Reduced exposure to coughed air by a novel ventilation method for hospital patient rooms

Zhecho Dimitrov Bolashikov, Arsen Krikor Melikov, Marek Brand

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A novel hospital bed integrated ventilation and cleaning unit (HBIVCU) for local airflow control and cleansing, limiting the airborne spread of contagious air coughed from a sick patient in a hospital room, was developed. The performance efficiency of the unit, to successfully reduce occupants’ exposure to coughed air, was studied in a full-scale, two-bed hospital room mock-up, 4.65 m x 4.65 m x 2.60 m (W x L x H), with two patients and a doctor. Four units were placed along the two sides of both beds close to the head. The room was ventilated by overhead mixing air distribution at 22 °C room air temperature. The sick coughing patient was simulated by a heated dummy with simplified geometry equipped with a cough generator. Similar heated dummy was used for the second patient. A dressed breathing thermal manikin with realistic human body and surface temperature was used to mimic a doctor standing beside the bed and facing the coughing patient. The generated cough consisted of 100% CO2. The mouth was simulated by a circular opening of 0.021 m diameter. The characteristics of the cough were: peak flow - 10 L/s, cough volume - 2.5 L, duration - 0.5 s and maximum velocity - 28.9 m/s. The performance of the novel unit, at background ventilation rates of 3 h-1and 6 h-1, was evaluated by measuring the excess CO2 concentration at the mouth of both the doctor and the exposed patient. When the novel method was not used, the CO2 concentration (exposure) measured in the air “inhaled” by the doctor exceeded 20 times the background CO2 level and more than 12 times for the exposed patient. No increase in the CO2 concentration in inhalation was measured for either the doctor or the second patient, when the HBIVCUs were operational.
Original languageEnglish
Title of host publicationProceedings of ICCCS 2012 - International Symposium on Contamination Control 2012
Number of pages6
Publication date2012
Article numberPaper ID: 111059
Publication statusPublished - 2012
EventInternational Symposium on Contamination Control (ICCCS) 2012 - Zurich, Switzerland
Duration: 3 Sep 20127 Sep 2012


ConferenceInternational Symposium on Contamination Control (ICCCS) 2012


  • Hospital Ventilation
  • Local control
  • Cough
  • Exposure
  • Concentration
  • physical measurements
  • Tracer gas

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