The need for sustainability and smaller ecological footprint leads to the construction of more airtight building envelopes with better thermal insulation in order to increase the energy efficiency of houses, according to the Energy Performance of Buildings Directive. The specific fire hazards possibly associated with such structures has raised questions amongst the fire community in Belgium. A full-scale experimental facility was built in the region of Mons to study the effects of the airtightness of the building envelope and the mechanical ventilation on fire hazards and especially on fire-induced pressure. Two different ventilation duct configurations were tested: one with mechanical ventilation on, the other one with the ducts closed with an airtight metal cap, the mechanical ventilation being off. Measurements were made for gas pressure, mass loss rate, gas temperature, volumetric flow rate in the ducts and, for some tests, O2, CO2, CO and THC concentrations were also quantified. Pressure peaks from 850 to 2035 Pa were measured without mechanical ventilation (ducts closed), while values from 420 to 750 Pa were observed with the mechanical ventilation on. The mechanical ventilation network is not sufficient to prevent pressure inside the rooms. The occupants may not succeed in escaping during a period of several minutes due to the impossibility to open inward opening doors linked to this fire-induced pressure. This experimental campaign was also used for validating the field model FDS predictive capability. The way to take into account the effective leakage, which depends on the pressure level inside the building, as well as the mechanical ventilation for obtaining satisfactory simulation results are presented in this paper. The use of validated software could be helpful to take into account the fire-induced pressure in confined dwellings in fire safety design.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 1 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 118 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-45.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-45>.