CHST Confined Space Entry and Rescue

Question 1

Which OSHA standard specifically governs confined spaces in construction?

Accepted Answer

29 CFR 1926 Subpart AA (1926.1200-1213)

Answer

OSHA's 29 CFR 1926 Subpart AA (1926.1200-1213) specifically addresses confined spaces in construction, establishing requirements for permit spaces, entry procedures, training, and rescue.

Question 2

What oxygen concentration range is considered acceptable for entry into a confined space?

Accepted Answer

19.5% to 23.5%

Answer

OSHA defines the acceptable oxygen range as 19.5% to 23.5%; below 19.5% is oxygen-deficient and above 23.5% is oxygen-enriched, both requiring special precautions.

Question 3

Before an authorized entrant enters a permit-required confined space, which atmospheric tests must be conducted?

Accepted Answer

Oxygen content, flammable gases, and toxic contaminants

Answer

OSHA requires testing for oxygen content, flammable gases/vapors, and potential toxic air contaminants before entry to ensure all atmospheric hazards are identified.

Question 4

At what percentage of the Lower Explosive Limit (LEL) must workers immediately evacuate a permit-required confined space?

Accepted Answer

10% LEL

Answer

OSHA requires evacuation when flammable gas concentrations reach 10% of the LEL, providing a safety margin well below the actual explosive threshold.

Question 5

Who has the authority and responsibility to cancel a confined space entry permit if conditions become unsafe?

Accepted Answer

The entry supervisor

Answer

The entry supervisor has the authority and responsibility to cancel the entry permit if conditions change or a hazard develops that makes the space unsafe for entry.

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST Confined Space Entry and Rescue