STSC Confined Space Entry Procedures 5 — Questions and Answers
Question 1: When testing the atmosphere of a confined space prior to entry, what is the correct order for measuring atmospheric hazards?
- Flammability, then oxygen, then toxic gases
- Oxygen content, then flammability, then toxic contaminants (Correct answer)
- Toxic contaminants, then oxygen, then flammability
- Any order is acceptable as all must be tested before entry
Correct answer: Oxygen content, then flammability, then toxic contaminants
OSHA and industry best practice require testing oxygen content first, then flammability (LEL), then toxic contaminants, because low oxygen can affect sensor accuracy.
Question 2: A confined space entry is interrupted by an uncontrolled condition not covered by the existing permit. What must the entry supervisor do?
- Reassess and update the existing permit to cover the new condition
- Ensure all entrants immediately exit and cancel the permit (Correct answer)
- Allow entry to continue while investigating the new condition
- Notify OSHA before taking any further action
Correct answer: Ensure all entrants immediately exit and cancel the permit
Any condition not covered or allowed by the permit requires all entrants to exit immediately and the permit to be cancelled until the new hazard is addressed.
Question 3: What is the primary purpose of a retrieval system in confined space entry operations?
- To supply fresh air to the entrant during operations
- To enable non-entry rescue of an entrant without requiring rescuers to enter the space (Correct answer)
- To lower heavy tools and equipment into the space safely
- To maintain communication between the entrant and the attendant
Correct answer: To enable non-entry rescue of an entrant without requiring rescuers to enter the space
A retrieval system allows entrants to be extracted from a confined space by the attendant or rescuers without requiring anyone else to enter the hazardous environment.
Question 4: Which scenario would classify a confined space as 'permit-required' under OSHA 29 CFR 1910.146?
- A space large enough for a worker to enter but with no mechanical hazards or atmospheric risks
- A large storage tank with continuous ventilation and no hazardous materials
- A utility vault that contains a potential engulfment hazard from accumulated water (Correct answer)
- A crawl space that is used infrequently for inspection purposes only
Correct answer: A utility vault that contains a potential engulfment hazard from accumulated water
A space with a potential engulfment hazard — such as accumulated water — meets the definition of a permit-required confined space under OSHA.
Question 5: After all entrants have exited and work is complete, what must happen to the entry permit?
- It is returned to the entry supervisor for possible reuse
- It must be cancelled, retained by the employer for at least one year, and reviewed to improve the program (Correct answer)
- It is destroyed after the space is secured
- It is filed with OSHA as proof of compliance
Correct answer: It must be cancelled, retained by the employer for at least one year, and reviewed to improve the program
Completed permits must be cancelled and retained for at least one year so employers can review them to identify and correct problems in the permit program.
Question 6: An attendant monitoring a confined space entry is approached by a supervisor who orders the attendant to perform a task away from the entry point. What should the attendant do?
- Comply with the supervisor's order and briefly leave the entry point
- Have entrants exit the space before leaving the monitoring station (Correct answer)
- Ask one of the entrants to monitor from inside the space temporarily
- Radio for another attendant to take over before moving
Correct answer: Have entrants exit the space before leaving the monitoring station
The attendant must never leave the entry point while entrants are inside; if they must leave, all entrants must exit the space first.
Question 7: What does 'IDLH' stand for, and why is it critical for confined space planning?
- Immediately Dangerous to Life or Health — it defines exposure levels that pose immediate severe risk, requiring air-supplied respirators (Correct answer)
- Initial Detection Limit for Hazards — it sets the threshold for when atmospheric testing is required
- Identified Daily Limit for Hazards — it determines maximum work hours in a confined space
- Incidental Detection of Lethal Hazards — it triggers an automatic space evacuation
Correct answer: Immediately Dangerous to Life or Health — it defines exposure levels that pose immediate severe risk, requiring air-supplied respirators
IDLH (Immediately Dangerous to Life or Health) describes airborne concentrations that pose an immediate risk of death or severe health effects, mandating the use of self-contained or supplied-air respirators.
STSC Confined Space Entry Procedures 5
When testing the atmosphere of a confined space prior to entry, what is the correct order for measuring atmospheric hazards?