Exposure of health care workers and occupants to coughed air in a hospital room with displacement air distribution: impact of ventilation rate and distance from coughing patient

Arsen Krikor Melikov, Zhecho Dimitrov Bolashikov, Kamen Kostadinov, Wojciech Kierat, Zbigniew Popiolek

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Abstract

The exposure of a doctor and a second patient to coughed air by an infected patient was studied in a simulated two-bed hospital patient room. The air temperature in the room, ventilated at two air change rates (3 h-1 and 6 h-1) was kept 22 oC. Thermal manikin with realistic body shape and surface temperature distribution was used as the doctor standing 0.55, 1.1 or 2.8 m downstream the cough. A coughing thermal dummy, lying in one bed and a second thermal manikin in the other bed (1.3 m away), were used as the “sick” and the “exposed” patients. The cough consisted of 100% CO2. The doctor and the coughing patient faced each other. The Peak Cough Time (PCT) was around 6 s, when the doctor was 0.55 m downstream the cough and increased when the distance between the sick patient and the doctor increased. The highest Peak Concentration Level (PCL) for the doctor, i.e. excess of CO2 level in inhaled air above background concentration (ppm), for the three measured distances was at 6 h-1. PCL decreased with distance. The exposure of the second patient was low when the doctor was at 0.55 or 1.1 m downstream the cough (blocking effect), but was quite high when at 2.8 m. 6 h-1, recommended in present hospital standards as minimum ventilation rate in hospital patient rooms, resulted in elevated exposure to coughed air for the doctor, suggesting increased risk from airborne cross-infection. Displacement air distribution does not reduce the risk from cross-infection.
Original languageEnglish
Publication date2012
Number of pages6
Publication statusPublished - 2012
Event10th International Conference on Healthy Buildings - Brisbane Convention & Exhibition Centre, Brisbane, Australia
Duration: 8 Jul 201212 Jul 2012
Conference number: 10
http://hb2012.org/

Conference

Conference10th International Conference on Healthy Buildings
Number10
LocationBrisbane Convention & Exhibition Centre
CountryAustralia
CityBrisbane
Period08/07/201212/07/2012
Internet address

Keywords

  • Air distribution
  • Hospital patient room
  • Airborne cross infection
  • Coughing thermal manikin
  • Physical measurements

Cite this

Melikov, A. K., Bolashikov, Z. D., Kostadinov, K., Kierat, W., & Popiolek, Z. (2012). Exposure of health care workers and occupants to coughed air in a hospital room with displacement air distribution: impact of ventilation rate and distance from coughing patient. Paper presented at 10th International Conference on Healthy Buildings, Brisbane, Australia.