The ultimate question being when do cavity closers need to have fire resistance.
Fire stops in cavity walls.
If a fire starts within the wall the top block stops the fire from getting into the attic.
It s important to add solid wood blocking as well if floor joists intersect a wall so that the fire can t go up a wall and then sideways in between floor or ceiling joists.
A cavity in the external wall can act as a chimney allowing flames hot gases and smoke to travel from one compartment of a building to another.
The bottom block stops the fire from getting into the wall cavity to begin with.
It can also be used for the control of sound flanking at wall junctions.
Varley insulation cavity fire barrier has been developed to give 4 hour fire integrity and restrict the spread of smoke and flames within external masonry and timber framed walls.
Cavity barriers also known as stop socks are blocks of fire resistant materials that seal cavities in the wall to prevent the spread of a fire.
Technical posted on 24 06 2019.
Stopping the spread of fire in cavity walls.
What are cavity barriers and fire stops.
One of the main challenges in these circumstances is ensuring that the breathability of the building is balanced with the ability to prevent the passage of smoke and fire through the channels.
Barriers used to close concealed spaces and prevent penetration of smoke or flame to restrict the movement of fire within a building.
An issue that has been causing much confusion among developers at the moment is the requirement for the prevention of fire spreading within cavity walls.