Oxygen Depletion in Cargo Spaces
How steel corrosion, cargo oxidation and microbial activity consume oxygen in a cargo space, the depletion rates, and the entry criteria that follow.
Oxygen depletion in a cargo space arises from three mechanisms: corrosion of bare steel, chemical oxidation of the cargo itself, and microbial activity where moisture supports it. IMSBC section 3.2.3 names most vegetable products and forest products, ferrous metals, metal sulphide concentrates and coal cargoes among the cargoes liable to cause it.
The full article will cover the depletion rates each mechanism produces, why a space sealed for a short period can already be below any safe entry figure, and the measured record on organic cargoes, where oxygen has been found at 0.8 percent in a loaded hold.
It will also cover the entry criteria and their sources, which differ by instrument and by cargo: 21 percent under several IMSBC schedules, 20.7 percent under others, 20.9 percent under MSC.581(110), and 19.5 percent under United States national law, which has no standing in any IMO instrument.