Confined spaces such as tanks and boilers are not easy to enter. And therefore not easy to leave either. The manhole could be too small to easily access. There often is a lack of ventilation, leading to a build-up of toxic gasses or unsafe levels of oxygen. The risk of an explosion could be high. Yet, these tanks and boilers need to be accessed regularly for inspection, cleaning, maintenance or repair purposes. This means that in any of these events – usually during a shutdown or turnaround – additional measures are required, to ensure the well-being of the engineers involved. Knowing who is inside a tank storage area and what is happening there is not only mandatory for both safe and efficient maintenance, but often required by law as well.