200557 Halon Withdrawal

It seems as though Annex VI of Marpol has sounded the death knell for Halon. This is a pity because unlike tin anti-fouling that acts as soon as it is submerged, halon only harms the environment when it is released and thankfully engine room fires are not that frequent. This is especially so after regulations to shield fuel pipes from hot surfaces came into effect.

I was not a crew member on the ship I am about to describe but I spent many days onboard her as a charterer's representative. I did not observe the incident mentioned but I am sure that it happened as I shall now relate without prejudice.

A serious engine room fire broke out on a tanker berthed alongside. The crew were able to extinguish it using Halon. However, they opened the space prematurely and the fire re-ignited. Fortunately the owners of the berth had an efficient well equipped fire fighting team that went onboard and extinguished the fire.

I do not know if there have been similar re-ignition incidents with CO2 but I have heard from some knowledgeable people that Halon was the better fire extinguisher and that it was used in the aviation industry quite extensively.

Now that owners on voyage charters are getting such high rates, there may be some pressure on Masters and Chief Engineers to reduce off-hire time. I believe that waiting say six hours after a fire has apparently been extinguished is prudent to say the least. I have heard people say that you should take the temperature of the space but I do not know how that could be done without opening up.

It would be interesting to hear of other incidents where re-ignition has occurred and the possible reasons for this. Please let me have some feedback on this issue. RB

Feedback March 2006

I noted your request for feedback regarding engine room fires and the time prudent to allow them to stay battened down to ensure extinguishment. The shortest time I have heard of from deploying the agent to opening the space without re-ignition was 36 minutes in the case of a New Zealand vessel Rotoma. The longest was two weeks, when a Japanese vessel came into port with a hold battened down and a fire on board. When the local fire department was ready, the space was opened and the fire extinguished.
The Manulani fire in Seattle involved nine days of waiting and adding carbon dioxide before the space had cooled sufficiently. While halon may be the better extinguishing agent, the issue of cooling down time applies to all agents. Even the new water-mist systems remain active for several minutes after the fire appears out so as to prevent re-ignition. It takes time for hot steel to cool down. The aviation industry is different in that spaces are smaller and of aluminum.
The steel will contain the smoke and flames but cannot stop the conduction of heat unless the steel is insulated (A60) and/or cooled (boundary cooling). This is easier said than done. Temperatures within the space may be ascertained by instrument readouts, by remote thermometers (pyrometers and laser thermometers) and, to a point observation of surrounding bulkheads and decks from adjacent spaces.
It is essential to close up and apply the agent as soon as possible. The Prinsendam was lost due to delay. The Westralia (1998) showed the importance of quick action - regrettably four sailors died in that response.
Thermal imaging cameras (TIC) are in common use aboard cruise ships and are also becoming common in fire departments as the price reduces. They can be of some value as seen with the Macarthur fire in Port Hueneme California about three years ago. In some instances two hours may be sufficient time; in others six hours will not be enough. Much depends on the time delay before closing down; the effectiveness of the closing; the boundary cooling; the initial fuel load and the state of the insulation. One thing is clear: once opened up, there is no second chance, even with halon. The prudent thing is to wait, wait, then wait a while longer.
When the local fire department had the fire site of the Ambassador (1994) opened against the wishes of the crew, the 'ensuing, more intense conflagration' was not manageable and the fight to contain the fire was probably much more difficult than if the fire had remained closed up (Canadian TSB Report no. M94M0057 1996).
So close the space quickly; open it without haste, Delay in the beginning must be balanced by delay at the end. I hope this may help. It's all ‘old stuff’ but we must constantly learn and re-learn as otherwise the hard-won knowledge of experience will be lost.