The typical infiltration load for a residential building has been found to range from one-third to one-half of the total space conditioning load. However, most infiltration measurements have been made on single-family houses.
Instruments full-scale agricultural and horticultural buildings with surface pressure sensors to measure wind loads under natural wind conditions. To show the effect of building geometry on wind loads, presents results of pressure coefficients on a selection of these buildings. The results in this report relate to transverse wind direction only. Shows that wind load does not reduce to a function of the geometric variables of height/span and roof pitch.
Describes a comprehensive investigation undertaken to determine the wind pressures on surfaces of models of typical low-rise buildings. For many practical applications building surfaces like facade coverings or tiled roofs are permeable. For those coverings the pressure equilibration across thepermeable surface is important when determining the net windload. Gives a survey of the physical parameters influencing the windload of permeable surface coverings. Presents results of a continuing study of the wind load on permeable facade coverings.
Uses wind tunnel model studies of houses to determine how best to reduce the surface pressure variations from wind and the associated air infiltration emphasizing the correct placement of suitably modelled coniferous trees. Finds that tree crowns convert the directed kinetic energy of approaching wind into random turbulent energy, which reduces pressure gradients on the windward walls, a prime region for air infiltration.
Compares measurements of surface pressure and response on the CAARC standard tall building model, made at 6 establishments. In general, the degree of accuracy is good and mostly within the scatter of reasonable experimental accuracy. Observes small trends in respect of pressure measurements which could be attributed to differences in the approaching longitudinal velocity spectrum and to the requirement for blockage corrections. Finds no obvious trends in the dynamic response measurements, where the majority of the data compares within +-15%.
Discusses the evaluation of building surface pressures resulting from the action of external wind, the modelling of individual components through which air flows, the determination of their characteristics under the action of pressure and temperature differences, and the solution of large airflow networks consisting of several such dissimilar components. Describes the integration of airflow calculations with heat transfer calculations in an attempt to produce a balanced approach to the determination of energy requirements for buildings.
States that it is accepted practice to determine wind effects on and around a building by measurements in a scaled model in a boundary-layer wind tunnel. At large scales of reproduction it is impossible to simulate the entire depth of the atm
Describes LBL's Mobile Infiltration Test Unit (MITU) which spent the 1980-1981 winter in the field collecting the data required for infiltration modelling. Data included measured infiltration rates, surface pressures, wind velocities, indoor and outdoor temperatures, leakage area and leakage distribution. Comparisons of measured infiltration rates with values calculated from surface pressures (using MITU) have shown no decrease in accuracy when a square-root flow model is used instead of the general power-fit model of leakage.
Investigates a rational method of utilizing recent improvements in wind tunnel techniques and meteorological data, to estimate potential wind-generated air flow through housing in hot humid climates. The method uses mean pressure differences obtained from solid wind tunnel models together with appropriate discharge coefficients for rectangular openings. Changes in pressure distributions due to typical openings through models indicated that the use of pressure data from solid models results in errors similar to those associated with the local wind data.
Compares full-scale pressure coefficients obtained from a 57-storey building in Toronto with wind tunnel results for tests in the 9m by 9m wind tunnel at the National Research Council of Canada. Demonstrates good agreement where sufficient full-scale data exists. Proposes a method of treating peak pressures based on the fit of an exponential distribution to a population of "significant independent events", called pressure spikes. This distribution provides a good fit to both full-scale and wind tunnel results, which generally agree.
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