Reports pressurization tests on eleven schools both with the air handling system on and with it off. Obtains air leakage through components of the building by comparing overall leakage rates before and after sealing each component. Uses leakage rates to calculate air infiltration using a simplified model of a school building. Finds that infiltration caused by stack effect is significant even for a single-storey building.
Describes sealing houses against air infiltration to allow controlled ventilation. Notes inherent risks in poor ventilation such as high radon content and its associated decay products, poor air quality, moisture, condensation, mould and allergy-producing dust particles. Treats requirements in swedish building code and stipulated minimum air change rate. Comprehensive series of graphs illustrates air change rate as function of wind speed and different grades of building air tightness.
Presents method for establishing conditions and an acceptance criterion for window air-tightness testing in relation to average energy (heating) saving per winter. Uses wind velocity data from israeli meteorological station of Ashdod to demonstrate difference between various methods of evaluating design wind velocity. Uses 41 different typical dwellings to determine unique criterion for acceptable air leakage under test conditions which ensures average of 1 air change per hour in most Israeli dwellings.
Reports theoretical and experimental calculations of heat balance of 5 houses. Discusses the extent of air leakage and various factors contributing to heat losses, particularly effects of wind and winter temperatures. Normal air leakage is 0. 5-0.7 air changes/h, mainly through chimneys, air outlets, window, and door cracks. Air leakage of floor, door, and roofs is 0.1-0.2 air changes/h. in winter, temperature differences have the same influence on ventilation as wind velocity. Measurements in attics show 3 air changes/h. This is largely dependent on wind velocity.
Discusses current knowledge concerning wind-induced ventilation in buildings. states major difficulty in estimating ventilation and infiltration rates in a building is ignorance of wind pressure distributions around structures. Examines properties of wind with special reference to mean velocity profiles, characteristics of turbulence and wind energy spectrum. Reviews internal and external pressure distributions on an isolated building. Studies effect of grouping of buildings on pressure distribution around a house by considering results of wind tunnel tests.
States that high-rise buildings can cause problems to occupants particularly since wind velocity and pressure fluctuations will be more pronounced than at ground level. Outlines ways in which smoke from chimneys can cause difficulties and gives reasons for difficulties when ventilating or air conditioning high-rise buildings. Recommends testing a model of the building in a windtunnel; lists points to be investigated; discusses rules for scaling giving formulae and outlines the testing procedure.
Investigates energy balance of centrally heated flat at coastal town of Kijkduin, based on daily figures of gas consumption and ventilation losses derived from meteorological conditions. Studies: 1) pressure difference over the building caused by windvelocity, wind direction and outdoor air temperature; 2) natural ventilation caused by pressure differences over fortuitous cracks and intentional opening of windows, grilles and shafts. Studies possibility of ventilation prediction via mathematical model.
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