Microclimatic and Ventilation Conditions in Existing Healthcare Facilities. A Study in the Waiting Room-Testing Centre of a Florentine Historic Hospital Carla Balocco 1* , Gerardo Lorenzo Petrone 2 1 Department of Architecture, DiDA, University of Florence, via Mattonaia 14, Firenze, Italy 2 Freelance Civil Engineering of the Sani-Ingegneria, via S. Reparata 40, Firenze, Italy Corresponding Author Email: carla.balocco@unifi.it https://doi.org/10.18280/ti-ijes.652-427 ABSTRACT Received: 26 March 2021 Accepted: 12 May 2021 The pandemic COVID-19 era we are experiencing has changed our way of seeing, thinking and designing indoor and outdoor environments and, above all, plant systems and building- plant management. Energy environmental sustainability is a common fundamental target for buildings and plant systems, but health protection and prevention are the priority issues for the basis of any retrofitting and refurbishment operation. This question becomes even more complex if the building is historic and used for hospital or for healthcare facilities. In this research we propose a methodological approach based on the combination of physical-real and “virtual”, i.e. measured and simulated information. The proposed method can be a useful tool for setting up continuous monitoring systems for microclimatic and ventilation conditions, user influx/presence and behaviour, real operation (on demand) of the plants and control/regulation system adjustment. Results show the importance of drawing up useful guidelines for training health workers and people/patient subjects, aiming at conscious interaction for health and wellbeing protection, but also better indoor environment management. This is particularly important for healthcare environments such as the one studied. Keywords: experimental monitoring, CFD, ventilation effectiveness, people health, historic hospital 1. INTRODUCTION It is well known that energy efficiency is a common task for buildings and related plant systems, but the issue concerning health risk prevention deriving from environmental and pollution factors, microorganism dispersion and environmental and surface contamination, has become a priority, so much so that it requires the involvement of different competent subjects and imposes an integrated interdisciplinary approach [1-7]. On the other hand, among stakeholders, researchers, technicians and public decision makers, awareness of the importance of indoor air quality (IAQ) for guaranteeing people's health and wellbeing is on the increase [8]. Crucial findings have been discussed by recent literature and research concerning experimental and simulated investigation on IAQ, effective ventilation, and occupant behaviour and satisfaction inside historic, existing and newly designed energy-efficient buildings. These studies highlighted the fact that low energy consumption, IAQ, efficiency and efficacy of different air flow patterns and behaviour and self- reported occupant wellbeing can be obtained by integrating solutions for building physics improvement and controlled mechanical ventilation systems [9-12]. Moreover, the current standards and provisions on IAQ, controlled mechanical ventilation, hygiene, health and prevention of contagion risks, imposed by international and national organizations (i.e. WHO, ASHRAE, RHEVA, AICARR and ISS), suggest that heating, ventilation and air conditioning plants (HVAC) must be working 24 hours a day and continuously 7 days a week, without air recirculation and possibly with night attenuation also provided for periods of environmental non-occupation [13-23]. As a consequence, controlled mechanical ventilation systems must be equipped with high air filtration systems without recirculation and with large air flows to be treated. Most of the literature on this subject shows how the IAQ and infection risks are closely related to the air flow field and specific air flow patterns, internal pressure regimes, indoor thermo-hygrometric conditions, air filtration systems, as well as the correct maintenance and cleaning of plants and their components [1, 11]. Therefore, plant adaptation, retrofitting and refurbishment design solutions for existing buildings and in some cases that are also historical and also subject to protection and conservation constraints, are very complex issues. Any intervention solution must find a compromise between energy saving, energy costs necessary to ensure ventilation effectiveness and air quality, health protection of people and cultural heritage objects. Physical distancing and the increase in natural ventilation, both with automatic and manual techniques, are not sufficient to ensure health protection and reduction of contagion and contamination risks. In this research, a methodological approach based on the combination of physical-real and “virtual”, i.e. measured and simulated information, is developed. The proposed method can therefore be a useful tool for setting up continuous monitoring systems on microclimate and ventilation systems, on user influx/presence and his behaviour, on the real operation (on demand) of the plants and control systems and their adjustment/management. The results obtained show the importance of drawing up useful guidelines for subject (i.e. health workers and people/patients) training and orientation towards a conscious interaction for health protection and wellbeing, but also for better management of environmental TECNICA ITALIANA-Italian Journal of Engineering Science Vol. 65, No. 2-4, July, 2021, pp. 317-323 Journal homepage: http://iieta.org/journals/ti-ijes 317