Container vessels are regarded as a relatively safe ship type. However, a series of major fires in cargo areas of such vessels have lately caused concern. DNV have consequently carried out a study, the aim of which has been to assess their seriousness and to identify measures that can be implemented in order to reduce their potential consequences.
The study is based on casualty data available for the worldwide container carrier fleet as well as on interviews of – and workshops together with – major ship owners or ship operators, some of them who have recently experienced such fires. The casualty data clearly indicates that failures of hull integrity, by collision, foundering and similar types of accidents, is the single most important risk with respect to experiencing crew fatalities and injuries onboard container carriers. Engine room fires are also important contributors to fatalities and injuries whereas cargo fires have so far, with a few notable exceptions, mainly resulted in property damages (damages both to the hull and to the cargo). Consequently, if reduction of crew fatalities and injuries is the main concern, implementation of safety measures for reduction of other risks than cargo fires should be in focus.
However, the cost of a major cargo fire onboard a container carrier is extensive – it can even exceed USD 100 mill. Even when conservatively averaging the cost of the latest cargo fires on all container ships, we end up with approximately USD 7.000 per ship per year for a 3.000 TEU vessel; figures that should encourage ship owners to invest more in the area of fire safety both for newbuilding ship projects and for ships in operation.
The challenges that a ship owner is facing can be summarised as follows:
- The content of a container is often not declared correctly. A fire can very well initiate in an area free of containers declared as dangerous goods. Furthermore, a fire may spread to containers adjacent to the one housing the initial fire and may cause a subsequent explosion – a scenario being a serious threat to personnel already engaged in fighting the initial fire.
- Cargoes located above the cargo hatches have no fixed fire extinguishing system. A fire has to be fought manually by the ship’s fire-fighting team, using fire hoses and any other portable equipment available on board.
- The ship’s fire-fighters have normally limited experience with container fires. At the same time, fire-fighting operations in cargo areas are by experience dangerous, even for well trained fire-fighters.
- A CO2 system that is provided below the cargo hatch is in reality almost useless in case the hatch collapses. This was the scenario for at least three of the recently experienced cargo fires, where the hatch fell down after explosions.
In order to cope with the challenges identified above, several fire safety systems have been assessed through this study. The conclusion is that none of the available systems can address all the identified needs and although there is still no consensus on what type of system that will provide the best protection. It is apparent that a water based system of some kind is the preferred extinguishing media. This conclusion is based on the fact that water can be applied efficiently to cool the containers adjacent to the initial fire and because all ships have large capacity seawater and fire pumps which can be operated even with an ongoing fire in the cargo area. It should in this context be mentioned that the seawater and fire main system may in some cases need to be upgraded with the following features:
- Isolating valves in deck fire main.
- Large capacity (diameter) for deck fire main.
- Increased pressure for pumps.
The most promising equipment for application of water are considered to be mobile fire monitors and fixed spray systems (inside cargo hatch and/or between container racks). Fixed monitors (on top of wheelhouse) are in general too expensive, whereas water mist lances have often not the required capacity and will require that fire fighters are exposed to the hazards of fire scene for a relatively long period.
For more details, we refer to our technical paper “Cargo fires on container carriers” and our presentation in London and Hamburg (see downloads).
This page was last updated 12th of February 2004.
Contact person: Anders Tosseviken, Section for Fire Safety