Measurement of ventilation rate in livestock buildings with radioactive tracer gas technique: Theory and methodology

Abstract

Natural ventilation systems are commonly used in livestock buildings, where the natural ventilation is a more energy efficient approach to provide effective ventilation. The foremost predicament of natural ventilation is the lack of precise, continuous and direct measuring techniques for ventilation rates, which is critical for monitoring gaseous emissions in livestock buildings for controlling the indoor air quality. Several ventilation rate measurement methods have been reported in the literature. However, these methods have some limitations and errors. The objectives of this study are to investigate the different tracer gas techniques (TGTs) especially using a radioactive tracer gas, to elucidate the applied methodology and instrumentation required and to investigate the methods of data analysis with results using radioactive TGT. The paper presents the technique of radioactive tracer gas preparation in the isotopes laboratory, tools used, the release methods, and locations, and calculations. This study has initiated a development of a radioactive TGT for an accurate determination of ventilation rates in naturally ventilated animal buildings. The radioactive TGT can be applied to other larger naturally ventilated buildings, such as warehouses, aircraft hangers and depositories, as well as to smaller rooms such as offices, class rooms and store.