It was generally recognised that because of occupants' behaviour, natural ventilation rates were usually much lower than the accepted criteria for calculation. A great deal of anecdotal data existed which showed that frequency of opening windows bore a direct relation to external temperature and that the greater the volume the less the frequency of opening. The recent BRE survey also shows that very low ventilation rates, below 4 cubic metres/ person/hr have been found to be acceptable.
Surface condensation and mould affect about 15 percent of the UK housing stock. This paper reports BRE studies in occupied dwellings on the effectiveness in various situations of a range of remedial measures, which included improvements to thermal insulation and heating, and the provision of extractor fans and dehumidifiers. The flats and 2-storey houses involved were all of traditional construction with brick walls and pitched roofs.
Thermal bridges are parts of the building envelope where, due to the two-dimensional or three-dimensional character of the heat conduction, either the inside surface temperatures are rather low, which can cause condensation, or the heat losses are rather high. In this paper thermal bridges are analyzed by numerical methods, shortly described in the first section. They are based on energy balance techniques.
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