English

From 1953 to 1975, some half a million high-rise flats were constructed in the UK in response to the need at that time for the rapid provision of substantial numbers of affordable dwellings. For a variety of reasons, including environmental and social problems, many of these buildings were subsequently demolished. However, many housing authorities still own a considerable number of high-rise developments which, while structurally sound, will require to be upgraded if they are to continue in service for rental purposes.

In Sweden, the activity on building new residences has been decreased for a number of years. The building stock as an average has therefore become older and in the future it will be subject for refurbishment. This paper deals with how to optimise retrofit measures, i.e. how to act in order to minimise the Life-Cycle Cost (LCC) of a building. Insulation measures are emphasised but also other retrofits are dealt with such as changing the heating system. It is shown that the heating system has a vital influence on the optimal amount of extra insulation which is to be applied.

Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from sick building syndrome (SBS) symptoms, even though existing standards and guidelines are met. The reason is that the requirements specified in these standards are rather low, allowing a substantial group of people to become dissatisfied and to be adversely affected. A paradigm shift from rather mediocre to excellent indoor environments is foreseen in the 21st century.

We studied the effect of ventilation and air filtration systems on indoor air quality in a children's day-care center in Finland. Ambient air nitrogen oxides (NO, N02) and particles (TSP, PM10) were simultaneously measured outdoors and indoors with automatic nitrogen oxide analyzers and dust monitoring. Without filtration nitrogen oxides and particulate matter generated by nearby motor traffic penetrated readily indoors. With chemical filtration 50-70% of nitrogen oxides could be removed. Mechanical ventilation and filtration also reduced indoor particle levels.