BVDAX-I

(BV)DAX-I

Roof-mounted smoke extract fan

■ Certification: Complies with DIN EN 12101-3, certified as smoke extraction fan F400 for 120 minutes

■ Induction effect: Up to 1.8 times higher volume flow due to induced entrainment of flue gases

■ Energy efficiency: Utilisation of a smaller, lighter and more efficient motor for high volume flows with low energy consumption

■ Wide performance range: Available in three casing sizes with several fans and motor sizes for different installation requirements

■ Versatile installation: Suitable for flat roofs and pitched roofs up to 20°

■ Robust construction: Thermally insulated casing incl. shut-off damper with chain drive for safe operation in the event of a fire

General information

Application

For installation on the roof
Thermally insulated casing
Motor-operated shut-off damper (chain drive)
As a smoke extraction fan (BVDAX-I)
As a ventilation fan (DAX-I)
As a component for an MRA system

Special characteristics

Free-hanging fan utilises induction effect
Up to 1.8 times the volume flow with the same fan performance
For flat and pitched roofs
Innovative fan suspension enables easy replacement of the active part (see MBW)

Nominal sizes

Casing S560

NG 355
NG 400

Casing S800

NG 400
NG 500
NG 560

Casing S1120

NG 500
NG 560
NG 710
NG 800

Variants

- / -

Construction

Thermally insulated casing
12/56 impeller with outlet guide vanes
8/56 impeller with outlet guide vanes (only for NG 710 & NG 800)
Freely suspended fan

Parts and characteristics

Thermally insulated casing with internal cabling
Thermally insulated shut-off damper
Chain drive for SL1000 with S560, S800 & SL700 with S1120
Active part with bellmouth, outlet guide vanes and aramid fibre slip ring
12/56 impeller
8/56 impeller (NG 710 & NG 800)
Fan suspension enables easy replacement (see MBW)

Accessories

- / -

Construction features
-/-

Material and surfaces

Casing:

Made of galvanised sheet steel as standard
Optionally powder-coated according to RAL

Active part consisting of:

Fan casing & inlet nozzle: Sheet steel powder-coated in accordance with RAL
Impeller: Die-cast aluminium alloy
Impeller: Steel wheel (NG 710 & NG 800)
Slip ring: Aramid fibre

Classification, standards and guidelines

F400 (120) to DIN EN 12101-3
SL 1000/700

Technical data

24-V chain drive
External terminal box
Internal wiring
Volume flow range:

Up to 75,000 m3/h

Technical information

Function, Specification text

The roof-mounted smoke extract fan (BV)DAX-I is a modern and efficient solution for smoke extraction in buildings that combines technology with maximum safety. The DAX-I complies with the DIN EN 12101-3 standard and is certified as an F400 smoke extraction fan for an operating time of up to 120 minutes.

Thanks to the use of a smaller and lighter motor with lower power, efficiency is not compromised, which allows the use of different fans and motor sizes that can be flexibly installed in the different casing sizes. As a result, the DAX-I offers a high degree of flexibility for various installation requirements.

The casing of the DAX-I is suitable for installation on both flat roofs and pitched roofs with an angle of inclination of up to 20°. Ideally, the opening of the thermally insulated shut-off damper should face north in order to avoid unpredictable backflows caused by strong winds.

The shut-off damper opens by means of a robust chain drive, which ensures safe operation in an emergency and enables rapid smoke extraction. The main feature of the DAX-I is its unique induction effect. This effect is caused by the free-hanging fan, which is small compared to the cross-sectional area of the casing. The resulting volume flow of the free jet that forms behind the fan can be increased by a factor of 1.8.

The DAX-I combines these innovative design features to provide a compact and powerful solution that delivers low energy consumption, increased airflow and maximum safety during normal operation and in the event of a fire.

This permanent support in fire conditions offers reliability and effectiveness for smoke extraction in buildings.

Smoke extraction fan type BVAXN/BVAXO for conveying smoke gases of temperature class F300/F400 with DoP F300/F400 in accordance with EN 12101-T3 or ventilation fan type AXO/ AXNAxial fan, integrated into a thermally insulated casing, (BV)DAX-I, with tightly closing, motor-operated shut-off damper in one unit.

The thermally insulated damper is closed and opened using a chain drive.Installation on flat roof or pitched roof (infinitely adjustable up to 20° pitch)Fan unit works on the induction principle and achieves high volume flows with low motor power.

The total volume flow results from the fan and induced volume flow.

In addition, the unit utilises the natural buoyancy of the fire gases and thus achieves even greater smoke extraction volume flows.

Thermal insulation according to EnEV requirement
Thermal transmittance class T4 according to EN 1886
Temperature bridge class TB4 according to DIN EN 1886
Leakage classification for casing: class A according to EN 1751
Tested class according to EN 12101-3, temperature class F300 and F400
Snow load class SL1000 (SL700 for S1120)
(BV)DAX-I casing with externally mounted terminal box wired on the motor side.
Volume flow measuring device as standard

Outer shell made of galvanised sheet steel, can optionally be powder-coated.

Highly efficient axial fans are installed with or without outlet guide vanes as required.

Axial fan consisting of:

Shaft casing in welded sheet steel design
Surface-protecting powder coating RAL 7030
With or without outlet guide vanes, depending on fan type
Volume flow measuring device
Special motor suitable for F300 or F400 with BV
Cast aluminium or sheet steel impeller
Impeller dynamically balanced to ISO 1940, quality grade 6.3

Opening device

Motor-operated chain drive
Supply voltage chain drive 24V
Snow load class SL 1000/700

Dimensions

	A	B	ØC	D	E	F	G	H	I	K
S560 NG355 S560 NG400 S800 NG400 S800 NG500 S800 NG560 S1120 NG500 S1120 NG560 S1120 NG710 S1120 NG800	850	684	517	700	124	684	992	770	790	884
	850	684	517	700	159	684	992	770	790	884
	1086	920	571	936	196	920	1228	1006	1026	1120
	1086	920	712	936	210	920	1228	1006	1026	1120
	1086	920	712	936	242	920	1228	1006	1026	1120
	1419	1253	712	1269	210	1253	1561	1341	1361	1475
	1419	1253	789	1269	242	1253	1561	1341	1361	1475
	1419	1253	972	1269	327	1253	1561	1341	1361	1475
	1419	1253	972	1269	378	1253	1561	1341	1361	1475

Product details

The induction roof ventilator ((BV)DAX-I) is characterised by an innovative operating principle that ensures efficient smoke extraction in the event of a fire. The system consists of a thermally insulated casing with an integrated shut-off damper. In the event of a fire, the shut-off damper opens automatically by means of a reliable chain drive and the axial fan, which is freely located slightly below the casing, starts to work.

The fan generates a primary volume flow along its axis. Thanks to the special design - the fan is deliberately not completely enclosed by the base casing - an additional volume flow is created: a negative pressure in the area between the fan and the casing ensures that flue gas from the surroundings is drawn in and entrained. This process is known as induction.

The result is a total volume flow that is up to 1.8 times higher than the pure volume flow generated by the fan, depending on the device configuration. This function makes it possible to move a large volume of flue gas with a comparatively small motor size. This induction effect contributes to efficient smoke extraction by quickly conveying large quantities of flue gas.

The combination of axial fan and free installation in the casing maximises the flow rate, while the system remains particularly compact and very energy-efficient.

Size	A	B	C	D
S560	780 mm	1250 mm	≥ 0	≥ 450 mm
S800	1020 mm	2500 mm	≥ 0	≥ 450 mm
S1120	1350 mm	3250 mm	≥ 0	≥ 530 mm

Downloads

product information

Product data sheet (BV)DAX-I

DAX-I_PD_2025_10_24_DE_en Product data sheet 2 MB pdf

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