Section 1: Product Overview

The Axial Fire Smoke Exhaust Fan is the axial-impeller counterpart to the Centrifugal Fire Smoke Exhaust Fan, sharing the same fundamental purpose — sustaining mechanical smoke exhaust operation through the critical phases of a building fire event — while delivering a different performance profile that is better suited to the specific system requirements of building smoke exhaust designs where high air volume at moderate static pressure is the dominant requirement.

The axial operating principle — moving air parallel to the fan shaft axis — produces the high-volume airflow characteristic that makes axial fans the natural choice for smoke exhaust systems where the duct resistance is moderate and the exhaust requirement is measured in tens of thousands of cubic meters per hour. For systems where very high static pressure is required against long, complex duct networks, the centrifugal type is the appropriate choice. For the majority of building smoke exhaust designs — which involve moderate duct lengths and prioritize maximum air volume clearance from the fire zone — the axial fan configuration delivers superior volumetric performance at the required duty point.

The Axial Fire smoke exhaust fan is also distinguished by its compact inline profile. The cylindrical housing connects directly to round ductwork at both inlet and outlet flanges, requiring no transition pieces and occupying minimal space in mechanical shafts, ceiling voids, and plant rooms. This compact inline form factor is a significant practical advantage in building mechanical systems where space is constrained and installation efficiency is a priority for the HVAC contractor.

The reversible rotation capability available in selected configurations adds a further dimension of operational flexibility — the same physical unit can switch between exhaust mode and pressurization mode under control system command, enabling a single fan to serve both smoke exhaust and stairwell or corridor pressurization functions depending on the fire scenario detected by the building alarm system.

Dezhou Pengkai Air Conditioning Equipment Co., Ltd. is a comprehensive HVAC manufacturer based in Dezhou, Shandong Province, integrating research and development, production, sales, installation, and after-sales service. We supply axial fire smoke exhaust fan products to fire protection engineering contractors, HVAC system integrators, building developers, and mechanical and electrical consultants across Southeast Asia and global markets.

Section 2: Product Structure and Key Components

Cylindrical Casing and Flanged Duct Connections The fan casing is a cylindrical housing fabricated from high-quality steel plate — typically galvanized steel or painted cold-rolled steel — with structural rigidity appropriate to support the impeller and motor assembly loads under both normal operating conditions and the elevated temperature and differential pressure conditions of fire emergency operation. Inlet and outlet flanges at both ends of the casing allow direct connection to round smoke exhaust ductwork, eliminating the duct transition pieces required when connecting centrifugal fan housings to round duct systems. The flange dimensions conform to standard ductwork connection specifications, simplifying installation coordination with the duct contractor. An inspection access port or removable cover section is typically provided on the casing body for impeller visual inspection and cleaning access without full disassembly.

High-Efficiency Axial Impeller The impeller uses an aerofoil-section, space-twisted axial blade profile developed through aerodynamic optimization for the specific operating requirements of fire smoke exhaust — high volume delivery at moderate static pressure against smoke exhaust duct system resistance, sustained through a wide range of airflow conditions as the building smoke zone fills and empties during the fire event. Blades are fabricated from high-strength aluminum alloy or high-quality steel by precision casting or welding processes, with each completed impeller subject to strict dynamic balance correction to the required grade. The impeller hub incorporates a streamlined nose cone that guides inlet airflow smoothly onto the blade faces, reducing inlet turbulence and the associated efficiency and noise penalties at the inlet. The impeller is designed to maintain its aerodynamic and mechanical integrity throughout the 280°C / 30-minute rated operation period without blade deformation, hub loosening, or bearing seizure.

External Motor with Cooling Structure The motor is positioned externally to the main airflow passage — mounted on a bracket outside the cylindrical casing — and connected to the impeller through a long shaft that passes through the casing wall via a thermally insulated bearing support. This external motor arrangement is the fundamental engineering mechanism that enables the 280°C / 30-minute rated performance. While 280°C smoke passes through the impeller and casing, the motor on the external bracket operates in clean ambient air at normal temperature. The long shaft arrangement may incorporate a cooling wheel or fin structure at the casing wall penetration to intercept heat conducted along the shaft from the hot impeller zone toward the cooler motor, further protecting the motor from thermal damage during fire operation. Motor insulation class is F or H — both capable of sustained operation at elevated winding temperatures — providing an additional thermal margin above the ambient operating conditions.

Dual-Speed Motor Configuration The dual-speed motor is the standard and most widely applied configuration of the Axial Fire Smoke Exhaust Fan. The motor incorporates two independently wound stator circuits — a high-pole-count winding for low-speed daily ventilation operation, and a low-pole-count winding for high-speed emergency smoke exhaust. The two windings are completely independent circuits, allowing the motor to run at two distinct synchronous speeds determined by the pole count of the energized winding. In daily operation, the low-speed winding is energized, providing ventilation airflow at reduced noise and energy consumption. On fire alarm signal, the control system de-energizes the low-speed winding, waits for complete motor stop, then energizes the high-speed winding, bringing the motor to full-speed smoke exhaust operation within the specified response time.

Reversible Rotation Capability — Selected Models For applications requiring the fan to serve both smoke exhaust and pressurization functions, selected models of the Axial Fire Smoke Exhaust Fan are available with reversible rotation capability. By reversing the motor rotation direction under control system command, the fan switches from drawing air from the fire zone to pushing air into a protected zone, providing pressurization function from the same physical unit. The control system manages this reversal safely, including a complete motor stop period between rotation direction changes to prevent mechanical stress.

Intelligent Control Panel The control panel integrates motor start-stop control, dual-speed switching logic, fire alarm interface wiring, status signal output, and local manual override controls. On receipt of the DC24V fire alarm signal from the building fire alarm control panel, the control system executes the automatic high-speed switching sequence and outputs a running status confirmation signal. Local manual high-speed and low-speed test switches allow commissioning and maintenance testing without requiring fire alarm system activation.

Section 3: Technical Specifications

Performance Data — HTF-I Series:

Complete performance data for all machine numbers and motor configurations available upon request. Please contact our sales team with your smoke exhaust system airflow and pressure requirements for model selection guidance.

Section 4: The 280°C / 30-Minute Standard — Engineering Basis and External Motor Solution

The 280°C continuous operation for 30 minutes performance standard that defines axial fire smoke exhaust fan capability is a nationally mandated requirement that directly determines whether a smoke exhaust system will remain functional throughout the complete evacuation period of a building fire event. Understanding the engineering basis of this requirement and how the external motor design meets it is essential context for specifying and deploying fire smoke exhaust equipment correctly.

Why the 280°C Threshold The 280°C threshold is the temperature at which smoke exhaust Dampers are designed to close — the point at which fire is directly entering the exhaust duct system and continued mechanical exhaust would actively spread fire rather than protect evacuation routes. A smoke exhaust fan that fails at temperatures below 280°C would stop functioning before the duct system closes down, leaving the smoke exhaust pathway open without mechanical driving force and potentially allowing fire to propagate unchecked through the duct network.

Why 30 Minutes for Axial Type The 30-minute duration is specified for the axial type based on the typical evacuation timeline for buildings served by axial-type smoke exhaust systems — generally mid-rise buildings and horizontal duct zone configurations where evacuation can be completed in under 30 minutes from alarm. The centrifugal type carries a 60-minute rating for larger and more complex building types where extended evacuation times must be accommodated.

How External Motor Position Achieves This When 280°C smoke passes through the cylindrical casing of the 280 Degree Axial Smoke Exhaust Fan, the casing walls, impeller, and shaft absorb heat from the smoke stream. If the motor were positioned within the smoke stream as in a conventional inline axial fan, it would be directly exposed to this heat and would fail within minutes. The external motor mounted on a bracket outside the casing operates in clean ambient air. The shaft connecting the motor to the impeller conducts some heat from the hot impeller zone toward the motor, but the long shaft length, the thermally insulating bearing support at the casing wall penetration, and the cooling wheel structure all limit this conductive heat flow to levels that keep the motor in its rated temperature range throughout the 30-minute rated period. This engineering arrangement is reliable, proven, and does not require exotic high-temperature motor specifications — standard Class F or H motors operating in clean ambient air meet the 30-minute requirement when the external motor design is correctly implemented.

Section 5: Dual-Speed Operation — Daily Ventilation and Emergency Smoke Exhaust

The dual-speed operating feature of the Dual Speed Fire Exhaust Axial Fan is the practical justification for the product's widespread adoption as the standard specification for building smoke exhaust systems that also require daily ventilation function. Understanding the operational profile of each speed mode clarifies why this dual-function capability is valued by building designers and owners.

Low-Speed Daily Ventilation Mode In daily building operation, the fan runs at low speed continuously or on a scheduled cycle. At low speed, the fan provides the air change rate required for the served building space — corridor ventilation, underground car park carbon monoxide dilution, mechanical room air quality management — with energy consumption and noise levels significantly below those of full-speed operation. The low-speed motor winding is independently designed for efficient, reliable operation at this operating condition, not merely a reduced-voltage version of the high-speed winding.

Automatic High-Speed Smoke Exhaust Mode Switching On receipt of the DC24V fire alarm signal from the building fire alarm control panel, the Axial Fire Smoke Exhaust Fan control system executes the switching sequence: low-speed winding de-energized, motor allowed to coast to stop, high-speed winding energized. The fan accelerates to full high-speed operation, delivering maximum airflow and pressure to the smoke exhaust duct system. The automatic switching requires no operator action and completes within the required response time specified in the fire protection system design.

Manual Override for Commissioning and Testing The control panel provides local manual high-speed and low-speed test switches, allowing commissioning engineers to verify both speed modes and the automatic switching sequence without requiring activation of the building fire alarm system. This capability significantly simplifies smoke exhaust system commissioning and annual fire safety inspection testing.

Section 6: Manufacturing Process and Quality Control

Dezhou Pengkai Air Conditioning Equipment Co., Ltd. applies comprehensive quality management throughout Axial Fire Smoke Exhaust Fan production:

Material and Component Incoming Inspection Steel plate, aluminum alloy and steel for impeller fabrication, motor units, shaft assemblies, cooling wheel components, and control panel components are all inspected against specification on receipt. Motor units for dual-speed configurations receive additional function testing — both speed mode operation and switching sequence verification — before assembly. Insulation class documentation for all motor units is verified against the fire smoke exhaust equipment requirement before acceptance.

Impeller Fabrication and High-Temperature Integrity Verification Impeller blades are fabricated using casting or welding processes that produce the specified aerofoil-section twist profile with dimensional accuracy. For fire smoke exhaust applications, material selection for impeller blades accounts for the thermal expansion and reduced yield strength of metals at 280°C — the impeller geometry must remain dimensionally stable throughout the rated temperature exposure period to maintain aerodynamic performance and impeller-to-casing clearances.

Dynamic Balance Testing Each assembled impeller undergoes dynamic balance measurement and correction to the required grade. For fire smoke exhaust impellers operating at high speed, balance quality is particularly important because even small residual imbalance generates significant vibration forces that could accelerate bearing wear under the combined thermal and mechanical loading of fire emergency operation.

External Motor Mounting and Shaft Alignment The external motor is mounted on its bracket and the connecting shaft is installed with precision alignment between motor shaft and impeller shaft. Shaft alignment quality directly affects bearing loads and vibration during operation — misalignment accelerates bearing wear under the high-temperature, high-speed conditions of fire emergency operation.

Cooling Structure Installation and Thermal Verification The cooling wheel or fin structure at the shaft-casing interface is installed and verified for correct positioning relative to the shaft and casing wall. Cooling structure effectiveness is a critical parameter for the 280°C / 30-minute rating — inadequate cooling of the shaft-to-motor heat conduction path would result in motor failure before the rated period.

Control Panel Assembly and Fire Alarm Interface Testing Dual-speed control panels are assembled, wired, and tested through complete automatic fire alarm switching sequences before installation. DC24V signal input response, motor switching timing, and status signal output are all verified. Manual override function is tested independently.

Final Running Test Every completed 280 Degree Axial Smoke Exhaust Fan undergoes a full running test in all speed modes, verifying smooth operation, correct current draw at each speed, and automatic switching function before dispatch.

Section 7: Product Features and Advantages

280°C / 30-Minute Rated Fire Protection Performance External motor thermal isolation enables continuous operation in 280°C smoke conditions for a minimum of 30 minutes, meeting the national standard requirement for axial-type fire smoke exhaust equipment. This performance sustains the smoke exhaust function throughout the complete evacuation timeline for buildings served by axial-type smoke exhaust systems.

High-Volume Axial Airflow for Maximum Smoke Clearance The axial impeller configuration delivers higher volumetric airflow at moderate static pressure compared to centrifugal fans of equivalent physical size, maximizing the smoke clearance rate from fire zones during the critical evacuation period and maintaining clear sight lines and breathable conditions in evacuation routes.

Dual-Function Economy — One Fan for Two Roles Daily low-speed ventilation and emergency high-speed smoke exhaust from a single installed unit reduces equipment quantity, installation space, and capital cost compared to separate dedicated units for each function in the same duct zone.

Compact Inline Profile for Space-Constrained Installations The cylindrical inline housing connects directly to round ductwork at both ends without transition pieces, occupying minimum space in mechanical shafts, ceiling voids, and plant rooms — a significant installation advantage in the space-constrained mechanical systems of modern high-rise and commercial buildings.

Reversible Rotation for Dual-Mode Fire Response Selected models with reversible rotation capability can serve both smoke exhaust and pressurization functions from a single unit, providing operational flexibility for complex building fire response scenarios where the optimal response strategy changes based on fire location and building configuration.

Automatic Fire Alarm Linkage The integrated control panel interfaces directly with the building fire alarm system, executing the low-to-high-speed transition automatically without operator intervention and outputting running status confirmation to the fire alarm panel and fire control room.

Wide Machine Number Range Machine numbers from No.3.5 to No.16 covering impeller diameters 350mm to 1,600mm and airflow from 3,500 to over 120,000 m³/h accommodate smoke exhaust system design requirements across the full range of building scales within a consistent product platform.

Section 8: Application Scenarios

High-Rise Residential and Commercial Towers Corridor smoke exhaust systems, stairwell pressurization systems, and underground level smoke exhaust in high-rise residential and commercial towers are the primary application domain of the Axial Fire Smoke Exhaust Fan. Machine number selection matches each smoke zone's required exhaust airflow volume, with larger machine numbers serving larger smoke zone floor areas.

Underground Car Parks Multi-level underground parking structures require mechanical smoke exhaust systems at each parking level. The Dual Speed Fire Exhaust Axial Fan serves the dual function of daily carbon monoxide dilution ventilation at low speed and emergency smoke exhaust at high speed from the same installed unit in each parking level mechanical room.

Shopping Malls and Commercial Complexes Large retail floor smoke exhaust systems, underground shopping level exhaust, food court area smoke exhaust, and enclosed mall corridor smoke exhaust applications require high-volume fans matched to the large smoke zone areas of commercial complex buildings. Medium to large machine number configurations of the Axial Fire Smoke Exhaust Fan cover these high-volume requirements.

Hospitals and Healthcare Facilities Hospital ward building corridor smoke exhaust, stairwell pressurization, and basement level smoke exhaust systems require fire smoke exhaust fans with the highest reliability standards due to the limited mobility of many patients. The externally mounted motor configuration and proven dual-speed switching reliability of the 280 Degree Axial Smoke Exhaust Fan meet these stringent requirements.

Transportation Infrastructure — Tunnels and Stations Road tunnel ventilation and smoke exhaust systems, railway station platform smoke exhaust, and underground transit infrastructure smoke control require high-capacity fans covering the large volumes and moderate pressures typical of transportation infrastructure smoke exhaust designs. Large machine number configurations in the No.11 to No.16 range serve these high-capacity applications.

Industrial Facilities Factory building smoke exhaust systems, warehouse smoke control, and industrial plant fire protection ventilation require smoke exhaust fans appropriate to the fire load and smoke zone areas of industrial building types. The wide machine number range accommodates both medium industrial building requirements and large-footprint industrial facility smoke exhaust designs.

Hotels and Hospitality Buildings Guest floor corridor smoke exhaust, basement car park smoke exhaust, back-of-house area smoke exhaust, and service level mechanical systems in hotel buildings require reliable, dual-function smoke exhaust fans. The Dual Speed Fire Exhaust Axial Fan serves these applications with the acoustic performance of low-speed daily ventilation and full fire protection capability when needed.

Section 9: Customer Application Feedback

Our axial fire smoke exhaust fan products have been supplied to fire protection and building services projects across Southeast Asia and international markets:

"We specified Pengkai axial fire smoke exhaust fans for the corridor smoke exhaust systems of a 28-floor residential tower. The dual-speed units provided acceptable daily corridor ventilation at low speed and passed fire system commissioning testing at high-speed mode. The compact inline profile was particularly valuable on this project where mechanical shaft dimensions were constrained. The units have performed correctly through two years of operation and two annual fire inspection cycles." — Fire Protection Engineering Contractor, Southeast Asia

"For a large underground car park project requiring smoke exhaust fans that also serve daily CO dilution ventilation, the Pengkai Dual Speed Fire Exhaust Axial Fan dual-function capability was the deciding factor. The units deliver effective daily ventilation at low speed and the fire system commissioning authority accepted the high-speed performance test results without queries. The complete technical documentation package from Pengkai simplified the fire authority submission process considerably." — HVAC System Integrator, Regional Project

"We have used Pengkai 280 Degree Axial Smoke Exhaust Fan products across several hospital and commercial complex projects. The annual fire inspection performance has been consistently reliable, and Pengkai's after-sales team provides prompt assistance with inspection documentation, replacement component supply, and technical queries from our maintenance engineers." — Building Services Maintenance Company

Section 10: Installation Guidelines

Pre-Installation Checks Verify that the machine number, speed configuration, motor insulation class, impeller diameter, duct connection dimensions, and power supply specifications match the fire protection system design documents. Confirm fire protection product certification documentation is present. Inspect the casing, impeller, motor, shaft assembly, cooling structure, and control panel for transport damage. Rotate the impeller by hand to confirm it turns freely without contact with the casing.

Foundation and Mounting For floor-mounted installation, install the unit on a level, rigid concrete or steel base with anti-vibration isolators between the unit base and the foundation surface. For suspended installation, use anti-vibration hanger isolators rated for the unit weight and verify suspension structure load capacity. For wall-bracket or duct-suspended installation of smaller machine numbers, verify that the bracket and ductwork structure can support the unit weight under both normal and seismic loading conditions applicable to the installation location.

Soft Connections at Duct Interfaces Connect all ductwork to the unit inlet and outlet flanges using fire-rated flexible soft connectors. Fire-rated soft connectors are essential for smoke exhaust applications — standard fabric connectors may not maintain integrity at the 280°C temperatures encountered during fire operation. Ductwork must be independently supported and must not apply weight or bending stress to the unit flange connections.

Motor and Shaft Access Space The externally mounted motor and shaft assembly require clear access space on the motor side of the unit for motor maintenance, bearing inspection, and shaft alignment verification. Maintain a minimum of 500mm clear space from the motor face for maintenance access. Do not obstruct the motor cooling air circulation path.

Electrical Connection and Fire Alarm Interface Three-phase 380V/50Hz supply connection and fire alarm DC24V interface wiring must be performed by qualified electricians. Verify phase sequence and supply voltage before connection. Connect fire alarm interface wiring to the control panel per the project wiring diagram. Test automatic switching sequence — low speed to high speed on DC24V signal — before completing installation. Verify status signal output to the fire alarm panel.

Commissioning Tests Before system commissioning, run the unit in both low-speed and high-speed modes and verify correct current draw at each speed. Test the automatic fire alarm signal switching sequence and verify the response time is within the specified limit. Verify status signal output. Measure high-speed airflow at commissioning and confirm compliance with the smoke exhaust system design airflow requirement. Document all commissioning test results for the fire authority submission.

Section 11: Maintenance Schedule

Monthly Inspection Listen for changes in operating noise or vibration during low-speed daily operation that may indicate developing bearing wear or impeller imbalance. Check that the control panel status indicators show correct operating mode. Inspect flexible duct connectors for condition. Verify that the motor external bracket mounting fasteners remain tight.

Quarterly Function Test Test the automatic switching from low speed to high speed by simulating a fire alarm signal at the control panel. Measure high-speed current draw and verify within rated range. Confirm status signal output to fire alarm panel. Reset to normal low-speed mode after testing and record results.

Annual Certified Fire Inspection Engage a qualified fire protection inspection body for annual performance verification including high-speed airflow measurement, current draw verification, automatic switching function and response time test, shaft alignment check, bearing condition assessment, and issuance of annual inspection certificate for building fire safety compliance records.

Shaft and Bearing Maintenance Inspect shaft bearing condition annually. Apply the specified lubrication to bearings that require periodic greasing. For sealed bearing designs, verify that bearing temperature during operation is within normal range by checking for unusual warmth at bearing housing locations. Replace bearings showing any sign of wear noise before failure occurs.

Impeller Cleaning Clean impeller blades and casing interior of accumulated dust annually or more frequently in dusty environments. Dust accumulation on impeller blades causes dynamic imbalance that increases bearing loads and accelerates wear — particularly important to address in fire smoke exhaust equipment where bearing reliability during fire operation is safety-critical.

Section 12: Packaging, Shipping, and Lead Time

Packaging Each Axial Fire Smoke Exhaust Fan unit is packaged in robust wooden crate packaging appropriate to the unit size and weight, with foam padding and structural blocking to prevent movement and contact damage during sea freight transit. For larger machine numbers, the unit may be partially disassembled for transport crating and reassembled at the installation site. Control panels and accessories are packed separately within the crate. Export-grade packaging is standard for all international shipments.

Minimum Order Quantity We accept both single-unit orders for specific project requirements and multi-unit orders for full building supply contracts. Please contact our sales team to discuss the specific machine numbers, configurations, and quantities required for your project.

Lead Time Standard machine numbers in common dual-speed configurations are available from production scheduling with lead times confirmed at order placement. Single-speed and reversible rotation configurations, and machine numbers outside the standard stocked range, are produced to order.

Shipping We ship from Dezhou, Shandong Province. Sea freight is the primary mode for international orders due to unit size and weight. Air freight is available for smaller machine number urgent orders. We work with established freight forwarding partners serving Southeast Asia, the Middle East, and global destinations. FCL sea freight is recommended for multi-unit project orders.

Sample Policy For project-specific pre-order technical evaluation, representative units can be supplied for inspection. Sample arrangements including cost, lead time, and shipping are agreed with buyers prior to dispatch.

Payment Terms We support T/T bank transfer and other payment arrangements as mutually agreed. Please contact our sales team for terms appropriate to your project order value and procurement process.

Section 13: Certifications and Quality Assurance

The Axial Fire Smoke Exhaust Fan is manufactured in compliance with GB 51251, GB 50016, and the applicable national standards governing fire protection ventilation equipment. Production quality management covers incoming component inspection with insulation class verification of all motor units, impeller fabrication and high-temperature material verification, dynamic balance testing of all impeller assemblies, cooling structure installation and thermal path verification, dual-speed control panel function testing, and completed unit running tests in all configured speed modes before dispatch.

Fire protection product certification documentation is available to support project fire authority submissions, building permit applications, and third-party inspection requirements. Dezhou Pengkai Air Conditioning Equipment Co., Ltd. welcomes pre-shipment inspection arrangements by buyer-designated inspection agencies for project-specific orders.