ISC Confined Space Entry 2 — Questions and Answers
Question 1: Under OSHA 29 CFR 1910.146, when is an employee considered to have 'entered' a permit-required confined space?
- When the employee is within 5 feet of the opening
- When any part of the body breaks the plane of an opening into the space (Correct answer)
- When the entire body is inside the space
- When the entry permit is signed by the supervisor
Correct answer: When any part of the body breaks the plane of an opening into the space
OSHA defines entry as the moment any part of the entrant's body breaks the plane of an opening into the space.
Question 2: Which atmospheric condition makes a confined space atmosphere hazardous under OSHA's definition?
- Flammable gas at 5% of its lower flammable limit
- Oxygen concentration of 24% (Correct answer)
- Relative humidity above 80%
- Oxygen concentration of 20.9%
Correct answer: Oxygen concentration of 24%
Oxygen above 23.5% is oxygen-enriched and hazardous because it greatly increases fire risk.
Question 3: In what order should the atmosphere of a permit space be tested before entry?
- Combustibles, oxygen, toxic gases
- Toxic gases, combustibles, oxygen
- Any order, as long as all are tested
- Oxygen, combustibles, toxic gases (Correct answer)
Correct answer: Oxygen, combustibles, toxic gases
Oxygen is tested first because many combustible gas sensors need adequate oxygen to read accurately, followed by flammables and then toxics.
Question 4: A permit space's only hazard is a potential hazardous atmosphere that continuous forced-air ventilation alone keeps safe. What may the employer use?
- A hot work permit instead of an entry permit
- No testing, since ventilation is running
- Alternate entry procedures under 1910.146(c)(5) (Correct answer)
- Reclassification as a non-permit space
Correct answer: Alternate entry procedures under 1910.146(c)(5)
Alternate procedures apply when the only hazard is atmospheric and continuous forced-air ventilation alone can control it, though periodic testing is still required.
Question 5: How long must the employer keep cancelled entry permits?
- At least 1 year (Correct answer)
- 30 days
- 6 months
- 5 years
Correct answer: At least 1 year
Cancelled permits must be retained at least one year to support the annual review of the permit space program.
Question 6: Which duty is the attendant NOT permitted to perform during a permit-required entry?
- Entering the space to rescue an unresponsive entrant without being relieved (Correct answer)
- Summoning rescue services when needed
- Maintaining an accurate count of entrants
- Ordering entrants to evacuate when a prohibited condition arises
Correct answer: Entering the space to rescue an unresponsive entrant without being relieved
Attendants may not enter the space to attempt rescue unless trained and relieved by another attendant, because untrained entry rescue causes many deaths.
Question 7: Why must atmospheric testing in a vertical space be done at several levels rather than only at the opening?
- Gases can stratify, with heavier gases settling low and lighter gases rising (Correct answer)
- Ventilation only works near the top
- OSHA requires a separate permit for each level
- Gas monitors only work at specific heights
Correct answer: Gases can stratify, with heavier gases settling low and lighter gases rising
Gases of different densities stratify, so testing must cover the top, middle and bottom of the space.
