Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
ASSESSMENT OF VENTILATION RATES USING METABOLIC CO2 CONCENTRATIONS IN A SURGICAL ROOM CONDITIONED WITH A WINDOW/WALL AIR-CONDITIONING SYSTEM
Submission Author:
Marcelo Pereira , SC
Presenter: Marcelo Pereira
doi://10.26678/ABCM.ENCIT2016.CIT2016-0687
Abstract
For air-conditioning systems design, a medical facility can be considered to contain six general areas including Critical, Sensitive, Clinic, Administrative, Support areas, and Patient Bedroom areas. Then, different type of air-conditioning systems and air flow pattern are used not only to maintain minimum requirements of comfort and ventilation, but also for the control of infection, removal of noxious odors, dilution and expelling of contaminants, and establishment of special environmental conditions conducive to medical procedures and patient healing. The type of system employed will have a significant influence on air flow patterns within the building and can have a significant impact on the indoor air quality. On account of easy handling and installation, as well as economic considerations, window/wall air-conditioning systems are used in many surgical rooms. Therefore, the objective of this study is to assess ventilation rates (outdoor air ventilation (cfm)), using metabolic CO2 as a natural tracer gas, in a surgical room conditioned with a window/wall air-conditioning system. CO2 concentration and occupancy were monitored in the room during surgical procedure. Ventilation rate provided by the window/wall air-conditioning system was estimated, based on CO2 generation, CO2 measured and room occupancy. Ventilation rate required to maintain the indoor CO2 concentration within acceptable levels (1000 ppm) was calculated, and then compared with the real ventilation rate provided by the window/wall air-conditioning system. The results showed that CO2 concentration increased continually during the whole surgical procedure, reaching approximately 3000 ppm (1000 ppm recommended by standards). These values represent that almost three times less outdoor ventilation was provided by the system than was necessary to maintain good indoor air quality. Consequently, the ventilation rate required, in order to maintain acceptable CO2 levels, was higher than provided by the window/wall system, especially when the room occupancy increased. This suggests that window/wall air-conditioning systems are not suitable for use in surgical rooms due to their insufficient renovation with outdoor air.
Keywords
aerial contamination, surgical room, Air conditioning system, infection, Ventilation
