CHST Confined Space Entry and Rescue 5

Question 1

Which atmospheric condition in a confined space is MOST immediately life-threatening and requires immediate evacuation without any other assessment?

Accepted Answer

LEL reading at 12% of lower explosive limit

Answer

An LEL reading of 12% indicates a significant flammable atmosphere; evacuation is required when LEL reaches or exceeds 10% of the lower explosive limit.

Question 2

A construction worker is performing hot work inside a confined space with documented atmospheric testing. The work is paused for a 30-minute lunch break. Upon return, the worker should:

Accepted Answer

Re-test the atmosphere before re-entering the space

Answer

Atmospheric conditions can change rapidly during breaks, especially with hot work; retesting before re-entry is required to ensure continued safety.

Question 3

The primary purpose of continuous forced-air ventilation in a permit-required confined space is to:

Accepted Answer

Replace and control hazardous atmospheres during occupancy

Answer

Forced-air ventilation continuously dilutes and removes hazardous gases to maintain a safe atmosphere while workers occupy the space.

Question 4

Which of the following rescue methods is always preferred over all others for confined space rescue per OSHA regulations?

Accepted Answer

Non-entry retrieval using mechanical means

Answer

OSHA requires that non-entry retrieval be used whenever it is feasible, because it protects rescuers from entering the hazardous space.

Question 5

A confined space attendant who must temporarily leave their post due to an emergency should:

Accepted Answer

Have another authorized attendant replace them before leaving

Answer

An attendant may not abandon their post unless relieved by another qualified attendant, as continuous external monitoring is essential to entrant safety.

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST Confined Space Entry and Rescue 5