Reviews air infiltration measurement methods, prediction models, and flow through components of buildings. Attempts to construct a device capable of measuring air flow through a building component under a given pressure difference and to investigate the existence of a coefficient which, when multiplied by the pressure difference, raised to an exponent, will yield the air flow through that component. Components were tested under differing pressure differences and the testing device was calibrated by a tracer gas technique.
Describes three research programmes measuring tightness of components, of specific areas of a building and of complete buildings. Defines the Belgian standards currently applicable. For air tightness, the area or building is depressurized by 5 to 100 Pa and the flow of air that enters is measured. Thenthe components are made air tight one by one, and each time the new flow rate is measured to give values for the different components. The specific area alone can be depressurized, the specific area plus the whole building or just the whole building.
The main objectives are 1) the collection, processing and evaluation of leakage data for opening doors and windows, obtained from certifications or tests, 2) evaluation of the influence of building technologies and component materials on leakage, 3) experimental evaluation of the reasons for the choice of wall/frame combination and of the relative components and 4) experimental evaluation of the correlation between air leakage and sound insulation in order to define new methods of acoustic measurement of air leakage for components after installation.
The heating and cooling loads due to air infiltration may be estimated by a mathematical model that requires knowledge of the leakage characteristics of each component of the envelope. To extend the modelisation to the pitched roofs common in Portugal, characteristics of roofs were determined by a differential pressure method.
Measures air permeability of 21 facades of occupied dwellings. Investigates what proportion of air permeability is due to various gaps (moveable sections) and joints (between fixed sections) in 12 of the facades. Results show that the contribution of joints to air permeability is greater than mentioned in the Dutch Standard NEN 3661. This standard stipulates conditions with regard to the manufacture of facade elements. It is apparent that the gaps of 5 out of the 12 measured facades do not meet the minimum requirements of the standard.
This is the second part of a study on natural ventilation in functional buildings. Reports the results of 23 measurements on a number of partitions, internal walls and one brick built internal wall. Measurements were made in 4 buildings. For the largest leakages measured in these 4 buildings, a strong influence was observed on the ventilation of neighbouring rooms. The opening of a window in a room has notable consequences on the ventilation and air flow in the other rooms. The measured air leakages ranged from 0038 to 0.068 m2 for a wall and .0131 -.0529 m2 for a room.
Reviews recent research in residential infiltration with an analysis of how the results are utilized in the design-build process. Identifies component testing as the research area most applicable to practical application efforts. Provides component and assembly test data. Discusses the need to reorient certain research efforts to more practically meet the needs of the residential industry. Presents clarifications and extensions of recently published work on component leakge.
Examines the sensitivity of the predicted air infiltration rate to measured building air tightness data and the wind exposure index determined from site inspection. Presents results of air tightness tests in New Zealand houses, which indicate the range of leakage resistance for components, for solid materials (such as wall and ceiling lining materials) and for cracks separating major components such as floors and walls.
Assesses energy saving as a function of window air tightness, and transforms value into a corresponding U-value. Uses a single-cell infiltration model, and shows that using the U-value is a convenient way of comparing different energy saving methods. As an example, computes the U-value for the windows in a detached single-family house in an urban area and for Gothenburg weather conditions.
A major pathway for loss of conditioned air in east Tennessee homes with externally located HVAC systems is leakage in the ductwork. The effect on infiltration rates, as measured by Freon-12 tracer gas dilution, becomes marked if the central duct fan is operating. Duct fan on and duct fan off measurements of the rate of air exchange gave mean values of 0.41 and 0.78 ach respectively in a total of 31 homes.
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