CMC Regulatory Compliance and Standards 2

Question 1

Under OSHA 29 CFR 1915.12, what is the minimum acceptable oxygen concentration for a worker to enter a confined space without supplied-air respiratory protection?

Accepted Answer

19.5%

Answer

OSHA 29 CFR 1915.12 defines an oxygen-deficient atmosphere as one with less than 19.5% oxygen by volume, below which supplied-air or SCBA is required.

Question 2

NFPA 306 classifies a vessel space as 'Gas Free' for hot work when flammable vapor concentration is at or below what percentage of the Lower Explosive Limit (LEL)?

Accepted Answer

10%

Answer

NFPA 306 requires flammable vapor to be at or below 10% LEL before a space is certified 'Gas Free' for hot work operations.

Question 3

Which federal regulation specifically governs hot work operations aboard vessels in shipyards and requires a Marine Chemist certificate for certain operations?

Accepted Answer

46 CFR Part 35

Answer

46 CFR Part 35 (Hot Work) governs hot work on vessels and specifies when a Marine Chemist or Coast Guard authorized person must certify the space.

Question 4

Under 29 CFR 1915.7, who is authorized to certify a vessel space as safe for hot work when a Marine Chemist is not available?

Accepted Answer

A Coast Guard Marine Inspector or a shipyard competent person

Answer

29 CFR 1915.7 allows a U.S. Coast Guard Marine Inspector or, in their absence, a shipyard competent person to certify spaces when a Marine Chemist is unavailable.

Question 5

When testing a confined space atmosphere before entry, OSHA 29 CFR 1915.12 requires testing to be performed in what sequence?

Accepted Answer

Oxygen, then flammable, then toxic

Answer

OSHA requires oxygen concentration to be tested first, then flammable gases/vapors, then toxic substances, because sensor accuracy is affected by oxygen levels.

(CMC) Certified Marine Chemist Practice Test

(CMC) Certified Marine Chemist Practice Test

CMC Regulatory Compliance and Standards 2