Engine comp fire extinguisher powder or gas ?

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Crowblack

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Upgrading the extinguishers on board and felt best way to go would be one of these here things.

http://www.safelincs.co.uk/fireblitz-automatic-fe36-fire-extinguisher/

Better than powder no mess etc - - then it occurred to me - isn't the gas it produces air born and the engine compartment has a fan which circulates air from outside so in the event of fire would the gas (all or partially) be sucked outside thereby reducing the effectiveness of the extinguisher - - or am I over egging that pudding ?

Would powder be better despite the potential mess ?
 
What part of the fire triangle are you trying to kill?

What type of fire can you expect in the engine compartment? Does this cover every type of fire type?
 
My engine compartment doesn't have a fan, unless you count the 30-horsepower 3-cylinder pump sitting in the middle of it :)

If you do have a fan, then I guess you need some kind of switch to turn it off if the extinguisher is activated.

Pete
 
Camelia said:
What part of the fire triangle are you trying to kill?

What type of fire can you expect in the engine compartment? Does this cover every type of fire type?
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Just interested - -

In your engine compartment what type of fire do you expect ?

What type of extinguisher do you have to cope with that threat ?
 
If you want the fire out Gas drench for me. I know its illegal, but ideally Halon. If the fire is out you at least live to make your Court appearance for polluting the environment.
 
Must be lots of boats out there with fans in the engine compartment and wondered what extinguisher they used.

Like Moody Sabre and others above don't like the idea of using powder.

So cogitating on PRV's suggestion - I'll go for a gas cylinder with a bigger capacity and see if I can find a temperature switch for the fan.

Thanks chaps.
 
superheat6k said:
If you want the fire out Gas drench for me. I know its illegal, but ideally Halon. If the fire is out you at least live to make your Court appearance for polluting the environment.
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Whether or not it's illegal here (Turkey), chandlers are almost as happy to sell it as I was to buy it.
As for the environmental ethics of the situation, I daresay there's more damage in a GRP boat burning to the waterline than in a bottle of halon.

To Crowblack: a thermal switch is probably a good idea. They're cheap as chips on Amazon/eBay. I used one to control an exhaust temperature alarm (inspired by a thread on here a couple of years ago).
If the engine has a manual stop lever (but no cable to an activating lever), it's also worth fitting this with a closing spring and fusible link, so it shuts off automatically in the event of a fire.
 
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macd said:
Whether or not it's illegal here (Turkey), chandlers are almost as happy to sell it as I was to buy it.
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Are you sure it is actually halon, rather than one of the various replacement gases? Given that it's been illegal throughout the EU and the US for many years, which must be the majority of the potential market, I would wonder who's still making them.

Pete
 
prv said:
Are you sure it is actually halon, rather than one of the various replacement gases? Given that it's been illegal throughout the EU and the US for many years, which must be the majority of the potential market, I would wonder who's still making them.
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Well, it says 'halon' on the bottle. I'm sure you're aware that Turkey is not part of the EU. More pertinently, it has a lively manufacturing industry, so I presume they're Turkish-made. I'll check next time I'm in the engine bay.
 
macd said:
Well, it says 'halon' on the bottle. I'm sure you're aware that Turkey is not part of the EU. More pertinently, it has a lively manufacturing industry, so I presume they're Turkish-made. I'll check next time I'm in the engine bay.
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Indeed, I know Turkey aren't in the EU, I'd just expect that most manufacturers on this side of the globe above the "cottage industry" level would be reluctant to make something they can't also sell in that market. I'm mildly surprised, that's all.

Pete
 
Len Ingalls said:
What would be wrong with CO2?
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An obvious and sensible question to which I didn't know the answer.
Essentially, here it is, courtesy Wiki:
At high temperatures, halons decompose to release halogen atoms that combine readily with active hydrogen atoms, quenching flame propagation reactions even when adequate fuel, oxygen, and heat remain. The chemical reaction in a flame proceeds as a free radical chain reaction; by sequestering the radicals which propagate the reaction, halons are able to halt the fire at much lower concentrations than are required by fire suppressants using the more traditional methods of cooling, oxygen deprivation, or fuel dilution.

In other words, halon doesn't simply work by excluding oxygen (although clearly it will displace it), but by a more active chemical process.
 
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When the boat is fitted with a diesel engine I believe the engine room fan should blow in not out usually to ensure sufficient air to the engine though sometimes to supply cooling air over the alternator. A fan blowing out will have the opposite effect.

However I accept that when a petrol engine is fitted a bilge scavenge fan would be set to exhaust potentially inflammable gases from the bilge before engine start.
 
I once observed first hand a BCF (Bromo Chloro Fuoride) fire extinguisher put out in an instant a fire on a large Olympus Gas Turbine (AKA Concorde / Vulcan Bomber jet engine). CO2 drench does just that by starving oxygen in the general space around the fire, but halons and indeed BCF pyrolise (as described by Macd) around the flame killing it.

The by products are horrendous (e.g. phosgene and hydrofluoric acid), but the most important aspect is that the fire is out.

The reason they were banned is because they were CFC's. The HFC replacements are not as effective, and no doubt now these are also to be effectively banned it will be dry powder for all of us by 2030. The replacements for HFCs - HFO's are mildly flammable, so not so effective for a fire extinguisher.
 
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