Maritime Questions › Enclosed Space Entry

A space tests safe at the point of entry, but the entrant is required to crawl into a void at the far side of the tank that was not directly tested. What is the correct approach?

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. Rely on visual inspection of the void instead of gas testing

B. Proceed — if the main space is safe, all connected voids are assumed safe too

C. Test the specific area to be occupied, not just the general space, before anyone enters or works there — a safe reading at the access point does not certify the whole space

D. Only test the void if it is more than 2 metres from the entry point

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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