fire extinguisher for engine room

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pcatterall

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Still focussing on our upcoming insurance survey and looking at fire extinguishers.
We have replaced several but doing some head scratching about the engine compartment.
We carry a 4kg CO2 unit which looks good and is in weight ( no date that we can see!). We thought that it would be ok for the engine room 5m/3 ?
We then realised that there was no way to safely 'deliver' the CO2 without removing the engine hatch cover and inviting lots of flame out and o2 in!.
We are considering a hole with a bung in the cover or a bulkhead or fitting a CO2 cylinder inside the compartment with a manual ( pull cord type) release.
The dangers of accidental release are understood so we are also considering a large 'water mist' solution rather than C02?
In both cases and whether mounted in or out ( with hole) how important is the direction of the CO2 or water mist? we would not be able to see what is going on so could not direct the device at the seat of the fire, or does the gas/mist simply fill the compartment?

The need for the survey is, if nothing else, making us aware of several safety issues!
Your usual good advice and experience appreciated as always.
 
Good starter. I've got a couple of foam ones- inside a cockpit locker and above engine box. That's as far as I'd got. Ages ago I had a halon one intended to poke thro hole in engine box. Halon replacement available; presumably better in some way than co2?
Be interested in suggestions on how best to deliver to engine compartment.
 
I have 3 of the water mist types. They all have a flexible delivery pipe with a nozzle about 3cm diameter. A small hole in the engine cover, with a flap, will give access. The mist jet is rapid and a cone of about 60 degrees so, with the turbulence of the flames, the mist will be driven round the compartment.

https://www.youtube.com/watch?v=G67B1gMs8EQ
 
CO2 doesn't need to be directed, it just floods the space. I'm not sure about water mist.

Normal for an engine bay is a halon-replacement (FE36 etc) automatic, activated by heat. Again that's a gas flood so doesn't need to be pointed anywhere specific, though if the head is too low then it might take longer to sense the heat build-up. The extinguishant is a liquid inside the cylinder, that vaporises as it comes out, so the unit needs to be mounted vertically with the head down. Mine is above the engine electrics (alternator, starter, and wiring from the battery) partly because that was a convenient location for mounting and partly because it seems the most likely source of fire.

Pete
 
I have 2 automatic CO2 extinguishers either side of the main engine , appreciate that space is one issue, with in engine compartmental fire extinguishers .
Have heard good thinks about the water mist ones.
 
Have you considered a remote activated CO2 or watermist fire extinguisher together with a smoke detector so you know when a fire has started and can shut down the engine before setting off the fire extinguisher
 
With absolutely no space to mount a FE36 or (hate them) dry powder auto extinguisher in the top of my engine compartment fitted a Pyrogen MAG "pyrotechnic aerosol" extinguisher: compact, fitted behind the engine with a heat sensing trigger on a cable above the engine. Not cheap though.

Many years ago involved in testing portable extinguishers. Halon (now banned) was fantastic, CO2 OK but inferior to Halon, powder just about sort of worked but the mess and damage dreadful.
 
Graham_Wright said:
Fire extinguisher ball?
Click to expand...

They're basically just a small thunderflash inside a polystyrene ball full of the same powder you'd get in a normal powder extinguisher. The thunderflash has a fast fuse wrapped around the outside of the ball to catch a flame and set the thing off.

It's a cheap way of making an automatic powder extinguisher but otherwise I can't see any benefit. Might possibly need the fire to reach a more advanced stage before there are flames licking around the ball to ignite the fuse.

Minchsailor said:
I have a couple of Halon replacement FE36s automatics in the engine room.
Click to expand...

Is each one rated for the volume individually, or do they have to be added together to fill it? FWIW the instructions on them always say not to do the latter, as they're unlikely to go off simultaneously.

Rogershaw said:
Have you considered a remote activated CO2 or watermist fire extinguisher together with a smoke detector so you know when a fire has started and can shut down the engine before setting off the fire extinguisher
Click to expand...

Flooding the air supply with a substance that inhibits combustion is going to stop an internal combustion engine anyway, without any special control needed :). I suppose you might possibly want to delay killing the engine, as a sort of "battle override", until you've made it past the rocks you're negotiating, but it seems a bit of an unlikely situation.

Pete
 
prv said:
Flooding the air supply with a substance that inhibits combustion is going to stop an internal combustion engine anyway, without any special control needed :). I suppose you might possibly want to delay killing the engine, as a sort of "battle override", until you've made it past the rocks you're negotiating, but it seems a bit of an unlikely situation.

Pete
Click to expand...


Your right but I always like to have options, and as I have had an automatic fire extinguisher go off due to just heat without fire I dont want this to happen again.
 
pcatterall said:
Still focussing on our upcoming insurance survey and looking at fire extinguishers.
We have replaced several but doing some head scratching about the engine compartment.
We carry a 4kg CO2 unit which looks good and is in weight ( no date that we can see!). We thought that it would be ok for the engine room 5m/3 ?
We then realised that there was no way to safely 'deliver' the CO2 without removing the engine hatch cover and inviting lots of flame out and o2 in!.
We are considering a hole with a bung in the cover or a bulkhead or fitting a CO2 cylinder inside the compartment with a manual ( pull cord type) release.
The dangers of accidental release are understood so we are also considering a large 'water mist' solution rather than C02?
In both cases and whether mounted in or out ( with hole) how important is the direction of the CO2 or water mist? we would not be able to see what is going on so could not direct the device at the seat of the fire, or does the gas/mist simply fill the compartment?

The need for the survey is, if nothing else, making us aware of several safety issues!
Your usual good advice and experience appreciated as always.
Click to expand...
Both my beneteaus come with a hole in the steps covering the engine room about 2” diameter with a plastic cap shoved in and a fire sign
 
Chaktoura said:
If you are in the market for a 2kg clean agent auto this was about the cheapest I could find at £99.99 inc postage. Force4 are discounting them from £239.95 to £169.95. Most of the others seem to be charging circa £200. It will cover 3.4m3

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/271499798263
Click to expand...

Thanks all for the advice. I will buy the one shown but also add a hole ( companion way steps) for the existing CO2. May also consider a water mist.
I hope I can ship them by road?
 
FlyingGoose said:
I have 2 automatic CO2 extinguishers either side of the main engine
Click to expand...
The instructions on the automatic extinguishers I have read emphasise the importance of not having more than one extinguisher. (Whether that is for the reason someone has already mentioned I do not know.)

Rogershaw said:
Have you considered a remote activated CO2 or watermist fire extinguisher together with a smoke detector so you know when a fire has started and can shut down the engine before setting off the fire extinguisher
Click to expand...

The automatic engine compartment extinguisher I have (dry powder) has connections to (a) shut down the engine, and (b) light a warning lamp to indicate that it has fired. I don't know how common such facilities are.

pcatterall said:
how important is the direction of the CO2 or water mist?
Click to expand...

I don't know in the cases of those two materials, but my dry powder extinguisher instructions merely said avoid severe obstructions/constraints, suggesting to me it wasn't highly directional.
 
Last edited:
I'm going with CO2 for the engine compartment, as it is non-directional and I feel I can flood the engine compartment and bilges effectively, where as other methods like Water Mist, Foam or Powder require directional accuracy.

I did consider the Halon replacement, but I can see no advantage over CO2, it costs a lot more and in a confined space might be unpleasant.

I'm planning on a cheap 3kg CO2, with a remote pull handle release.
 
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