What Is a Permit-Required Confined Space?

Under OSHA’s definition, a confined space meets all three of these conditions:

1. It is large enough and configured so that a worker can bodily enter and do assigned work.
2. It has limited or restricted means of entry or exit.
3. It is not designed for continuous employee occupancy.

Common examples include:

Being a confined space does not by itself mean it is dangerous. The next question is whether it is permit-required.

A confined space is a permit-required confined space (permit space) if it has one or more of these characteristics:

Employers must evaluate the workplace to find permit spaces, post danger signs (or use an equally effective method) to tell workers about them, and prevent unauthorized entry. A space can be reclassified as a non-permit space only when all hazards are eliminated, and that must be documented.

Before anyone enters, the internal atmosphere must be tested with a calibrated, direct-reading instrument. Test in this order:

1. Oxygen, because most combustible gas meters need enough oxygen to read accurately.
2. Combustible (flammable) gases and vapors.
3. Toxic gases and vapors, such as hydrogen sulfide and carbon monoxide.

OSHA treats the atmosphere as hazardous when, among other conditions, oxygen is below 19.5% or above 23.5%, flammable gas or vapor is above 10% of its lower flammable limit (LFL), combustible dust is at or above its LFL (roughly when it hides a target 5 feet away), or a toxic substance is above its permissible exposure limit. Test vertical spaces at different levels, since some gases are heavier and others lighter than air, and keep monitoring during the entry.

The entry permit documents that the space is safe to enter. It must list the space, the purpose and duration of entry, the authorized entrants, the attendant and entry supervisor, the hazards, how they are isolated or controlled, acceptable entry conditions, test results with the tester’s initials and times, rescue services and how to call them, communication methods, required equipment and any other permits (such as hot work). The permit cannot last longer than the job. Cancelled permits are kept for at least one year so the program can be reviewed.

• Authorized entrant: knows the hazards and signs of exposure, uses the equipment properly, stays in contact with the attendant, and gets out when told to or when they notice a warning sign.
• Attendant: stays outside the space for the whole entry, keeps count of entrants, monitors conditions, orders evacuation, calls rescue, and never enters to attempt a rescue unless trained and relieved.
• Entry supervisor: checks the permit, confirms tests and rescue arrangements, signs the permit to authorize entry, and cancels it when the work is done or conditions change.

NIOSH research found that about 60% of confined space deaths were would-be rescuers, often co-workers who went in without protection to help. That is why OSHA requires a rescue plan before entry.

• Rescue can be an in-house team or an outside service, but it must be able to respond in time for the hazards in that space.
• Rescue team members must be trained, and at least one must hold current first aid and CPR certification. They must practice a permit-space rescue at least once every 12 months.
• Non-entry rescue is preferred. To make it possible, entrants usually wear a full-body harness attached to a retrieval line, and a mechanical retrieval device is required for vertical spaces more than 5 feet deep.

Employers must train every worker with permit space duties so they can do those duties safely. Training is required before the worker is first assigned, before any change in duties, when a new hazard appears, and when the employer sees the worker is not following procedures. The employer must certify the training with each employee’s name, the trainer’s signature or initials, and the dates.

OSHA does not approve, certify or accredit online training providers. An online confined space course covers the rules, hazards, atmospheric testing, roles and rescue planning. Your employer must add site-specific training on its own spaces, permit system, gas monitors and retrieval equipment, plus hands-on practice. With Gama Safety you pass the exam with 80% or better (unlimited free retakes) and download your certificate and printable wallet card right away.