Backward Curved Centrifugal Fans
High Efficiency Performance for Clean Air Applications
Backward curved centrifugal fans are widely regarded as the industry standard for energy-efficient air movement in clean to mildly contaminated air applications.
Featuring aerodynamically optimised blades that curve away from the direction of rotation, backward curved fans deliver high static efficiency, low noise levels, and a stable non-overloading power curve.
Industrial Fan Systems (IFS) backward curved centrifugal fans are engineered, manufactured, and tested for demanding Australian and New Zealand conditions. ISO 5801 performance tested and ISO 13347 acoustically tested, these fans are ideally suited to HVAC systems, cleanrooms, data centres, process ventilation, and industrial air handling where energy efficiency and acoustic performance are critical.
Backward Curved Centrifugal Fans – High Efficiency Performance for Clean Air Applications
What Is a Backward Curved Centrifugal Fan?
A backward curved centrifugal fan uses blades that curve away from the direction of rotation. This blade geometry reduces aerodynamic losses, resulting in high static efficiency and lower power consumption compared to forward-curved or radial fan designs.
Backward curved fans operate on a non-overloading power curve, meaning absorbed power peaks near the design point and decreases beyond it. This inherent characteristic protects motors from overload and ensures stable operation across a wide range of system conditions.
Why Choose a Backward Curved Fan?
Advantages
High Static Efficiency: Among the most efficient centrifugal fan types for clean air.
Non-Overloading Power Curve: Protects motors and drive systems.
Low Noise Levels: Reduced turbulence and smooth airflow.
Lower Lifecycle Energy Cost: Reduced operating costs over the fan’s service life.
Stable Performance: Reliable operation across varying airflow conditions.
Backward curved centrifugal fans are selected when energy efficiency, reliability, and low noise operation are the primary design drivers.
Key Features & Benefits
Backward Curved Impeller Design: Aerodynamically engineered blades curve away from the direction of rotation, optimising airflow while minimising turbulence and energy loss. This design delivers excellent efficiency and predictable performance.
Energy-Efficient Operation: Backward curved fans maintain high efficiency across a broad operating range and inherently prevent motor overload, making them ideal for variable-duty industrial systems.
Low Noise Characteristics: The smooth airflow generated by backward curved blades significantly reduces sound power levels compared to radial or forward-curved fans, making them suitable for noise-sensitive environments.
Robust Industrial Construction: IFS backward curved fans are manufactured from carbon steel, stainless steel, or specialised alloys and can be supplied with protective coatings for corrosive or high-temperature environments.
Flexible Drive & Mounting Options: Available in direct drive or belt drive configurations with horizontal or vertical mounting to suit a wide range of installation requirements.
Performance Range &
Technical Specifications
Airflow
Up to 115 m3/s (SWSI) and
205 m3/s (DWDI)
Impeller Diameter
310mm to 3050mm
Pressure
Up to 16,000 Pa (SWSI) and
7,500 Pa (DWDI)
Model Range
IFSBC-050 to IFSBC-320
Maximum Speed
Up to 3661 RPM
Configurations
SWSI (Single Width Single Inlet), DWDI (Double Width Double Inlet)
Impeller Type Comparison Table
SWSI & DWDI Configurations
The Airfoil Fan is available in two configurations to suit different airflow and pressure needs.
SWSI (Single Width Single Inlet)
Best suited for moderate to high
pressure applications where
flexibility in fan arrangement
and compact installation are
required.
DWDI (Double Width Double Inlet)
Typically selected for high-volume
airflow applications such as
large HVAC systems and central
plant ventilation, where increased
capacity is required.
Backward curved fans offer the best balance of efficiency, noise control, and robustness for clean air industrial applications.
Technical Information
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Fully welded impellers manufactured to AS/NZ 1554
Dynamic balancing to ANSI/AMCA 1940-1 standards or better
Fully welded, externally braced fan housings
Precision-machined EN8-grade steel shafts
Spherical roller bearings in grease-lubricated split plummer blocks
Multiple shaft seal options for general, medium-duty, and airtight applications
Structural channel bases with optional anti-vibration mounts
Protective guards to AS/NZ 4024:2019
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IFS backward curved centrifugal fans can be customised to suit specific operating requirements:
Split housings for maintenance access
High-temperature construction up to 600 °C
Spark-resistant designs (AMCA Type A, B, or C)
Inlet boxes for improved airflow stability
Discharge cowls for weather protection and airflow control
Inlet and outlet dampers
Flexible bellows for vibration isolation
Anti-vibration mountings
Inlet and outlet silencers
Variable Speed Drives (VSDs)
Protective surface coatings for corrosive environments
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Backward curved centrifugal fans are widely used in:
HVAC supply, return, and exhaust systems
Cleanrooms and laboratories
Data centres and electronics cooling
Baghouse clean-air side applications
Air pollution control systems
Industrial process ventilation
Building exhaust and make-up air systems
Industries & Applications
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HVAC
HVAC ventilation that improves airflow, reduces energy use, and supports optimal indoor air quality efficiently.
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Industrial Processes
Control heat, dust, fumes, and boost energy efficiency across manufacturing operations.
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Mining & Smelting
Provides underground ventilation, dust control, and gas dilution, ensuring a safe environment for workers.
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Oil & Gas
Explosion-proof fans meeting ATEX/IECEx standards for use in hazardous areas.
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Recycling
Improve dust control, fume extraction, airflow efficiency, and ensure environmental compliance.
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Agriculture
Ensure climate control, humidity regulation, and air quality in barns, greenhouses, and storage facilities.
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Air Pollution Control
Customised designs for dust extraction, fume removal, VOC management, and emission control.
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Food & Beverage
Hygienically design fans for food processing, cold storage, and cleanrooms.
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Furnace & Oven
Ensure energy-efficient airflow, temperature control, and safety in kilns and furnaces.
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HVAC Systems
Reliable, energy-efficient fans for commercial and industrial HVAC applications.
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Manufacturing
Ensure reliable airflow, cooling, dust control, and energy-efficient operation in production facilities.
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Paper & Pulp
Industrial fans for paper and pulp mills, dust control, moisture management, and airflow for production & drying.
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Pharmaceuticals
Ensure air quality, filtration, and safety in controlled manufacturing environments.
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Spray Booths
Spray booth ventilation fans for fume extraction, overspray control, and odour removal.
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Tunnel Ventilation
Ensure efficient airflow and ventilation in mining, transport, and construction tunnels.
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Water Treatment
Ensure ventilation and airflow, odour control, corrosion resistance, and regulatory compliance.
Backward curved centrifugal fans are selected when energy efficiency, reliability, and low noise operation are the primary design drivers.
Warranty & Support
We stand by the quality and reliability of our products, offering both performance and workmanship guarantees. Our guarantees cover 12 months of operation or 18 months from delivery, whichever occurs first, ensuring peace of mind and confidence in our engineering excellence.
Warranty
Comprehensive fan selection and system design support services to ensure optimal fan performance throughout its service life.
Support Services
Certifications &
Compliance
This ensures the product complies with international standards for performance, quality, and safety.
ISO 9001
(Quality Management Systems)
ISO 14001
(Environmental Management Systems)
ISO 45001
(Occupational Health & Safety)
Why Choose Industrial Fan Systems?
Industrial Fan Systems combines proven aerodynamic design with Australian‑based engineering expertise. Our airfoil centrifugal fans are selected, tested, and supported to perform reliably in real‑world industrial environments.
ISO 5801 tested performance data
ISO13347-3:2004 for sound
Engineered for Australian and New Zealand conditions
Application‑specific fan selection support
On-site support
Ready to improve your industrial ventilation and reduce operating costs?
Our Products
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Airfoil Centrifugal Fans
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![Industrial-Fan-Systems-IFS-Products-PW-Paddle-Bladed-Centrifugal-Fans]()
Paddle Bladed Centrifugal Fans
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![Industrial-Fan-Systems-IFS-Products-Backward-Inclined-Centrifugal-Fans]()
Backward Inclined Centrifugal Fans
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Radial Bladed Fans
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Radial Tip Fans
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High Pressure Fans
Frequently Asked Questions
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They are among the most efficient for clean air applications. Airfoil fans can achieve slightly higher peak efficiency, but backward curved fans provide greater robustness and cost effectiveness.
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No. They operate on a non-overloading power curve, protecting motors even if system resistance changes.
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They are suitable for clean to very lightly contaminated air. For heavier dust, backward inclined or radial designs are recommended.
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Yes. With high-temperature construction, they can operate reliably at temperatures up to 600 °C or more.