Cased Axial Fans
Cased axial fans are the workhorses of ducted commercial and industrial ventilation, moving high volumes of air through a rigid circular casing that bolts straight into the duct run. At Alpha Air we supply cased axial flow fans from 250mm up to 800mm diameter, with single phase and three phase motor options across the range — including case mounted axial fans from Elta, one of the UK’s best-known commercial fan manufacturers.
Which cased axial fan do I need?
For general supply and extract duties, start with the TCBT short cased axial fans (250–800mm, with a choice of motor duty variants on the larger sizes) or the TCBB range (250–630mm). Where a single-stage fan won’t reach the pressure you need, the TCBBx2 contra rotating axial fans (450–630mm) use two impeller stages running in opposite directions to develop far more pressure from the same duct diameter.
From Elta we offer the Compact SCD (315–630mm), a weatherproofed short cased axial designed to move large air volumes against low resistance; the Raptor SDA (250–630mm), built around the Ziehl-Abegg FE2owlet aerofoil impeller for quiet, efficient ductwork ventilation and available in AC and EC versions; the long cased Revolution SLC, with a hot-dip galvanised casing for demanding industrial and external installations; and the Turboflow Max TF long cased kitchen axial (450–630mm) for higher-pressure commercial extract duties.
Ordering cased axial fans from Alpha Air
We’re a UK ventilation supplier based in Leicester. Stocked items ordered by 3pm are dispatched for next-day delivery, made-to-order fans show their lead time on the product page, and delivery is free to mainland UK on orders over £400 ex VAT. Most AC fans in this section can be paired with an S&P speed controller, and matching fan flanges, fast clamps and flexible connectors are available to complete the installation.
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Compact SCD
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Raptor SDA
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Revolution SLC
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TCBB Short Cased Axial Fan
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TCBBx2 Contra Rotating Cased Axial Fan
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TCBT Short Cased Axial Fan
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Turboflow Max TF
What Is a Case Fan?
A case fan (also called a box fan or cabinet fan) is a ventilation fan enclosed in an insulated, sound-attenuating cabinet. The enclosed design dramatically reduces noise breakout compared to an uninsulated inline fan, making case fans the preferred choice for noise-sensitive commercial installations where the fan is positioned near occupied spaces — for example above a suspended ceiling in an office or hotel.
Construction
The casing is typically fabricated from galvanised steel panels lined internally with acoustic insulation (mineral wool or foam). Spigot connections on the inlet and outlet faces allow direct connection to ductwork. Access panels or removable sides provide maintenance access to the motor and impeller. Many models include an integral backdraught shutter on the outlet to prevent reverse airflow when the fan is off.
Impeller Types
Forward-Curved Centrifugal
Forward-curved (FC) impellers generate high airflow at low to moderate pressures. They are compact, cost-effective, and suitable for general commercial ventilation. However, they are less energy efficient than backward-curved designs at higher pressures.
Backward-Curved Centrifugal
Backward-curved (BC) impellers are more aerodynamically efficient, especially at higher pressures. They are the preferred choice for systems with long duct runs, filters, and multiple fittings. EC (electronically commutated) motor versions offer the highest energy efficiency and speed controllability.
Applications
- Office supply and extract ventilation
- Hotel corridors and common areas
- Retail and restaurant HVAC
- Healthcare ventilation (wards, consulting rooms)
- Education buildings (classrooms, halls)
- Any application where fan noise must be minimised
Selecting a Case Fan
Match the fan’s performance curve to your system’s airflow requirement and total static pressure. Verify that the noise level at the operating point meets the room’s NR (Noise Rating) criteria — typically NR 30–35 for offices, NR 25–30 for hotel bedrooms. Our team can help you check these calculations.
Why Choose Alpha Air?
Alpha Air has supplied case fans to M&E contractors and building services consultants. We stock models from trusted manufacturers for same-day dispatch and offer expert advice on fan selection, noise criteria, and system design. Free delivery on orders over £400 — call 0116 246 0031.
Frequently Asked Questions
What is the advantage of a case fan over an inline fan?
The insulated cabinet dramatically reduces noise breakout from the fan casing. An inline fan radiates noise directly from its housing into the ceiling void or plant room; a case fan contains that noise within the acoustic lining. This makes case fans far quieter in the immediate vicinity of the unit.
Where should a case fan be installed?
Case fans are typically installed in ceiling voids, plant rooms, or risers where they are accessible for maintenance. Position the fan as close to the centre of the duct system as practical to minimise duct lengths and balance static pressure across branches.
Do case fans come with speed controllers?
Most case fans do not include a speed controller in the box but are compatible with external transformer-type or inverter speed controllers. EC motor models often have built-in speed control via a 0-10V signal. Ask us which controller suits your fan model.