BESB box fans

BESB250 og BESB500
Description of BESB box ventilator


The BESB box ventilator is a low-energy fan with backward-curved B impeller and sound-damping insulation.

BESB is available in 4 sizes - BESB250, 315, 400 and 500. BESB315, 400 and 500 are supplied with an airflow measurement outlet.


All BESB box fans are equipped with an EC motor. See the individual sizes of the performance range under Capacity below and find technical data for the individual sizes under BESBxxx Technical Data.  


BESB tolerates temperatures up to 80°C in normal operation and up to 300°C for 60 min. in case of fire.

If there is a need for a certified combustion gas fan, we draw your attention to the FSB box fan, described under the product group Fire Protection 

Outdoor variant:

BESB can be ordered in an outdoor version (OD), which has the following features.

  • Suitable for outdoor installation
  • Temperature range - tolerates hot air up to 200 °C
Capacity - overview

BESB box fans


  Capacity m³/h
  Min. Max.
BESB250-4-1EC 350 2260
BESB315-4-1EC 570 3590
BESB400-4-1EC 950 6000
BESB500-4-1EC 1180 7300
BESB500-4-3EC 1330 10800


BESB box fan


BESB kontruktion

BESB box fans are made from Aluzinc® AZ185 class C4 in accordance with EN/ISO12944-2 and insulated for sound and condensation with 50 mm mineral wool.

As standard BESB can handle a gas temperature of up to 80°C, but can be ordered in a special version for temperatures right up to 200°C.

When used as a smoke extract fan, BESB can as standard handle up to 300°C for 60 min.

Fan impeller

BESB ventilatorhjul

The fan impeller is a B-impeller made from cast aluminium.

It has backward curved blades, thus ensuring low energy consumption and the further advantage that less dirt is attracted, with impaired impeller efficiency as a result.


BESB gummikapning The spigots on BESB have rubber gaskets, with a transition piece on the extract side specially developed for minimum pressure drop.

Oscillation dampers

BESB svingningsdæmpere

To minimise noise and vibration, the box fan is fitted as standard with efficient oscillation dampers mounted on brackets.

Split hinges

BESB hængsel

The BESB box fan has split hinges, which enable the door to be removed for installation and servicing, even in very confined conditions or for transport to difficult locations.

Condensation outlet


The BESB box fan is designed to transport air with an air humidity of less than 80% RH.

BESB is available as a special model with a condensation outlet for air with over 80% RH.

Split version

BESB split

If there are problems moving the BESB box fan in one piece, it may be ordered in a SPLIT version.

- The box fan must be assembled by an EXHAUSTO-approved fitter
- The box fan must receive final testing before handover by the fitter.


BESB box fan

The BESB box fan is a low-energy fan, in which fan housing, centrifugal impeller and motor all work together as one technology.

All BESB box fans fulfil the future requirements for 2015 laid down in the Ecodesign Directive EC327/2011.

BESB is listed by the Danish electrical power utility companies as an 'energy-saving fan'® – that is a highly energy-efficient fan.


Motor types

BESB box fan

BESB box fans are equipped with an EC motor, which is directly connected to the fan impeller.

The motor is made to protection class IP54, has inbuilt overcurrent protection and all materials are as a minimum class F (155 °C). 

EC motor

The EC motor for BESB is a permanent-magnet motor of class IE5 with motor control for 1 x 230 V or 3 x 400 V connection. The motor control and the motor are protected from overloading, blocking, over and under voltage, and over heating.

The motor control is factory programmed by EXHAUSTO for optimal operation of the fan. It only requires mains connection and a control signal from an EXHAUSTO EFC1P or MAC12 controller or a 0-10V signal.

The motor controls also provide a Modbus interface for fan control and alarm read-offs etc.


BESB box fan

The box fan can be mounted in various positions. Note, however, that the fan must not be positioned with the motor turned downwards.

Standard installation: A

Alternative installation options B/C/D:

BESB monteringsmuligheder


During installation, consideration must be given to opening the door for servicing and to access to door screws (see dimensions table on pages 7 and 15 in the product instructions where opening radius R is given). There should also be enough space to insulate the ducts.

In installation options B and D, with the door facing upwards, special fittings must be used to hold the door (accessory).

The box fan should not be screwed onto the supporting base. The base must be stable and vibration free, with no sagging. The outdoor model can be installed according to options A and B.


BESB box fans

FLF Flexible connector

FLF Flexforbindelse FLF flexible connector is made from reinforced glass fabric with integral clamps.

FLF is fitted directly onto EXHAUSTO box fans as a coupling to the fan ducts and minimises any possibility of vibrations moving along the duct system.

THA/THAV Roof terminal

THA THAV afkasttaghætter 150 x 100 Roof terminals THA and THAV are designed for air exhausts from EXHAUSTO box fans BESB and BESF.

THA is insulated for condensation and has a horizontal exhaust, while THAV is insulated for both sound and condensation and has a vertical exhaust.

More information on roof terminals.

Add all about the product series BESB box fans


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DK 5550 Langeskov

Tel +45 6566 1236

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Teaser ecodesign

Ecodesign Directive

EXHAUSTO VEX air handling units and fans comply with the Ecodesign Directive. Read more here.

See more about Ecodesign here