22 Confined Spaces MINIMUM CONDITIONS FOR ENTRY Oxygen Between19.5%-23.5% Flammable Dusts Visibility > 5 ft. Flammable gasses < 10% of LEL Engulfment hazards None present Hydrogen sulfide (H2S) < 10 ppm Hazardous flows Secured and locked/tagged out Carbon monoxide (CO) < 50 ppm Hazardous energies Secured and locked/tagged out Other toxic substances < PEL for substance External hazards Controlled If conditions are not met, entry is prohibited. If occupied, the space must be immediately evacuated.