AES VDMA 24177

Controllers for fans for keeping buildings free

of smoke and heat in case of fire

Excerpt from VDMA standard sheet VDMA 24177 Sept. 2003

Foreword

Fans for keeping buildings free of smoke and heat (hereinafter referred to as smoke

extraction fans) serve in case of fire to extract flue gases from the section affected by the fire

with the aim of maintaining a low-smoke layer beneath the smoke layer over a defined period

of time in order to enable persons to rescue themselves and to allow the fire brigade access

for fire extinguishing and rescue actions or to establish controlled pressure differences and

hence to prevent the escape of smoke into escape and rescue routes.

Motor control

Smoke extraction fans that are also used for daily ventilation can be manufactured so that

they are controllable in ventilation mode.

They are almost always controlled by means of frequency controllers or dual-speed motors

(Dahlander circuit or separate windings).

The motors may not be operated via frequency controllers or similar control devices in smoke

extraction mode due to the increased risk of failure; instead they must be connected directly

to the main distributor via the electricity network.

This does not apply if the function of the frequency controller/motor unit has been tested

according to the test standards EN 12103-3 or DIN 18232-6 and carries building authority

approval.

Modes of operation

Smoke extraction fans can be operated single-stage, i.e. with a single speed, or multi-stage,

which means dual-speed or Dahlander circuit; this makes needs-based ventilation possible

(e.g. dependent on the CO content in garages).

Further modes of operation, such as speed regulation by lowering the voltage with a

transformer or control using a frequency controller are permissible only if the motor

manufacture has expressly approved the motor for this.

In the event of fire it must be ensured in every case that the upstream speed controller is

bridged and that operation takes place at the rated speed.

Repair switch

In accordance with DIN EN 60204-1 (VDE 0113-1) a repair switch must be provided in direct

proximity to the fan for maintenance and repair work if the control cabinet is not visible from

the fan.

The repair switch is to be secured in the operating position against unauthorised operation.

(e.g. by a padlock or implementation as a key switch).

Control cabinet

The control cabinet is to be installed in a room separated from the smoke extraction area by

means of fire protection measures.

Requirements for maintaining the function of cabling systems and distributors

The maintenance of the power supply for the smoke extraction fans must be guaranteed in

the case of fire. The duration of maintenance of the function must correspond at least to the

time classification of the component to be supplied. The duration of maintenance of the

function of the cabling systems must be at least 90 minutes.

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Controllers for fans for keeping buildings free of smoke and heat in case of fire Excerpt from VDMA standard sheet VDMA 24177 Sept.
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Electrical installation In the case of electrically operated systems, the cables must be monitored for short-circuit, earth connection and open circuit if the operated condition is not achieved by switching off the power supply. An acoustic or visual signal on the control panel must indicate when there is an error. The switching equipment for the smoke extraction fan must be located outside the smoke extraction area and must be accessible from escape and rescue routes.