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605 Confined Space Safety
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Confined Space Basics

What is a Confined Space?

OSHA's definition of a confined space is a space that:

  • is large enough and configured so an employee can enter and perform assigned work;
  • has limited or restricted means for entry or exit;
  • and, is not designed for continuous employee occupancy.

Permit-Required Confined Spaces (PRCS)

Some confined spaces require a permit to enter. By definition, a permit-required confined space is a space that meets the criteria for a confined space and has one or more of the following characteristics:

  1. It contains or has the potential to contain a hazardous atmosphere;
  2. It includes a material with the potential to engulf someone who enters the space;
  3. It has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section; or
  4. It contains any other recognized serious safety or health hazards.

OSHA requires employers to determine if a permit is required when entering a confined space. To do that, they can use OSHA's Confined Space Entry Decision Flow Chart to the right.

Click to see a Sample Confined Space Entry Permit.

Knowledge Check Choose the best answer for the question.

1-2. Which of the following, in addition to the three criteria for a confined space, would be a criterion for a permit-required confined space?