A survey of environmental tobacco smoke (ETS) controls in California office buildings was carried out to obtain information on the type and distribution of ETS controls in office buildings and to evaluate the effectiveness of various ETS controls. A total of 118 smoking areas in 111 county and city buildings were inspected to collect information on the type of ETS controls. Only 31 % of the smoking areas inspected were physically separated from nonsmoking areas with full floor-to-true-ceiling walls, 25% exhausted air to the outside, and 38% did not recirculate air to non-smoking areas.
This study compares the characteristics of two tracer gases - sulphur hexafluoride (SF 6), and nitrous oxide (N20) – whose densities are different from that of air (i.e. 5.11 and 1.53, respectively). The study is based on exclusively experimental work; and concerns the behaviour of the two gases with regard to their distribution and dispersion in an experimental cell, incorporating into the comparison method an index that is intended to characterise the ventilation of an enclosed space, namely ventilation etfectiveness,
This paper reports the design, development, calibration and testing of a fast-response, multi-channel tracer gas concentration measuring instrument. The instrument uses aninnovative application of Infrared Absorption techniques to measure Sulphur Hexafluoride (SF6) concentrations. This approach allows the overall cost of a multi-channel continuous-recording unit to be reduced without sacrificing overall performance. A calibration over the range of 5.0 to 50.0 ppm V SF6 is shown. The current measurement resolution is 0.06 ppm V, and the accuracy is + or - 5.0%.
This paper examines the influence of the tracer gas on the accuracy of the single tracer gas decay method for measurement of interzonal airflow. The use of sulphur hexafluoride (SF6), nitrous oxide N2O) and carbon dioxide (CO2) is examined for measurement of airflow between two tightly sealed chambers and these measurements are compared with measurements made using a calibrated flowmeter. Tracer gas measurements made using SF6 were found to be in closer agreement with flowmeter measurements than those made using N2O or CO2.
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