Ships Sweat, Chemical and Biological Degradation of Cargo Results in Combustion

489

Summary:

On 21 September 2016, V Due arrived at the port of Panama City, Florida, USA and commenced loading on the same day at 0830 (LT). During loading, the weather was fair and dry, with an air temperature of about 30 °C. The loading operation was completed on 30 September 2016 and the vessel departed from the port of Panama City on 01 October 2016, laden with the 29,425 mt of wood pellets. The voyage was uneventful with several days of rough, near head seas and wind of Beaufort forces ranging from 7 to 9.

V Due dropped her anchor off Point Lynas on 18 October 2016 at 2105 in position 53º 24.3’ N 004º 12.2’ W. After 22 days at the anchorage, V Due finally came alongside at Liverpool Gladstone Dock on 10 November 2016. During the discharging from cargo hold no. 3, the stevedores noted an excessively high cargo temperature and stopped all the work. V Due was ordered to sail out of the port of Liverpool and drop anchor again, but since Gladstone Lock had developed a fault, the vessel could only sail out on 20 November 2016 at 1228. Subsequently, the vessel dropped anchor just off Point Lynas, in position 53º 23.7’ N 004º 09.9’ W.

On 29 November 2016, the second engineer walked out on the main deck after his watch, some minutes after 2000. As he walked out of the accommodation block on the vessel’s starboard side, he noticed smoke coming from cargo hold no. 5, aft rotating type mushroom ventilator. This was reported and the crew commenced firefighting with fire hoses rigged for boundary cooling around cargo hold no. 5. The efforts continued during the night. On the following day, i.e. 30 November 2016, the smoke was seen escaping from the sides of the cargo hold hatch cover. On the same day, the owners’ and insurers’ appointed salvage team boarded the vessel. The team consisted of a fire expert, a chemical expert and a technical consultant.

A decision was eventually made to allow the vessel back inside the port and on 08 December, V Due heaved up anchor and proceeded towards Liverpool docks, arriving on the following day at 0709. The discharge of cargo proved to be a complex operation, necessitating the release of the CO2 fixed installation because of the high CO levels. The cargo self-igniting during the discharge operation but was eventually safely discharged about one week later.

The safety investigation found that the immediate cause of the fire was excessive heat generated within the stowed bulk cargo, as a combination of ship sweat, moisture, chemical and biological degradation of the cargo. It was also not excluded that the partial discharge of the cargo during the first port call, the delays at anchor upon arrival from the trans-Atlantic voyage, and during the anchorage periods before entry and after the vessel had left the port, had aggravated the situation as a result of increased moisture and air inside the cargo holds.

One recommendation has been made to the flag State Administration, to publish an Information Notice in order to raise awareness on the potential of fire hazards related to this type of cargo.

Probable cause:

The immediate cause of the fire was excessive heat generated within the stowed bulk cargo, as a combination of moisture from ships sweat, chemical and biological degradation of the cargo.

Findings:

  1. It was also not excluded that the delays, both at anchor upon arrival from the trans-Atlantic voyage and during the anchorage after the vessel had left the port, in addition to the partial discharge of the cargo before the second anchorage had aggravated the situation as a result of increased moisture and air inside the cargo holds.
  2. The formation of ship sweat as a result of the vessel’s transit from a warm to a cold climate contributed to an increase in the moisture content inside the cargo hold.
  3. The increase in temperature inside cargo hold no. 3 is attributed to the fact that the cargo was excessively slack within the hold, creating an increased volume of air over the cargo surface.
  4. The fact that the fire started in cargo hold no. 5, which was only slightly slack after the partial discharging, suggested a seat of moisture, which could have potentially led to self-heating and combustion.
  5. A risk assessment for the loading, carriage and discharge of the cargo had not been compiled, however, with no cargo temperature range guidance available to the crew, this would have been of limited value
  6. As much as the ship was ordered to remain on anchor for 22 days after her arrival from a warm climate, there was no specific concern expressed by the crew, or other parties involved in the shipment, on whether this delay could have led to the generation of ship’s sweat and as a consequence increase in the moisture content inside the cargo holds.
  7. Since the release of the CO2 gas occurs through holes located high up in the cargo hold in way of the hatch coaming, it does not appear that this was effective in extinguishing a fire caught deep inside the cargo.  

Recommendations:

The Merchant Shipping Directorate is recommended to:

  • Publish an Information Notice to raise awareness on the potential of fire hazards related to this type of cargo.

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Source: Transport Malta

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