According to OSHA, a confined space is a space that is "large enough and so configured that an employee can bodily enter and perform assigned work, has limited or restricted means for entry or exit (e.g., tanks, tankers, silos, storage bins, vaults and pits) and is not designed for continuous employee occupancy". Certain confined spaces present hazards that require special circumstances for entry. These are called permit-required confined spaces.
A permit-required confined space a confined space that has one or more of the following characteristics:
• Contains or has a potential to contain a hazardous atmosphere;
• Contains a material that has the potential for engulfing an entrant
• Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section;
• Contains any other recognized serious safety or health hazard.
Do not enter a permit-required confined space without a permit. The permit can be found here: Confined Space Permit
For more information, view the Confined Space Entry Program