This paper describes a framework and methodology for developing and evaluating surveys of occupants for indoor air quality studies. Factors to be studied, and how they can be classified, are addressed. How the often substantial information can be obtained in a stepwise fashion without burdening theparticipant unduly, and ways of judging the efficacy of the questions are also discussed.
As part of a programme to develop measurement methods for determining the ventilation rates of large buildings, we performed two series of tests in a single-celled laboratory with a volume of 600m3. The first series utilised constant concentration, constant emission and rate of decay tracer gas techniques to determine the characteristics of the infiltration pattern in varying winds and external temperatures. We used both discrete and continuous injection and sampling methods.
Describes the technique employed, including the mathematical model as well as results from a validation test using an experimental chamber. The model assumes an exponential decay of the tracer gas concentration. The precision of the analytical procedure is estimated at better than 9%, while the error of the measured ventilation rate of the test chamber was 5%.
Describes three research programmes measuring tightness of components, of specific areas of a building and of complete buildings. Defines the Belgian standards currently applicable. For air tightness, the area or building is depressurized by 5 to 100 Pa and the flow of air that enters is measured. Thenthe components are made air tight one by one, and each time the new flow rate is measured to give values for the different components. The specific area alone can be depressurized, the specific area plus the whole building or just the whole building.
Describes measurements made in a real factory building and comparisons with the scale model tests presented in the previous report. The ventilation system of the factory building is a mechanical one with the necessary rate of ventilation designed to be less than that calculated by the conventional method. The parameters studied included air velocities measured with hotwire anemometers at the inlet openings and the temperatures in the work hall itself measured from a crane.
Notes the considerable savings in heating energy that could be made if ventilation rates could be modulated so that only the requirements of the actual number of occupants was supplied. Explains how this can be done by ventilating to maintain a constant concentration of carbon dioxide. Describes carbon dioxide monitoring system based on infrared absorptiometry. Illustrates diagrammatically the layout of a cinema ventilation system which monitors carbon dioxide levels and explains its operation. Notes other buildings where the system is used.
Measurements of radon and radon daughters in 11 buildings in five states, using active or passive solar heating showed no significant increase in concentration over the levels measured in buildings with conventional heating systems. Radon levels in two buildings using rock storage in their active solar systems exceeded the U.S. Nuclear Regulatory Commission's 10 CFR 20 limit of 3 pCi/l for continuous exposure. In the remainder of the buildings, radon concentrations were found to be at levels considered to be normal.
Radon concentrations were measured in about 1000 Dutch dwellings and at 200 outside locations using passive monitors. A median concentration of 24 Bq/m3 was found for the dwellings with a highest value of 190 Bq/m3. Seasonal effects were found to be small. Correlations were observed between median radon concentrations and construction parameters including ventilation rate. The concentrations outside show an unexpected dependence on the location. Comparison with previous grab-sampling data on radon-daughter concentrations reveals an average equilibrium factor of 0.3.
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