Building Better
Employing Air Purifiers and Effective Ventilation to Improve Indoor Air Quality in Classrooms
Paper Presentation in a Themed Session Constantinos Sioutas
The scope of this study is to illustrate the effectiveness of ventilation and air purification systems in reducing indoor pollutants concentrations in densely seated classrooms. Real-time measurements of particulate mass (PM), particle numbers (PN), and CO2 concentrations were conducted in occupied classrooms. In addition, a series of tests employing an aerosol-generating system were carried in an empty classroom in order to evaluate air cleaner removal efficiency in the existence of indoor pollution source (i.e., NaCl). The results of this study show a significant contribution of the ventilation systems equipped with efficient filters in maintaining the indoor air quality in classrooms. In the first scenario, the mechanical ventilation system reduced ambient PM and PN by more than 80%. The indoor-to-outdoor concentration ratios (I/O) were relatively low (0.1 or less) in most classrooms due to the presence of in-line air filters in the ventilation systems, which did not allow the air cleaner to show considerable reductions in indoor PM and PN. The results in the empty classroom showed the efficient use of HEPA air cleaner since it significantly increased the particles decay rates. The decay rate value increased on average from 4-4.7 hr-1 in the natural condition to 6.5-6.7 hr-1 with the use of cleaner at high flow rate, which indicates the effective work of the cleaner unit in reducing indoor air pollution. This work highlighted the importance of classroom air pollution mitigation measures in light of the continuous spread of SARS-CoV-2 variants and the return of classes in-person attendance.
Featured Systematic Review of Technical and Process Frameworks Integrating Building Information Modelling (BIM) for Building Deconstruction
Paper Presentation in a Themed Session Chukwumaobi Ibe, Md Mohataz Hossain, Andreea Serbescu
This study evaluates the integration of Building Information Modelling (BIM) into building deconstruction processes to improve planning, execution, and material recovery, ultimately contributing to sustainable construction. A systematic review was conducted by examining academic databases, including Web of Science, Scopus, IEEE Xplore, and Google Scholar. A comprehensive set of keywords and Boolean operators were used to identify frameworks that incorporate BIM in deconstruction processes. Data were extracted and analysed thematically, supported by a quality assessment using a modified Critical Appraisal Skills Programme (CASP) checklist. The review identified 48 frameworks that demonstrated BIM’s potential to optimize various aspects of deconstruction. Four key themes emerged: Materials Passports, Life Cycle Assessment (LCA) Integration, Reverse Logistics, and Automated Deconstruction. BIM was found to significantly improve material recovery efficiency, reduce environmental impacts, and enhance planning and coordination among project stakeholders. However, challenges related to the complexity of BIM implementation, as well as the need for comprehensive data integration, were noted. From a practical perspective, this study suggests that while BIM offers considerable benefits, its adoption in deconstruction requires overcoming challenges such as complexity, adequate training, and effective data management. The insights gained can help practitioners and industry stakeholders to implement BIM-based deconstruction strategies more efficiently. This review also contributes to the broader knowledge on BIM and deconstruction by providing a critical evaluation of existing frameworks, offering recommendations for both future research and practical applications.
Natural Ventilation in the Climate Crisis: Simulating Wind- and Buoyancy-driven Flow Using Scale Model Measurements in a Wind Tunnel
Paper Presentation in a Themed Session Christina Higgins
A significant portion of office buildings rely on mechanical ventilation, leading to substantial energy consumption and CO2 emissions, and this is a barrier to achieving Net Zero in the sector. Natural ventilation offers a more sustainable alternative, but its effectiveness depends on various factors, including the influence of wind- and buoyancy-driven airflow. Buoyancy-driven flow arises from temperature differences between indoor and outdoor environments and is influenced by internal heat sources such as occupants and equipment. This study investigates wind- and buoyancy-driven ventilation rates with tracer gas decay measurements in an atmospheric wind tunnel, using a scale model of an existing office space. Different window configurations and wind directions were tested, with temperature differences simulated by carrier gases of varying densities. Results indicate that for certain wind directions, buoyancy forces dominate the ventilation flow, and even in wind-driven scenarios, buoyant effects can contribute to higher ventilation rates. Considering buoyancy-driven flow could improve the assessment of natural ventilation feasibility, contributing to more sustainable building design and retrofit.
