Firefighting on Ships - Strategic Considerations

In the last article we looked at some of the tactical considerations which the person in charge of fighting a fire should be thinking about, but maybe I should have started with the strategic considerations. These after all, come first and will dictate how the fire will be fought.

These considerations are the domain of the Master but having an understanding of the decisions being made will benefit all of those involved in the emergency, and of course, if the Master is incapacitated or unavailable, his deputy will be in the hot seat.

The firefighting strategy dictates the approach to fighting the fire that the crew will take. There are broadly three different strategies for fighting a fire on a ship which are discussed below; offensive, defensive, or the defensive offence, but so we don’t confuse matters we will refer to the third as using fixed fire fighting systems. Which strategy we use will depend on several factors including location, manpower, available equipment, ships location etc, but all three should be included in drills so that when used, we ensure their effectiveness.

Offensive Firefighting Strategy

This is the subject of the majority of our drills and involves taking a fire-fighting medium to the seat of the fire and extinguishing it. Generally, this will also place the most risk to the health and safety of our fire teams. It is however, very effective and even more so if the fire hasn’t had time to become fully established.

The considerations for adopting an offensive strategy are generally to rule out the other two strategies detailed below. However, an offensive strategy may be used initially if we believe that missing persons are in the fire compartment. Then once all are accounted for, it may be appropriate to switch to another strategy.

Defensive Firefighting Strategy

An often overlooked strategy which can be effective for the right type of compartment and when crewing is limited. It involves shutting down the compartment and allowing the fire to run its course, eventually burning itself out as the oxygen or fuel is used up. This isn’t suitable for large spaces, or those which contain or are adjacent to fuel supplies, but for smaller spaces such as cabins, small store rooms or similar spaces the defensive strategy will be appropriate and can be highly effective.

The key to the defensive strategy is the ability to monitor and implement boundary starvation and cooling on all six sides of the space in order to contain the fire within that space only. As no one will enter the space, the smoke boundary and fire boundary remain the same and so more resources can be applied to the immediate boundary to help contain the fire.

The progress of the fire can be monitored from outside by using small amounts of water to monitor the temperature on the steel bulkhead. As the oxygen is used up, the bulkheads will increase in heat starting at the highest point and moving down as the neutral plane descends. When the majority of the oxygen has been used up, the full height of the bulkhead will become very hot and boundary cooling will become the main focus. At this point it is important not to be tempted in to opening the door to monitor the fire, as a sudden inrush of fresh air can cause the fire to flare up and potentially result in a backdraft. 

The space should remain shut down until the bulkheads cool naturally and do not require external cooling. At this point, the door can be opened enough to allow a spray of water into the compartment to cool the gasses before being shut again. This can be repeated until firefighters are confident that the fire is out and there is little risk of the fire re-igniting. In reality we would expect the vessel to be alongside by this point and the local authority fire brigade to be in attendance.

Using Fixed Firefighting Systems (the defensive offence)

The use of fixed firefighting systems where available is potentially the safest and most effective firefighting strategy we have. As in the defensive strategy, the space remains closed down, the smoke boundary remains aligned to the fire boundary and crew (once accounted for) can be employed in containing and monitoring the fire from outside the space.

In our drills, it is often the case, that the use of fixed firefighting systems are only drilled after an unsuccessful entry. In reality, the best time to initiate fixed systems is as soon as possible, without putting anyone in any danger first.

Depending on the space and the ship, we have several fixed systems available to us, from sprinkler systems in paint lockers, CO2 in machinery spaces or galley flues, hi-fog or bespoke systems on certain equipment. Regardless of the type, all crew should be made familiar with the operation.

Considerations for using fixed systems, is any secondary effects of using the system and how that would impact on the safety of the vessel and crew. The only system that really needs the consideration is the CO2 system in the machinery space. The biggest consequence of which is oxygen depletion creating an unsafe atmosphere for anyone without breathing apparatus. So as we already do, we must ensure that everyone is accounted for before initiating fixed system.

The other consideration is what could happen to machinery in that space. Internal combustion engines require oxygen and so there is a risk that the engines will stop. Clearly one of the considerations is therefore whether the ship is navigably safe or could be made safe (by anchoring for example - something the OOW should have in his mind when the alarm is first sounded).

Once the CO2 system has been used, checks should be carried out to ensure that the gas has been correctly released from the cylinders, and crew should be instructed to remain clear of any vents to prevent inhalation of noxious gasses.

The space should not be ventilated again until it is definitely established that the fire has been extinguished which is likely to take several hours. The fire boundary should continue to be monitored and cooled in the same way as in the defensive strategy and when it is believed that the fire is out, a re-entry should be made on air, using as many persons as you have fire suits for, to confirm.