Confined Space Entry Exam Guide: OSHA 29 CFR 1910.146 Permits, Testing and Roles
Reviewed by Gary B. Xavier, HVACR Instructor & Author, EPA 608 Universal ·
The confined space entry exam tests what OSHA 29 CFR 1910.146 requires before, during and after entry into a permit-required confined space. This guide covers definitions, atmospheric testing, permits, the three entry roles, rescue, training, what the test costs, the pass score and a study plan, all checked against the eCFR text.
What Does OSHA 29 CFR 1910.146 Cover?
29 CFR 1910.146 sets practices and procedures to protect general industry workers from the hazards of entry into permit-required confined spaces. It does not apply to agriculture, construction or shipyard employment, which have their own rules.
A confined space meets three tests: it is large enough to bodily enter, it has limited means of entry or exit (OSHA's examples include tanks, vessels, silos, storage bins, hoppers, vaults and pits), and it is not designed for continuous occupancy.
A permit-required confined space also has one or more of these: a hazardous atmosphere or the potential for one, a material that could engulf an entrant, an inside shape that could trap or asphyxiate an entrant with inwardly converging walls or a sloping, tapering floor, or any other recognized serious hazard.
Confined Space Hazardous Atmosphere Limits in 1910.146
| Condition | Hazardous when |
|---|---|
| Flammable gas, vapor or mist | Over 10% of its lower flammable limit (LFL) |
| Airborne combustible dust | At or above its LFL (roughly, dust that obscures vision at 5 feet or less) |
| Oxygen | Below 19.5% or above 23.5% |
| Toxic substances | Above a published permissible exposure limit |
Entry happens the moment any part of the body breaks the plane of an opening. That definition shows up often on tests.
Confined Space Atmospheric Testing Order
OSHA requires testing first for oxygen, then for combustible gases and vapors, and then for toxic gases and vapors. Pre-entry testing uses a calibrated direct-reading instrument. Entrants, or their authorized representatives, have the right to watch the testing, get the results immediately and ask for a reevaluation if they believe the evaluation was not adequate. In large or continuous spaces such as sewers, where isolation is not feasible, the work areas must be monitored continuously.
Alternate Procedures and Reclassification
Paragraph (c)(5) allows simpler alternate procedures when the only hazard is an atmospheric one that continuous forced air ventilation alone can control. The employer must remove hazards before opening covers, guard the opening, test the atmosphere, ventilate from a clean source until everyone has left, and document it all in a signed, dated certification. If a hazardous atmosphere shows up, everyone leaves at once.
Under (c)(7), a space can be reclassified as non-permit only if it has no actual or potential atmospheric hazards and all hazards are eliminated without entry, or if an entry made under the full permit procedures eliminates them and testing confirms it. The basis must be documented in a dated, signed certification. OSHA states that controlling atmospheric hazards with forced air ventilation does not count as eliminating them.
Confined Space Entry Permit Rules Under 1910.146(e) and (f)
- The entry supervisor named on the permit signs it before entry begins.
- The permit is posted at the entry portal or made available by an equally effective means.
- Its duration may not exceed the time needed to complete the job.
- The entry supervisor cancels it when the work is done or a condition not allowed by the permit arises.
- Canceled permits are kept for at least 1 year, and problems are noted on them.
The permit lists 15 items, including the space, purpose, date and duration, entrants, attendants and entry supervisor by name, hazards, isolation measures, acceptable entry conditions, test results with testers' names or initials, rescue services, communication procedures, equipment and any other permits such as hot work.
Entrant, Attendant and Entry Supervisor Duties
| Role | Key duties |
|---|---|
| Authorized entrant | Know the hazards, use equipment properly, communicate with the attendant, alert the attendant to warning signs or prohibited conditions, and exit when ordered, when symptoms appear, when a prohibited condition is found or when an alarm sounds. |
| Attendant | Stay outside until relieved, keep an accurate count of entrants, watch for behavioral effects of exposure, order evacuation, summon rescue, warn away unauthorized persons, perform non-entry rescue and take on no duties that interfere with monitoring. |
| Entry supervisor | Verify the permit's tests, procedures and equipment before signing, confirm rescue is available and can be summoned, remove unauthorized persons, and cancel the permit when needed. |
An entry supervisor may also serve as an attendant or entrant if trained and equipped for that role, and supervisor duties may pass from one person to another during an entry.
Confined Space Rescue Requirements Under 1910.146(k)
Employers that use an outside rescue service must evaluate its timeliness and proficiency, tell it about the hazards and give it access to the spaces so it can plan and practice. In-house rescuers need PPE and training at no cost, entrant-level training, and first aid and CPR, and at least one member must hold a current first aid and CPR certification. Rescue teams practice at least once every 12 months.
Retrieval systems are required whenever an entrant enters a permit space, unless they would increase overall risk or not help the rescue. A mechanical device must be available for vertical spaces more than 5 feet deep. Respirator rules for IDLH atmospheres come from 29 CFR 1910.134.
Confined Space Training Under 1910.146(g)
Training is required before first assignment, before a change in duties, when a change in operations creates a new hazard, and when the employer sees deviations from procedures or gaps in knowledge. It must establish proficiency. The employer certifies it with each employee's name, the trainers' signatures or initials and the dates.
Confined Space Exam Cost, Questions, Pass Score and Retakes
OSHA does not run a confined space exam. 29 CFR 1910.146 requires proficiency and certification of training, but it sets no exam fee, question count, time limit, open-book rule, retake rule or pass score. Your employer or training provider sets these, so ask before the course. Our Confined Space Full Mock Exam uses 70% only as an unofficial target.
In terms of difficulty, the rule is short, but tests probe the details: the testing order, oxygen limits, the 10% LFL figure, who signs the permit, how long permits are kept, and which role does what.
Confined Space State Differences
1910.146 is the federal general industry rule. States that run their own OSHA-approved State Plans must have standards at least as effective as it, and some add more. Construction work falls under a separate OSHA standard. Check which rule covers your job and state. For related prep, see our HAZWOPER Exam Guide: OSHA 29 CFR 1910.120 Training, Refresher and Test and OSHA General Industry Practice Test.
Confined Space Study Plan
- Day 1: learn the definitions in (b), especially confined space, permit space, entry, hazardous atmosphere and IDLH.
- Day 2: study (c) and (d): evaluation, signs, alternate procedures, reclassification, contractors and the written program.
- Day 3: study permits in (e) and (f), then the duties of the three roles in (h), (i) and (j).
- Day 4: cover rescue in (k), training in (g) and employee participation in (l).
- Day 5: take the Confined Space Practice Test and the timed mock, and retest any group under 80%.
Frequently Asked Questions
Which OSHA standard covers confined space entry?
For general industry it is 29 CFR 1910.146, Permit-Required Confined Spaces. It does not apply to agriculture, construction or shipyard employment.
What makes a confined space permit-required?
A confined space is permit-required if it has one or more of these: a hazardous atmosphere or the potential for one, a material that can engulf an entrant, an internal shape that could trap or asphyxiate an entrant, or any other serious safety or health hazard.
In what order do you test a confined space atmosphere?
OSHA requires testing first for oxygen, then for combustible gases and vapors, and then for toxic gases and vapors.
What oxygen levels are safe in a confined space?
OSHA treats oxygen below 19.5 percent or above 23.5 percent as a hazardous atmosphere.
How long must canceled entry permits be kept?
At least 1 year, so the employer can review its permit space program.
How often must confined space rescue teams practice?
At least once every 12 months, using simulated rescues from the actual spaces or representative spaces.
How much does the confined space exam cost and what is the pass score?
OSHA sets neither. Your employer or training provider sets the course price, the test and the pass mark. Our mock uses 70% only as an unofficial target.
How often is confined space training required?
OSHA ties training to events, not a calendar: before first assignment, before a change in duties, when operations change, and when the employer sees deviations or gaps in knowledge.
Who signs the confined space entry permit?
The entry supervisor named on the permit signs it before entry begins.
Is there a free confined space practice test?
Yes. Our 159-question practice test quotes 29 CFR 1910.146 for every answer, and a timed mock follows.
TradeExamHub is independent and not affiliated with OSHA or any training provider. Our questions quote eCFR text and do not come from any actual exam.