A comparative study of two tracer gases: SF6 and N2O.

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,

Appraisal of the regulations governing the use of gas powered domestic appliances having consideration of NOx emissions.

Domestic gas apparatus generate oxides of nitrogen (NOx), which have been classed in recent years as problem products in the context of indoor air quality (IAQ). These, together with carbon monoxide which may also be present in the products of gas combustion, mean that the formulation of regulations for health protection presents complex problems. The present work shows the importance of this matter and presents interesting case studies taken from the Basque Country and our area of influence. It also makes specific recommendations as to how existing regulations should be changed.

The influence of tracer gases on the accuracy of interzonal airflow measurements.

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.