Reports results of studies conducted in Switzerland in small apartment buildings. Air change rates were measured in ten different apartment buildings using N2O as a tracer gas. Measurements were taken for various wind conditions andtemperature differences and with the windows partly open. Finds that ventilation rate increased by a factor of 4 when the windows on one facade were opened by only a few centimetres.
The airtightness of windows is an important feature in deciding habitability. in additional to the conventional, the window sashes featuring improved soundproofing and insulation performance have appeared. Summarizes the results of measurements of the air-tightness of these sashes made using carbon dioxide as a tracer gas, as well as double sliding and single sliding windows using actual size samples. Explains experimental apparatus and measuring method.
Proposes a method for measuring the rate of air change in factories using ammonia as a tracer gas and measuring its rate of decay by a colorimetric method. The advantage is that extremely small quantities can be detected. The method is cheap, easy to use, reasonably accurate and unobjectionable to the occupants.
Discusses the principles involved in measuring air change rates using tracers and gives the theory. Outlines the preparation of the tracer and the test procedure in stables. Finds that satisfactory results can be obtained when the concentration of krypton-85 is only one tenth of the maximum allowable. Lists the advantages of the method.
Ventilation rates in two test home were measured using helium as a tracer gas. Pressure differences across the exterior walls of the house were recorded using pressure taps. Gives results for air infiltration tests and the calculated air infiltration. Finds that during summer air infiltration rates varied approximately linearly with wind velocity. During the winter, the pattern and extent of air infiltration were influenced by both house stack action and furnace operation.
Reports investigation of air change rates in two residences using helium as a tracer gas. Gives results of measured air change rates, wind speed and direction and internal to external temperature difference. Uses statistical method to compare results from the two residences and concludes that temperature coefficients were statistically different but that wind coefficients were not. Finds high dependence of infiltration rates on indoor to outdoor temperature difference and that values for air leakage obtained from current methods of estimation were lower than those actually experienced.
Examines the use of radioisotope tracers to measure ventilation rates of simple and multiple enclosures. Discusses accuracy of the methods in relation to results obtained in an experimental room with controlled ventilation. Describes an instrument which measures ventilation rates directly, following release of aradioisotope tracer. Demonstrates its accuracy and operating advantages.
Describes retrofitting a wood-frame residence, having only limited insulation in the attic, to reduce its energy requirements for heating and cooling. The three retrofit stages comprised : reducing air leaks ; adding storm windows : andinstalling insulation in the floor, ceiling and walls. The housewas extensively insulated to evaluate energy savings and other performance factors. an economic model was used to evaluate the cost effectiveness of the retrofit options.
Describes the results of an investigation carried out to determine the rate of fresh air infiltration that is experienced during the winter in a modern air conditioned office building. Six different methods were employed to estimate the rate of infiltration through the building, four by direct measurement and two by calculation. The methods of direct measurement were,tracer gas decay, measured air flow through one floor, measured air flow through one air conditioning unit and measured change on power demand.
Describes method of measuring the air-change rates using sulphur hexafluoride as a tracer gas. The system comprises a highly portable gas chromatograph with an electron capture detector. The system will detect tracer gas without interference from other materials which may be present. The technique takes about six minutes to determine the ventilation rate. Gives practical examples and suggest extensions of the technique for carrying out cross air movements, for example in a hospital.
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