What is a confined space?
A space must meet all of the following criteria to be considered a confined space:
- Large enough to bodily enter
- Limited means of entry or exit
- Not designed for continuous occupancy
When is a Confined Space Entry Permit Needed?
If any of the hazards listed below are present, a permit is required for entry. Remember that certain work activities in a confined space can also necessitate a permit.
- Oxygen concentration below 19.5% or above 23.5%
- Flammable gas greater than 10% of the Lower Explosive Limit (LEL)
- Atmospheres exceeding the OSHA Permissible Exposure Limit (PEL)
- Airborne combustible dust that obscures vision at 5 feet or less
Internal configurations that could entrap or asphyxiate an entrant by inwardly converging walls, or floors that taper to a smaller cross-section, i.e. hoppers, bins and tanks
Where there is a potential for a liquid or solid material to drown, capture or asphyxiate an entrant, i.e. water, grains and soils
Other hazards may include electrical hazards, chemical hazards, extreme temperatures, slippery floors and noise.
Working Safely in Confined Spaces
First, avoid entry into confined spaces whenever possible. If they must be entered, Cal/OSHA has regulations for working safely in confined spaces. Please refer to the specific standard for your industry and operations. For general industries such as manufacturing facilities, T8CCR 5157, “Permit-Required Confined Spaces” requirements apply. For employers and employees in Construction, Agriculture, Marine Terminals, Grain Handling, Telecommunications, Natural Gas and Electric Utilities, and Shipyard Operations, the regulations in T8CCR 5158, “Other Confined Space Operations” and other regulations apply.
In general, confined space regulations require all employers to have:
- A written confined space plan, including recognizing and marking all confined spaces on site;
- Procedures to test and monitor the air inside confined spaces before and during all employee entries;
- Procedures to prevent unauthorized entries and to have an attendant outside the space at all times;
- Effective controls of all existing atmospheric or safety hazards inside the confined space;
- Employee and supervisor training on safe work procedures, hazard controls, and rescue procedures; and
- Effective rescue procedures which are immediately available on site.
Sources and further information: