Illustration for Confined Space Safety in Construction: Essential Student Supplements and Training Aids

OSHA Confined Space in Construction: 2025 Complete Guide + Free Templates (29 CFR 1926 Subpart AA)

Updated December 2025
If you work on construction sites in 2025, you must follow OSHA’s dedicated confined space rule — 29 CFR 1926 Subpart AA (Confined Spaces in Construction). It is NOT the same as the general-industry rule (1910.146).

This guide gives you everything you need today: exact OSHA requirements, step-by-step procedures, roles, testing order, alternate procedures, rescue rules, and free downloadable templates that are 100% compliant in 2025.

What Is a Confined Space in Construction? (OSHA Definition – 1926.1202)

A confined space meets ALL three criteria:

  1. Large enough for a worker to enter and perform work
  2. Has limited or restricted means of entry or exit
  3. Is not designed for continuous occupancy

Common construction examples:

  • Manholes & utility vaults
  • Storm/sanitary sewers
  • Crawl spaces
  • Storage tanks & process vessels
  • Boilers
  • Excavations with restricted access
  • Pier caissons & pipelines

When Does It Become Permit-Required (PRCS)?

A space becomes permit-required if it has (or has potential for) ANY of these:

  • Hazardous atmosphere (oxygen <19.5% or >23.5%, LEL ≥10%, toxic above PEL)
  • Engulfment hazard
  • Inwardly converging walls or floor that slopes downward and tapers
  • Any other recognized serious safety or health hazard

Key Differences: Construction Rule vs. General Industry

Issue Construction (1926 Subpart AA) General Industry (1910.146)
Multiple employers Explicit roles for host & controlling contractor Less detailed
Changing conditions Must re-evaluate constantly Less emphasis
Alternate procedures Allowed with strict conditions Same, but construction is stricter
Information sharing Controlling contractor MUST coordinate No equivalent requirement

Roles and Responsibilities on Multi-Employer Sites (2025)

  • Host Employer – Owns the site, shares known hazards
  • Controlling Contractor – Coordinates all entry operations, shares info, posts signs
  • Entry Employer – Develops permit program, issues permits, trains their people
  • Entry Supervisor – Authorizes entry, signs permit, can cancel it
  • Attendant – Monitors outside, never enters to rescue
  • Authorized Entrant – Wears harness, follows permit

Step-by-Step Atmospheric Testing Order (Required by OSHA)

Test in this exact sequence with a calibrated monitor:

  1. Oxygen first (19.5% – 23.5%)
  2. Flammable gases/vapors (must be <10% LEL for entry)
  3. Toxic gases (CO, H2S, etc. – below OSHA PEL or manufacturer limits)

Test top, middle, and bottom in vertical spaces (stratification). Continuous monitoring required when relying on ventilation.

Ventilation & Alternate Entry Procedures (1926.1203(e))

You may use alternate procedures (no permit, no attendant) ONLY when:

  • The ONLY hazard is atmospheric
  • Forced-air ventilation alone keeps conditions safe
  • You document the determination and monitoring data

Rescue Requirements – What OSHA Actually Prefers

  1. Non-entry retrieval (tripod + winch + full-body harness) whenever possible
  2. On-site rescue team OR pre-arranged local service that can arrive in time
  3. Annual practice rescue drill required

Free 2025 Downloadable Templates (All OSHA-Compliant)

Click to download instantly – no email required:

Training & Refresher Requirements (2025)

Every person must be trained before initial assignment and whenever:

  • Duties change
  • Hazards change
  • Program deficiencies are observed

Annual refresher is the most common way employers prove ongoing compliance.

Most Common OSHA Citations in 2025 (Avoid These)

  1. No written program
  2. Failure to inform controlling contractor of hazards
  3. No annual rescue drill
  4. Incorrect atmospheric testing order
  5. Missing or incomplete permits

FAQ – Quick Answers

Q: Can we reclassify a PRCS to non-permit in construction?
Yes – only when ALL hazards are physically eliminated (not just controlled). Document it.

Q: Do we need an attendant with alternate procedures?
No – alternate procedures eliminate the need for permits and attendants.

Q: Is 10% LEL the hard limit?
Yes – OSHA’s construction rule accepts entry below 10% LEL when ventilation is used.

Q: Who can cancel a permit?
Only the Entry Supervisor.

Q: How long do we keep canceled permits?
At least 1 year (1926.1205(c)).

Ready to make your next confined space entry 100% compliant and audit-proof?

Download the OSHA Protecting Construction Workers in Confined Spaces: Small Entity Compliance Guide → Free, No Sign-Up Required

Stay safe out there.
National Safety Compliance Team – December 2025


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