Sunday, February 17, 2013

FREE RADICALS

Why are cruise ships so damaged by engineering fires in this day and age?

As I read the news I am once again struck by how the modern cruise ship industry is plagued by morons and radicals. The morons run the ships into reefs and other things while the radicals rule the engine rooms. How does a fire break out and burn out of control in a modern cruise ship? In particular, how does it happen in a cruise ship engineering space? I don't think there is a good answer.

We had installed twin agent firefighting systems actuated from stations within the engine rooms and from the damage control decks above which used (aqueous fire fighting foam (AFFF) and potassium bicarbonate powder (PKP). We also had CO2 flooding systems in addition to CO2 extinguishers and then we had PKP extinguishers that worked on spoiling the fire triangle by acting on the free radicals required for combustion even when the fire triangle was present; fuel, heat and O2. If all that failed we had HALON flooding systems that would flood the affected space and put the fire out instantly and keep it out unless the ventilation was still running or there were significant holes in the fabric of the compartment allowing fresh air in.

So how in the world does a cruise ship suffer catastrophic damage to its generators and switchboards that cannot be made good by shifting to alternates? I haven't seen the engine rooms of the ships that keep doing this but it I can't believe they don't have separate generators and main propulsion spaces. Even with electric drive there is no reason to have the switchboard in the main engine room. I guess the real questions are just who in the world controls the specifications for modern passenger ships; who designs it to fail catastrophically; why and how can none of these fire fighting systems put out fires in cruise ships? They all worked in my ships. An electrical fire lasted no longer than it takes to turn the burning unit off. The class A and B fires didn't survive the application of twin agent long enough to notably heat the spaces. None required dumping halon or CO2 systems and only one required PKP.

It's a modern cruise ship so why are unmanned spaces not equipped with fire detectors (smoke, heat) attached to automatic fire suppression systems that will flood the space with chemicals?

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