English

A retrofit study was conducted in an unoccupied manufactured house to investigate the impacts of airtightening on ventilation rates and energy consumption. This report describes the retrofits and the results of the pre- and post-retrofit assessment of building airtightness, ventilation, and energy use. Building envelope and air distribution systems airtightness were measured using fan pressurization. Air change rates were measured continuously using the tracer gas decay technique.

The airtightness of inclined roofs is important in order to avoid hygrothermal problems and to guarantee the durability of the construction itself. Previous research in building physics showed that perfect airtightness of inclined roofs is difficult to achieve and maintain. In practice, air transport through the construction, i.e. in/exfiltration, cannot be avoided due to for example imperfections or bad workmanship. The heat and moisture conditions in the building component are strongly influenced by advection, i.e.

Recently, insulation retrofits of existing houses have been thought to be one of the effective measures from the viewpoint of global warming prevention. However, the overall reduction effects of environmental loads by the insulation retrofits have not yet been clarified. This study intends to accumulate basic data concerning the insulation retrofits and to promote the energy saving of existing houses. 

Starting January 1st, 2013 the French thermal regulation will impose a minimum requirement for residential buildings air-tightness. However, nothing is planed for non-residential building, for two reasons:

Recently, the requirements regarding global building airtightness to reduce the exfiltration losses became more severe as result of the trend towards very low energy buildings and Passive Houses. These very strict requirements regarding airtightness are currently achieved with an interior air barrier, which is labour intensive and consequently expensive. At the same time it is observed that new wind barrier solutions - to reduce windwashing of the insulation - can have a major contribution to the global airtightness of timber frame constructions.

This study documented that houses in the southeastern United States built on typical wall-vented crawl spaces possess the following characteristics: 1) bulk water, water vapor and associated moisture issues, 2) mold spores, 3) measured holes between the crawl space and living space and 4) measured transmission of mold spores from the crawl space to the living space.

Accidental releases occurring in industrial platforms or during transportation of hazardous materials can entail the dispersion of toxic gas clouds. In case of such an event, the best protection strategy for people is to identify a shelter in a nearby building and stay in this room until the toxic cloud has finally been swept off.

It has been demonstrated that there is a strong relationship between occupant behaviour and the thermal performance of dwellings. At the same time, some aspects of this behaviour, especially with respect to natural ventilation, constitute some of the most important sources of uncertainty in the field of building energy simulation.

In a great portion of Danish primary schools the mechanical ventilation systems is outdated or simply rely on opening of windows to ventilate the classrooms. This leads to high energy consumption for fans and/or ventilation heat losses and poor indoor environment, as the ventilation systems cannot provide a sufficient ventilation rate. A recent study with 750 Danish classrooms show that 56 % had CO2-concentrations over a 1000 ppm, which is the recommended limit by the Danish working environment authority and this adversely affects the performance and well being of the pupils.

The aim of this study is to check the accuracy of a nodal model to predict correctly the flow fields involved inside a building by wind-induced pressure. The model is confronted to experimental tests involving a one-storey dwelling of 84 m² at a reduced scale of 1/10 placed in a wind tunnel facility. Different configurations are tested considering openings of different sizes for outside openings as well as for internal doors. For each configuration, various wind incidences are studied.