HTF-Ⅱ Series / Two-Speed Smoke Control
HTF-Ⅱ Double-Speed Fire Smoke Exhaust Axial Fan
Double-speed axial fan combining normal ventilation and emergency fire-smoke exhaust in one system. Low-speed operation serves daily ventilation, while high-speed operation provides increased airflow and pressure for emergency smoke extraction.
No. 5–10 3,410–45,679 m³/h 127–770 Pa
AIRFLOW
3,410–45,679 m³/h
FULL PRESSURE
127–770 Pa
OPERATION
Two-Speed
FAN SIZE
No. 5–10
HTF-Ⅱ Series
Technical Index
01 Overview 02 Two-Speed Duty 03 Construction 04 Performance 05 Installation 06 Applications 07 Selection 08 HTF-Ⅰ vs Ⅱ 09 Resources 10 FAQ
Quick Facts
Double-Speed Axial Fan
No. 5–10
Daily Ventilation
Emergency Smoke Exhaust
Two Operating Duties
No. 5–10
Daily Ventilation
Emergency Smoke Exhaust
Two Operating Duties
01 / Engineering Overview
One Fan for Normal Ventilation and Emergency Smoke Exhaust
HTF-Ⅱ is the double-speed version of the HTF fire-smoke exhaust axial fan family. The two operating speeds allow one ventilation system to serve different airflow and pressure requirements under normal and emergency conditions.
Low-speed operation is generally used for routine ventilation. When the fire-smoke exhaust system is activated, the fan switches to the higher-speed operating condition according to the project control logic.
02 / Two-Speed Operating Logic
Separate Daily and Emergency Operating Points
LOW SPEED
Normal Ventilation
Reduced airflow and pressure for daily building or parking-area ventilation.
HIGH SPEED
Smoke Exhaust
Higher airflow and pressure when the emergency smoke-control system is activated.
Both duty points must be provided.
Do not select HTF-Ⅱ using the emergency airflow alone. The normal ventilation operating point and emergency smoke-exhaust operating point should both be checked against the selected fan and control scheme.
03 / Construction
Axial Fan with Two-Speed Motor Configuration
01
Axial Impeller
Axial-flow impeller selected to satisfy the required two operating conditions.
02
Two-Speed Motor
Motor pole and power combination should be confirmed against the selected production specification.
03
Cylindrical Casing
Inline casing allows installation within smoke-control and ventilation duct systems.
04
Control Interface
High/low speed switching should be coordinated with the project fire alarm and ventilation control system.
04 / Reference Performance
HTF-Ⅱ Double-Speed Selection Range
Published HTF-Ⅱ series data is shown below as a reference selection envelope. Final motor output and detailed operating points should be confirmed against the selected production specification.
SIZE
Ø mm
AIRFLOW m³/h
PRESSURE Pa
SPEED rpm
NOISE
No.5
500
3,410–9,824
188–752
1450 / 2900
≤75
No.6
600
6,599–16,090
127–760
1450 / 2900
≤75
No.7
700
12,518–24,380
267–728
960 / 1450
≤80
No.8
800
17,222–31,421
263–723
960 / 1450
≤80
No.9
900
18,216–33,510
246–765
960 / 1450
≤81
No.10
1000
24,019–45,679
276–770
960 / 1450
≤81
HTF-Ⅱ motor power and pole combinations vary between published production versions. Confirm the final high-speed / low-speed motor specification together with both required duty points before quotation.
05 / Installation & GA Review
Confirm the Installation Drawing Before Fabrication
Fan Diameter
Confirm selected No.5–10 casing and flange dimensions.
Overall Length
Allow space for the double-speed motor and maintenance access.
Mounting Base
Support spacing and mounting-hole positions should follow the approved GA drawing.
Electrical Access
Provide suitable access for high/low speed motor wiring and control connections.
Final dimensional data will follow the confirmed HTF-Ⅱ production configuration. Do not fabricate duct flanges or supports from generic catalog dimensions alone.
06 / Application Fit
Projects Requiring Both Ventilation and Smoke Exhaust
Underground Garages
Daily vehicle-exhaust ventilation combined with emergency smoke extraction.
Commercial Buildings
Mechanical ventilation systems that also form part of the smoke-control strategy.
Industrial Buildings
Normal air exchange with a separate high-speed emergency operating condition.
Underground Facilities
Dual-duty ventilation and smoke-control systems where equipment count should be reduced.
07 / Before Selection
Send Two Operating Conditions, Not One
01
Normal Airflow
Required low-speed ventilation airflow.
02
Normal Pressure
System resistance under routine ventilation duty.
03
Emergency Airflow
Required high-speed fire-smoke exhaust airflow.
04
Emergency Pressure
Required pressure at the smoke-exhaust duty point.
05
Temperature Duty
Required smoke temperature and operating duration.
06
Control Logic
High/low speed switching and fire-control interface requirements.
07
Electrical
Voltage, frequency, phase and destination-market requirements.
08 / Product Path
HTF-Ⅰ or HTF-Ⅱ?
HTF-Ⅰ
Single Speed
Primarily for a defined fire-smoke exhaust operating condition.
HTF-Ⅱ
Double Speed
Combines routine ventilation and emergency smoke exhaust in one fan.
09 / Technical References
Related Engineering Guides
AIRFLOW & PRESSURE
Industrial Fan Airflow and Pressure Explained → TEMPERATURE
Gas Temperature and Industrial Fan Performance → FAN SELECTION
Industrial Fan Selection Center → 10 / FAQ
HTF-Ⅱ Double-Speed Fan Questions
What is the main difference between HTF-Ⅰ and HTF-Ⅱ?
HTF-Ⅰ is a single-speed fan, while HTF-Ⅱ uses a two-speed motor so the same fan can serve normal ventilation and emergency smoke exhaust.
What sizes are commonly available?
The commonly published HTF-Ⅱ series covers No.5 through No.10.
What is the reference airflow range?
Published reference data covers approximately 3,410 to 45,679 m³/h across both operating speeds.
Do I need to provide two duty points?
Yes. Provide the required airflow and pressure for both normal low-speed ventilation and emergency high-speed smoke exhaust.
Why is the motor power not fixed only by fan size?
Different HTF-Ⅱ production configurations use different motor pole and power combinations. The final motor should be matched to both operating points.
What project information is needed for quotation?
Send normal airflow and pressure, emergency airflow and pressure, smoke temperature and duration, installation arrangement, voltage, frequency, control requirements and quantity.
HTF-Ⅱ Double-Speed Fan Selection
Send Both Normal and Emergency Duty Points.
Low-Speed Airflow & Pressure · High-Speed Airflow & Pressure · Smoke Temperature · Installation · Voltage · Frequency · Quantity
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