Abstract
Nowadays, construction requirements and practices are rapidly moving towards more airtight building envelopes, thermal insulation and energy saving according to the Energy Performance of Buildings Directive. In such structures, one might wonder if there are specific risks in case of fire. Some fatal accidents during the intervention of fire brigades were reported in the past due to a backdraft phenomenon in airtight and insulated renovated apartment. However, the occupants of better insulated and sealed buildings can also be exposed to news kinds of hazards. This paper presents the fire that occurred in an apartment in Germany on the 5 February 2013. This fire broke out during night in an apartment in a newly renovated building to meet the passive standard. Awakened by the noise of the flames, the occupant of the apartment quickly noticed that a fire had just broken out in his living room. After an unsuccessful attempt at fire extinction, he decided to abandon his dwelling. Unfortunately, the inwards-opening door to reach the outside via the corridor turned out to be completely blocked. After an interminable waiting period estimated by the investigators of nearly two minutes the occupant was finally able to open the bedroom door leading to the balcony where he was rescued by the emergency services and escaped with burns. After some investigations and based on fire simulations results from CFAST modeling, it was concluded that the door were blocked due to the fire induced overpressure.
From this real fire case there is no doubt about the capacity of the building structure to withstand high levels of overpressure, the integrity of the sealing of the passive house being not deteriorated in the first moments of the fire. This new fire hazard has to be taken into account in the fire safety design of confined dwellings.
