A steady state multi-cell calculation model has been developed in order to predict the interconnection between airtightness and ventilation rates. The model has been tested with measured leakage data of a detached house.
For optimum building design it is of importance to investigate the comfort and the energy conservation obtained with different types of ventilation systems and levels of airtightness of buildings. This could be achieved by aid of computer models based on full-scale and model measurements. In order to obtain experimental data as input data to such a computer model, an experimental, detached one-family house has been built near to Gothenburg on the Swedish west coast.
The total energy consumption for five detached houses with air change rates of around 3 per hour right after construction, was measured and compared with estimated values, over a three-year period. Air change in the bedrooms was also measured. It was found that the recommended value was only obtained in very tight houses. If two windows are open, the ventilation system is partly short-circuited. A modified exhaust air ventilation system was designed to provide a sufficient air change in the bedroom with a reduced total air changein the house as a whole.
Natural and forced ventilation are directly and indirectly influenced by the pressure distribution around a building. Results of full-scale pressure measurements on a typical Swedish timber house are presented. The rate of air infiltration has been calculated by employing the values obtained from full-scale pressure distribution, air leakage characteristics and temperature differences. The results are compared with the actual ventilation obtained from tracer gas measurements.
Research was undertaken to provide buildings equipped with mechanical exhaust ventilation systems or natural ventilation with reasonable draught-free efficient ventilation. One possible solution for existing detached houses and multi-storey residential buildings is a supply air window. Recent research in Finland shows that, for the best method, about 6.0 dm3/s of outdoor air per light area m2 can be taken in through the wooden construction double-paned window without draught. The incoming air was heated to about 50% of thetemperature difference between the inner and outer air.
This survey describes how external walls and joints are constructed in practice. The paper gives you an opportunity to compare how successful the implementation of airtightness has been in Sweden in comparison with the results presented in the report D2:1983 "Air infiltration control ..." by A Elmroth and P Levin. The survey covers the majority of all Swedish prefabricated single family houses constructed in 1984. All big prefabrication companies are included in the survey.
Roof space ventilation is necessary to evacuate water vapour to avoid condensation and to conserve the wooden roof supports. It has been affected by 1. increased insulation, 2. snow screens fitted under the roof, 3. increased humidity due to
Since 1970 measurements of air change rate have been carried out in about one thousand buildings by the Swedish Institute for Building Research (SIB). In this paper we present results from these measurements. The studied buildings are of various design and have ventilation systems of different types, natural as well as mechanical. The buildings include single family houses, row houses, and multi family residential buildings, erected between 1900 and 1982. The measurements have then been carried out using tracer gas (decay) techniques to determine the rate of air exchange.
In 1981 Norwegian building regulations introduced quantitative requirements to air leakages in different types of buildings. The requirements were formed as maximum allowed air changes per hour at 50 Pa pressure difference according to the pressurization method. To evaluate the consequences of these new requirementsimposed to Norwegian building industry a model proposed by the Nordic Committee for Building Regulations (NKB) was used. The average air leakages of residential buildings , built before the new requirements,are known through a research project performed i n 1979.
Air change rates were measured in one two-storey detached house with five basic types of passive ventilation systems: an intake vent in the basement wall, an outdoor air supply ducted to the existing forced air heating system, an exhaust stack extending from the basement to the roof, and two combinations of the supply systems and the exhaust stack. An expression was developed for estimating house air change rate from house airtightness, neutral pressure level and indoor-outdoor air temperature difference.
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