YONGFAN HVAC - Premium Header
Engineered HVAC & Industrial Air Systems
Product Finder Technical Support Download Center
YONGFAN HVACYOFAN HVAC Home
Request a Quote
Contact UsGlobal sales team contacts Request a Quote (RFQ)Submit BOQ or equipment list Request Product SelectionGet customized engineering sizing
Explosion-Proof Dampers | BFHF & BFD | YONGFAN
Ex d IIC T6 Gb · Certificate CE21.1729 · IP65 Flameproof Enclosure

Explosion-Proof Dampers: BFHF Fire & BFD Control Series

Explosion-proof dampers must match the classified atmosphere and the airflow-control function; the wrong Ex marking or damper type can invalidate an otherwise correct duct design.

Compare YONGFAN BFHF Explosion-Proof Fire Dampers (normally open, 70 °C thermal closure, DC 24V 0.7A actuator) and BFD Explosion-Proof Electric Control Dampers (remote and automatic airflow regulation, 220V 12W, ambient −20 °C to +40 °C). Both carry documented Ex d IIC T6 Gb marking and IP65 enclosure protection under certificate CE21.1729.

Ex MarkingEx d IIC T6 Gb
CertificateCE21.1729
Actuator IngressIP65 Enclosure
Gas GroupGroup II (IIC Hydrogen)
Select an Explosion-Proof Damper BFHF vs BFD Matrix
YONGFAN explosion-resistant ventilation damper
Classified Area Airside Control Ex d IIC T6 Gb · Certificate CE21.1729 · IP65 Flameproof Actuator
01 / Hazardous-Area Risks

Hazardous-Area Failures Start Before the Actuator Is Energized

A damper can fit the duct opening, move through its full stroke and still be completely wrong for the classified site atmosphere.

The first failure is specifying generic “explosion-proof” without defining the required gas group, temperature class or equipment protection level. YONGFAN’s current source documents Ex d IIC T6 Gb. That marking is specific and should not be shortened.

The second failure is choosing the correct Ex actuator but the wrong damper function: BFHF is an explosion-proof fire damper (normally open, closes thermally at 70 °C), whereas BFD is an electric control damper (used to regulate airflow through remote/automatic control). They are not interchangeable.

The third failure is treating the gas marking as proof for combustible dust. Ex d IIC T6 Gb is a Group II gas-atmosphere marking. Combustible-dust protection requires separate Group III certification under the IEC 60079 framework.

The fourth failure is ignoring ambient limits: BFD is documented for −20 °C to +40 °C.

Petrochemical refinery process ventilation ductwork

Selection Sequence: hazard classification → damper function → complete Ex marking → actuator/electrical data → duct size and control sequence.

Ex d IIC T6 Gb Marking

d: Flameproof enclosure (IEC 60079-1:2014); IIC: Hydrogen gas group; T6: 85 °C surface temp; Gb: Zone 1 protection level.

IEC 60079-0 / 60079-1 Context

BFHF 70 °C Fire Isolation

Normally open fire damper closing automatically on 70 °C fusible link melting with DC 24V solenoid trip and closed-signal feedback.

BFHF Fire Damper

BFD Electric Control

Motorized electric control damper for remote and automatic airflow regulation in classified gas areas (220V 12W, IP65).

BFD Control Damper
02 / Product Architecture

BFHF Fire Isolation vs. BFD Airflow Control

Technical specifications, actuators, electrical ratings, and application boundaries for BFHF and BFD series.
Product 01 · Normally Open Fire Isolation BFHF-W×H · 70 °C Fusible Release

BFHF Explosion-Proof Fire Damper

Constructed from cold-rolled steel or hot-dip galvanized sheet. Remains normally open during routine ventilation and closes automatically when duct-air temperature reaches 70 °C.

Actuator ModelDL-φ5 explosion-proof actuator with IP65 enclosure protection
Certification & ExCertificate CE21.1729 · Ex d IIC T6 Gb
Electrical DataDC 24V power supply · 0.7A rated current · 220V / 3A signal rating
Action & Reset70 °C thermal trip · Closed-position feedback signal · Manual reset
Configure BFHF Fire Damper
YONGFAN explosion-resistant damper product set
BFHF Fire Damper Series Normally Open · 70 °C Thermal Closure · Ex d IIC T6 Gb · DL-φ5 Actuator
Product 02 · Remote & Automatic Flow Control BFD-□ · 220V 12W · IP65

BFD Explosion-Proof Electric Control Damper

Serves routine airflow regulation in classified ventilation systems. Uses an explosion-proof electric actuator for remote and automatic blade positioning with open-position and close-position feedback.

Actuator ConfigurationsExternal DL-φ-1 or Internal DL-φ-4 actuator arrangement
Certification & ExCertificate CE21.1729 · Ex d IIC T6 Gb · IP65 protection
Electrical Data220V supply voltage · 12W rated power consumption
Ambient RangeOperating temperature −20 °C to +40 °C
Configure BFD Control Damper
YONGFAN explosion-resistant ventilation damper
BFD Control Damper Series Remote / Automatic Airflow Control · Ex d IIC T6 Gb · DL-φ-1 / DL-φ-4
03 / Specification Matrix

Explosion-Proof Damper Specifications

Side-by-side technical parameter matrix comparing BFHF and BFD configurations.
Parameter BFHF Explosion-Proof Fire Damper BFD Explosion-Proof Electric Control Damper
Product mark
BFHF
BFD-□
Main function
 Normally open fire isolation Remote / automatic airflow control
Thermal action
Closes at 70 °C
 No 70 °C thermal action stated
Actuator
 DL-φ5 External DL-φ-1 / Internal DL-φ-4
Actuator protection
IP65
IP65
Certificate
CE21.1729
CE21.1729
Ex marking
Ex d IIC T6 Gb
Ex d IIC T6 Gb
Electrical supply
 DC 24 V 220 V
Current / power
 0.7 A 12 W
Feedback
 Action / closed signal Open-position / close-position
Ambient range
 Not separately stated −20 °C to +40 °C
Materials
 Cold-rolled steel / hot-dip galvanized sheet Cold-rolled steel / hot-dip galvanized sheet
04 / Operating Scenarios

Choose BFHF or BFD from the Operating Scenario

Application guidelines across petrochemical processing, chemical/coating workshops, transport tunnels, and energy facilities.
Petrochemical

Petrochemical Process Ventilation

Use BFD for commanded airflow control inside classified ventilation networks; use BFHF where 70 °C fire-barrier isolation is required.

Gas Group IIC Verification
Chemical & Coating

Chemical and Coating Workshops

Solvent handling requires BFD for exhaust airflow balancing and BFHF for fire-boundary containment. Confirm chemical gas compatibility.

Process Exhaust Control
Tunnels & Transport

Tunnels & Enclosed Transport

BFD for remotely controlled ventilation; BFHF for 70 °C fire isolation. Do not confuse with 280 °C smoke-exhaust dampers.

Remote Actuation
Coal, Oil & Power

Coal, Petroleum and Power

IIC gas atmospheres use Ex d IIC T6 Gb; combustible-dust coal handling requires dust-specific Ex certification.

Gas vs Dust Distinction
05 / Procurement Protocol

What Information Is Needed for Ex Damper Selection?

Essential parameters to confirm before ordering BFHF or BFD explosion-proof dampers.
Ex Damper Sizing Checklist

Key Sizing Parameters

Submitting your hazardous zone, gas group, required damper function (BFHF fire vs BFD control), actuator voltage, and opening dimensions enables our team to confirm certified configurations.

1. Hazardous Classification (Zone 1/2, Gas Group IIA/IIB/IIC)
2. Temperature Class (T6 · max surface 85 °C)
3. Function: BFHF (70 °C Fire Damper) vs BFD (Control Damper)
4. Power Supply: DC 24V (BFHF) vs 220V AC (BFD)
5. Actuator Position: External DL-φ-1 vs Internal DL-φ-4
6. Ambient Temperature (−20 °C to +40 °C range)
7. Duct Opening Dimensions (W×H mm)
8. Certificate Verification: CE21.1729 Submittal Request
06 / Compliance & Standards

Certificate CE21.1729 and Ex Documentation

Configuration-level technical data, IP65 actuator rating, and Ex d IIC T6 Gb marking under certificate CE21.1729.
Ex Marking

Ex d IIC T6 Gb Marking

Flameproof enclosure protection for Group II gas atmospheres up to IIC (hydrogen) with T6 temperature classification.

Certificate

CE21.1729 Documentation

Documented explosion-protection certificate CE21.1729 for both BFHF and BFD actuator series.

Enclosure

IP65 Ingress Protection

Dust-tight and water-jet resistant actuator enclosure for harsh industrial plant and process environments.

Disclosure: Request the current CE21.1729 certificate, model coverage schedule, approved drawing and functional-test documentation for project submittals.
07 / Architectural Boundaries

Explosion-Proof Dampers Do Not Replace Every Hazardous Component

Connect hazard classification, damper function, complete Ex marking, actuator data, and duct interface in one approved configuration.

70 °C vs 280 °C Thermal Limits

Do not use BFHF where smoke-exhaust requires a damper that remains open to 280 °C; that is a separate PFHF high-temperature function.

70 °C Fire vs 280 °C Smoke

Gas Ex vs Combustible Dust

Do not treat documented gas Ex marking (Ex d IIC T6 Gb) as combustible-dust certification without a dust-specific Group III certificate.

Dust Specific Rating

Process Gas Compatibility

Do not assume cold-rolled or galvanized steel is suitable for aggressive corrosive process gas without a dedicated material review.

Material Review Required
ALERTS — NOT PART OF THE PAGE. RESOLVE BEFORE PUBLISHING.
The supplier text says BFHF/BFD can handle air containing explosive gas or dust, but the documented Ex d IIC T6 Gb marking is a gas-atmosphere marking. Do not claim combustible-dust certification without a dust-specific marking and certificate.
Certificate CE21.1729 is listed in the source, but the retrieved file does not show the issuing body, validity period or exact model coverage. Obtain the current certificate before publication.
The source does not state that YONGFAN manufactures BFHF/BFD in its own plant or identify a production location for this family.
Batch testing, application-lab capability and family-specific supply-continuity data are not documented.
08 / Technical Q&A

Explosion-Proof Dampers Frequently Asked Questions

Direct engineering answers covering BFHF vs BFD, certificate CE21.1729, Ex d IIC T6 Gb marking, and actuator power.

Which YONGFAN explosion-proof damper closes at 70 °C?

Use BFHF. It is normally open and closes automatically when the duct-air temperature reaches 70 °C.

Which product is used for normal airflow control in a classified area?

Use BFD when the project needs remote or automatic airflow regulation with an explosion-proof electric actuator.

What Ex marking is documented for BFHF and BFD?

The current supplier source lists Ex d IIC T6 Gb for both product families.

What certificate number is listed?

The source lists explosion-protection certificate CE21.1729 for both BFHF and BFD.

What actuator protection grade is documented?

Both product families are listed with IP65 actuator protection.

What power does BFHF require?

The BFHF actuator is documented at DC 24 V and 0.7 A rated current.

What power does BFD require?

The BFD source lists 220 V supply and 12 W rated power.

Is BFD suitable outside −20 °C to +40 °C?

That is the documented ambient range for BFD. A project outside it should request a separately confirmed configuration.

Can the same Ex marking be used as proof for combustible dust?

No. Ex d IIC T6 Gb is the documented gas-atmosphere marking. A combustible-dust installation needs the appropriate dust classification and certificate.

09 / Application Engineering Handoff

Select an Explosion-Proof Damper

Connect hazard classification, damper function, complete Ex marking, actuator data, and duct interface in one approved configuration. Send your hazardous-area schedules to our application engineers.

Ex d IIC T6 Gb Certificate CE21.1729 IP65 Flameproof Actuator BFHF Fire Damper (70 °C) BFD Electric Control Damper DL-φ-1 / DL-φ-4 Actuator DC 24V / 220V AC Power
Select an Ex Damper Go to Selection Center Ask an HVAC Engineer
YONGFAN application engineers reviewing explosion-proof damper submittals
Direct Technical Selection Support
Ex certificate submittals, actuator torque sizing, and dimensioned CAD drawings.
YONGFAN HVAC - Premium Footer