Self-Heating and Spontaneous Combustion of Bulk Cargoes
The oxidation, microbial and heat-retention paths to self-heating in a bulk stow, the monitoring that detects it, and the ventilation rule that follows.
Self-heating in a solid bulk cargo is the accumulation of heat generated inside the stow faster than it can conduct away, and it runs through three paths: chemical oxidation of the cargo, microbial decomposition where moisture supports it, and simple heat retention in the core of a large mass. Left to run it progresses to smouldering and, given an oxygen supply, to flaming combustion propagating through the cargo.
The full article will cover which IMSBC cargoes carry the MHB(SH) classification and which self-heat without it, the test criteria at section 9.2.3, and the monitoring that detects a developing event, in which the temperature trend and the carbon monoxide trend matter more than any single reading.
It will also cover the ventilation rule that follows from the mechanism, at IMSBC section 3.5.6: where a cargo may heat spontaneously, ventilation other than surface ventilation shall not be applied, and on no account shall air be directed into the body of the cargo.