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HVAC Fan Boxes | Packaged Cabinet Ventilation & Smoke Control | YONGFAN
Packaged Acoustic Cabinets · Multi-Duty Air Movement

HVAC Fan Boxes: Packaged Cabinet Ventilation & Smoke Control

A fan box is more than a bare fan. It integrates acoustic insulation, multi-angle duct connections, filter modules, and fire smoke capabilities into a rigid enclosed cabinet.

Compare YONGFAN DFX standard ventilation cabinets, DFX Purification multi-stage filtered units, DFS compact duct centrifugal fans, HTFC fire smoke-exhaust boxes (280 °C / 30 min), and BHTFC explosion-proof units across airflow (800 to 171,000 m³/h) and total pressure (140 to 1,460 Pa).

5 Cabinet FamiliesDFX · Purification · DFS · HTFC · BHTFC
Airflow Spectrum800 – 171,000 m³/h
Total Pressure140 – 1,460 Pa ΔPt
Safety Duty280 °C / 30 min Fire · GB 3836 Ex
Compare Fan Box Families Cabinet Sizing Checklist
Packaged HVAC fan box cabinet in mechanical equipment room
Packaged Cabinet Systems Acoustic Double-Skin Panels · Multi-Stage Filtration · Fire Smoke Emergency Duty
01 / Selection Methodology

Fan-Box Problems Appear When the Cabinet Is Treated as Only a Fan

Commissioning failures occur when fan boxes are selected from bare fan catalog curves without accounting for internal cabinet resistance, filter loading, or fire duty.

A fan box combines a centrifugal wheel, drive motor, double-skin acoustic insulated cabinet, vibration isolators, and multi-orientation inlet/outlet spigots.

In purification cabinets, primary (G4), medium (F8), and HEPA (H13/H14) filter modules add 100 to 350 Pa of internal working resistance. The base fan must be sized to overcome both internal module loss and external duct static resistance.

Similarly, a standard ventilation cabinet cannot be converted to fire smoke duty merely by changing the motor — HTFC fan boxes are purpose-built with certified high-temperature thermal barriers for 280 °C / 30 min operation.

HVAC fan box manufacturing and acoustic panel assembly

Acoustic Attenuation

Double-skin insulated panels significantly reduce casing breakout noise, allowing ceiling void and plant-room installation.

Double-Skin Casing · Low Breakout Noise

Integrated Filtration Loss

DFX Purification units incorporate G4+F8+HEPA stages; base fan selection must add 150–350 Pa filter working delta P.

Filter Module ΔP · Clean Air Delivery

HTFC Smoke & Ex Ratings

Dedicated HTFC cabinets certified for 280 °C / 30 min fire smoke exhaust, with BHTFC variants for hazardous gas zones.

280 °C / 30 min Fire · GB 3836 Ex
02 / Portfolio Architecture

Five Purpose-Built Fan Box Families for Every Project Demand

Detailed technical specifications and performance boundaries across DFX, DFX Purification, DFS, HTFC, and BHTFC series.
Family 01 · General HVAC Exchange 800 – 171,000 m³/h · 190 – 1,460 Pa

DFX Series Ventilation Fan Boxes

The core packaged cabinet fan family for general commercial building ventilation, office air supply, hotel extract, and industrial plant room exhaust.

Covers 800 to 171,000 m³/h airflow and 190 to 1,460 Pa total pressure. Available in compact direct-drive external-rotor configurations (DFX-I-10 to 18) for low maintenance, and high-capacity belt-drive configurations (up to DFX-I-40) for precise speed matching.

Direct Drive DFXExternal rotor motor · Zero belt maintenance · Compact size
Belt Drive DFXHigh volume up to 171,000 m³/h · Speed adjustment flexibility
Acoustic LiningInternal sound-absorbing insulation reduces breakout dB(A)
Multi-DischargeTop, bottom, straight-through or side discharge spigots
Explore DFX Ventilation Request DFX Sizing
DFX ventilation fan box cabinet
DFX Ventilation Series 800 – 171,000 m³/h · Direct & Belt Drive · Low Breakout Sound
Family 02 · Multi-Stage Filtered Air G4 + F8 + H13/H14 + Carbon · Air Treatment

DFX Series Purification Fan Boxes

Engineered for healthcare clinics, pharmaceutical workshops, electronics cleanrooms, food processing plants, and commercial kitchens requiring simultaneous air movement and high-efficiency purification.

Integrates primary panel filters (G1–G4), secondary pocket filters (F5–F8), terminal HEPA filters (H11–H14), activated carbon odor adsorption, and auxiliary PTC heating modules directly within the fan cabinet housing.

Coarse & PrimaryWashable nylon mesh (20 Pa) & G1–G4 panel filters (70 Pa working)
Medium & SecondaryF5–F8 synthetic pocket filters (170 Pa working ΔP)
HEPA & CarbonH11–H14 cleanroom filters (300 Pa working) & VOC carbon beds
Access DoorsQuick-release hinged service doors for clean filter replacement
Explore DFX Purification Filter Sizing Guide
DFX purification fan box with multi-stage filter modules
DFX Purification Series Multi-Stage Air Treatment · Primary + Secondary + HEPA + Carbon Modules
Family 03 · Compact Ceiling Duct Fan 1,300 – 46,965 m³/h · 140 – 940 Pa

DFS Series Duct Centrifugal Fans

When ceiling plenum height is too shallow for a standard rectangular fan box, the DFS Series provides a compact casing-less in-line duct fan solution.

Published performance spans 1,300 to 46,965 m³/h and 140 to 940 Pa total pressure. Mounts directly into straight rectangular or circular duct runs, saving substantial ceiling height while maintaining strong centrifugal static head.

Ultra-Low ProfileReduced height profile designed for tight suspended ceilings
In-Line Duct MountDirect rectangular duct flange connection on inlet and outlet
Forward CentrifugalDouble-inlet forward-curved impeller for quiet high volume
Easy MaintenanceBottom drop-out motor and wheel assembly for quick service
Explore DFS Duct Fans Ceiling Sizing Guide
DFS duct centrifugal fan in ceiling void
DFS Series Duct Centrifugal Ultra-Low Profile · In-Line Rectangular Duct Mounting · Up to 940 Pa
Family 04 · Dual-Duty Fire Smoke Exhaust 280 °C / 30 min · Single & Dual Speed

HTFC Series Fire Smoke-Exhaust Fan Boxes

Engineered for commercial basements, high-rise stairwell pressurization, and building smoke control systems requiring combined daily low-speed ventilation and emergency high-speed fire smoke exhaust.

Performance covers 1,400 to 171,000 m³/h and 190 to 1,460 Pa total pressure. Certified for continuous operation at 280 °C for 30 minutes. Available as HTFC-I (single-speed) and HTFC-II (dual-speed) configurations.

HTFC-I Single SpeedDedicated emergency fire smoke-exhaust duty
HTFC-II Dual SpeedDaily low-speed ventilation + high-speed 280 °C fire exhaust
Thermal BarrierHigh-temperature mineral wool insulation & cooling chamber
Fire CertificationMeets national high-rise building smoke management standards
Request HTFC Sizing Fire Submittal Data
HTFC fire smoke exhaust fan box testing
HTFC Fire Smoke Series 280 °C / 30 min Certified · HTFC-I Single & HTFC-II Dual Speed
Family 05 · Hazardous Cabinet Ventilation ExdIIBT4 / ExdIICT4 · Chemical Process

BHTFC & BDFX Explosion-Proof Fan Boxes

When cabinet packaging, filtration, or fire smoke duty is required within classified hazardous gas zones, YONGFAN manufactures certified explosion-proof cabinet configurations.

Features spark-free non-ferrous impellers, certified flameproof motors (GB 3836 ExdIIBT4 / ExdIICT4), antistatic acoustic panel insulation, and conductive earthing throughout the cabinet frame.

Ex Flameproof DriveCertified GB 3836 Ex motor with flameproof terminal enclosure
Spark-Free WheelAluminium alloy centrifugal wheel with copper rubbing clearances
Antistatic CasingConductive earthing straps prevent electrostatic charge ignition
Gas Group MatchesAvailable in IIB and IIC (hydrogen) certified configurations
Request BHTFC Sizing Ex Certification Data
BHTFC explosion-proof fan box cabinet
BHTFC Explosion-Proof Series ExdIIBT4 / ExdIICT4 Certified · Non-Sparking · Hazardous Cabinet
03 / Selection Matrix

HVAC Fan Box Family Routing & Comparison Table

Cross-reference all five fan-box families by primary mechanical function, published capability range, and key selection trigger.
Product Family What It Solves Range Boundary from YONGFAN Data First Input to Confirm Action
DFX Ventilation Fan Boxes
 General packaged building supply/exhaust with low breakout noise
800 – 171,000 m³/h · 190 – 1,460 Pa total pressure
 Confirm airflow, external duct resistance, and direct vs belt drive Configure DFX
DFX Purification Fan Boxes
 Ventilation combined with multi-stage coarse, medium, HEPA or carbon filtration
Integrated filter modules (G4, F8, H13, Carbon); +150–350 Pa working ΔP
 Define required filter train (G4/F8/HEPA/Carbon) and add module resistance Configure Purification
DFS Duct Centrifugal Fans
 Compact in-line volute fan for shallow suspended ceiling plenums
1,300 – 46,965 m³/h · 140 – 940 Pa total pressure
 Confirm ceiling void height clearance and rectangular duct dimensions Configure DFS
HTFC Fire Smoke Fan Boxes
 Dual-duty normal ventilation and certified 280 °C / 30 min fire smoke exhaust
1,400 – 171,000 m³/h · 190 – 1,460 Pa · HTFC-I / II
 Confirm single-speed (I) vs dual-speed (II) and verify 280 °C smoke rating Configure HTFC
BHTFC Explosion-Proof Boxes
 Cabinet ventilation and smoke handling in classified hazardous gas areas
ExdIIBT4 / ExdIICT4 production qualification · Non-sparking alloy
 Provide site hazardous area classification schedule (Zone 1/2, IIB/IIC, T4) Configure BHTFC
04 / Procurement Protocol

What Operating Data Is Required for Fan Box Selection?

Essential parameters to confirm before finalizing fan-box models, ensuring adequate motor power margins and correct filter pressure drop allowances.
Engineering Sizing Checklist

10 Key Inputs for Fan Box Sizing

Submitting these 10 parameters enables our engineering team to calculate total system resistance (external duct loss + internal filter working delta P) and verify cabinet dimensions.

1. Required Airflow (m³/h / CFM)
2. External Duct Static Pressure (Pa ΔPs)
3. Filter Train Modules (G4 / F8 / HEPA / Carbon)
4. Operating Mode: Ventilation vs 280 °C Smoke
5. Speed Control: Single-Speed vs Dual-Speed
6. Hazardous Area Ex Classification (GB 3836)
7. Drive Preference: Direct Drive vs Belt Drive
8. Inlet / Outlet Discharge Spigot Orientations
9. Available Ceiling Plenum / Plant Room Space
10. Noise Limit (Casing Breakout dB(A))
05 / Quality Control

YONGFAN Fan Box Manufacturing & Acoustic Integrity

Extruded aluminium pentapost frames, double-skin thermal-acoustic panels, and dynamic wheel balancing guarantee long-term reliability.
Frame Rigidity

Aluminium Pentapost Frame

Cabinets utilize high-strength extruded aluminium alloy corner profiles with thermal break gaskets to eliminate casing deflection under high static pressure.

Acoustic Double Skin

High-Density Mineral Wool

25 mm / 50 mm double-skin steel panels packed with 48 kg/m³ non-combustible mineral wool provide superior acoustic attenuation and thermal insulation.

Dynamic Balancing

ISO 1940 G2.5 Rotor Balance

Forward and backward curved centrifugal wheels are dynamically balanced to G2.5 standards, mounted on internal spring vibration isolators.

Traceability

100% Factory Run-Test

Every unit undergoes electrical current verification, casing airtightness leak testing, and smoke/Ex compliance inspection with certified QC reports.

Bespoke Engineering Packages: 3D BIM Revit families, octave-band acoustic submittals, electrical schematics, and dimensioned drawings supplied. Configured Dispatch: Lead time quoted based on direct/belt drive build, filter stages, and fire/Ex certification requirements.
06 / Technical Q&A

HVAC Fan Boxes Frequently Asked Questions

Direct engineering answers covering DFX vs DFS, filter resistance allowances, HTFC fire duty, and explosion-proof cabinets.

Which YONGFAN fan box should I use for normal building ventilation?

DFX Series Ventilation Fan Boxes are standard for general building supply and exhaust, offering direct-drive and belt-drive options across 800 to 171,000 m³/h.

Which family should I use if filters must be built into the cabinet?

Choose DFX Purification Fan Boxes, which integrate primary G4, medium F8, terminal HEPA, and activated carbon odor modules in one factory-sealed cabinet.

How is a DFX Purification fan properly sized?

Calculate external duct static resistance, then add 150 to 350 Pa for filter module working resistance. Sizing the fan without filter pressure loss causes severe airflow reduction.

Which product is best when ceiling space is severely restricted?

DFS Series Duct Centrifugal Fans feature an ultra-low profile height, mounting directly into straight rectangular ductwork inside tight ceiling plenums.

Which fan-box family is certified for fire smoke exhaust?

HTFC Series is purpose-built and certified for 280 °C / 30 min emergency fire smoke exhaust.

When should I choose HTFC-II instead of HTFC-I?

Choose HTFC-II for dual-speed operation: low speed for daily continuous building ventilation, and high speed for 280 °C emergency smoke exhaust.

Which fan boxes have explosion-proof versions?

YONGFAN manufactures BHTFC and BDFX explosion-proof cabinet units certified under GB 3836 (ExdIIBT4 / ExdIICT4) with non-sparking impellers.

Is a DFX Purification fan box the same as a chemical-filtration system?

DFX Purification handles particulate and moderate odor adsorption. Heavy corrosive industrial gas streams (e.g. H2S, SO2) require dedicated deep-bed chemical scrubbers.

07 / Application Engineering Handoff

Select the Right HVAC Fan Box for Your Project

Send your required airflow, external duct resistance, filtration stages, acoustic limits, and space dimensions — our application engineers will confirm total pressure requirements and provide complete technical submittals.

Airflow (800 – 171,000 m³/h) Pressure (140 – 1,460 Pa ΔPt) DFX Ventilation · Direct / Belt DFX Purification · G4/F8/HEPA DFS Low-Profile Ceiling Duct HTFC 280 °C / 30 min Smoke BHTFC ExdIIBT4 / IIC
Request Fan Box Sizing Go to Selection Center Ask an HVAC Engineer
YONGFAN application engineers reviewing fan box submittals
Direct Technical Selection Support
Filter pressure drop calculations, acoustic reports & 3D BIM models.
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