Airside design is not a fan-selection exercise. Airflow, pressure, distribution, control, sound and duty mode have to be solved as one system.
Coordinate YONGFAN axial fans (DTF, DTXF, T35-11), mixed-flow tube fans (SWF-I/II/III to 144,260 m³/h, 1,314 Pa), centrifugal fans (4-72), roof fans (DWT-I/II), DFS-I duct centrifugal boxes, JG/T 436-2014 dampers, pressure-independent YFVAV-S-T100 terminals, YF-MOA distribution plenums, and acoustic silencers/louvers.
Selecting fan static pressure without accounting for dirty filter loading and high-loss duct fittings starves distant room terminals.
High duct velocity through undersized control dampers or abrupt louver transitions generates noise in occupied spaces.
Operating VAV terminals without coordinated duct static pressure control causes excessive throttling, noise, and hunting.
Applying standard ventilation fans to fire smoke exhaust or Ex explosion-hazard areas without verifying certification.
Straight-through axial air movement for high airflow and moderate pressure duties. Includes DTF standard axial, DTXF low-noise series, and T35-11 / BT35-11 bifurcated designs where the motor is completely isolated from the conveyed airstream.
Bridges axial form factor with centrifugal pressure capability (1,430–144,260 m³/h, 125–1,314 Pa total pressure, Ø300–1500 mm, 0.25–37 kW, 960–2,900 r/min). SWF-I for single-speed, SWF-II for dual-speed, and SWF-III for high pressure. Also includes CDZ and HL3-2A families.
Accelerates air radially through an impeller and scroll casing to overcome high duct resistance from filters, coils, and industrial process equipment. Full duty curves documented; airflow, pressure, motor current, and vibration checked before dispatch; direct or belt drive.
Solves roof-level air extraction and discharge (1,560–50,000 m³/h, 11–407 Pa, 0.06–5.5 kW, 720–1,450 r/min). DWT-I is the centrifugal route for higher pressure; DWT-II is the axial route for higher flow. Equipped with weather cap and IP54 minimum motor protection.
Adds casing, acoustic insulation, and filtration to fan duty. DFX covers standard ventilation and purification (G4/F8/carbon); DFS-I integrates a volute-less centrifugal fan in a compact galvanized duct casing (1,300–46,965 m³/h, 140–940 Pa, 50–74 dB(A)). Also includes HTFC fire smoke and BHTFC Ex boxes.
Regulates branch airflow and fresh/return air mixing per JG/T 436-2014. Available in manual, electric (DC24V / AC220V), and pneumatic drive modes. Classifications include standard, low-leakage, high-airtight, zero-leakage, and insulated cold-chain designs with EPDM blade seals.
Controls zone air supply independently of duct pressure fluctuations using an integrated airflow sensor and actuator. Nine inlet sizes (Ø125 to Ø400 mm), 122 to 6,232 m³/h airflow range, optional 1-row/2-row hot-water reheat coils, lined acoustic attenuator, and pairing with YF-MOA plenums.
YF-MOA distribution plenums convert single VAV outlets into multiple round diffuser branches (Types A–F, customizable outlet count/size, internally lined). Acoustic louvers (300 mm depth) and duct silencers reduce transmitted noise with verified pressure losses (276 Pa @ 4 m/s to 1,487 Pa @ 10 m/s).
| System Duty | First Product Family to Evaluate | Why | Key Boundary |
|---|---|---|---|
| Straight in-line ventilation | Axial Fans (DTF/DTXF) | High airflow in compact tubular form | Moderate pressure duty envelope |
| In-line ventilation with more pressure | Mixed-Flow Fans (SWF) | Combines tubular form with higher pressure (to 1,314 Pa) | Select from actual fan system curve |
| High-resistance duct network | Centrifugal Fans (4-72) | Better suited to higher static pressure | Space, scroll orientation & drive type |
| Roof-level air exhaust | Roof Fans (DWT-I/II) | Integrated weather cap & roof curb discharge | Shaft and duct resistance still count |
| Contained low-noise duct fan | Fan Boxes / DFS-I | Casing, acoustic insulation, optional filters | Cabinet internal losses included in selection |
| Branch airflow regulation | Air Volume Control Dampers | Adjusts or isolates air path per JG/T 436 | Adds pressure loss to branch calculation |
| Low-leakage / insulated duct control | Airtight & Insulated Dampers | Leakage and condensation control with EPDM seals | Specify leakage grade and insulation thickness |
| Zone-level variable airflow | VAV Terminals (YFVAV-S-T100) | Controls individual zone airflow independently of ΔP | Requires upstream fan pressure & control |
| One terminal to several diffusers | YF-MOA Distribution Plenum | Divides one terminal airflow into round branches | Does not add airflow or pressure |
| Intake/exhaust noise reduction | Silencers / Acoustic Louvers | Reduces transmitted sound from fan/air movement | Adds resistance (e.g. 276–1,487 Pa) |
Calculate room supply/exhaust airflow, temperature, and normal vs fire/Ex duty mode.
Sum duct friction, transitions, dampers, coils, filters, VAV boxes, and silencers for critical index path.
Select fan family (SWF, DTF, 4-72, DWT, DFS), damper leakage grades, and VAV terminal sizes.
Define VFD fan control setpoints, VAV min/max airflow, and verify occupied room sound criteria.
YONGFAN airside application engineers will verify system curves, calculate acoustic insertion losses, match VAV terminals with YF-MOA plenums, and provide fan selection curves.
SWF, DTF, and 4-72 fans undergo pre-dispatch verification of airflow, static pressure, motor current, and vibration.
Rotating impellers are dynamically balanced to ISO 1940 / AMCA 204 grades to eliminate vibration and bearing wear.
YFVAV-S-T100 terminals are tested for sensor accuracy, damper casing leakage, and 1.5× hydrostatic coil testing.
Airtight and volume control dampers undergo torque and seat leakage testing per JG/T 436-2014 standards.
Start from airflow and required static pressure. Axial suits high-flow/moderate-pressure; mixed-flow adds pressure while retaining tubular form; centrifugal fans are appropriate for high-resistance duct networks.
Use SWF mixed-flow fans when in-line installation is required but duct pressure exceeds the comfortable range of axial fans. The documented SWF range reaches 1,314 Pa total pressure.
DWT-I uses a centrifugal impeller for higher-pressure roof exhaust; DWT-II uses an axial impeller for high-volume/lower-pressure exhaust (1,560–50,000 m³/h combined).
DFS-I uses a volute-less centrifugal fan inside a compact galvanized duct casing (1,300–46,965 m³/h at 140–940 Pa), eliminating large scroll bulges in tight ceiling voids.
A damper creates resistance. Balancing and VAV dampers intentionally adjust resistance to regulate flow; that pressure drop must be included in fan sizing.
No. The VAV terminal regulates airflow within its operating range, but the central duct must supply sufficient minimum static pressure to satisfy the critical terminal.
Yes. YONGFAN’s YF-MOA plenum is purpose-designed for this, converting one VAV outlet into multiple customizable round branches (Types A–F).
No. Silencers and acoustic louvers add significant pressure drop (e.g. 276–1,487 Pa) and must be included in the original system resistance calculation before finalizing fan duty.
No. Explosion-proof fans (BT35, BHTFC, BDFS) must be certified to the specific hazard zone, gas group, and temperature class.
This page identifies fire duty as an airside boundary; detailed 280 °C / 30 min fire sequences belong under Fire & Smoke Exhaust Systems.
Category airflow/pressure ranges are routing data only; final fan model selection must use the full per-model performance curve.
Pressure-independent VAV operation is valid only within the terminal’s documented minimum and maximum differential pressure envelope.
300 mm acoustic louver pressure loss rises sharply with face velocity (276 Pa @ 4 m/s to 1,487 Pa @ 10 m/s); include in fan ESP.
Fire-smoke (280 °C / 30 min) and Ex explosion-proof configurations require certified builds and do not inherit standard ventilation specs.
Send your duct layout, zone airflows, static pressure calculations, and control strategy. YONGFAN application engineers will verify fan curves, match VAV terminals, size plenums, and supply submittal datasheets.
