Diesel Engine Fires

[Blue Stocking]

Whether they extinguish the fire fire by displacing the oxygen ( Co2 and DCP), or by altering the chemical chain reactionsof combustion (CFC and HCFC), they are all Suffocants, and will not support life.
Do not be mislead by the "non-toxic" BS.
Small engine fires still cause deaths.

[delmarrey]

Originally Posted by Blue Stocking

Whether they extinguish the fire fire by displacing the oxygen ( Co2 and DCP), or by altering the chemical chain reactionsof combustion (CFC and HCFC), they are all Suffocants, and will not support life.
Do not be mislead by the "non-toxic" BS.
Small engine fires still cause deaths.

Water is the only non-suffocant, unless submersed!
I believe what they mean by non-toxic is blowing that white powder all over the place like with the dry chemical dispensers. I would only use that crap on the outside of a boat. CO2 for the inside and Halon for a confined space (engine room).

Back in the 70's and prior, the Navy only used water and CO2.

[Kettlewell]

It didn't start a fire but one time I had the nut crack on a fuel return line sending a fine atomised mist of hot diesel fuel all over the engine space, but luckily I smelled it before anything caught on fire. Where the crack was wouldn't have shut the engine down until the fuel ran out, so there was a potential for a huge mess if not a fire. But, I do agree that most onboard fires are probably electrical in nature.

[gjordan]

I had a pin hole leak in a fuel filter that sprayed a mist of diesel into the whole cabin. Opened the hatch to go below and could hardly see inside the boat. Raw diesel is somewhat hard to ignite, but vaporized diesel is almost as explosive as gas. I was very very lucky. No extinguisher would have made any difference if that had ignited. A friend of mine was delivering a large motor yacht from St Thomas to New England, and had an engine room fire. They got off a distress call just before the electrics all failed ,and took to the life raft. He said it was 15 or 20 minutes before he heard the Halon system go off ,and it was too late by then. There should have been a manual discharge lever in the pilot house , but there wasnt. A discharge as soon as there was a sign of fire probably would have saved the boat. Diesel is a lot less dangerous than gas, but it can still cause fires._____Grant.

[WorldWind]

Not sure what caused the fire on our tug,but I'll tell you that it went up fast.I used both fire extinguishers to no avail.Probably took no more than 15 minutes.50 gallons of diesel and 5 in a Jerry jug.
I hope to never relive this experience.

[skipmac]

From anecdotal evidence it certainly seems that most engine room fires are electrical. I can confirm from personal experience that diesel is hard to ignite. Drained my tanks for cleaning and after using most of it in my tractor had a little left in the jerry jugs. Poured this on a pile of brush I wanted to burn and holding a match under a saturated branch it was very difficult to get it to ignite. Once it did catch the flame did spread pretty quickly.

Vaporized diesel on the other hand would be a different matter.

[delmarrey]

Just happened across this today.

The Halon Alternatives-FE-241 and FM-200

With the phase-out of Halon 1301, the search for a replacement resulted in the development of a number of "clean" fire suppression agents. Both FE-241 and FM-200 have been shown to be effective, safe for people and equipment, and environmentally friendly. Although both agents do pose some threat to the environment, it is considered to be substantially less than that of Halon. Their characteristically rapid extinguishing performance is considered by most to mitigate the detrimental effects of fire. Both agents' relatively short atmospheric lifetime (somewhere between 7-42 years) assure minimal direct contribution to global warming. When choosing which system is best for you, keep in mind that FM-200 is considered to be safe for use in occupied spaces, whereas, FE-241 is not as safe, but is significantly less expensive. Both require more agent by weight than Halon 1301 did, so your storage requirements for the extinguishers may increase. Both are Factory Mutual (FM) and USCG-approved.

[knottybuoyz]

Fireboy-Xintex Marine Safety Equipment for both recreational and commercial boats. I picked up a 300 cu ft Fireboy from Great Lakes Skipper for half of retail.

I was once on a ship that had a diesel engine fire. Wartsila diesels. One high pressure fuel line split shooting out atomized fuel which hit the exhaust manifold of the engine beside it. At the time the ship was fitted with Halon flooding system. I believe they've been switched over to FE-241 Chlorotetrafluoroethane.

[gjordan]

Sometimes the loss of a boat from fire is because an owner is to cheap to put the last little bit of equipment in. The large motor yacht that I mentioned in a previous post is a good example. The manual pull (discharge) probably would have saved a million dollar yacht. I worked on a 100 ton motor yacht that had a big lever just outside the engine room door. Pulling that lever was designed to cut the power to the exhaust vents, drop large metal plates to block air in the vents, close all 4 fuel valves and let go 2 huge CO2 bottles. The trouble was that the system was disconnected . We spent $125,000 on a refit one summer but the fire system didnt get fixed. I like the idea of CO2 or Halon or any other system, but I think they all need an external discharge method that can be pulled at the first sign of fire. My 2 cents worth.____Grant.

[Cheechako]

I dont think Halon has been available for years. But something is.

[delmarrey]

Originally Posted by gjordan

Sometimes the loss of a boat from fire is because an owner is to cheap to put the last little bit of equipment in. The large motor yacht that I mentioned in a previous post is a good example. The manual pull (discharge) probably would have saved a million dollar yacht. I worked on a 100 ton motor yacht that had a big lever just outside the engine room door. Pulling that lever was designed to cut the power to the exhaust vents, drop large metal plates to block air in the vents, close all 4 fuel valves and let go 2 huge CO2 bottles. The trouble was that the system was disconnected . We spent $125,000 on a refit one summer but the fire system didnt get fixed. I like the idea of CO2 or Halon or any other system, but I think they all need an external discharge method that can be pulled at the first sign of fire. My 2 cents worth.____Grant.

I'm with you on that. Auto systems are great if no one is around. But I would be on the pull pin at the first sign of a fire. It's one of the reasons I reworked my vessels motor compartment to be totally inclosed with the Halon bottle plumbed in and sitting right next to the battery switch.

[clsailor]

I can tell you about my diesel engine fire on my maiden voyage. When we put a contract on the sailboat it included a sea trial. When we went for the sea trial the Westerbeke 4-108 would not start. The boatyard sent the injector pump and injectors off for rebuilding. What we did not know is when the boatyard re-installed the pump they caught a small section of wire in one corner of the injector pump. This acted like an injector nozzle and when mixed with a electrical spark, this provided a nice engine room fire on my voyage home to my new marina. I was lucky in that I got the fire out and was able to be towed into the marina.

[hellosailor]

"I am having a hard time picturing how a fire would start in my engine room that has nothing but a dinky diesel, battery, starter and alternator. "
Very easy, Mike. We were rewiring and redoing everything. But the main negative cables all tied together at the aft engine mount "way back there" so we were ignoring it. Until testing out some new wiring and Hey! What's all that big yellow sparking back there about? Yes, the main ground post had loosened up enough to spark.
Now all you need is one pinhole, one connection working loose in the high pressure diesel lines. One crush washer that you bled the system with, and didn't replace. that puts a diesel fuel-air atomized mist into the air, and that's explosive when it hits a spark. Like that loose bolt.

Diesel makes a mighty fine BOOM when atomized, that's why it is used in fuel-air bombs, aka hyperbaric weapons.

About HALON, :they are all Suffocants, and will not support life.:
Nope. That's simply not true. When DuPont introduced Halon (1960-70?) it was a very big deal because Halon chemically interferes with the combustion process, and you can still breath and survive after the Halon concentration is high enough to extinguish the fire. Making it the chemical of choice on submarines, aircraft, and sealed vault rooms.

Now, if you use too much Halon (which is available as liquid OR gas, two different formulas, two different systems) sure, you can displace everything else and suffocate. That would be an improperly used and deployed system.

Banning Halon may have been a very dumb move. In certain purposes, it does an essential job. There are a couple of replacements available, something like twice the cost and twice the volume, but there are replacements that work the same way.

What you need to beware of, is that while Halon is non-toxic, the combustion products are carcinogens. If you use Halon, stop breathing and evacuate to fresh air.

[belizesailor]

I've also seen boats with a small port in the engine room door or bulkhead to insert a fire extinguisher nozzle. Seems like a reasonable solution to me.

[gjordan]

Automatic fire sensors are almost always heat dependant. I have sat and watched my fireplace at home with a pretty good fire and tossed some paper into the fire box(off to the side) and been amazed at how long it took for the paper to catch. If your sensor is not directly over the point of origin of the fire, it might be too big to put out by the time the sensor heats up. ___Just a thought!____Grant.