This is done by means of a fan pressing air into the interior of a not air-tight greenhouse. The amount of exchanged air is measured by equipping the fan with a wind tunnel, it is depending on the difference of pressure between the inside and outside of the greenhouse. The difference of pressure and the air exchange figures are applied to the natural conditions in the case of different air velocities.

Comfort in an air-conditioned room depends to a high degree on the prevailing movement of air. As air velocities in excess of 0.1 m/sec can be regarded as draft phenomenon, a measuring device has been developed which will facilitate measurement to a sufficient accuracy and independent of any fluctuations in the air temperature even with low velocities.

Flow patterns at ground level in groups of buildings result from the complex interaction between the wind (impact, average speed distribution with height, and turbulence) and the buildings themselves (shapes, sizes, arrangements, etc.). The

One important factor in the spread of airborne infection must be the movement of the air itself i.e. the ventilation, although an exact correlation of it with the risk of infection has yet to be found. As part of an infection survey in a hospital ward we made a detailed study by physical methods of the movements of the air and of the transport of particles by this means. A description is given of the methods employed.

In the early stages of the project on thermal performance of our experimental masonry building, measurements were made to determine the magnitude of air exchange between the building and the surrounding chamber during the process of cyclic temperature changes. Since wind forces were negligible during the testing period,the major driving force influencing the change of air was the thermal difference between the air inside of the building and that of the surrounding air in the chamber.

Domestic demands account for about 40% of total energy supplies in Sweden. This article reviews research by the Building Technology Division of the Swedish Royal Institute of Technology over many years into the thermal behavior of houses. It highlights the importance of effective insulation and of solar heat gains in particular situations, entailing modifications to conventional design calculations.

Several empirical models of house air infiltration, available from the literature, were reviewed and evaluated. Without exception, the limitations, inherent in these models, were found to stem from inadequate accounting of the interactive forces controlling air infiltration. In general, each of the available models was found to accurately reflect the specific real case used for verification, but extension of the model to other structures and situations was found to be totally inadequate.

Reviews some of the results of the project "The requirement-adapted ventilation system", which is part of an extensive research project "Indoor air quality and ventilation requirements" begun in Finland in 1983. Deals with the results of field measurements in which the relationship between CO2, particles and combustible gases in various buildings were measured and analysed. Also presents results of tests with an air quality-controlled ventilation system in one building.

The air change rate in a single story office building was measured using atracer gas technique. The air change rate was determined by the rate of decay method using sulfur hexafluoride as the tracer gas. A total of eight tests were conduc