Fitting sn auto fire extinguisher, were to aim.

Contest1

Contest1

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Hi, need to fit a replacement auto powder extinguisher in the cramped engine space of my Centaur.
There are two previous brackets. One pointing at the alternator, the other at the bilge behind the cabin access hatch.
I,v some room fot maneuver and wonder which part of the engine is most likely to cause a fire.
 
Don't do it! Go for Halon replacement. If you want to know why, let off a dry powder extinguisher in a confined space.

The powder has a bad reputation for damaging machinery as well, it is abrasive and corrosive (see other thread about soda-blasting fall-out).

Also the YM crash boat test using DP to put out a fire, being filmed under test conditions, resulted in the boat being evacuated and a fireman having to enter wearing breathing apparatus to put out the fire, by another means!

I know of a yacht (Nic 36) which was having its gearbox coupling changed, the engineer had to contort himself and carefully worm his way past the engine and jam himself in to a small awkward space. Whereupon the "auto" DP extinguisher let off! He had to unworm himself quick, resulting in injuries needing hospital treatment, and massive cleaning-up job for his company. DP is truly horrible stuff.

I dodn't know why people use DP. Hope this helps Jerry
 
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jerrytug said:
I dodn't know why people use DP.
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Because it's cheap!

To be fair, the whiteout effect isn't relevant in a closed engine bay. So dry powder autos aren't dangerous particularly, just damaging. If you're willing to take the risk of possible engine damage and a major cleanup job in the unlikely event of the thing firing, then ok. The varnish-dissolving effect is unlikely to matter in an engine bay.

As for where to mount it, I believe they're meant to be above the engine, they shower the powder downwards. This can of course be a problem if you don't have sufficient height. The gas ones will fill the space wherever you let them off, which is another advantage.

To answer the specific question, I reckon exhausts and electrics (especially the electrics) are most likely to cause a fire in the typical yacht engine bay.

Pete
 
So, £86.40 plus delivery for an FE36 Halon Replacement auto fire extinguisher compared to £29.96 for the dry powder

A whopping £56 or so difference.

But .....

The FE36 extinguisher will put an engine bay fire out, the dry powder one almost certainly won't

The dry powder will likely ruin anything hot like ... oh, the engine. Potentially beyond economic repair. The FE36 won't

And cleaning up after the activation of a dry powder extinguisher is a nightmare

Yes, dry powder is a quarter of the price, give or take, of FE36 but for the sake of the cost of a decent night out on the town ...

PS. I won't have dry powder on board at any price or for any purpose. This is a result of a> attempting unsuccessfully to put out several types of fire with dry powder during training as a fire marshall and b> having to clean up the consequences of an accidental dry powder extinguisher going off in a caravan

We also rigidly ensured that there were no dry powder extinguishers anywhere near the rostrum or back stage areas when we ran tech at festivals. Some idiot hits an amp rack with one of those things because a cap has gone pop and that's several grand out the window not to mention it being an instant show stopper!

It's FE36 and foam on board, I'd like a hand held FE36 or small CO2 for dealing with equipment fires but the beast ain't available
 
jerrytug said:
Don't do it! Go for Halon replacement. If you want to know why, let off a dry powder extinguisher in a confined space.

The powder has a bad reputation for damaging machinery as well, it is abrasive and corrosive (see other thread about soda-blasting fall-out).

Also the YM crash boat test using DP to put out a fire, being filmed under test conditions, resulted in the boat being evacuated and a fireman having to enter wearing breathing apparatus to put out the fire, by another means!

I know of a yacht (Nic 36) which was having its gearbox coupling changed, the engineer had to contort himself and carefully worm his way past the engine and jam himself in to a small awkward space. Whereupon the "auto" DP extinguisher let off! He had to unworm himself quick, resulting in injuries needing hospital treatment, and massive cleaning-up job for his company. DP is truly horrible stuff.

I dodn't know why people use DP. Hope this helps Jerry
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However if the extinguisher had been Halon he would have been suffocated. That's how Halon works and it's as dangerous as fire if you are trapped.
 
AuntyRinum said:
However if the extinguisher had been Halon he would have been suffocated. That's how Halon works and it's as dangerous as fire if you are trapped.
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Halon doesn't work by displacing oxygen like CO2, it chemically disrupts the flame. So I always understood that one of the benefits of it (as well as being a very effective extinguishing agent) was that you could still breathe in a space that had had a correctly sized halon system activated. Not recommended, and would give you a bit of a headache, but no lasting effects and a lot safer than a CO2 flood that would kill (indeed they use it to do just that to rats).

Anyway, this is all somewhat irrelevant since Halon has been illegal to fit for decades, and illegal to keep existing systems for many years.

Pete
 
AuntyRinum said:
However if the extinguisher had been Halon he would have been suffocated. That's how Halon works and it's as dangerous as fire if you are trapped.
Click to expand...

Very unlikely that he would have suffocated in the circumstances Jerry describes with Halon. Halon 1301 flooding systems, such as used in days of yore in some computer rooms, normally operated at a target concentration of 7% to 10% of the room volume and you won't lose consciousness at that level (from memory ISTR it would be 15% to 20% concentration before you would start to suffer sufficiently to be unable to function)

CO2 on the other hand will kill you dead at significantly lower concentrations than those required for effective fire fighting and rooms equipped with CO2 flooding systems would be rendered nigh on instantly lethal (well not quite but within a very few minutes) by activation of the system. It was, and is, CO2 flooding systems that led to the requirement for panic alarms, panic door releases, gas masks and so on in facilities equipped with gas flooding fire suppression systems

FE36 being heavier than air would pool in the bilges of the boat but I doubt if a 1kg or 2kg extinguisher could sufficiently fill an unenclosed engine bay (since presumably the covers would be off for the engineer to gain access) to a sufficient concentration to cause death.

Dry powder, on the other hand, would fill the air with a choking cloud of foul unbreathable dust making breathing well nigh impossible
 
Already bought the DP extinguisher and was the only type available in the local chandlery.
As it was going in the relativly sealed off engine compartment probably little chance of getting into the cabin if discharged under working conditions. A potentially wrecked engine, not on my list of acceptable risks!
The one I,m replacing was powder and while I,m annoyed that I didn,t know the downside, even though I try to keep up with current best practice, I,m going to check for a more sensible replacement.
Also thanks to the advice offered will replace DP galley extinguisher.
You would think these potentially dangerous extinguishers would carry a warning regarding use in a confined space!
Thanks to all.
 
Anyone had experience of Water Mist extinguishers as shown on the Safelinks website? (as a substitute for dry powder)

Any downsides? the videos look impressive.
 
mudkipper said:
Anyone had experience of Water Mist extinguishers as shown on the Safelinks website? (as a substitute for dry powder)

Any downsides? the videos look impressive.
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PM Fishyinverness, he was singing their praises about 18 months ago. As a fire warden at work, I'd like to see them in action.
 
I also fitted an automatic Halon replacement in the engine compartment and foam extinguishers in saloon and stern cabin. More expensive than dry powder but worth the extra cost.
 
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