Risks for Spreading of Pollutants in Hospital Wards with Demands for Cleanliness

This master thesis studies the design and function of HVAC-systems in hospital wards concerning the risk of pollutant spreading. From a survey of an existing hospital building the study aims to identify risks for this spreading and illustrate the connection between pressure differences and directional airflow. An operating room and its direct surroundings have been studied closer. A clean indoor environment in hospitals is of great importance. Health care activities generate pollutants that can affect humans negatively and nosocomial infections are common among hospital treated patients. HVAC-systems’ design and function, together with hospital routines and the building design play important parts in the prevention of pollutant spreading. Differences in air pressure are the driving force for airflow. Pressure relationships between rooms are mainly created by HVAC-systems and by balancing the airflow to and from a room a positive or negative pressure relationship to adjoining rooms can be created. By this control of supply and exhaust air one can also control the direction of airflow between adjacent rooms. Airflow in ducts to operating rooms and pressure relationships between rooms in a hospital ward have been measured. Tests to investigate the airflow through openings in a closed door at various pressure differences have been performed. The test doors represent the real doors to operating rooms in the existing hospital