1998 Volume 18 Issue Supplement1 Pages 51-54
Field tests for air change rates in a test house were performed to develop a new method of measuring air change rates using a video imaging technique. Air change rates were measured from the decay curves of video image signals obtained by the step down method assuming perfect mixing of smoke particles inside the spaces. With the proposed video method by adjusting the pedestal level and f-stop of the video camera, it was possible to measure air change rates with virtually the same precision as derived from the decay curves of smoke particle concentrations using an aerosol monitor. As a new tracer, smoke liquid mists without dirty residuals were also tested and compared to the gas method using SF 6. It was verified that the video method using smoke liquid mists could also precisely measure air change rates with an error of less than 6% in comparison with the gas method.
