inside of the structure, as well as the requirement to move laterally to a defined exit point before one can surface in the event of an emergency.

Full penetration involves the greatest level of risks, including the risk of getting lost within the structure, the risk of complete darkness in the event of multiple light failures, and the inability to escape unassisted in the event of a complete disruption to breathing gas supply.

These categorisations broadly coincide with the traditional division between "recreational"

1.Previous
3.Next