Från liten till stor brand : Brandspridning till vindsutrymmen i flerbostadshus

Sammanfattning: A fire that reaches the attic spaces in a multifamily building often comes with devastating consequences. Only 1 % of all attic fires have their starting point in the attic. The remaining 99 % begin in another fire cell, such as an apartment. A fire cell is a delimited part, such as ceilings, floors and walls, and each apartment in a multifamily building should form a separate fire cell. According to BBR (Boverket´s Building Regulations), attic spaces and ceiling voids, the attic should also form a separate fire cell with an area of maximum 400 m2 . The fire cell works as a shell to limit a fire and prevent proliferation. Besides fire cells, the choice of material has a significant impact on a fire and its spreading capacity to the attic spaces. A fire that starts for example in an apartment will emit hot gases and a common route for these gases is through the ventilation ducts. If there are any leaks in the ventilation ducts and visible materials, these hot gases might ignite surrounding insulation material. Insulation materials are divided into combustible and non-combustible materials. If a fire gets into contact with a combustible insulation material, this will be a contributing factor to its spreading to the attic spaces. Another way the fire can spread to the attic spaces is that the fire gets into contact with the eaves and then to the trusses. The purpose of this project is to examine the spreading of a fire to attic spaces in multifamily buildings. The goal of the project is to assist with proposing solutions that prevent the spreading of a fire to the attic spaces in a multifamily building. The project has been based on a literature study and interviews with people that work in the fields of fire- and construction technology and possesses high competence and together form a reliable source. The project´s conclusion shows that today’s standards and requirements in BBR are not always the cause for the fire to spread from a fire cell to the attic spaces in a multifamily building. Contributing causes for a fire that starts in another fire cell to spread to the attic spaces are leaks in the ventilation ducts, not appropriate choices of materials where ESP-insulations is a fire hazard and should be eliminated entirely as an insulation material, defective fire cellsboundaries, not prioritizing fire safety, lack of knowledge in case of an addition to the existing building, lack of knowledge in the construction-stage when it comes to the placement of iv openings from the ventilation ducts and absence of fire protection in the form of fire detectors, smoke detectors and other fire preventions solutions.