Health & Safety

Confined Spaces: Hierarchy of Permit-Spaces


What is a "Permit Required Confined Space"?

A permit-required confined space means a confined space that has one or more of the following characteristics:

  1. Contains or has a potential to contain a hazardous atmosphere;
  2. Contains a material that has the potential for engulfing an entrant;
  3. Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section; or
  4. Contains any other recognized serious safety or health hazard.

At UWM, the best option is no entry into permit-required confined spaces! In other words, perform the work without entering the permit space. When this isn't possible, then follow the "hierarchy" listed below. All references are to OSHA 29 CFR 1910.146:

Permit Space Entry - Hazards Cannot Be Eliminated nor Controlled (c)(4):

  • written program and procedures (d)
  • permit specifications (e and f)
  • training specifications (g)
  • attendant specifications (d)(6)
  • entry supervisor specifications (e)(2)
  • testing specifications (d)(5), (see CPL 2.100, pgs. 23-24)
  • rescue specifications (k)

Alternate Entry - Hazards Controlled (by continuous forced air ventilation)(c)(5):

  • Only hazard is actual or potential hazardous atmosphere. Continuous forced air ventilation alone is sufficient to maintain safe entry.
  • No formal written program required for this option (i.e., a "mini-program"); requirements in (c)(5)(ii) act as a substitute written program for this option.
  • Document determinations and supporting data. The determination and special requirements will be included in the UWM Confined Space Inventory. ((c)(5)(i)(E), see CPL 2.100, pgs. 19-20).
  • No permit system or permits; however, a signed, written certification is required.
  • Certification is made available to entrants (c)(5)(ii)(H). Document determinations and supporting data (i.e., write down your air monitoring data and submit to your supervisor for evaluation and documentation).
  • Will work operations within the space introduce any new hazards? (e.g., Will welding be conducted or flammable or hazardous cleaners be used?) If yes, the space is ineligible for (C)(5) procedures.
  • No attendant or supervisor required (but may be necessary depending on the circumstances).
  • No rescue provisions required (but may be necessary depending on the circumstances).
  • Training is required.

Reclassification - Hazards Eliminated (c)(7):

  • Space poses no actual or potential atmospheric hazards.
  • Certify that all hazards within the space have been eliminated. Consider atmospheric hazards, engulfment, configuration, and energy hazards.
  • Document the "reclass" determination in writing. This information will be included in the UWM Confined Space Inventory.
  • Certification made available to entrants (c)(7)(iii).
  • No rescue provisions required (but may be necessary depending on the circumstances).
  • Training is required.

Remember: If the conditions change, you must re-evaluate the space!

Source: OSHA Training Institute, Course 226-Permit-Required Confined Space Entry, December 1998, Madison, Wisconsin.