Natural louvred ventilator designed for rainproof day-to-day ventilation, for daylight entry and automatic smoke extraction.


The WCO is a natural multi-functional ventilator which provides rain-proof day-to-day ventilation and smoke and heat extraction, and which is used in industrial, commercial and municipal buildings. The WCO can be adapted to all kinds of projects as the result of its wide range of product variants. The ventilator can allow the entry of natural daylight.

The WCO body, including the side dampers, is made of corrosion-resistant aluminium. Wind baffles are attached to the WCO on all sides, and ensure that the exhaust airflow is positively optimised. They protect the louvres if it is windy, thus enabling ventilation in windy conditions.

The louvres of the WCO are centrally pivoted, which, due to their own weight, open smoothly even when there is no voltage or pressure. Its features and benefits are evident: its control and operation are cost-effective and efficient.

Rain-proof extraction

Side dampers are integrated into the WCO body which can be opened for rain-proof day-to-day ventilation. Aerodynamically shaped vanes prevent the penetration of rainwater, while at the same time allowing ventilation. The rainwater is directed through channels onto the roof.

Features and benefits

  • Clever louvre design
  • An excellent price / performance ratio
  • Many different variants
  • Manufactured in accordance with the requirements of ISO 9001 (quality management standard)
  • High volume smoke extract
  • Can either illuminate or blackout the interior of the building
  • Available up to a maximum width x length of 1900 x 3298 mm
  • Low installation costs
  • A wide range of colours
WCO Natural Louvred Ventilator - NBS Specification

Available versions


  • Unit width: from 550 mm to 1900 mm
  • Unit length: from 638 mm to 3298 mm


Available in many different sizes and base types which makes it easy to fix it onto curb and into most types of roofs.

Lightweight components reduce installation costs.


Base made from corrosion-resistant aluminium.


The WCO louvres are fitted either with aluminium insulated panels or polycarbonate multi-wall sheets. The louvres are either single-skin or double-skin.

These louvre variants are available:

  • 9 mm thick polycarbonate multi-skin sheet
    Colour: transparent or non-transparent
  • Single-skin or double-skin aluminium louvres


The louvres of the WCO are opened or closed either manually, electrically or pneumatically by one or two drive units.

The following louvre drives are available:

  • Manual controls (cable or drive coupling)
  • 24 V DC spring return actuators
  • 230 V AC spring return actuators
  • Single action pneumatic cylinder
  • Double action pneumatic cylinder
  • Pneumatic cylinder with four opening positions

The side dampers of the WCO ventilator are opened or closed either manually, electrically or pneumatically.

The following side damper drives are available:

  • Manual controls (cable)
  • 24 V DC electric actuator
  • 230 V AC electric actuator
  • Single action pneumatic cylinder with spring return

Optionally the side dampers of the WCO can also be designed to be fixed open, without any drives.

Thermal release

For the WCO louvred ventilator, a large number of different thermal releases with different release temperatures (for example 68°C or 182°C) are available.

Performance classes

Additional performance classes

  • Sound insulation: up to 15.0 dB