Ventilation measurement using spot sampling of sulphur hexafluoride on a solid adsorbent

A technique for measuring the ventilation rate using spot sampling of sulphur hexafluoride (SF₆) on a solid adsorbent for subsequent thermal desorption and gas chromatographic analysis has been developed. This paper describes the mathematical model used, the analytical details of the technique, as well as results from a validation test using an experimental chamber. The mathematical model assumes an exponential decay of the tracer gas concentration. The precision of the analytical procedure was estimated to be better than 9% whilst the error of the measured ventilation rate of the test chamber was 5%.