The simple definition of a confined space is an area that is large enough for a worker to enter and work, but that is tough to get in and out of and isn’t designed for regular occupancy. With a definition like that, there are so many spaces that would qualify - under the sink, an attic crawl space, the shed that houses an air compressor. While all of them qualify as a confined space, not all of them will be classified as a permit-required confined space (PRCS). OSHA has copious files relating to the differences between permit required and non-permit required spaces. For a better understanding we can start with the fact that non-permit required spaces do not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serious physical harm. These are places that may be tough to get into, but aren’t going to hold dangers to your breathing, or the sort of engulfment hazards you might find in a grain elevator or similar facilities. Permit-required confined spaces, however, are more complex, and it may take some training to spot the difference. A PRCS meets the simple definition of a confined space plus one or more of these additional criteria:
- Space contains or has the potential to contain a hazardous atmosphere.
- Contains a material (water, grain, petroleum products) that has the potential to engulf an entrant.
- Has a design that may either trap an entrant or hold a toxic atmosphere that may asphyxiate that worker.
- Contains any other hazard to health or recognizable serious safety issue.