Bulk calcined petroleum coke (calcined or uncalcined) must have its cargo temperature controlled before loading because it is classified as a Group B solid bulk cargo under the IMSBC Code with self-heating and spontaneous combustion hazards. Uncontrolled temperature can directly trigger fire or even explosion, which is why the Code sets clear “red lines” for loading temperature.
1. Core Risk: Self-Heating → Spontaneous Ignition → Fire
Although calcined coke has been processed at 1,200–1,350°C and has very low volatile matter, uncalcined or partially calcined petroleum coke still retains small amounts of combustible volatiles and reactive sulfur. In a piled state, these substances undergo slow oxidation reactions with atmospheric oxygen. If the heat generated cannot dissipate in time, it continuously accumulates inside the cargo heap, causing the temperature to keep rising — this is self-heating. Once the temperature breaks through the critical point, spontaneous ignition occurs.
Self-heating also brings two secondary disasters: first, it consumes oxygen in the cargo hold and releases toxic gases such as carbon monoxide, endangering personnel safety; second, it produces large amounts of corrosive gases such as sulfur dioxide, damaging the ship’s structure.
2. Temperature Control Requirements under the IMSBC Code (Mandatory Rules)
According to the International Maritime Solid Bulk Cargoes Code (IMSBC Code) and the implementation requirements of China’s Regulations on Safety Supervision and Administration of Solid Bulk Cargoes by Sea, bulk petroleum coke temperature control has the following hard-and-fast rules:
1) Loading temperature upper limit: must not exceed 107°C
The Code explicitly states: if the cargo temperature exceeds 107°C, it shall not be loaded. This is an absolute red line that cannot be breached under any circumstances.
2) Loading temperature reference: not higher than “ambient temperature + 10°C” or 55°C (whichever is lower)
Loading is only permitted when the cargo temperature is not higher than the surrounding temperature plus 10°C, or not higher than 55°C — whichever is the lower value. This means that in hot seasons (e.g., summer when deck temperatures can exceed 50°C), the cargo temperature must be suppressed even lower before loading.
3) Layered loading requirements for high-temperature cargo
When loading cargo at 55°C or above with a loading depth greater than 1.0 meter, a 0.6–1.0 meter thick layer of cold material not exceeding 44°C must first be laid as an “insulation pad” before the hot material is loaded on top. This prevents heat from the hot cargo heap from conducting upward and igniting adjacent compartments or affecting the ship’s structure.
4) Special requirements for loading above fuel oil tanks
If the cargo hold is directly above a liquid cargo tank containing fuel oil with a flash point below 93°C, a cold layer of at least 0.6 meter thick and not exceeding 44°C must be loaded first before any hot coke above 55°C is placed on top. The purpose is to prevent heat from conducting through the tank bulkhead and igniting fuel tank vapors.
5) The master must post “High Temperature Warning” signs near the cargo spaces
This is a mandatory requirement, intended to ensure that all crew members and emergency personnel immediately know that the compartment carries a high-temperature risk.
3. Why “Controlling Temperature” Is More Critical Than Other Measures
Looking at actual accident cases, the vast majority of bulk petroleum coke maritime incidents are not caused by problems arising during the voyage — the hazard is already embedded at the time of loading. If cargo piles are exposed to strong sunlight at the terminal for too long, internal temperatures can easily rise to 80–100°C or even higher. Once loaded at that temperature, with insufficient ventilation during the voyage and heat unable to dissipate, the cargo can break through the ignition point within just a few days.
Therefore, controlling loading temperature is the most effective way to cut off the self-heating chain reaction at the source. The logic of the Code is clear: rather than trying to cool down, seal the hold, and send people in breathing apparatus to fight the fire at sea (at enormous cost and extreme risk), it is far better to suppress the temperature below the safety line before the cargo even goes on board.
4. One-Sentence Summary
Bulk calcined petroleum coke requires cargo temperature control before loading because it has self-heating and spontaneous combustion characteristics; the IMSBC Code sets an absolute 107°C no-load line, a 55°C / ambient+10°C loading condition, and mandatory layered insulation loading for high-temperature cargo — all designed to eliminate cargo hold fires, toxic gases, and oxygen depletion disasters right from the point of loading.
Post time: May-14-2026