French ventilation system performances in residential buildings.

The comparison of the performances of ventilation systems must take into account different issues. For indoor air quality, different kinds of pollutant sources have to be defined. To make an evaluation of the results, the best approach is to consider the people exposure. Four generic pollutants are taken into account : rooms components or furniture, human metabolism, cooking activities, passive smoking. As the definition of the unit for each pollutant is free, it is useful for their comparison to press them on a common "normalised" basis. This enables to make a distinction between the simulations based on generic pollutants and their interpretation which could be derived for many kinds of pollutants without having to do additional calculations as far as the considered pollutant follows the conventional patterns. The pressure difference , for example can be related to radon issues as to running of some heat appliances. The room parameters are mainly related to humidity issues as condensation, mould growth or house dust mites. For energy issues, a distinction has to be made between the direct energy use (fans) and the heat needs due to ventilation. Such a methodology has been defined within the IEA annex 27 project. After a presentation of the different parameters taken into account, we describe the computer code SIREN95 developed at CSTB in order to obtain the required results and we present a sensitivity analysis for the basic ventilation system used in France (mechanical exhaust).