Title: Permit vs. Non-Permit Confined Spaces
Type: Lesson
As discussed in Lesson 1, a confined space is any space that:
Is large enough to enter and work in
Has limited means of entry or exit
Is not designed for continuous occupancy
However, when a confined space also contains hazards that could cause injury or death, it is classified as a Permit-Required Confined Space (PRCS).
A confined space becomes permit-required if it contains any of the following:
Hazardous atmosphere (toxic gases, flammable vapors, low oxygen)
Engulfment hazard (water, grain, sand)
Internal configuration hazard (walls that taper inward, sloping floors)
Other serious safety or health hazard (electrical, mechanical, chemical)
Sewer manholes with toxic gas buildup
Grain silos that could engulf a worker
Tanks with chemical residues
Vaults with limited air flow
These still meet the definition of a confined space but do not have any recognized hazards that could cause injury or death.
Examples:
Crawl spaces with no utilities
Equipment closets with proper ventilation
Empty clean tanks with no engulfment or atmospheric risk
Note: Even non-permit spaces can become dangerous if conditions change.
A qualified person or safety professional must evaluate the space. If any PRCS hazard is present, entry requires a written permit program including rescue plans, atmospheric testing, and proper PPE.
When in doubt, treat the space as permit-required until proven otherwise through a documented evaluation.
Click “Mark Complete” to move on to Lesson 3: Common Confined Space Hazards, where we’ll explore specific risks found inside real-world confined spaces.