Contaminant Air Propagation between Naturally Ventilated Scale Model Pig Buildings under Steady-state Conditions

Propagation of pathogens or viruses such as salmonella is a major concern. Such viruses can be spread by airborne transmission and it is important to understand the airflow between animal production buildings to limit or eradicate contamination. Wind tunnel tests were performed to examine how contaminant air transportation was affected by the distance between the buildings and the location of the contaminant source. Two identical scale models were used, one placed upwind and another downwind. Ethylene gas was used as the contaminant. The gas concentration and the airflow in and around the buildings were measured. It was found that the contaminated air reached the upwind building even if it was generated in the downwind building. When the contaminant was generated in the downward building, the concentration in the upwind building became 10−3 of the concentration of the contaminant source when the buildings were placed at a separation distance equal to the ridge height. However, it was diluted to a level of 10−5 when the separation building distance was three times of the ridge height. When the contaminant was generated in the upwind building, the contaminant concentrations in the downwind building were higher compared to the case of contaminant generated in the downwind building.