Architectural retrofit and multidisciplinary HVAC modernization with BIM methodology: A study of the Carlos Tortelly Municipal Hospital

The modernization of existing hospitals requires a multidisciplinary approach that integrates architecture, HVAC engineering and facility management throughout the entire building life cycle. In the Brazilian context, many hospitals constructed during the 1970s and 1980s present architectural and technical deficiencies when compared to current requirements for indoor air quality, ventilation performance, energy efficiency and infection control. The Carlos Tortelly Municipal Hospital, inaugurated in 1982 in the city of Niterói and continuously operating for more than four decades, exemplifies this condition and demands retrofit strategies that go beyond the replacement of HVAC equipment. This paper analyzes the HVAC modernization of typical outpatient environments of the Carlos Tortelly Municipal Hospital through the application of Building Information Modeling (BIM), from diagnostic and design stages to performance verification. BIM is addressed not only as a multidisciplinary coordination tool, but as a platform for BIM-based compliance checking, integrating architectural constraints, HVAC systems and regulatory requirements. This approach enables the evaluation of outdoor air ventilation rate, air change rate (ACH), filtration stages, pressure differential and humidity control under the hot and humid climate of Niterói, in accordance with Brazilian healthcare ventilation standards. The methodology combines on-site technical inspections, document analysis, multidisciplinary BIM modeling and environmental performance simulations, supported by climatic data analysis and a quantitative comparison between alternative outdoor air treatment strategies. Quantitative parameters were primarily defined based on ABNT NBR 7256:2022 and complemented, when necessary, by international standards. The results demonstrate that BIM-based retrofit strategies can significantly improve indoor environmental quality and regulatory compliance in existing public hospitals, even under severe spatial and operational constraints. The study confirms BIM as an effective framework for integrating HVAC performance, architectural retrofit and facility management, contributing to resilience, sustainability and long-term operational reliability in medium-sized public healthcare facilities.