Coated textile wall
High-tenacity polyester with PVC coating provides a flexible, cleanable and weldable air barrier. Coating formulation and weight are selected by duty.
Negative-pressure extraction · project-configured
Flexible Exhaust Duct
A finished, wire-reinforced duct assembly for routing exhaust air, fumes, dust and process heat around machinery, confined spaces and changing industrial layouts.
DERFLEX coordinates coated textile selection, helix reinforcement, welded duct forming, cuffs and suspension details around the actual airflow plan—not a one-size-fits-all hose description.
Product definition
Built to Stay Open While the Fan Pulls Air Out
A flexible exhaust duct is a compressible air passage used on the suction or extraction side of a ventilation system. Its continuous wire helix supports the wall against collapse while the coated textile body allows the route to bend around equipment, pass through restricted access points and pack down for transport.
The product may also be described as a flexible exhaust hose, negative-pressure duct, fume extraction duct or industrial air suction duct. The important distinction is not the wording—it is whether the wall, helix pitch, wire gauge, seam, cuffs and suspension system are matched to the actual vacuum and handling conditions.
Procurement distinction: a layflat positive-pressure duct inflates when air is pushed into it. A spiral wire-reinforced exhaust duct remains mechanically supported when air is pulled through it. Specifying the wrong construction can reduce airflow or cause the duct to flatten.
Application-led selection
Select the Duct Around the Exhaust Duty
Temperature alone does not determine the right product. Air chemistry, vacuum, particles, movement, bend radius and installation method should be reviewed together.
Do not use a general PVC grade for very hot, explosive or highly corrosive exhaust without a written compatibility and safety review.
| Exhaust duty | Suggested construction direction | Details to confirm | Common buyer |
|---|---|---|---|
| Portable fan exhaust | Flexible PVC-coated body, moderate helix pitch, quick-connect cuff or buckle. | Fan inlet diameter, suction level, section length, relocation frequency and storage space. | Rental fleets, contractors, confined-space teams |
| Welding fume extraction | Flame-retardant grade by specified test method, abrasion protection and grounded/antistatic option where required. | Spark exposure, fume temperature, distance from source, local extraction velocity and safety documentation. | Fabrication shops, integrators, ventilation contractors |
| Dust collection connection | Wear-resistant wall or external wear strip with tighter helix support for repeated handling. | Particle type, loading, abrasion points, static risk, vacuum and whether material contacts the wall. | Woodworking, grinding, cement and process plants |
| Machinery heat removal | PVC-coated textile within the confirmed service range; higher-temperature technical textile when continuous or peak temperature exceeds that range. | Continuous and peak temperature, radiant heat, airflow volume, condensate and distance from hot surface. | Machine builders, OEMs, plant engineering teams |
| Chemical or solvent vapors | Material selected only after media compatibility review; no universal chemical-resistance assumption. | Full chemical name, concentration, temperature, humidity, exposure time and required documentation. | Chemical plants, coating lines, laboratories |
| Mine, tunnel or civil works | Heavy-duty coated textile, reinforced suspension, durable cuffs and wire/wear-strip configuration for the route. | Diameter, pressure, section plan, drag contact, low-temperature duty, flame/antistatic requirements and inspection regime. | Mining contractors, tunneling projects, underground works |
Material structure
01
02
03
04
Four Components Control Field Performance
Duct performance is created by the interaction of the wall, reinforcement, seam and connection—not by fabric weight alone.
Continuous helix support
Spring-steel wire supports the cross-section under suction. Gauge and pitch influence collapse resistance, flexibility, bend behavior and weight.
Welded seam and reinforcement
High-frequency welding and localized reinforcement are used to control air leakage and protect repeated load points.
Cuffs, suspension and wear details
Connection ends, hanging points and external wear strips are configured around installation speed, route movement and abrasion exposure.
Reference specification
Custom Flexible Exhaust Duct Parameters
The table is a quotation framework, not a universal rating sheet. Final construction is confirmed against project conditions.
- Product form
- Finished flexible exhaust duct with formed body, spiral reinforcement, specified ends and optional suspension/wear details.
- Airflow mode
- Negative-pressure extraction as the primary configuration; positive-pressure or reversible operation can be reviewed separately.
- Body material
- PVC-coated high-tenacity polyester for general industrial duty; alternative technical textiles reviewed for temperature or media requirements.
- Nominal diameter
- Project-selected. Common portable and industrial sizes are available; large diameters require pressure, wire and handling review.
- Section length
- 5 m, 10 m or custom. Shorter sections may improve handling and bending in frequently relocated systems.
- Temperature
- Reference PVC configuration: approximately -20°C to +80°C, subject to formulation, test method and operating conditions. Higher-temperature duty requires material review.
- Helix reinforcement
- Continuous spring-steel wire; diameter and pitch selected according to duct diameter, vacuum, bend radius and portability.
- Connection options
- Soft cuff, buckle, zipper, hook-and-loop, ring, clamp or project-specific transition details.
- Safety treatments
- Flame-retardant, antistatic, low-temperature, oil-resistant or abrasion-focused grades may be supplied when specified and supported by the agreed test documentation.
- Color
- Yellow, black, blue, green or custom colors subject to material grade and order conditions.
- Processing
- Cutting, forming, high-frequency welding, wire assembly, cuff installation, suspension reinforcement, inspection and packing.
- Documentation
- Product data, inspection records and available test reports are confirmed according to the selected grade and order agreement.
Pressure and vacuum capability cannot be stated responsibly from diameter alone. Wire gauge, helix pitch, section length, temperature, bends and installation support all affect performance. Request a project-specific confirmation before ordering.
Industrial applications
Where Flexible Exhaust Ducting Adds Practical Value
The product is most useful where rigid metal ducting is slow to route, difficult to move or impractical around temporary and changing work zones.
Confined-Space Ventilation
Connect portable blowers to tanks, pits, manholes, vessels and enclosed maintenance zones where the duct must pass through restricted access points.
Portable routingWelding & Cutting Fumes
Carry extracted smoke away from fabrication workstations, with material and safety treatments selected around temperature and spark exposure.
Source extractionDust Collector Connections
Bridge machinery and collectors where vibration, maintenance access or equipment movement makes rigid transitions inconvenient.
Flexible connectionMachine Heat Exhaust
Remove warm air from production equipment, printing lines, generators and process enclosures after confirming continuous and peak temperature.
Thermal reviewVehicle & Engine Extraction
Route exhaust from service bays or test areas when gas temperature, condensate and chemical exposure have been assessed for the selected textile.
Media check requiredTemporary Industrial Ventilation
Support shutdowns, maintenance, emergency airflow and construction phases with compressible sections that can be deployed and stored repeatedly.
Reusable sections
Custom engineering workflow
1
2
3
4
5
From Fan Data to a Finished Duct Section
DERFLEX combines coated-fabric manufacturing with finished duct conversion so the material, reinforcement and connection details can be reviewed as one assembly.
Define the air route
Confirm source, fan position, duct length, bends, suspension points and how often the route will move.
Identify the exhaust medium
State air composition, dust loading, chemical exposure, moisture, continuous temperature and peak temperature.
Match wall and helix
Select coated textile, wire gauge, pitch and wear protection according to vac, uum, diameter and bend requirements.
Specify interfaces
Define fan connection, section-to-section cuff, clamp, buckle, zipper, ring or transition fitting geometry.
Confirm inspection and packing
Agree on dimensions, seam checks, available test documents, labeling, compressed packing and shipment format.
Quality checkpoints
Inspection Focused on the Finished Assembly
A fabric test alone does not confirm how a completed exhaust duct will fit, seal or handle. The finished section should be checked across the details that affect installation.
DERFLEX manufacturing profile
3Calender systemsSupport PVC material production and formulation choices for different coated-fabric programs.
3Coating machinesProvide manufacturing capacity for coated textile structures used across industrial applications.
5Lamination machinesExpand the available composite structures and finishing routes for flexible materials.
OEMProject customizationDiameter, length, wire pitch, cuffs, color, packing and selected treatments can be discussed by order.
Coated Textile Capability Connected to Finished-Product Conversion
This operating model supports material selection, roll production and finished flexible duct processing within a coordinated supply discussion.
Frequently asked questions
Flexible Exhaust Duct FAQ
What is the difference between flexible exhaust duct and layflat ventilation duct?
A flexible exhaust duct uses continuous helix reinforcement to hold the passage open under suction or negative pressure. A layflat duct normally depends on positive internal pressure to inflate. The two products may look similar when packed but serve different airflow conditions.
Can DERFLEX make a custom diameter and length?
Yes. Diameter, section length, wire pitch, cuff style, suspension details, color and packing can be discussed by project. Final availability depends on the pressure, material grade, handling requirements and order conditions.
Can PVC flexible exhaust duct carry hot air?
A reference PVC-coated configuration may be suitable around -20°C to +80°C, but the exact limit depends on formulation, test method, airflow, radiant heat and mechanical load. Continuous or peak temperatures above the confirmed PVC range require an alternative technical textile review.
Is the duct chemical resistant?
Chemical compatibility depends on the exact substance, concentration, temperature and exposure time. Provide the media data before selection. DERFLEX does not treat “chemical resistant” as a universal claim across all acids, alkalis, oils or solvents.
What connection methods are available?
Common choices include soft cuffs, belt or buckle ends, zippers, hook-and-loop cuffs, rings and clamps. The fan inlet, mating duct and installation sequence should be supplied so the connection can be matched correctly.
Can flame-retardant or antistatic grades be supplied?
Optional flame-retardant and antistatic constructions can be discussed. The required standard, test method, limit value and document format should be stated in the inquiry because terminology differs between industries and countries.
Send the Airflow Conditions, Not Just the Hose Size
Share the exhaust medium, temperature, fan data, diameter, length, route and connection drawings. DERFLEX can use that information to prepare a more relevant material and finished-duct proposal.