Full definition
Area with limited entry/exit (manhole, hatch), not designed for continuous occupancy, with potential for hazardous atmosphere. Types: non-permit confined space (minor risk) and permit-required confined space (hazardous atmosphere, engulfment or entrapment risk). Hazards: oxygen deficiency (<19.5%), toxic gases (H₂S, CO), flammability (LEL >10%), mechanical entrapment. Requires: continuous atmosphere monitoring, forced ventilation, rescue equipment, constant communication, external attendant and entry permit. Standards: OSHA 29 CFR 1910.146, ISO 45001.