Shows by comparison with simplified methods for dimensioning structural beams that the degree of tightness of a shell is not the arithmetic sum of the leakage of components. States that leakage occurs where there is a pressure difference caused by wind, temperature difference and fans. The amount of leakage depends on whether the air flow is laminar or turbulent. Gives equations for the calculation of leakage in buildings without ventilation, with natural ventilation, with mechanical evacuation and with both mechanical inlet and evacuation.
States that considerable research has been carried out in Sweden in an attempt to conserve energy. Results of measurements of air infiltration obtained with tracer gas do not correspond well with those obtained by a pressure method. Air leakage in frame houses has been higher than expected. States need for air-tight components and reviews the consequences of tighter houses.
Describes the two major methods of measuring air leakage in buildings; the tracer gas method and the pressure method. The three ways of using tracer gas are with decreasing gas concentration, constant gas concentration, and with constant gasrelease. In Sweden nitrous oxide is normally used. The results of the tracer gas method may depend on the weather at the time of measurement. The pressure method is fast and accurate, but only gives the total leakage through the building. Local differences can be detected by use of infrared photography.
Reports two-year programme to evaluate the effect of air infiltration on the heating needs of 29 electrically heated homes. Air-change rates before and after retrofitting tominimize infiltration were measured by a pressure method and heat energy consumption and occupancy effects were monitored. Thirty similar homes were also tested for infiltration and retained as controls.< Describes the retrofit methods, their effect upon the induced air infiltration, the other data which are being collected, and the data analyses which are expected at the completion of the programme.
States that aim of research project is to develop a method of testing entire buildings for air infiltration. Suggests apressure method using a powerful fan to pressurize or depressurize the house and measuring air flow through the fan and internal pressure to give a figure for air infiltration.
Presents method for collecting air infiltration data in a large sample of dwellings. The method consists of a tracer gas dilution technique using sulphur hexafluoride and employing air sample bags which are analyzed in a central laboratory. Themethod is easy to perform and inexpensive and will be used in approximately 300 dwellings on 16 sites to give air exchange rates under typical heating season conditions. Presents preliminary data on air infiltration rates in low-income housing in Portland, Maine.
Describes briefly mechanisms and sources by which air infiltration occurs in dwellings. Compares leakage rates through windows and through houses with european standards to illustrate values that can occur in the U.K. Discusses importance of infiltration to both natural and mechanical ventilation and gives examples of the ways in which infiltration can adversely affect the thermal environment in well insulated dwelling. Concludes that more attention should be paid to infiltration through adventitious openings including improving building construction to minimise infiltration.
Summarizes measurements made on a flat. These include inside to outside temperature and pressure differences, infiltration rates using helium as a tracer gas, duration of opening windows and doors and weather conditions. Also describes wind tunnel measurements made on a model of the building with and without obstacles and terrain roughness.
Gives a summary of the work in building thermography in the scandinavian countries, especially Sweden. Deals with the principles of thermography, how to detect thermal resistance deficiencies and air leakage. Discusses applications in building and factors influencing the thermograms. Reviews test requirements in Scandinavia and discusses the results of measurements made on about 500 building projects.
Suggests the use of sound waves to locate openings in buildings that allow air infiltration. Reports results of an experimental program, including laboratory tests of a specially constructed partition and field tests on eight buildings.
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