Microclimate and Indoor Air Quality in an Operating Theatre under real use conditions: an experimental and numerical investigation

In the present chapter, the authors deal with the complex task concerning reduction of airborne contaminants while maintaining an optimal microclimate and indoor air quality (IAQ) inside an operating theatre (OT) using experimental measurements and computational fluid dynamic (CFD) simulations. This question is particularly important when the OT real use conditions introduce further unexpected constraints during functioning, with reduction of unidirectional/turbulent air flow efficacy and air quality levels. The authors argue our investigation on the airflow patterns in a real OT and the influence of incorrect operational use conditions, due to surgical staff movements and sliding door opening/closing, on air temperature, velocity distribution and pollutant diffusion. The research, presented and discussed in this chapter, is based on experimental and numerical studies developed to solve fluid dynamics and thermal fields, and then to monitor ventilation efficiency, CO2 and particle concentration in the OT global environment, as well as in the ASHRAE zones. Implementation, solution and post-processing of Finite Element models were performed by multi-physical commercial software. A particular procedure was implemented in order to simulate dynamics due to sliding door and people moving effects on the airflow, that belongs to the indirect approach for a numerical simulation of solid object movements in a fluid. An innovative method was also proposed to estimate, by an iterative comparison between experimental data and numerical results, the emission rate of particles (differentiated by diameters) released by the occupants to be considered as source terms in the numerical model. Air temperature and velocity values and contaminant concentration were compared with threshold standard values. Some crucial indoor air quality (IAQ) indexes were evaluated. In the development of this chapter, the authors provide a better understanding of the effect of additional environmental “load”, induced by real use conditions on microclimate and IAQ of the OT.