Maritime Questions › Enclosed Space Entry

What is the default assumption that must underpin the entire enclosed-space risk assessment process under MSC.581(110) para 4.8?

Q: Under MSC.581(110), what is the maximum acceptable CO2 reading (by volume) before an enclosed space can be considered safe for entry?

Less than 0.5% by volume (5,000 ppm) Para. 7.4 sets the CO2 exposure limit at below 0.5% by volume (5,000 ppm) before entry; if this is not achieved, the space remains unsafe. CO2 is now explicitly addressed as a major asphyxiation hazard alongside oxygen depletion.

A. The space must be assumed hazardous until it has been positively proven safe for entry — the burden of proof sits with demonstrating safety, not with disproving danger

B. The space may be assumed safe if no cargo has been carried in it for over 30 days

C. The space may be assumed safe based on the most recent entry record in the Enclosed Space Register, without re-testing

D. The space's status should default to whatever the previous watch determined, unless conditions have visibly changed

Under MSC.581(110), what is the maximum acceptable CO2 reading (by volume) before an enclosed space can be considered safe for entry?

A. Less than 0.5% by volume (5,000 ppm)

B. Less than 2% by volume

C. Less than 21% by volume

D. There is no specific CO2 limit, only an oxygen limit

Under the revised recommendations, is single-person entry into an enclosed space ever permitted?

A. No — the company must ensure single-person entry into an enclosed space is not permitted

B. Yes, provided the person carries a personal gas detector

C. Yes, for spaces that have previously tested safe within the last 24 hours

D. Yes, but only for spaces below 5 metres in depth

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