If you determine that a space does meet the definition of “confined space,” then you need to further evaluate the space to determine whether it meets the definition of “permit-required confined space.” A permit-required confined space is a confined space that has one or more of the following characteristics:
Contains or has a potential to contain a hazardous atmosphere; or
Contains a material that has the potential for engulfing an entrant; or
Has an internal configuration that could trap or asphyxiate an entrant by inwardly converging walls or a floor which slopes downward and tapers to a small cross section; or
Contains any other recognized serious safety or health hazard.