CMC Confined Space Entry Requirements 2

Question 1

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

Accepted Answer

19.5% by volume

Answer

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

Question 2

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

Accepted Answer

Entry permit signed by the marine chemist or competent person

Answer

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

Question 3

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

Accepted Answer

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

Answer

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

Question 4

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

Accepted Answer

50 ppm

Answer

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

Question 5

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

Accepted Answer

The atmosphere is safe for entry without respiratory protection

Answer

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

(CMC) Certified Marine Chemist Practice Test