In its earlier-published guide for prevention of cargo fires and explosion onboard, the Club cites a number of risks related to refrigeration units:
- Cargo shifting in heavy weather can lead to ignition e.g. by rupturing gasoline tanks, damaging electrical cables and causing friction.
- Vehicles being driven can lead to fire, if they are faulty. Working on vehicles to try to start them can lead to ignition e.g. using petrol to top up tanks and using jump leads to start vehicles that have flat batteries. These risks are higher when dealing with used vehicles that may be in poor condition.
- Electrical faults. Many vehicles have electrical circuits that remain energised even when the ignition is switched off. Electrical faults do not commonly cause fires in cars that are not being driven, but large numbers of cars are transported by ship and occasionally a fault can develop to cause ignition during shipment. Refrigeration units too are subject to electrical faults.
Case study 1
A ro-ro vessel was underway and was expected to sail through heavy weather at Beaufort 10 the following day with waves of about 6-8 metres. The cargo comprised vehicles, containers and jerrycans on flat racks.
Before loading commenced the Chief Officer went ashore to inspect the cargo. He inspected the jerrycans which were secured with quick lashings through the handles of each row and secured to bars on the flat racks.
He was concerned that the jerrycans were placed on flat racks and not in containers, as there were no sides around the flat racks to protect them. However, he decided to accept the cargo on board.
The flat racks on the forward part of the weather deck were secured with two lashings (and some with three or four) at each end. Some of the units were secured with lashings along the length of the unit. The containers were secured with a combination of web lashings and chains.
The following morning the Chief Officer and crew inspected the cargo and the Chief Officer found only minor issues to correct, with some slack lashings that needed to be tightened, and some lashings needing to be added to certain units that were a bit loose or did not have ideal angles.
Later in the morning the wind increased, the vessel started to roll and the Master slowed down to about 10 knots. Around lunch time the wind increased even further and the vessel slowed down to about 6 knots. The vessel was now sailing through Beaufort 10 and waves of about 8 metres.
This caused one of the containers to come loose which hit one of the flat racks containing jerrycans.
Due to the heavy rolling, the Master believed it to be unsafe for the crew to go onto the weather deck and re-lash the container. A number of the jerrycans fell onto the deck and spilled fuel.
As water was washing over the weather deck, the Master assumed that any fuel would have been washed away by the water, but it could be seen that this was not the case.
From the cameras on the bridge, sparks could be seen on the weather deck from the moving containers. To prevent a fire from starting the electricity was turned off for the reefer units on the weather deck and the sprinkler system was started. The Master hoped that this would wash away all the fuel on deck, but this too was unsuccessful.
Large flames could then be seen on the weather deck through the vessel’s cameras. The Master activated the fire alarm and broadcast a mayday over the VHF. The crew were assembled and all accounted for.
The burning cargo was in the forward part of the weather deck. The fire crew approached the blaze from the side walkways and from the stern on the weather deck. The sprinklers were also running. There were now flames up to 30 metres high.
Several explosions occurred from fuel containers and jerrycans. The crew fought the fire for about five hours until they finally got it under control.
The vessel eventually berthed safely at the next port.
Case study 2
While a ro-ro vessel was sailing, an AB was checking the reefer containers during his deck patrol when he saw smoke coming out from one of the trailers on the weather deck.
The AB could not detect the source so he started the fire alarm. The smoke alarm had not yet been triggered on the fire detection system.
The OOW started the general alarm after he had been informed by the AB. All the crew were assembled and accounted for.
The sprinkler system was started and a fire team approached the fire.
The Master slowed the vessel down and altered course so that there was almost no relative wind on the weather deck.
The fire team managed to extinguish the fire quickly before it spread from the trailer. It was suspected that the fire had started in the trailer’s refrigeration unit.
Case study 3
A reefer container on board a container vessel caught fire. The container was loaded with cartons of frozen meat and the container was connected to the vessel’s power supply.
The area of the control panel where the fire started was located close to the stowage zone of the electrical feeding power cable. The 30-metre feeding power cable was found in good condition but aluminium parts from the container were found melted around the control panel. The fire most likely started in the 440V cable that was folded in a basket.
Once the fire took hold, it melted the aluminium coating, foam insulation and other parts of the panel. As the reefer fans were still working, fire and smoke was sucked into the container.
All the meat was considered to be waste.
Not all risks of fires in vehicles can be eliminated. Risks of significant fire damage can be reduced by following proper procedures when working on cars, and by ensuring that ships’ fire precautions and procedures are correct and are followed properly,
...the Swedish Club advised.