2 Kilo Auto Fire Extinquisher

ducked

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Most engines on pleasure vessels do.

I have vents into my engine compartment with valves to close the air flow as required by out safety authority


In this case the engine would need to be shut down as the engine would still run as the fire extinguisher would not deprive the engine of the require air
Well, yeh, but I thought the focii of concern were (a) putting out an engine compartment fire, and (b) not permanently wrecking the engine, especially in a case where an automatic triggering of a fire suppression system was due to a false alarm. Direct ducting to the engine air intake would promote both those objectives.

Is automatic engine shutdown a design objective?

I'd doubt an engine compartment fire is the main fire threat to a boat anyway, especially with a diesel engine, compared to exhaust containment failures, (particularly failures of exhaust water cooling), cooking fires, electrical fires, and smoking (particularly smoking-in-berth)
 

RunAgroundHard

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Just drill a small hole that accesses the engine bay, fit a cover, use the hole to stick the nozzle of your extinguisher of choice into the space to fight the fire. This was an acceptable method for coded yachts, I don't know if still valid. I would fit a CO2 extinguisher if I had this arrangement.

I currently have 2 x clean agent automatic extinguishers in the engine bay, both sized for the space.

I bought mine from here a few years ago, good prices Wall-Mounted Automatic Extinguishers
 

Sticky Fingers

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Just drill a small hole that accesses the engine bay, fit a cover, use the hole to stick the nozzle of your extinguisher of choice into the space to fight the fire. This was an acceptable method for coded yachts, I don't know if still valid. ….
Not acceptable for insurance purposes for a motor boat, don’t know about Mobo coding but would be very doubtful.
 

penberth3

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...Nope, both old units in the RED on the gauges..
and what does one do with the old bottles ?

I'd speak nicely to my local extinguisher supplier. They might take them.

The DIY approach would be to fire them off, then if you're 100% sure there's no pressure left, unscrew the tops and dispose as scrap metal. Don't put pressurised bottles in the refuse bin, and don't take them to your local tip.
 

rogerthebodger

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Just drill a small hole that accesses the engine bay, fit a cover, use the hole to stick the nozzle of your extinguisher of choice into the space to fight the fire. This was an acceptable method for coded yachts, I don't know if still valid. I would fit a CO2 extinguisher if I had this arrangement.
Do you mean like one of these

2060405_w.jpg
 

RunAgroundHard

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Do you mean like one of these

2060405_w.jpg

That would do it, but I have also seen about a 1” hole with the core converted to a plug, and even a softwood bung used. I had been involved in coding an age ago, charter fleets, and the hole was a common solution for engine bay fire fighting to satisfy coding in the UK. I am not current on coding, but the link to HNJ advisory sheet suggests it is acceptable.
 

Sticky Fingers

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I'd speak nicely to my local extinguisher supplier. They might take them.

The DIY approach would be to fire them off, then if you're 100% sure there's no pressure left, unscrew the tops and dispose as scrap metal. Don't put pressurised bottles in the refuse bin, and don't take them to your local tip.
I have just replaced 7x time-expired manual 2kg dry powder extinguishers on my boat, my local supplier took the old ones for disposal, no charge levied.
 

LittleSister

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I currently have 2 x clean agent automatic extinguishers in the engine bay, both sized for the space.

It's inadvisable to have two (or more) undersized extinguishers.

That goes against current practice. When the fire sets off one extinguisher, it will not be adequate to cover 4 cu m so the fire will continue; the fire then sets off the second extinguisher that again will not be adequate to cover 4 cu m. Current practice and recommendation is to have a single extinguisher to cover the total volume of the engine bay, minus the volume of the engines etc. Belt and braces would be to have two 'full volume' extinguishers, one at each end or side of the bay, but that would be expensive.

Exactly so I installed an auto system in a previous boat (because the purchase surveyor recommended it, and therefore the insurance company required it) maybe 15 years ago. (It was expensive!) The installation manual specifically stated one must have a SINGLE extinguisher rated for the volume of the engine compartment, and that multiple extinguishers were unacceptable for the reasons outlined.

The problem I would think with any automatic extinguisher is the possibility that it will discharge inadvertently. . .

That is extremely unlikely. (Has anyone heard of this happening? Certainly didil;t to me over many years. p.s. I had somehow missed Rappey's report of it happening.) If you have temperatures in your engine compartment high enough to set off the the extinguisher, you have at least an imminent very high risk risk of a fire, but almost certainly a fire..

. . . You would excuse a dry poweder mess if it was a real bad fire but get grumpy if it was a false firing. I would go for the halon replacement type extinguisher if you want automatic operation. ol'will

The trouble is, or at least was, that the gas ones are MUCH more expensive. At the time I bought an automatic system the price for a dry powder system was itself a stretch for me, and a halon replacement gas one beyond my means.

Yes it will make a mess, but in an engine compartment it will be contained, and such a mess would, in my view, be a small price to pay for avoiding a serious fire.

People avoid dry powder stating it will damage the engine if it goes off, but my auto dry powder extinguisher had an integral switch and wiring connectors to shut off the engine if the extinguisher fired. It also had connections and a remote warning lamp that indicated the extinguisher had fired. (One might well otherwise not know if it had gone off.)


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Below gratuitous mystery image I can't delete for some reason! :rolleyes:
 

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LittleSister

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Just drill a small hole that accesses the engine bay, fit a cover, use the hole to stick the nozzle of your extinguisher of choice into the space to fight the fire. This was an acceptable method for coded yachts, I don't know if still valid. I would fit a CO2 extinguisher if I had this arrangement.

The trouble with this is that you wouldn't know you had an engine fire until it had already spread out of the engine compartment.
 

Momac

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Halon in a confined space is deadly! I worked in a place protected by a serious halon system with many massive cylinders of the stuff. We were warned that if the fire alarm went off we had some small number of seconds to get out before the halon was released, and that if we didn't, we'd be dead. I think it asphyxiates on its own, but releases serious poisons in contact with fire.
Not just Halon but other inert gas fire suppression eg Nitrogen is equally deadly. Would it not be a requirement to ensure people are evacuated before any such system is activated .
 

RunAgroundHard

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Not just Halon but other inert gas fire suppression eg Nitrogen is equally deadly. Would it not be a requirement to ensure people are evacuated before any such system is activated .

That’s not a universal truth. Large switch board rooms and engine spaces in ships that use Inergen, do so because it is crew safe.

Inergen Clean Agent Fire Extinguishing System | Survitec

Most systems have high decibel alarms and visual annunciation as well as a time setting before activation.

New vessels are moving to water mist, which cools as well as starves the fire of oxygen, and is less expensive.
 

AntarcticPilot

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Not just Halon but other inert gas fire suppression eg Nitrogen is equally deadly. Would it not be a requirement to ensure people are evacuated before any such system is activated .
Probably nowadays, but this was back in the 70s. There was no mechanism to ensure the area (a large warehouse) was vacated; the precaution was that there was a delay between the alarm sounding and the halon being released sufficient to enable anyone working there to get out. We were carefully instructed that if the alarm sounded we were to get out ASAP!

The warehouse contained high value, flammable data from the oil industry - in those days, the primary storage was hard copy. We held tapes too.
 

oldgit

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My ACM 38 has got what was until very recently a mysterious hole 75mm (unplacarded of course ) in the bulkhead between engine room and saloon, Enquires on the forum suggested it was to do with fire.
It has a sheet of something semi opaque over the hole, not possible to glimpse anything in the engine compartment unless presumeably something is on fire, hinting that it might not be a terribly good idea to lift the engine hatch ?
The little glass or plastic window appears to be fairly robust, not sure you could breach it with anything less flimsy than a hammer.
 
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maxi77

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Warm it up a bit and see if it goes back in the green.
Does each extinguisher have enough capacity for the entire engine bay volume?
Multiple extinguishers are not recomended as the temperature sensors that set them off can be activated at different temperatures so one extinguisher goess oof and fails to put the fire out and it becomes big enough to set of the next extiguisher which fails to put the fire out. One unit of enough capacity for the engineroom will put the fire out first time
 

Momac

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Multiple extinguishers are not recommended as the temperature sensors that set them off can be activated at different temperatures so one extinguisher goes off and fails to put the fire out and it becomes big enough to set of the next extinguisher which fails to put the fire out. One unit of enough capacity for the engine room will put the fire out first time
Yes I know that which is why I asked the question.
Two extinguishers would be okay if each is enough to do the job all by itself.
 
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