Confined Space Entry Procedure: OSHA Requirements Step by Step
A permit-required confined space can kill in minutes, and most fatalities are would-be rescuers who entered without following the procedure. Here is how OSHA 1910.146 structures a safe entry, from permit to atmospheric testing to rescue.
QUICK ANSWER
The OSHA 1910.146 confined space entry procedure requires: identify and classify the space, issue an entry permit, isolate hazards and control energy, test the atmosphere before and during entry, station a trained attendant outside, maintain communication, and have a rescue plan that never depends on entering to save someone. Entry without a valid permit and current atmospheric readings is prohibited.
Permit-Required vs Non-Permit Confined Spaces
OSHA 1910.146 defines a confined space as one large enough to enter, with limited means of entry or exit, and not designed for continuous occupancy, tanks, vaults, silos, pits, sewers, and similar spaces. It becomes a permit-required confined space (PRCS) if it has a hazardous atmosphere, engulfment potential, an internal configuration that could trap or asphyxiate, or any other serious hazard.
The Entry Procedure, Step by Step
- Identify and classify the space. Determine whether it is permit-required, and post it accordingly.
- Issue the entry permit. The permit documents the hazards, the controls, the atmospheric readings, the authorized entrants and attendant, and the time window. No valid permit, no entry.
- Isolate hazards. Lock out energy, blank or bleed lines, and control any engulfment or mechanical hazard before entry.
- Test the atmosphere. Test in order, oxygen first, then flammable gases, then toxics, before entry and continuously or periodically during entry.
- Ventilate as needed. Use forced-air ventilation to bring the atmosphere into acceptable limits, and keep it running.
- Station an attendant. A trained attendant remains outside, monitors conditions and entrants, and orders evacuation if anything changes.
- Maintain the rescue plan. Non-entry rescue (retrieval systems) is the default. Rescuers never enter to save a downed worker without their own permit, atmosphere check, and equipment.
60%
Well over half of confined space fatalities are would-be rescuers who entered without following the procedure. The rescue step is where training matters most, and where it is hardest to practice safely.
Why This Procedure Is So Hard to Train
You cannot rehearse a real emergency in a real confined space, that is the point of the hazard. So most training stops at the classroom, and the attendant, entrant, and rescuer never practice their roles under realistic pressure. Immersive simulation is one of the few ways to let a team run the full entry and a deteriorating-atmosphere emergency, including the decision not to enter for rescue, without exposing anyone. See our confined space VR training and safety and operations VR training.
WE BUILD THIS IN VR — THE PRIME VR
We develop VR confined space programs where entrants, attendants, and rescuers rehearse the full entry and a deteriorating-atmosphere emergency, including the decision not to enter for rescue, without ever exposing a person to the space.
Book a discovery callFrequently Asked Questions
What makes a confined space permit-required? +
Under OSHA 1910.146, a confined space becomes permit-required when it contains or could contain a hazardous atmosphere, has engulfment potential, has an internal configuration that could trap or asphyxiate an entrant, or contains any other recognized serious safety or health hazard.
What order do you test the atmosphere in? +
Always test in this order: oxygen first, then combustible or flammable gases and vapors, then toxic gases and vapors. Oxygen is tested first because most combustible gas meters need adequate oxygen to read accurately.
Can a coworker enter to rescue a downed entrant? +
Not without following the full procedure themselves. Non-entry retrieval is the default. Entry rescue requires the rescuer to have their own permit, atmospheric verification, and equipment. Most confined space fatalities are untrained rescuers.
Who must be trained for confined space entry? +
Authorized entrants, attendants, and entry supervisors all require role-specific training under 1910.146, and rescue personnel need additional training and practice, including simulated rescues at least annually.
Let teams practice the entry, and the emergency
VR is one of the only ways to rehearse a confined space emergency without exposing anyone.