English

Reviews experimental techniques for determining the infiltration characteristics of buildings. Discusses the use of wind tunnel models to determine surface pressure distributions and ventilation rates. Reviews the measurement of open areas and leakages. Discusses correlation of measured leakage and ventilation. Describes the British Gas method of measuring ventilation rates using tracer gas. The system, known as "Autovent" provides a constant concentration of tracer gas and can be used for the continuous monitoring of ventilation rates.

Describes a dynamic pressure anemometer which belongs to the group of pressure-tube anemometers (pitot-static tubes) and is intended for measurement of one velocity component in a three dimensional flow field at air velocities of 0.1 to 10 m/s. The usable flow direction is unlimited (0...360 deg.) in three dimensions. The maximum error in the indication of the velocity component is less than 5% (if the actual velocity is put at 100%).

There is a need for correlating results of pressurization tests with infiltration tests, making it possible to predict the infiltration rate of a building on the basis of a pressurization test. Discusses problems with calculation models

Describes an automatic measurement system for air infiltration and discusses factors influencing the measurements in single rooms or in a group of connected rooms. The system works on the decay rate method and is controlled by a purpose-designed controller. The test data are evaluated off-line by computer. Discusses in detail the instrumentation and test procedure Gives results of measurements made in a detached house and correlations of the test data with wind and temperature difference data. Gives a comparison with pressurization data.

Presents a survey of tracer gas techniques for measuring air infiltration and includes a theoretical derivation of the equations, a description of each method, and a short description of the experimental procedure. Derives a qualitative error analysis which concentrates on mixing problems and uses it to compare the strengths and weaknesses of each method.< Derives the theory of multi-chamber infiltration measurements in situations involving many interconnected spaces (network type models).

Examines the problem of defining a mean wind speed which reflects the general characteristics of the surrounding terrain for the particular case of the area around Sheffield University. This problem has arisen in connection with the data analysis procedures for a full-scale wind force measurement project where a reference wind speed is required for data presentation.< Compares the mean wind structure over the area, taken from wind tunnel models with an analysis of data from three anemometers on site.

Presents a method of analysis to separately quantify the amounts of heat loss due to transmission and to air infiltration. The analysis is based on daily gas and electricity readings for a flat. Discusses three models for calculating heat losses; the regression model, the static thermal model andthe dynamic thermal model. Only the static and dynamic models have the ability to predict some of the individual terms in the heat balance equation.< Concludes that all three models may be used for a first estimate of the total amount of energy consumption.

Reports work done at the Building Research Establishment on natural ventilation rates. Outlines a current project in cooperation with BSRIA to determine whole house and individual ventilation rates in 30 houses. Also mentions work under way at the National Engineering Laboratory to develop a simple low-cost heat exchanger.

Briefly describes instrumentation and techniques for measuring concentrations of radon daughters in air. Reports measurements of radon daughter levels made in nine structures in Grand Junction, Colorado. Tailings from uranium mines had been used in their construction and measurements were made in the basement or first-floor of slab type structures. Gives results in the form of average concentration with standard deviation.

Describes a system which automatically operates a small gas chromatograph and measures parts per billion concentrations of sulphur hexafluoride in air. It samples air on a 10-minute cycle and records the response on a strip chart recorder. When SF6 in distributed in the air of a building, data is obtained from which air infiltration rates may be determined.