Flow uses nozzles to reinforce the discharge airstream and deliver conditioned air toward distant occupied zones. Available static pressure, mounting height, heating or cooling duty and the required terminal velocity are assessed together.
Increasing airflow rate alone is not enough. The duct layout, discharge direction and nozzle specification must work as one system; CFD design validation can be used to review performance before installation.
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#Modular Layout
Yes. The modular duct layout can combine straight sections, elbows, branches, T-junctions, reducers and transitions to suit the AHU location and building structure.
The design accounts for ceiling beams, columns, machinery, working routes and the zones that require heating or cooling. Each branch is checked for the airflow rate and static pressure needed to achieve the design air velocity.
If the production layout changes, selected modules can be extended, branched or rerouted. The modified system should be reviewed to maintain the intended air distribution.
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#Condensation
FlowSox® can help control surface condensation by using permeable fabric. A controlled portion of supply air passes through the fabric surface, forming a thin air layer around the duct and reducing the conditions that promote condensation.
The fabric permeability is selected for the room temperature, relative humidity, dew point and supply-air conditions. This is particularly relevant in smart farms, food processing plants and other high-humidity environments.
Condensation performance is assessed for the complete operating conditions. The selected fabric and airflow design must be matched to the individual project.
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#Durability
Fabric thickness and tensile strength are key to durability because the duct repeatedly inflates and relaxes during operation. FlowSox® fabric specifications described here include a thickness of 0.47–0.57 mm and tensile strength of 2,300–3,300 N, depending on the selected fabric.
These properties help maintain duct shape and perforation alignment while limiting wear and deformation under repeated loading. Fabric, seams, zippers and suspension attachments are considered as parts of the complete system.
Long-term performance also depends on operating pressure, contamination and appropriate washing and maintenance. The fabric specification is confirmed for the project.
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#Flame performance
FlowSox® uses flame-retardant fabric specified to meet the Korean National Fire Agency requirements. Under the stated test conditions, afterflame time and afterglow time are both 0 seconds.
Afterflame time is the period during which flaming continues after the ignition source is removed. Afterglow time is the period of glowing combustion without a flame.
The applicable fabric specification and test reports are reviewed against the project requirements. Flame-retardant performance should be distinguished from non-combustibility under all possible fire conditions.
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#Combustion gases
FlowSox® fabric has been evaluated under the KS F 2271:2021 combustion-gas toxicity test referenced for the selected material. The test assesses the effects of combustion gases under defined laboratory conditions.
The result applies to the tested fabric and test method. It does not mean that no smoke or hazardous combustion gases can occur in an actual fire.
Flame-retardancy and combustion-gas test reports should be reviewed together when selecting the fabric. Supporting test results can be provided during technical consultation.
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#Noise
Fabric ductwork can help attenuate noise because the fabric surface absorbs and damps sound rather than reflecting it in the same way as rigid metal ductwork. Distributed perforations can also reduce concentrated air-discharge noise when correctly designed.
This can be useful for unit cooler noise reduction in food processing plants and other occupied workspaces. The actual acoustic result depends on the fan or unit cooler, discharge air velocity, room surfaces and the complete installation.
Where a noise limit applies, the equipment and duct system should be assessed together against the project acoustic requirements.
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#Antistatic fabric
Yes. Antistatic fabric can be specified for applications where electrostatic charge buildup must be controlled. FlowSox® uses conductive yarn woven into a grid to provide continuous conductive paths through the fabric.
This helps limit static buildup and electrostatic discharge. For battery storage, hazardous-material handling and other static-sensitive areas, fabric selection must be reviewed together with grounding, equipment and facility operating requirements.
The appropriate antistatic specification is confirmed through a project-specific technical review.
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#Cleanroom applications
FlowSox® offers low-particle-emission fabric with an ISO 14644-1 Class 3 cleanliness test result, for the selected fabric specification. Uniform air distribution and suitable particle-release characteristics are important when evaluating cleanroom applications.
The airflow model and laser-engineered perforations are selected to achieve the required process-zone air velocity. Antistatic specifications can be considered where static control is also required.
A fabric test result does not establish the cleanliness class of an entire installed cleanroom. Filtration, AHU configuration, airflow design and project-specific qualification must be assessed together.
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#Energy efficiency
Uniform air distribution and spot cooling can help improve HVAC energy efficiency. Delivering conditioned air to the target zone can reduce local overcooling, temperature stratification and unnecessary conditioning of unoccupied space.
Fan pressure losses and variable-speed operation should be assessed as part of the complete HVAC system. Duct layout, airflow rate, perforation pattern and equipment controls are reviewed together.
Actual energy savings depend on the building, existing equipment, operating schedule and control strategy. Project-specific assessment is required to quantify the improvement.
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#Installation cost
FlowSox® can reduce installed cost through lightweight construction, simpler suspension and faster installation. The cost difference can be greater when the alternative is insulated metal ductwork or stainless-steel (STS) ductwork.
Savings of up to 70% compared with STS ductwork may be achievable. The actual cost depends on duct diameter, length, fabric specification, insulation, ceiling structure and installation scope.
Compare quotations on the same project conditions and scope of supply and installation. This provides a meaningful comparison of the complete systems.
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#Hygiene
Antibacterial fabric can be specified for hygiene-critical environments such as food processing plants, smart farms and high-humidity facilities. Material selection should be combined with appropriate operating conditions and cleaning procedures.
Zipper-connected modules can be removed for washing or partial replacement when contamination requires it. This supports hygiene management without replacing the entire duct line.
Antibacterial performance does not replace moisture control, supply-air filtration or maintenance. Humidity, contamination and cleaning practices all affect long-term hygiene.
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#Suspension System
The fabric duct body is much lighter than conventional metal ductwork. Fabric specifications around 300–400 g/m² can help reduce structural load, making the system useful in lightweight structures and retrofit projects.
The total installed load also includes the suspension system, hangers, shape retention rings and attachment components. The ceiling structure and fixings must be checked for the complete installed configuration.
Suspension type is selected according to mounting height, available clearance, maintenance access and the structural conditions.
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#Lead time
For domestic production, reference manufacturing and delivery lead times are within 3 days for quantities up to 100 m and within 1 week for quantities up to 500 m, subject to specification and production scheduling.
Diameter, fabric specification, shape retention rings, transport and on-site installation scope can affect the final schedule. Manufacturing and delivery lead time should be distinguished from the complete installation period.
The project schedule is confirmed after the quantity, specification and site conditions have been reviewed.
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#Modular changes
Yes. Zipper-connected modules allow selected sections to be replaced, extended or rerouted without replacing the complete fabric duct system. Straight sections are typically modularized at approximately 7 m, with elbows and branches made as separate modules.
This supports changes to production lines, equipment locations or occupied work zones. Individual modules can also be removed for inspection and washing.
Any layout modification should include a review of airflow rate, static pressure and the required target-zone air velocity.
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#Washing
Fabric duct modules can be detached from the suspension system for washing, drying and reinstallation. Follow the cleaning instructions for the supplied fabric; a general reference is mild detergent and lukewarm water at 40°C or below.
Avoid strong alkaline cleaners, high-temperature washing and excessive machine drying. Remove shape retention rings and other fittings where required by the product instructions.
Washing frequency should reflect contamination and operating conditions. Inspect the duct first and use local cleaning where appropriate; unnecessary washing can place repeated stress on fabric and fittings.
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#Service life
A fabric duct system may provide a service life of 20 years or more under suitable operating and maintenance conditions. Actual service life depends on fabric properties, pressure cycles, contamination and cleaning practices.
FlowSox® uses durable fabric and a modular system that supports removal, washing, reinstallation and partial replacement. This allows individual sections to be maintained during long-term operation.
Expected service life and the product warranty period are separate. The applicable warranty scope and maintenance requirements are confirmed for the supplied product.
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#Repair and replacement
Usually, no. FlowSox® uses zipper-connected modules so that a contaminated or damaged section can be detached for washing, repair or partial replacement.
Straight sections, elbows and branches can be addressed individually. This avoids unnecessary replacement of the entire duct line when the problem is limited to one area.
The appropriate maintenance action depends on the type and extent of contamination, abrasion or damage.
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#Zippered End Cap
The zippered end cap can be opened to inspect the duct interior and remove accumulated dust or debris. Zipper-connected modules can also be detached for targeted inspection and cleaning.
Good supply-air filtration helps limit internal dust accumulation. Inspect the condition first, then select local cleaning, washing or partial replacement as appropriate.
The end cap also provides access for maintenance and, subject to design review, connection of an additional duct module.
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01 Your space and the problem
Building use, temperature, condensation or airflow issues
02 Drawings or site photographs
Dimensions, ceiling height and equipment locations
03 Equipment details and timing
Available airflow, static pressure and target dates