Specially designed for use when high pressure characteristics are required. Centrifugal roof models are delivered on-site ready for installation, fully assembled including service isolator. The range consists of 9 sizes with duties from 0.248m 3/s to 4.5m3 /s(892m3 /h to 16200m3 /h) with high pressure development available up to 900 Pa making this range particularly suited for ducted applications.

The mounting plate is moulded with an integral fixed bellmouth to ensure optimum efficiency and precise alignment. The weather-cowl is also moulded to produce a smooth internal surface and a tough UV resistant finish. Colour: BS 10A07. Alternative colours available on request. Equally suitable for flat or inclined roofs, backward curve centrifugal roof models are suitable for kerb or purlin box mounting and feature a wide range of accessories for many different industrial applications.

Vent-Axia centrifugal roof fans are designed for either kerb or inclined fixing (max. angle 30°).

Motors

The Centrifugal roof range features a proven external rotor motor and backward curved aluminium impeller assembly selected for performance and non-overloading characteristics. The assembly is dynamically balanced to VDI 2060. The motors in this range are protected to IP44 according to BS EN 60529. Ball bearings are greased for life and are designed to run at any angle. Insulation is Class 'B' (from -30°C to +40°C). Manufacture is controlled to BS EN ISO 9001 standards.

Electrical

Single phase 220-240V Hz. Capacitor start and run. Three phase 380-415V 50Hz. A service isolator switch is provided for local isolation to meet COSHH requirements. The enclosure is protected to IP65 according to BS EN 60529, except on size 250 dia where a service switch is provided.

All motors are fitted with Standard Thermal Overload Protection (S.T.O.P), which for three phase fans should be wired into all controller circuits and into starter contactors. Most models are available with 4, 6 and 8 pole motors.

Sound Levels
Published dB(A) figures are free field sound pressure levels at 3m with spherical propagation at a reference level of 2 x 10–5Pa (20 micro-Pascals).

The sound power levels spectra figures are dB with a reference level of 10–12 Watts (1 pico watt).

Centrifugal Roof Fan Accessories

Purlin boxes
Available in sizes to suit all models. Should be used to support the fan in conjunction with a soaker flange sheet.

Roof attenuators
Available in all sizes to cover the range of centrifugal roof fans in three lengths: 600, 900 or 1200mm according to the attenuation required.

Shutters
Robust construction and designed to fit beneath the fan using the fittings provided. Airflow operated, manual or motorisable shutter. A minimum distance of half the attenuator width is required between an airflow shutter and a roof attenuator for satisfactory operation.