Industrial workplaces are full of confined spaces. These are restrictive areas that occasionally need to be accessed to perform certain maintenance activities, but that are not designed for continuous human presence. The space is large enough to be entered by an employee, but has restricted means for entry and exit. Think of storage tanks, vaults, wells, and utility tunnels. Confined spaces are considered dangerous places. Human presence in confined spaces should therefore carefully be monitored. This is traditionally done by confined spaces attendants, also called manhole watch. However, the use of digital confined space monitoring solutions is gaining popularity.