BIMsensor: An OpenBIM-IoT Platform Implementing an Interoperable Workflow for Sensor Integration and Spatial Contextualisation

The integration of IoT sensors into OpenBIM-based monitoring environments requires not only data acquisition but also the consistent organisation of sensor identity, semantic information, monitored variables, spatial context, and information exchange. This study proposes a four-stage OpenBIM-IoT workflow comprising project creation, sensor registration, georeferencing and spatial assignment, and integration within a digital monitoring environment. The workflow was implemented through the BIMsensor platform, which combines AllBIMclass-based sensor classification, a common monitored-variable catalogue, association with IFC entities through their GlobalId values, GNSS-based mobile positioning, alert and event management, and external information exchange through IFC and GeoJSON. The approach was evaluated using two complementary scenarios: a 24 h residential-building campaign with four fixed IoT nodes and a mobile GNSS-enabled monitoring campaign. In the building case, 6301 of 6624 nominally expected environmental observations were stored, corresponding to 95.12% data completeness. Supplementary tests yielded a mean server-side request processing time of 33.71 ± 17.21 ms for 552 environmental requests and a mean IFC loading and processing time of 8.61 ± 0.60 s for the 12.77 MB building model. External reuse was additionally verified by importing the exported IFC4X3_ADD2 sensor-network model into BIMvision, an independent IFC viewer, validating the file with the buildingSMART IFC Validation Service, and importing the GeoJSON output into QGIS, an open-source geographic information system (GIS). The results support the feasibility of coordinating sensor-management and spatial-contextualisation operations within a common workflow under the evaluated conditions, while manufacturer and communication-protocol independence and large-scale scalability remain outside the scope of the present validation.