Sulfur hexafluoride tracer release

Burgess et al." describe a study of gas storage cabinets. In the study, coefficient of entry (CJ for various inlet/outlet configurations was measured. A tracer gas study is also described. The tracer gas study involved releasing sulfur hexafluoride (SF ) at 0.032 L s" at a critical leak position in the cabinet and measuring SFg concentration in the exhaust stream. The tracer gas was turned off when a steady exhaust stream concentration was observed and the time for the concentration to decay to 5% of steady state was measured. 

Routes of air-borne eontamination into BFS containers have been investigated during a study using sulfur hexafluoride (SFg) tracer gas [3]. During this experiment, the tracer gas was released into a elean room, housing an aseptic BFS machine, at a known concentration. Levels of the traeer gas were measured within subsequently filled BFS units. The study coneluded that the container was effeetively protected by the localized air shower. Although not necessarily representative of deposition of microbial contaminants, there was also eonclusive evidence of some room air within... 

Sulfur hexafluoride is very insoluble for small-scale experiments it can be dissolved by presaturating drums or tanks of water with the gas. However, the practical limit for the amount which can be injected in this way is a few moles, sufficient for tracer experiments on the 10-100 km scale only. For large open ocean releases, we designed an injection package which releases liquid SFg into water by pumping it through fine orifices at high pressure, so that it breaks into an emulsion of fine droplets on contact... 

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