Development and validation of a one-zone fire model to predict fire induced pressure in multi-compartment low-energy buildings

The need for sustainability and smaller ecological footprint leads to the construction of more airtight building envelopes with better thermal insulation, like passive houses, in order to increase the energy efficiency. But this type of structures has specific risks when a fire occurs inside due to the high level of airtightness. These risks are related to the pressure increase due to the thermal expansion of fumes. This was confirmed in February 2013 when a fire occurred in a passive apartment in Cologne. The occupant was blocked for 2 minutes inside his apartment due to the thermal expansion of fumes. Consequently, passive houses are an object of study in order to find a better configuration that minimizes all the risks for the occupants if a fire occurs. Before of this thesis work, eleven full-scale firetests had been carried out in Bauffe (BE) between summer 2016 and summer 2019. These tests were done in different configurations of passive house and with different fire loads. The experimental data were used to validate two software as CFAST and FDS, commonly employed in this field in order to simulate fires inside this kind of buildings. Unfortunately CFAST doesn’t take into account the leakages area and the time of calculation is very high with FDS. During this thesis work a new zone model code has been devoleped for the calculation of the fire induced pressure in a multiple rooms airtight building, taking into account the effects of the fire induced pressure on both the effective leakages area and the characteristic curve of the fans. This new code has been validated thanks to the novel experimental results obtained at large scale and satisfactory results were obtained for the main parameters of interest during the fire. Moreover, three new tests were performed in this Master thesis, in order to have a better understanding of HVAC modelling and to find a way to decrease the pressure inside the building when a fire is occuring.