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What is the maximum validity period for an Enclosed Space Entry Permit under MSC.581(110)?

Q: What is the maximum validity period for an Enclosed Space Entry Permit under MSC.581(110)?

8 hours — it should never be exceeded Para. 5.2 introduces a defined validity period for the Entry Permit that must never exceed 8 hours, requiring SMS procedures to be updated and Responsible Persons trained to enforce this limit.

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. 8 hours — it should never be exceeded

B. 24 hours, renewable once

C. The duration of the voyage leg

D. There is no defined maximum; it is left to the Responsible Person's discretion

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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