Smoke extraction from an object

Smoke-free rooms give people orientation in case of fire. Smoke extraction from a building is therefore vital.

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8 March 2024 Fire Safety

Smoke extraction from buildings and rooms using smoke and heat extraction systems (SHEVS) ensures that rooms are free of smoke in the event of a fire and provides people with orientation. In the following article, we look at natural smoke extraction (NRA) and mechanical smoke extraction (MRA). These types of smoke extraction are used in underground car parks, lift shafts and stairwells, for example.


Sense and purpose of smoke extraction

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Smoke extraction involves exchanging the air in the building, as the toxic smoke in the event of a fire is more dangerous for people than the fire (keyword: smoke inhalation). This means that the toxic smoke and heat are removed from the upper part of the building. At the same time, fresh air or oxygen is supplied to the lower part of the building. The supply air from below is important here so that the smoke in the lower part of the room is forced upwards (chimney effect).

As a result, the smoke load is reduced and escape and rescue routes remain clear for longer.

Advantages of smoke extraction or a smoke-free room:

  • People in the building can orientate themselves more easily and get to safety.
  • Rescue forces can more easily save people, animals and property.
  • Fire brigade can orientate themselves more quickly and fight the fire.
  • The danger of an explosive flashover is reduced.
  • Consequential fire damage is reduced and thus also business interruptions.

Natural smoke extraction

The natural smoke extraction system is installed in rooms that have an external wall or ceiling and in which hot smoke can arise.

The basis of natural smoke extraction is the thermal lift principle, i.e. hot smoke, heat and fire gases rise upwards. In the event of a fire, the system is triggered automatically or manually. As a result, the smoke and heat extraction device opens, e.g. the skylight dome on the roof, and discharges hot smoke and fire gases above it.

The natural smoke extraction system can have an electrical, pneumatic or pyrotechnical release. It is installed in particular in:

  • Stairwells
  • Places of assembly
  • Production halls or warehouses
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In addition, the NRA can also be used as a ventilation system for natural smoke extraction, i.e. it can be controlled manually to ventilate a room well on very warm days, for example.

Good to know: There are two additional buttons on the orange manual button of the natural smoke and heat extraction system for opening and closing the system for use as a ventilation system. The release button behind the safety disc of the manual button is only intended for use in the event of a fire.

Mechanical smoke extraction

The mechanical smoke extraction system is usually installed in interior rooms or in rooms where no sufficient opening to the outside can be installed. These can be the following rooms, for example:

  • Basement rooms
  • Underground garages
  • Sales areas
  • Interior rooms in a multi-storey building
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The smoke extraction system is coupled with mechanical ventilation and fans in order to direct heat as well as cold or warm smoke from the room through ventilation pipes to the outside via an opening element. At the same time, fresh air is fed into the building via other air openings or supply air fans (air exchange).

With mechanical smoke extraction systems, it is imperative that the motor drive or fans are supplied with power all the time, i.e. corresponding electrical lines must be separately protected from fire and heat.

Don't forget maintenance

Reliable smoke extraction in an emergency requires annual maintenance by a competent person.

In addition, the operator must carry out and document a visual inspection at least once a year.

We would be happy to carry out the maintenance of your MRA system. Request a quote now.

Do you still have questions about smoke extraction?

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