Confined Space Entry Requirements Flashcards

Under OSHA 29 CFR 1915, what is the minimum oxygen concentration considered acceptable for entry into a confined space aboard a vessel?

Answer: 19.5% by volume

OSHA 1915 requires a minimum of 19.5% oxygen by volume for safe entry into a confined space.

Which document authorizes workers to enter a permit-required confined space on a vessel?

Answer: Entry permit signed by the marine chemist or competent person

An entry permit, signed by the authorized entrant or marine chemist, formally documents that safe conditions have been verified.

What action must be taken before testing the atmosphere of a tank that previously contained flammable cargo?

Answer: Ensure the space is gas-free of cargo vapors before entering

The space must be rendered gas-free of flammable cargo vapors before atmospheric testing and entry.

What is the maximum permissible concentration of carbon monoxide (CO) for safe entry into a vessel's confined space per OSHA 1915?

Answer: 50 ppm

OSHA 1915 sets 50 ppm as the ceiling for CO in confined spaces aboard vessels.

When a marine chemist labels a space 'Safe for Workers,' what does this designation specifically mean?

Answer: The atmosphere is safe for entry without respiratory protection

'Safe for Workers' means the atmosphere meets oxygen, flammable vapor, and toxic gas requirements for entry without supplied air.

Which type of ventilation is preferred for confined spaces with heavy vapors that settle near the bottom?

Answer: Bottom-exhaust mechanical ventilation

Bottom-exhaust mechanical ventilation removes heavy vapors that accumulate at the lowest points of the space.

If continuous atmospheric monitoring detects a flammable vapor reading of 12% LEL during entry operations, what must occur?

Answer: Immediately evacuate all personnel from the space

A reading above 10% LEL requires immediate evacuation until the atmosphere is re-evaluated and controlled.