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

Abstract

A flame and fire resistant ventilation device includes 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 a heat insulating structure to prevent fire spread through the ventilation device by heat conduction, at least for the initial period of swelling of the swelling element.

1 . Method for blocking fire in a ventilation device arranged in building or similar structure, comprising:
 providing at least one mesh element for quenching flames to which the device is exposed;   providing at least one element which can absorb heat from the flames to which it is exposed;   providing at least one element which accumulates the heat absorbed by the heat absorbing element for an initial period exceeding the swelling period of the swelling element;   providing an intumescent swelling element which swells upon exposure to heat, converting the device from open to closed state; and   retarding transfer of heat by providing a thermal break to the heat absorbed during the period of fire resistance.   
     
     
         2 . Method according to  claim 1 , additionally comprising passing air trough an open space between the swelling element and the mesh element, and the heat absorbing element. 
     
     
         3 . Method according to  claim 1 , wherein a plurality of mesh elements are provided. 
     
     
         4 . Method according to  claim 1 , wherein a centrally located mesh element is provided. 
     
     
         5 . 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.   
     
     
         6 . A ventilation device according to  claim 5 , wherein at least one said mesh element with a plurality of openings with quenching abilities for the fire gas introduced at a fire, is arranged downstream to the swelling element. 
     
     
         7 . A ventilation device according to  claim 6 , wherein the integrated mesh element is arranged in a distance downstream to the swelling element to leave a heat absorbing airspace. 
     
     
         8 . A ventilation device according to  claim 6 , comprising a further mesh with at least a plurality of openings with quenching ability, said further mesh being arranged downstream to the first mesh, at a distance therefrom. 
     
     
         9 . A ventilation device according to  claim 5 , wherein the swelling element has a plurality of evenly distributed openings permitting an air flow therethrough. 
     
     
         10 . A ventilation device according to  claim 9 , comprising two said swelling elements to provide bidirectional function, arranged symmetrically to a said mesh element with a plurality of openings provided to quench flames. 
     
     
         11 . A ventilation device according to  claim 5 , comprising a supportive metal mesh upstream of the swelling element. 
     
     
         12 . A ventilation device according to  claim 11 , wherein the supportive metal mesh is integrated with the swelling element. 
     
     
         13 . A ventilation device according to  claim 5 , for blocking fire in a cavity in a building through which air flows, which cavity may extend over at least a substantial part of a wall or a floor, comprising:
 an elongated swelling element, and   a longitudinal channel element of mesh which is arranged to surround at least a part of the swelling element, to provide a quenching element and a heat sink and a heat absorber at least at the upstream side of the device,   said swelling element being arranged coplanar to a direction in which the air flows through the cavity.   
     
     
         14 . A ventilation device according to  claim 13 , wherein the longitudinal channel element is tubular and arranged to fill the cavity in cross section. 
     
     
         15 . Device according to  claim 14 , comprising two said longitudinal channel elements, at least one of said longitudinal channel elements being provided with an intumescent element and wherein said two tubular elements are joined by a web of the mesh material. 
     
     
         16 . Device according to  claim 13 , wherein the mesh is a perforated metal sheet. 
     
     
         17 . A ventilation device according to  claim 5 , wherein the mesh element comprises a dish with multiple perforations each having a maximum size corresponding to a quenching gap size of fire gases. 
     
     
         18 . A ventilation device according to  claim 5 , wherein the heat storing capacity element comprises at least one material or structure selected from the group consisting of a mesh grid, water-filled tubes, water-filled pellets, gypsum pellets, chemical endothermic ampoules, powder pellets, sand and gravel. 
     
     
         19 . 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.