Fire Extinguisher for Diesel?

[DavidTav]

I have removed an out of date automatic fire extinguisher from my engine compartment. I have a diesel engine, but I know the boat used to have a petrol engine. I was going to fit a new auto fire extinguisher, but a couple of people have said to me, why bother, you don't need one with a diesel. I have a 2kg extinguisher in the galley and a fire blanket in the galley. What do others on here think? I would appreciate advice on this.

 

[elton]

Diesel has a high flash point (>60C), so it's not a fire risk. You don't need the extinguisher.

 

[sarabande]

It's a well known fact then, Elton, that diesel doesn't catch fire ?

Well known to you, that is.


On the other hand, quite a number of disbelievers fit automatic or manual ones, powder or CO2, or other proprietory gas or foam, provided it's designated as a Class B one.

In fact, the only one which is almost no use is a bucket of water. That's always useful for putting one's head in.

 

[LORDNELSON]

Fire extinguisher for diesel

I think it is worthwhile having an automatic extinguisher in the engine department and am just about to buy one for my present boat. The size of extinguisher will depend upon the volume of the engine compartment. In my boat this is just under a cubic meter. I have identified the Fireblitz FE36 which costs about £80. There is alos the Seafire range which tend to be more expensive. Has anyone any views about these two products.

 

[vyv_cox]

I have removed an out of date automatic fire extinguisher from my engine compartment. I have a diesel engine, but I know the boat used to have a petrol engine. I was going to fit a new auto fire extinguisher, but a couple of people have said to me, why bother, you don't need one with a diesel. I have a 2kg extinguisher in the galley and a fire blanket in the galley. What do others on here think? I would appreciate advice on this.

Well, here's a scenario. A small wire falls onto the exhaust manifold before the cooling water enters it. Over a bit of time the insulation melts and the wire begins to short, causing the wire to overheat. (This is totally realistic, I nearly lost a VW van when the insulation on the headlamp wiring melted without blowing a fuse.) The plastic insulation eventually catches fire. Various other bits of oily plastic catch fire, sufficient that some diesel hose melts and begins to fuel the fire. The wiring and fire are sufficiently hot that the diesel burns. You are sunning yourself on the foredeck, motoring under autopilot and keeping a good lookout........

Diesel will not ignite as a puddle, or even a spray, if the temperature is low. It will most definitely burn if you spray it onto a fire already alight and hot.

 

[elton]

It's a well known fact then, Elton, that diesel doesn't catch fire ?

Well known to you, that is.

I asked my dad I was wondering what the risk was of a loose injector union creating a spray of fuel onto a hot exhaust. Still he said forget it. Let's face it, anything could happen. I mean you wouldn't fit a mine detector for fear of running over a semi-submerged WW2 mine would you?

 

[Chris_Robb]

I have removed an out of date automatic fire extinguisher from my engine compartment. I have a diesel engine, but I know the boat used to have a petrol engine. I was going to fit a new auto fire extinguisher, but a couple of people have said to me, why bother, you don't need one with a diesel. I have a 2kg extinguisher in the galley and a fire blanket in the galley. What do others on here think? I would appreciate advice on this.

I would beg to differ with the view that Deisel does not burn. In the right circumstances it will.

I would not use a powder exstinguisher on an engine, as it will ruin anything it gets onto, especially any hot surface including the alternator. If the engine is running, it will ingest the powder - so good bye engine.

As you may be aware, Halon was the best, but we are not allowed to use it any more, and there are more modern gases available. However, if the engine is running when a Gas one goes off, most of the exstinguishant will be exhausted through the engine, and the fire will break out again. So an engine has to be stopped when the extinguisher is fired.

I am very naughty, in that in addition to my automatic fire exstinguisher, I also carry a Halon manual one, which would be poked into the engine bay via a keyhole.

 

[billcole]

Apologies for broadening the topic somewhat, but what do people think of the idea of fitting an automatic fuel shut off valve to a diesel engine installation? They seem to go for between £5 and £25 from suppliers of oil-fired central heating bits, either just a valve that snaps shut when a bit of lead melts, or something like a gas flame failure device but cutting off when the bulb gets hotter than 60 or 90 Celsius rather than cutting off when the gas flame goes out and the bulb gets cold. Sounds like it might be worth having to me, but I've not heard of any boats with them fitted, so wonder if there might be a snag that I haven't thought of.

 

[seamaster30]

I would not use a powder exstinguisher on an engine, as it will ruin anything it gets onto, especially any hot surface including the alternator. If the engine is running, it will ingest the powder - so good bye engine.

I have an automatic powder system with Diesel engines.
My main concern would be to put the fire out and survive. - The insurance company can deal with the engines if they get ruined - I doubt they would even pay out if I didn't have one fitted.

 

[Chris_Robb]

I have an automatic powder system with Diesel engines.
My main concern would be to put the fire out and survive. - The insurance company can deal with the engines if they get ruined - I doubt they would even pay out if I didn't have one fitted.

Thats one way of looking at it, but it means you will be a sailing boat, with no chance of restarting the engine. I am not sure what the insurance company would say, if there are other types of extinguishers that do not cause such a problem.

 

[AndrewF]

I have CO2 for the engine space, and a water fog system for the engine and generator which activates if 2 seperate flame detector heads operate. Oh the engine is 7,150KW and have 3 700kw generators. The water fog suprisingly doesn't damage electronics or running engines (alledgelly)

 

[Chris_Robb]

I have CO2 for the engine space, and a water fog system for the engine and generator which activates if 2 seperate flame detector heads operate. Oh the engine is 7,150KW and have 3 700kw generators. The water fog suprisingly doesn't damage electronics or running engines (alledgelly)

The best of all systems - water mist - set off with very high pressure, and such a fine mist, you only need 1 pint to put out a large fire. Actually much better than CO2 which needs rather a big tank, and is probably not very suitable in a yacht. Are these system available for yachts - affordable???

 

[oldharry]

I am very naughty, in that in addition to my automatic fire exstinguisher, I also carry a Halon manual one, which would be poked into the engine bay via a keyhole.

Two reasons why Halon was banned: 1: it seriously damages the Ozone layer (as if you were worried when your boat is on fire!). 2: When heated as when used as an extinguishant, it convets to a highly toxic gas which kills in even quite small doses. So when your engine catches fire, remember to hold your breath for at least several minutes after the fire has gone out or it will extinguish you as well!

 

[Chris_Robb]

Two reasons why Halon was banned: 1: it seriously damages the Ozone layer (as if you were worried when your boat is on fire!). 2: When heated as when used as an extinguishant, it convets to a highly toxic gas which kills in even quite small doses. So when your engine catches fire, remember to hold your breath for at least several minutes after the fire has gone out or it will extinguish you as well!

I will remember the last bit - as I hold my breath!

 

[vyv_cox]

Two reasons why Halon was banned: 1: it seriously damages the Ozone layer (as if you were worried when your boat is on fire!). 2: When heated as when used as an extinguishant, it convets to a highly toxic gas which kills in even quite small doses. So when your engine catches fire, remember to hold your breath for at least several minutes after the fire has gone out or it will extinguish you as well!

As an ex-fire warden for many years, I dispute your second point. The gas produced is toxic, but certainly not as much as you say. Advice given to us by the fire service was always that the product of Halon extinguishers was less toxic than the smoke from the fire, particularly when modern furnishings, cables, other plastics, were being burnt.

On the first point, halon's CFC properties are modified when it hits the fire, so the truth is that it was training with halons that probably was the bigger contributor to ozone layer depletion. Although compared with breaking up old refrigerators it was almost negligible. Yet another knee-jerk reaction as regards global warming - removing the best fire extinguisher available for misguided reasons.

 

[Chris_Robb]

As an ex-fire warden for many years, I dispute your second point. The gas produced is toxic, but certainly not as much as you say. Advice given to us by the fire service was always that the product of Halon extinguishers was less toxic than the smoke from the fire, particularly when modern furnishings, cables, other plastics, were being burnt.

On the first point, halon's CFC properties are modified when it hits the fire, so the truth is that it was training with halons that probably was the bigger contributor to ozone layer depletion. Although compared with breaking up old refrigerators it was almost negligible. Yet another knee-jerk reaction as regards global warming - removing the best fire extinguisher available for misguided reasons.

Vyv - I won't be holding my breath for so long then! However I had heard the same as you about Halon - from a guy in the industry selling those Very High pressure water mist systems - which really are fantastic, and portable enough for a yacht- they just don't seem to have marketed to this section. I must ask him why not!

 

[Dockhead]

The banning of Halon doesn't mean you have no choice besides powder. There are good legal halon replacements, like the FM-200 gas agent sold by among others Sea Fire.

Automatic gas extinguisher in engine rooms and automatic fuel shut-off ought to be obligatory on yachts. I certainly wouldn't do without it. Fires do happen on boats, diesel does burn (it's a fuel -- doh), and it is a nightmare scenario at sea. Surely it's required by your insurance policy? I'm pretty sure mine requires it.

The cost is negligible compared to other boat bits:

http://www.force4.co.uk/6525/Force-4-FBA-G1-Automatic-FE-36-Fire-Extinguisher-Max-Volum.html

http://www.force4.co.uk/6523/Seafire-FG150A---4-2-M3-Automatic-Fire-Extinguisher.html

 

[footsoldier]

Diesel has a high flash point (>60C), so it's not a fire risk. You don't need the extinguisher.

Yes, it's difficult to get diesel itself to ignite, but that isn't the problem. I have seen two diesel engines go on fire - 1 x truck, 1 x mobile plant. The ignition source was never established but was doubtless along the scenario suggested by other posters. The potential of fire starting in the engine compartment has always been my major cause for unease on a boat.

No-one has yet picked up billcole's very good suggestion - automatic shut-off valves. Any thoughts or experience?

 

[Chris_Robb]

No-one has yet picked up billcole's very good suggestion - automatic shut-off valves. Any thoughts or experience?

Yes it was, though I think I would prefer a remote manual shut off, and a subsequent manual firing of the exstinguisher, which then requires an audilble fire alarm to alert you in the first place. Well worth following up.

 

[Dockhead]

Yes it was, though I think I would prefer a remote manual shut off, and a subsequent manual firing of the exstinguisher, which then requires an audilble fire alarm to alert you in the first place. Well worth following up.

A manually actuated system would not deal with the scenario above -- sunning oneself on the foredeck etc.

My boat has the Seafire system which actuates the extinguisher, shuts down the engine, shuts off the engine space blower, and shuts off fuel, automatically when a fire is detected. You can actuate any of these functions manually, by cable control, from the safety of the lazarette. You can override the engine shutdown from the helm. These are all worthwhile precautions.

Some of the systems are here: http://www.interlinksolutions.com/marine_controls.htm

The cost is trivial. The system which shuts down engine and blower, sold with the helm panel and override switch, costs $150 in the U.S. -- http://www.go2marine.com/product.do?no=156246F