Monitoring Workers Safety in Restricted Working Areas: A Case-Study with LoRaWAN Technology

This paper addresses the usability of wireless transmission technologies, for giving connectivity to wireless monitoring systems aimed at safeguarding workers operating within areas restricted for safety reasons, like human-dangerous spaces, or underground tanks. In such areas, critical conditions may arise, so that sensing is required in order to prevent incidents. For instance, possible emission of poisonous gases could be detected to ensure healthy conditions. To this aim, workers can be provided with portable Internet of Things (IoT) sensing devices in charge of measuring a set of physical and environmental parameters. The corresponding collected data is transmitted in real-time to a centre responsible for logging the collected information and engaging proper emergency procedures. Since, restricted areas may be built with materials intrinsically able to shield the electromagnetic field to some extent, the feasibility of wireless links traversing such structures, should be assessed. To this end, in the presented study two measurement campaigns were sorted out, in a context replicating real-life cases. During tests, the Long Range Wide Area Network (LoRaWAN) protocol was considered, since it has rather robust transmission capabilities where a low bitrate is needed. There, three combinations of transmission parameters were evaluated, specifically aiming at reproducing standard, emergency, and enhanced receiver sensitivity conditions. Test results proved the feasibility of performing at least a reliable single-hop wireless link traversing the underground tank. Moreover, the testes conditions can give valuable insight to practitioners in the field during the design phase of similar monitoring systems.