Comparison of Fire Hazards in Passive and Conventional Houses

The concept of Passive House or Passivhaus (PH) refers to the current highest energy standard for buildings, with a promise to spare up to 90 % of heating, or cooling, energy compared to common buildings. In order to be certified, a PH must meet tough requirements for air tightness and thermal insulation, so that energy losses are kept as low as possible. The difficulty to achieve the required level of performance in part explains the limited number of PH so far. However, while the member states are implementing the European Directive on Energy Performance of Building, it is expected for instance that by 2015, 100% of the new buildings in Brussels will be PH! The fire hazards possibly associated with PHs have recently raised questions amongst the fire community in Belgium (chiefly the fire brigades) reported by the press. In an attempt to answer those questions, ISSeP and University of Mons have conducted a study funded by the SPF Interior whose main objective was to determine to which extent the characteristics of PHs (mainly the forced / controlled ventilation and the thermal insulation) affect the fire spread and fumes propagation. The project "Passive House and fire = Inferno?" compares a PH and a conventional house in terms of fire hazards for the dwellers. It has been shown that the time available for escape of the dwellers calculated according to ISO 13571 is approximately the same for the two houses for identical interior wall lining and fire scenario.