What is one of the criteria for a confined space?

A confined space is defined primarily by its design and accessibility features. One of the key criteria is that it has a restricted means of entry and exit. This is significant because it poses challenges for personnel who may need to enter or work within the space, particularly during emergencies. The limited access points can make evacuation difficult and increase the risk of accidents or exposure to hazardous conditions.

The other options, while relevant to safety considerations, do not align with the fundamental definition of a confined space. For instance, a space designed for continuous human occupancy typically refers to areas meant for regular use, which would not be classified as confined spaces. Additionally, while effective ventilation systems are important for safety, they are not a defining characteristic of confined spaces. Lastly, it's essential to note that confined spaces may contain various hazards, making the presence of hazards a critical concern rather than a criterion for defining the space itself.