I’m getting grief for how I handled a recent stack fire. I’d like to hear about experiences you’ve had and also what you’ve been trained to do.
so what burned? what’d you do?? I’d want to see if you did better than me before exposing myself !!!
Let me guess you didn’t call the office before putting the fire out??
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I’m guessing a bit of steel and some hydrogen.
Reduce load and thus exhaust temps to the extent possible while maintaining steerageway, or less if weather and operational conditions permit.
Identify (this is an often ignored part of fire response planning) the adjacent spaces and prepare to zone cool them. Post fire watch where sparks and embers are able to drift down.
If they thought you should have shut the engine down, they’re dumbasses. That’s a last ditch option and should only be attempted if there is clear access to the stack opening, the fire crew is up there and ready, and the stack is close to losing integrity.
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You need to give more information before we can decide.
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I’m not trying to get an opinion on what I did right or wrong. I was lucky - it was in the exhaust stack for one of my two generators, and didn’t do any damage. There are a couple things I was told I could or should have done that are contrary to what I’ve learned in 20 years on the water.
I’d like to see how experienced mariners - especially anyone who’s dealt with an exhaust system fire - would deal with one, in general terms.
Pretend you’re in a classroom and the teacher opens the class with “How would you fight a stack fire?”
Mostly I want to see if I’m thinking about the situation correctly, but also if there are ways out there to address the problem that I haven’t thought of, in case the next one is worse.
I called the office with my left hand while I held the fire hose in my right.
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Been though CG, Navy (MSC), union and shipboard training. Never encountered a stack fire scenario. So I’d have to answer that I’d follow the basic E/R firefighting scenario which always includes boundary cooling.
Beyond that I’ve no specific training or experience.
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I’ve never experienced a stack fire, but all instruction I’ve received indicates two methods, traditional and non traditional. The first step of traditional method is always to shut down the main(s).
When you shut down the engine, you stop the flow of non-combustible exhaust gases which immediately causes oxygen to draft down to the fire. Unless the fire crew is in position that’s a bad idea.
Shutting down the engine removes heat, but there’s enough residual heat in a burning exhaust pipe to maintain combustion. Maintaining exhaust flow until either whatever built up flammable deposits burn off or your crew has access to do a direct attack is a better method.
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That doesn’t surprise me, after the fact almost everyone has 20/20 (or better) hindsight.
If there is no procedure in place beforehand the response is going to be improvised to a large degree (following basic principles hopefully) and most likely the situation is going to have a high degree of uncertainty and chaos.
As far as the after-the-fact critics; a good question for them is how many shipboard fires have they fought. Unless they have successfully fought a stack fire they should probably STFU.
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‘I have never had a stack fire’ sometimes means ‘The Chief didn’t trust my judgement, so he didn’t tell me and just let it burn out’.
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From Marine Fire Fighting which is the text book I’ve seen used.
Two scenarios using the “Traditional Method” for early stage and high-temp step 1 is to shut down the main engine
For nontraditional there are two alternatives, one involves shutting down the main the other slowing the main.
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I concur. Shutting down the engine is a bad idea. Not all stack dampers work properly and the last thing you want is to allow more oxygen. The fire will burn itself out.
Having some experience with stack fires in steam and diesel plants I agree that boundaries should be monitored but under no circumstance direct water onto the hot stack. I have been on vessels that had CO2 injection available in case of stack fires, in those cases you have to shut down the engine to extinguish the fire…
The best way to avoid stack fires is not to run under low load for long periods of time. Running at 90% of load after low load running for long periods will prevent most stack fires from occurring. It is better to have a planned Roman candle event than an unplanned one.
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I remember reading a coastguard incident report about a stack fire aboard a Maersk ship on the East Coast. The fire was caused by the superheat tubes leaking. What I was taught was to prepare to fight the fire using copious amounts of water all at once. The fire is self sustaining and adding less than a deluge just adds fuel by way of water splitting in hydrogen and oxygen with the intense heat of molten steel. Boundary cooling using every hose on the ship is a must.
It is unlikely that generators would produce the amount of heat to trigger such a fire and it was probably burning soot.
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Some pretty big assumptions made in your comment. Diesel engine or boiler? What load is the engine running at (or how much excess air on the boiler).
Running the engine may keep feeding the fire from below with plenty of air that still has unconsumed oxygen. Shutting off the engine/boiler fans may stop feeding the fire oxygen from below and the tall stack + heat will limit fresh oxygen ingress from above----hot air rises.
It’s probably easier to discuss what theory would be the most practical: starve the fire of oxygen, or starve the fire of fuel.
If you can dig that incident report up pass it on.
Superheat tubes can only emit water vapor. Water is not fuel. Carbon from unburned fuel is the cause of fire in stacks. If there was a stack fire a leaking superheat tube may be your best friend.
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https://www.google.co.nz/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjj6fzNtu71AhWfzTgGHagtDbkQFnoECAwQAw&url=https%3A%2F%2Fwww.marineinsight.com%2Ftech%2Fboiler%2Ftypes-of-exhaust-gas-boiler-egb-fires-and-ways-to-prevent-them%2F&usg=AOvVaw2MceD0qY1bcnySgUPGaGCC
This article offers a good overview. I will continue to look for the article but I remember it being a subject we were instructed in when I was in the navy but my knowledge is a little dated as that was more than 55 years ago.