Auto fire system

[rubberduck]

OK, I have fitted an FM200 auto fire system in engine room with the fire detecting tube that runs over the engines & generator, apparently it puts out a fire at the nearest point to where it starts, reducing damage etc.
Do I also need auto engine shut off, or will this type of system put out any fire before the engines suck in & dilute the FM200.
Already asked a knowledgeable member by pm, but am A/ inpatient, B/ interested in others opinions. Cheers.

 

[jfm]

OK, I have fitted an FM200 auto fire system in engine room with the fire detecting tube that runs over the engines & generator, apparently it puts out a fire at the nearest point to where it starts, reducing damage etc.
Do I also need auto engine shut off, or will this type of system put out any fire before the engines suck in & dilute the FM200.
Already asked a knowledgeable member by pm, but am A/ inpatient, B/ interested in others opinions. Cheers.

All depends on what you have installed; you don't even mention the brand so it's hard to guess. A decent system would, on triggering of the alarm, A/ shut off engine usually by electrical signal, B/release the FM200 gas, C/give you audible alarm and helm indication, and if you have fire sensors in multiple locations on the boat then it would tell you that this particular fire is in the e/room.

If you have just one FM200 cylinder then it cannot "put out fire nearest to where it starts". All it can do is squirt FM200 gas from its nozzle. The mechanism is that the FM200 gas is released into the e/room air, getting to a concentration around 20%, and functions as a "negative catalyst" that prevents the operation of the chemistry of combustion . It doesn't smother things in foam and it doesn't remove oxygen substantially. Because it only gets to a certain concentration (about 20%) there is still breathable air in the e/room, which is handy if you happen to be in there when the cylinder releases

 

[CHI]

Hi Rubberduck

On my boat i have a FM200 auto fire extinguisher system.

I also have fitted the auto shut down system by Seafire that will cut the engines and vent fans etc so that all the FM200 is used to fight the fire and not be consumed by the engines/ fans.

However i dont have the fire detecting tube? Interested to learn more about this.

Best Wishes

Keith
CHI

 

[Forty_Two]

I have two Seafire systems.

One is a "Stinger" which has what i think the OP has or similar. The extinguisher outlet has a 2m pressurized tube. This melts where the heat is detected & releases the FM200 at the source of the heat. I use this for my Onan geny, leading the tube into & around inside the sound shield. Extinguisher is outside the box. Auto shuts the Onan down.

My main engine room is a normal large FM200. I choose not to autostop my main engines in case it's a very inappropriate moment. I do have very loud (& different to others) alarms on the Fly Bridge & inside helm. Normally i would expect to react fast & shut down the engines if no other risk at that time.

I think it's a choice but i prefer to be in control. Of course at 8kn there is more time & you can move around easily so that may be a significant factor in the decision as to whether to auto shut down or not.

heres a pic of the head unit https://www.google.co.uk/search?q=Seafire+stinger&tbm=isch&imgil=LipG8Ms-QgTg4M%253A%253BMjL6J0lDx-JHtM%253Bhttp%25253A%25252F%25252Fwestheart.nl%25252Fft-stinger-systemen%25252F&source=iu&pf=m&fir=LipG8Ms-QgTg4M%253A%252CMjL6J0lDx-JHtM%252C_&usg=__l_bZt-kC9j--E4BIoYT8bxixSik%3D&biw=1576&bih=931&dpr=0.9&ved=0CDoQyjc&ei=J9IWVdLdBsX1auWHgPAO#imgrc=LipG8Ms-QgTg4M%253A%3BMjL6J0lDx-JHtM%3Bhttp%253A%252F%252Fwestheart.nl%252Fwp-content%252Fuploads%252F2014%252F07%252FStinger-achterkant.png%3Bhttp%253A%252F%252Fwestheart.nl%252Fft-stinger-systemen%252F%3B600%3B600

 

[MyMarine]

Ideally you would want to put the engine shut down system in place or basically all that will happen with the extinguishnant is that it will get sucked out by the bilge blowers.

The fire suppression unit with not only shut down the engines but also the blowers and generator too. Then if you need to restart or have controlled the fire you have an override switch/button to restart.

Ideally you would want to wire the suppression unit to the domestic batteries and not just the engine ignitions, as suggested, as then as you make the boat live then you know you will be protected from any issues that may occur.

Peter

 

[jfm]

Ideally you would want to wire the suppression unit to the domestic batteries and not just the engine ignitions, ...

Do you mean have the suppression unit turn off your domestic battery supply? That would kill all your lighting, nav lights, communications and nav electronics - I don't like the sound of that in a night time fire!

This has expanded into what people do, beyond Rubberduck's question. I have automatically closing motorised louvred panels in the engine room air intake and exhaust, three each side about 500mm square. When the e/room fire is sensed, the engines and gensets shut down (but can be restarted on demand), the engine room fans turn off, and the st steel louvres close to make the e/room nearly airtight. All my lighting stays on, including e/room lighting, camera and helm MFDs so I can see the camera. The dashboard readout tells me which sensor triggered the fire alarm, an engine room sensor or one of 11 others that are not in e/room, and of course all the engine shut down only occurs if one of the engine room sensors was triggered

The reason for the louvres is that as soon as a motor boat is disabled it turns broadside to the wind, and that can blow the FM200 out of your e/room if all your vents are open to the breeze, as they usually are if you don't fit closers

 

[MyMarine]

Wiring to the domestic batteries with not shut down the lights, because with the suppression box you wire in the circuits that you wish to switch off. So if you have twin engine installation, blowers and a geneat or would would need a suppression box to control 5 circuits

 

[rubberduck]

I have two Seafire systems.

One is a "Stinger" which has what i think the OP has or similar. The extinguisher outlet has a 2m pressurized tube. This melts where the heat is detected & releases the FM200 at the source of the heat. I use this for my Onan geny, leading the tube into & around inside the sound shield. Extinguisher is outside the box. Auto shuts the Onan down.

My main engine room is a normal large FM200. I choose not to autostop my main engines in case it's a very inappropriate moment. I do have very loud (& different to others) alarms on the Fly Bridge & inside helm. Normally i would expect to react fast & shut down the engines if no other risk at that time.

I think it's a choice but i prefer to be in control. Of course at 8kn there is more time & you can move around easily so that may be a significant factor in the decision as to whether to auto shut down or not.

heres a pic of the head unit https://www.google.co.uk/search?q=Seafire+stinger&tbm=isch&imgil=LipG8Ms-QgTg4M%253A%253BMjL6J0lDx-JHtM%253Bhttp%25253A%25252F%25252Fwestheart.nl%25252Fft-stinger-systemen%25252F&source=iu&pf=m&fir=LipG8Ms-QgTg4M%253A%252CMjL6J0lDx-JHtM%252C_&usg=__l_bZt-kC9j--E4BIoYT8bxixSik%3D&biw=1576&bih=931&dpr=0.9&ved=0CDoQyjc&ei=J9IWVdLdBsX1auWHgPAO#imgrc=LipG8Ms-QgTg4M%253A%3BMjL6J0lDx-JHtM%3Bhttp%253A%252F%252Fwestheart.nl%252Fwp-content%252Fuploads%252F2014%252F07%252FStinger-achterkant.png%3Bhttp%253A%252F%252Fwestheart.nl%252Fft-stinger-systemen%252F%3B600%3B600

That's the one, we have 6 metres of tube covering the whole room. Like your thinking, if we were doing 38 knts, auto shutdown could send someone flying, causing yet more problems, what alarm system do you have ?

 

[Forty_Two]

That's the one, we have 6 metres of tube covering the whole room. Like your thinking, if we were doing 38 knts, auto shutdown could send someone flying, causing yet more problems, what alarm system do you have ?

Did it myself. Have an indicator light for each extinguisher near the helm & dual frequency sirens at the inside & fly bridge helms. The indicator lights are normally on to show continuity of the control circuit & power is active. Have a test button under a lift up guard to test the sirens. Another button will silence the alarm. All powered off the house battery bank

Also have the pull cable for manual activation of the main extinguisher.

I have an engine room camera with dedicated monitor by the helm & also on the fly bridge.

The sirens will sound as soon as the normally closed contacts on the extinguishers open or the circuit is damaged. Mine are very loud, no mistaking them for something else!

I have stop buttons at both helms & electric valves on each fuel tank controlled from the inside helm together with remote controlled battery isolators on all four battery banks.