Fire Detection and Suppression

Yesterday I learned of a Bayliner 4788 that was lost to a fire originating in the engine room.

The last "at sea" fire that I remember also originated from the engine room.

So....

The question for the crowd is, What systems, and strategies do you have onboard to detect and suppress a engine room fire.

Do you have a automatic system?
Do you have a permenant mounted manual system?
Do you rely on portable fire extinguishers, and if so how large are they.
Do you have smoke detectors in the engine room?
If you have smoke detectors are they linked to an external siren?

I'll start with my boat.

We have an automatic Kidde fire suppression system
I do not have the manual release hooked up to it, but I will this next week.

We do not have the automatic engine shutdown hooked up. Yes I know its a requirement but I am not comfortable with the concept of having all my engine shutdowns running through one single point of failure.

We do have a process in place that if the discharge alarm sounds that we immediately shut down the engines and generator.

We also have several 5 pound fire extinguishers onboard, but we haven't even looked at them except to visually verify the arrow in in the green for several years.

We feel that a huge component of our system is the ability to detect a fire early. Before the suppression system activates which is at 170 degrees.

To do this we have a smoke detector on the ceiling of the engine room, and it is linked to a on board siren.

I'll admit that it's not a perfect system, but at least it's something. There is certainly room for improvement here.

We have an automatic system and it also has a manual trigger just outside the ER door. And its linked to a shutdown system that kills the engine, generator, fans, and propane if the fire bottle deploys. Also hand held extinguishers, including a large one in the ER.

The laz is set up the same way, with shut down on the diesel heat, propane, and. Laz fans.

I don't have heat, smoke, or CO detectors, and should. They are on my list.

BTW, it's pretty easy to wire a bypass switch at the shutdown box. The shutdown all have an over ride function to restart the engines, but you are right that if the shutdown device itself fails, and they do, you can find yourself disabled. I know a lot of people who wire in simple bypass switches as an add assurance of being able to quickly restart.

Along with an ancient Halon system (that still passes inspection) I have a number of Purple K extinguishers throughout the boat. All four of them are spread out so you are never too far from one of them and can use them to help clear a path off the boat. Forward between galley and v-berth, aft cabin, upper helm and back deck.

Would not trust anything but a Purple K extinguisher to put out a oil/diesel fire.

wwestman said:

Along with an ancient Halon system (that still passes inspection) I have a number of Purple K extinguishers throughout the boat. All four of them are spread out so you are never too far from one of them and can use them to help clear a path off the boat. Forward between galley and v-berth, aft cabin, upper helm and back deck.

Would not trust anything but a Purple K extinguisher to put out a oil/diesel fire.

Click to expand...

even better to follow Purple K with AFFF. dry chem doesn't cool, remove O2, or remove the fuel. So, reflash is possible.

There was a long thread on this topic some time ago (maybe on the sister forum) that had a lot of good thoughts. A couple I remember:

1. In the engine room, if the engine is running when suppression is activated, the engine will ingest, and exhaust, the suppressant. This may prevent the suppressant from working and make a mess in the engine.
2. There are cases of fires re-flashing after the suppressant is used up. So cooling (water?) is necessary. But the water can't come first, as it will just spread an oil/fuel fire.

So engine shutdown, suppressant, quickly followed by water.

An effective system is non-trivial.

The thread I referred to, above, was occassioned by the story about a year ago, in which a cruising sailboat (so it probably was on the sister forum) caught fire and sank in the SoC.

They had an engine room fire. Put it out with handhelds. But it reignited after the handhelds were exhausted, and so quickly and violently the couple were lucky to get off the boat without being engulfed. Now they were in the water, no dink, no life jackets, miles from shore.

But they were lucky. Another cruiser saw the flames and rescued them.

A very sobering story.

Cottontop said:

1. In the engine room, if the engine is running when suppression is activated, the engine will ingest, and exhaust, the suppressant. This may prevent the suppressant from working and make a mess in the engine.

Click to expand...

Right, this is why the shutdown system is so important. I think manually turning things off in response to an alarm risks being too slow to respond, and forgetting something like ventilation fans.

Both my lobster boat and 90/90 are built of Fire Retardant resin.

The interior furnishings can burn but not the hull , unlike conventional GRP which is hard to extinguish..

A smoke alarm , multiple extinguishers , and exits from every space below is about it.

The 90/90 has a 2 inch fire hose , but it would probably be better for working a fire on a neighbors boat , as the engine has to operate .

I do not believe in auto systems tbat can kill my engines.

Flew too much to accept that.

Now I wish I had a total boat agent flood for when I wasnt aboard....I cant control anything then.

But when I am aboard, I am in control....not some idiot system.

I have had my new wifi alarms go off in the last 2 trips to florida. Amazon Kidde or whatever when the engine room sets off the saloon one.

Once when I left the oil fill cap off, and 2 times when the dampner plate was failing and rubbing parts caused just a tiny bit of smoke.

So my detection meets my standards for early enough warning, and I can still make the decision to fight underway or have everything shut down at a bad time.

Someone here at some point recommended wireless linked smoke detectors, so I have that (one on FB on in cabin one in ER) plus a probably defunct definitely undersized halon automatic system (no shutdown) plus one large Co2 hand held plus a half dozen small dry chem.

We have a Fireboy automatic system with the engine shut option. We also have a 190 degree f remote fire detector in the engine room that is tied into our Aqua Alarm system (very loud). There are fire extinguishers outside at both engine room hatches and an old hand held halon in the engine. So far we haven't needed any of them.

I am looking at adding an engine room camera (or 2) so I can see if an alarm goes off, what's going on before a hatch gets opened.

psneeld said:

I do not believe in auto systems tbat can kill my engines.

Flew too much to accept that.

Now I wish I had a total boat agent flood for when I wasnt aboard....I cant control anything then.

But when I am aboard, I am in control....not some idiot system.

Click to expand...

Agree! A auto deploy system is great, an AUTO shutdown can be a liability. Certainly engine fires are much more rare when they are off and cold!

I do think a reality check is in order for those contemplating "attacking" an ER fire on a boat. So, there is a fire. To attack (manually) that fire, you will open a door to a poorly ventilated, relatively small compartment, below decks. As likely as not, your wearing bermuda shorts and flip flops. You will get a blast of heat out the now open door on your bare face. Your HH CO2, chem, whatever is still no where close to where it needs to go. Most folks would bail at this point. Yeah, I like the auto deploy systems. I kept my Halon alive for as long as possible.

I was USN and went to firefighting school 3 times in 5 years. The navy takes firefighting seriously. Much doesn't pertain to yachts. We we trained to put out oil fires, usually with only water. But, if your out in the ocean on your own, tackling an engine room fire may be your best survival choice. Auto fire suppression would be a good choice for yacht engine rooms. I have 2 on mine. CO2 and Halon. And a 2nd CO2 that can be manually activated. Also my engine room can be made air tight. Leaving the engines running would quickly eliminate the oxygen. I prefer to control the stopping of the engines for lots of reasons.

Has anyone run the calculations to determine how much time you have after auto trigger of a CO2 system to shut down engine.
If engine keeps injecting air into the ER it will negate the ability of CO2 or Halon to put out the fire.

Haven't done the research or calcs but wondering if anyone has.
It will involve or depend on engine, rpm/fuel/air rates, ER volume, vol of CO2....but would be useful to know when you have negated the system are on your own

I have an automatic Fireboy halon system. No automatic engine shutdowns or fire system controls in the wheelhouse. 2 CO2 extinguishers and 3 dry chemical for the staterooms galley saloon and wheelhouse.

Fireboy and a load of extinguishers.

Auto activation 100 percent of the time and no auto engine shutdown I believe has been proven to be a bad idea.

Either both or neither.

Except for at the dock when the engine isnt running, then auto extinguish would be more effective.

For auto extinguish to work...auto engine shutdown and auto ventillation shutdown to compartment is highly recommended.

The issue with engine and vent shutdown is to ensure that the extinguishing agent stays in the ER long enough to stop the fire. A running engine sucks a large amount of air from the ER and blows it out the exhaust. And the vent fans do the same, expelling the air out various vents. If that equipment if left on, the extinguishing agent will quickly end up outside the ER rather than inside, and will be useless. There also is the issue of fanning the fire, but my understanding is that shut down is much more about containing the suppressant.

Someone asked about numbers. That's an interesting question, so I did a rough estimate on my ER. The Er is about 15'l x 8'w x 5' ave height. That's 600 cu ft of air space. My vent plus engine air flow into and out of the ER is around 2000 CFM. So the ER air changes over every 18 seconds. So if the fire suppressant is deployed, the engine and fans will remove it all in 18 seconds. So you need to shut down pretty quickly if you want the fire suppressant to do anything.

Wouldn't the halon shut down the engine, since it displaces the oxygen? Anyways, any new automatic shutdowns won't be installed before I leave this summer.

Cant say about the new halon replacements, but the originsl didnt actually displace oxygen, it just inhibited combustion....

Do msybe no diffetence in it shutting down an engine if it was taken in at the right percentage.

Twisted tree
That was my guess and point but didn't have the time to even eat the time.
If one delays the activation to maneuver it guys time but the fire advances... I think I'll stick w my auto activate and engine shutdown but realize others have their own preferences.

If you have decent smoke detectors, my guess is they will alert you long before the heat activated suppression activates.

It is all a gamble, but my experience taught me most emergencies are not measured in seconds.

We can have all the best equipment but without training it is nearly useless. Like Lepke I have been to fire school many times. As Lepke says much of it does not apply to yachts. But there are two take homes from fire school that apply to yachts and boats with small crews.

1 - Do everything you can to not have a fire in the first place. Take care of your machinery, DC wiring is a common cause of recreational boat fires. Be careful where you store flammables.

2 - Learn to use your portable fire extinguishers. It is enlightening to know how much fire you cannot put out on your first attempts. It is comforting to know how much fire you can put out with a bit of training and experience.

I saw a post from the owner of the 4788 that burned a couple of days ago on a different site. He thinks that it was the turbo that caught fire. He didn't say why he believed that but he did include a couple of photos of the boat burning.

Comodave said:

I saw a post from the owner of the 4788 that burned a couple of days ago on a different site. He thinks that it was the turbo that caught fire. He didn't say why he believed that but he did include a couple of photos of the boat burning.

Click to expand...

Based on his email address on the post I initially thought it was you. Had to have a second look. Happy to see it wasn't.

Fire supression is good damage control for enginerooms. The USN took fires aboard very seriously, with all of us going thru weeks and years of damage control and fire fighting training with live fire fighting and simulated sinking damage control.
After several engine room and fire room fires a program was initiated to covered every piping system mechanical fitting with devises to contain any spraying of combustibles. These devises contained any rupture and or spray, the first generation was fire retardant clothe covers but was changed to metal covers later. The Bayliner 4788 fire may have been caused by diesel fuel sprayed onto a hot surface as has been reported. The hull has been recovered and even though all the topside material burned and is contained in the hull it may be possible to discover the cause of the fire.
I for one will be checking into installing spray shields on our boat.

Unless that was a dry turbo and not likely...there are very few hot surfaces in many modern rec boat engine rooms.

In mine, the hottest is the last exhaust port for about an inch, under the exhaust manifold and ot is only 350 degrees.

If something flammable sprayed on it, the smoke alarms may go off, but without a ignition dource, probably it would not ignite.

I had a fuel line spray/mist for maybe 3 days till it was discovered...not even smoke, let alone a fire.

psneeld said:

If you have decent smoke detectors, my guess is they will alert you long before the heat activated suppression activates.

It is all a gamble, but my experience taught me most emergencies are not measured in seconds.

Click to expand...

I also believe that early detection is the key.

If you can detect the smoking before major flames break out then you can potentially avoid a total loss, abandon ship situation.