When you hear someone talking about working in a "confined space," that doesn't just mean that they are working in tight quarters. "Confined space entry" is actually a tightly (pun intended) defined term that comes with a certain set of safety requirements for personnel.
In order for an area to be called a confined space, it needs to meet all 3 of the following criteria:
- Large enough for personnel to perform work
- Limited openings for entry and exit
- Not intended for continuous human occupancy
Examples of these types of spaces include tanks, vessels, manholes, silos, storage bins, hoppers, vaults, and pits.