Method for fire blocking in a ventilation device and a fireblocking ventilation device

A flame and fire resistant ventilation device, comprising:

• a mesh element having a plurality of vent openings dimensioned to quench transient flames,
• a swelling element formed of or coated with an intumescent material, to permanently seal the ventilation device during sustained fire exposure;
• at least one heat sink body providing a surface for absorbing and dissipating heat;
• at least one heat storing capacity element associated with the heat sink body to prevent fire spread by sustained direct exposure to flames;
• and
• heat insulating means to prevent fire spread through the ventilation device by heat conduction, at least for the initial period of swelling of the swelling element.

A flame blocking ventilation device, comprising

• at least one mesh element comprising a board with heat insulating properties, with a plurality of openings with quenching abilities for the fire gas introduced at a fire, each of the plurality of opening being stepped in size, from a larger portion to a smaller portion;
• and
• a swelling element arranged within an opening of the at least one mesh element in the larger portion thereof, comprising an intumescent material with the ability to swell during a swelling period when exposed to the heat of a fire, to close the passage for an air flow,
• wherein the mesh element has heat absorbing and heat accumulating capacities for the swelling period, and providing a thermal break.