Combining off-the-shelf IoT technologies and equipment with mathematical models that simulated the propagation of Covid-19, a pilot at the Kremlin-Bicêtre AP-HP university hospital in Paris has demonstrated how building managers can limit the spread of viruses.

The eight-month trial in 2021 included nearly 200 students and about 20 staff volunteers who wore Bluetooth-enabled badges during their classes, labs and shifts at the faculty of medicine at Kremlin-Bicêtre Assistance Publique-Hôpitaux de Paris (AP-HP).

In addition to continuous monitoring of building air-quality, the system monitored occupants’ movements and whereabouts using dedicated mathematical models developed by two Paris-Saclay University scientists. These models simulated the propagation of Covid-19 in the student population, based on contact-tracing matrices.

“This made it possible to investigate the importance of actual contacts between individuals in the transmission process, and more generally to estimate the role of the population’s actions, such as gathering in ill-ventilated rooms and the length and type of communication – casual short conversation or longer collaboration – between individuals in the overall spread of the epidemic,” said Bertrand Maury who, with colleagueSylvain Faure, created the algorithms. “This evaluation clearly showed this IoT-based solution can help building managers in the future to limit the spread of viruses such as Covid-19.”

The contact-tracing application in the buildings was paired with air-quality monitoring that included: CO₂ levels in the premises in relation to occupancy rates and hours, and ventilation adjustments; malfunctions in the ventilation or required maintenance of ventilation equipment; and hourly renewal rate (HRR), or complete renewal of the air in a room, which is a key performance indicator (KPI) monitored by building managers in their day-to-day operations.

The contact-tracing matrices were inspired by an algorithm developed by France’s National Center for Scientific Research (CNRS) and Paris-Saclay University that defines epidemiological models for virus transmission. It also provides a first assessment of the influence of CO₂ concentration as an indicator of poor air quality that may accelerate viral transmission, for example a CO₂ level indicating insufficient indoor air renewal.

The pilot project has been validated by the clinical research unit of the Paris-Saclay faculty of medicine, while the protection of private data and the identities of the pilot-project participants fully complied with GDPR law.

Olivier Lambotte, vice dean of the faculty of medicine at Kremlin-Bicêtre AP-HP, said Covid-19 virus transmission and the desire to develop an “improved-alerting” tool based on epidemiologic models were the initial triggers for this demonstrator project and they have been successfully completed with air-quality monitoring through CO₂-level analysis.

“After these initial results, the faculty of medicine will be able to refine its systems for combatting the spread of epidemics thanks to a better knowledge of the interactions between students and thanks to a mastery of air quality,” he said. “Mathematical modelling of air renewal in a classroom or amphitheatre allows us to estimate in advance the maximum number of people who can be present to maintain a CO₂ level below a set threshold.”

The system used technology jointly developed by IoT specialist Kerlink, data management company Microshare and sensor maker Enless Wireless.

The LoRaWan-based system used Kerlink Wanesy Wave multi-purpose powered anchor combining wifi, Blutooth LE and LoRaWan for contact-tracing data collection from Bluetooth badges, and a Kerlink Wirnet iFemtoCell indoor gateway to transmit the data to Microshare’s universal contact tracing application, which ensures end-to-end security, privacy and reliability for the delivery of critical information where it is needed.

The data it produce are GDPR-compliant and delivered through Microshare’s patent-pending rules and sharing engine to only appropriate, designated people in the organisation at the right time. Enless Wireless provided the pilot project with easy-to-install and connect indoor air-quality transmitters with embedded CO₂ sensors and D-type batteries.

Based in France, with subsidiaries in the USA, Singapore, India and Japan, Kerlink is a co-founder and board member of the LoRa Alliance and the uCIFI Alliance. Microshare provides smart building data technologies at scale that enhance safety, wellness and sustainability, and drive cost savings and efficiencies. French firm Enless Wireless has been an automation and IoT player in building energy efficiency and comfort for more than 12 years.