The study, carried out in an atmospheric wind tunnel (reproduction of natural wind conditions, particularly turbulence), quantifies wind flows around built-up obstacles in their realistic location context, and the associated pressure fields. For various types of buildings (detached house, block of flats), the article presents in illustrated form the chart of these flows and pressures in general (mean values, standard deviations, extreme values), but deals more specifically with the wind resistance of solar collectors.
A test method for determination of air flow resistance of exterior membranes and sheathings is described. The test specimen is placed between two chambers with different air pressures and the volumetric air flow rate through it at a steady state is determined. The relevant experimental quantities can presently be measured with precision better than 0.5% and with an accuracy of 2 to 3%, using commercial instruments. However, the instrumental precision does not mean much, due to the uncertainty introduced by material variability normally occurring in commercial products.
Describes use of water tanks to simulate two- and three-dimensional natural ventilation air flows through open doors and windows. Density differences are produced by dissolved salt. The technique is inexpensive and visualisation of flows through complicated patterns of doors and passageways, and even separate floors can be easily set up.
Describes qualitative experimental investigation of the air flow in a scale model representing a typical, average hall. Smoke was used to display the air flows. A mathematical model was also developed. Determination of the turbulent air flow in the model confirms the suitability of the mathematical model foruse in quantitative experiments, in particular for measuring the heat flux density.
Two techniques for estimating natural wind airflow through buildings for comfort cooling utilizing data derived from boundary layer wind tunnel studies are presented. One method is based on pressure and discharge coefficients. The other uses wind speed coefficients determined from model studies in a boundary layer wind tunnel.
This paper deals with a new computer program, MOVECOMP, which calculates the in- and exfiltration and the airflows between the rooms of a multicell building. The calculations are made due to wind and thermal forces and the characteristics of the leakage openings. MOVECOMP was developed to be user friendly: input data are limited and output data are very flexible. The userchooses which output he wants from a menu. The building is described with asystem of pressure nodes, connected to each other through flow-pressure difference functions.
Fan pressurization techniques are being employed by an increasingly large number of contractors and auditors to determine the leakage characteristics of structures. In this study, a large data base of flow exponents and flow coefficients are compiled to determine the degree of correlation that exists between flow parameters. The resulting empirical relationships are then used to determine the feasibility of predicting these flow parameters directly from a single pressure difference test. On the basis of these correlations, a new pressure independent tightness parameter is proposed.
Air leakage is the single most important quantity in the determination of air infiltration in residential structures. Air leakage is most commonly measured using the fan pressurization technique (ASTM standard E779): the data gathered with this method is often used to determine a leakage constant and a flow exponent. In this report, data gathered from measurements in the USA and Canada is compiled into a list of leakage constants and flow exponents, and the variability of these values over climate and housing types is examined.
The aerodynamic forces affecting wind and rain penetration of roofs are described. They are: 1 the wind and its turbulent nature, 2 the induced pressure field, 3 the air flows in contact with the roof and 4 the characteristics of the roof (internal pressure, permeability, structure, etc).
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.
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