Centrifugal Single Width Fan (SISW)
Heavy-duty SISW centrifugal blower for commercial and industrial supply, exhaust, smoke-spill, dust collection, fume and grain-drying duty — indoor and outdoor.
About the Centrifugal Single Width Fan (SISW)
The Single-Inlet Single-Width (SISW / SWSI) centrifugal blower is the workhorse of high-static, high-flow industrial ventilation. A single inlet feeds one impeller, producing a clean low-turbulence flow profile and supporting very high pressures — making it the right choice for filter banks, long duct runs, smoke-spill ducts, dust collectors, fume scrubbers and grain dryers where smaller cabinet fans run out of pressure. Available in indoor and outdoor weatherproof builds, with spark-resistant construction (AMCA Type A/B/C) on request for hazardous-service duty.
Engineering Advantages
Covers the widest application range in the catalogue — supply, smoke-spill, dust, fume, grain drying
High static-pressure capacity ideal for filter banks, scrubbers and long ducts
Single inlet means cleaner flow path and fewer bearing assemblies than DIDW
Heavy-gauge construction stands up to industrial duty without panel rumble
Spark-resistant variant available for hazardous-service / fume duty
Discharge orientation selectable: top horizontal, top angular, bottom, etc.
Configurations & Variants
Buyer-selectable build options available at order. Specify on quote request.
Key Features
- High-pressure capacity for larger ducted systems and filtration
- Heavy-duty high-GSM galvanised housing construction
- Statically and dynamically balanced impeller
- Low power consumption
- Three-phase only
- Indoor and outdoor (weatherproof) builds available
Construction & Materials
- Heavy-gauge GI scroll housing with internal stiffeners
- Statically + dynamically balanced steel impeller (G6.3 grade or better)
- Cast-iron pillow-block bearings, regreasable
- Three-phase TEFC motor with class F insulation
- Inlet cone matched to impeller for high volumetric efficiency
How to Choose the Right Variant
- 1Specify required airflow at design static pressure — pick fan from the published curve
- 2For filtered systems, design at the dirty-filter pressure to avoid undersized motor
- 3Choose discharge orientation matching duct path to avoid extra elbows
- 4Specify Arrangement 1, 4 or 9 per AMCA 99 based on motor mounting preference
Installation Notes
- Always mount on an inertia base or spring isolators for clean rooms / sensitive sites
- Provide flexible duct connectors at both inlet and outlet
- Allow at least 3× equivalent diameter of straight duct on the discharge for stable flow
- Match motor frame size to bearing supports — never over-belt the design
Maintenance Schedule
- Lubricate pillow-block bearings every 6 months
- Inspect impeller for build-up — process dust can unbalance the wheel
- Re-balance the wheel if vibration exceeds 7 mm/s RMS at the bearing housing
Industries Served
Standards & Compliance
- AMCA 99 fan arrangement / classification
- Performance tested in line with AMCA 210 / ISO 5801
- Balance grade per ISO 1940 G6.3
Frequently Asked Questions
Single-width vs double-width?
Single-width handles up to ~25,000 CMH per fan and is simpler to maintain. Double-width (DIDW) doubles the airflow with two inlets sharing the same shaft — useful when you need >25,000 CMH but does not increase the pressure.
What is the airflow regulation method?
Three options: VFD on the motor (best part-load efficiency), inlet vane dampers (good for occasional turn-down), or outlet damper (cheapest, lowest efficiency).
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Need help selecting the right fan?
Our engineers will help you size the centrifugal single width fan (sisw) to your exact application — capacity, static pressure, and installation constraints.
