Engine Room Fire Suppression

for those interested....general info...not specific to your boat.

USCG: Fixed Fire Extinguishing Systems for T-Boats

$12 discount? YAHOO!

Smoke detectors are great for alarms alerting you of a potential fire but you want the system to dump on an actual fire. For an auto discharge system, use thermal detectors. Where I used to work, we had a computer room protected by smoke detector activated Halon 1301 system. A small instrument power supply overheated one night and dumped $140K worth of Halon based on a little smoke. A 50 cent fuse down powered the power supply before getting anywhere near a fire.

FF said:

The old system , where a cable is pulled , the exhaust blower is de-powered and the ER vents are closed ,
then massive CO2 is released seems reliable.

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This is what I've got courtesy of previous commercial survey requirements.

All manual, simple to operate, and totally over the top.

Unless my ER is on fire of course.

Nice!

To my thinking there is no point in having an automatic discharge Halon type system without an automatic shutdown. If the engine keeps running during the discharge, it will just pass the agent out through the exhaust and you'll never get enough of a concentration to put out the fire.

This wasn't an issue with CO2 systems as the CO2 would shut the engine down. Of course the draw back was that it would kill you if you happened to be in the engine room when it went off.

The nice thing about the current extinguishing agents is that they will put out fires at lower concentrations than it takes to kill you. That's also why you don't oversize the system just to be sure you have enough.

Capt.Bill11 said:

While I agree systems like that are great. A complete system like you describe is not that easy to put together nor cheap to assemble and install. And as Scott mentioned, you better be able to override them in a hurry if need be.

Also since they are not required on a private vessel, other than one built to class, I doubt you would save much on your insurance premium. But it would be comforting to have on board.

And of course you can't buy a true Halon system anymore. But you probably know that.

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Yep.All the newer systems I have seen were custom designed,and they may have used CO2 or something else.

psneeld said:

for those interested....general info...not specific to your boat.

USCG: Fixed Fire Extinguishing Systems for T-Boats

Click to expand...

Thanks for the info.Bookmarked.

High Wire said:

$12 discount? YAHOO!

Smoke detectors are great for alarms alerting you of a potential fire but you want the system to dump on an actual fire. For an auto discharge system, use thermal detectors. Where I used to work, we had a computer room protected by smoke detector activated Halon 1301 system. A small instrument power supply overheated one night and dumped $140K worth of Halon based on a little smoke. A 50 cent fuse down powered the power supply before getting anywhere near a fire.

Click to expand...

Those would be hard to hear on some boats but I can't leave well enough alone.Modify them suckers with an external alarm.

Ouch! Dumping that much halon had to hurt some feelings and pockets.

eagle419 said:

This is what I've got courtesy of previous commercial survey requirements.

All manual, simple to operate, and totally over the top.

Unless my ER is on fire of course.

Click to expand...

That is a sweet set up.

HopCar said:

To my thinking there is no point in having an automatic discharge Halon type system without an automatic shutdown. If the engine keeps running during the discharge, it will just pass the agent out through the exhaust and you'll never get enough of a concentration to put out the fire.

This wasn't an issue with CO2 systems as the CO2 would shut the engine down. Of course the draw back was that it would kill you if you happened to be in the engine room when it went off.

The nice thing about the current extinguishing agents is that they will put out fires at lower concentrations than it takes to kill you. That's also why you don't oversize the system just to be sure you have enough.

Click to expand...

I thought halon would shut down an engine?I know a large diesel may not be choked out.

CO2 is pretty thick and will choke about anything.

Yeah,I hate being sprayed with CO2.Glad it isn't to rough on person. :lol:

Mark: I would ask- if you heard the audio alarm what would you do? If your answer is to go into the engine room, I would warn you not to. Both your older Halon and CO2 displace the oxygen if the audio alarm is used to warn you to get out of the engine room then that is a good thing. Some systems do come with an audio alarm to clear engine room just prior to the release of the agent.
Good luck, I miss the old halon it worked great.

captrigney said:

"The old system , where a cable is pulled , the exhaust blower is de-powered and the ER vents are closed ,then massive CO2 is released seems reliable."

I haven't been around trawlers for very long, but I don't recall seeing engine room vent covers installed on any that I looked at before buying. I installed them myself on my previous boat. Anybody have photos of theirs or a place to purchase or designs to build?

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I bought a yard of contact paper which I can quickly (I think) stick over the vent drill from outside the boat to stop air from getting into the engine room.

Just my thoughts; in trying to get a better understanding of how the fire suppression and auto shutdown works from an electrical stand point I called fire boy with the unit number on my boat and they said they would get back to me with relevant info. They never did.

I would prefer an alarm system with a manual shutdown of the engines and a manual discharge. Things malfunction and like Keith said sometimes the smoke gets out of electrical systems and they break.

So a malfunction could shutdown the engines and deploy the retardant at the wrong time. Aircraft do not auto shutdown engines for obvious reasons, why should boats.

Memory item for engine fire warning:
* Shutdown engines unless doing so would cause a greater emergency
* Turn off blowers
* Deploy supression agent
* Call CG
* Evaluate situation and consider next course of action

Typically, unless you have engine breathers / direct inflow of air to engine's air intake from somewhere other than the engine room the CO2 or Halon is going to shut the engine down for you in about a heartbeat.
One drawback to the manual discharge system is something starting on fire when no one is on board. Everything is a compromise.
dan

ulysses said:

Everything is a compromise.
dan

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And that is what insurance is for.

This thread has caused me to contemplate installing an automated system on my boat. Even if it only serves to give one more time to abandon ship there's still no real downside IMO. Nice topic.

OK, I have purchased a Fireboy Xinex automatic/manual fire suppression system. I have read about these and can offer the following...

The unit discharges by heat detection. 175 degrees and the unit discharges. It does not discharge by smoke. Very simple, no electronics involved.

The unit has a simple circuit that is a contact closure if the tank is pressurized and open if the unit is not pressurized. This makes automatic shutdown easy. Fireboy makes a shutdown panel with redundant relays, etc... I may or may not go with this pre-made panel. Automatic engine shutdown is a AYBC requirement, their brand panel is not. I have a career history in engine automation so I think this will not be a design challenge. Simple is best. 12V through a relay to the fireboy. Normally open contacts control the 12V to the key switches. Unit discharges, relay denergizes, contacts open, engines stop. Simple, reliable.

I will be installing bypass switches right above the engine key switches. If the unit malfunctions a simple toggle switch and I'm back in service.

I already have a temperature sensor in the engine compartment. I can set the temperature at which it alarms, and I intend to set it at a point depending on my climate to help detect heat.

I am also going to install smoke detectors in the engine compartment that have a relay which will tie into my alarm system and klaxon. That way if a smoke detector activates I can investigate sooner, preferably before a fire grows to a size that will set off the automatic system. I'm also putting a smoke detector behind my electrical panel since thats a major place where fires start.

I know of a guy on another forum I frequent that had an engine room fire. He had between 2 and 3 minutes to abandon ship. Thats not allot of time to deploy the life raft and or the skiff and get people in it. I purchased this unit in part because of what he went through.

Kevin

Smoke detectors in the engine room will not fare well. They are not suitable for the outdoorsy environment and will fail in a short time. Consider flame detectors or more heat detectors at a lower temperature.

O.B.

obthomas said:

Kevin

Smoke detectors in the engine room will not fare well. They are not suitable for the outdoorsy environment and will fail in a short time. Consider flame detectors or more heat detectors at a lower temperature.

O.B.

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OK, If I remember correctly you are a fire system engineer (oil field fire and gas?)

I was thinking of the Xintrex fire detection system.

Fireboy-Xintex recreational marine and offshore analog addressable fire detection systems

Any thoughts on that system? I was thinking of a couple sensors in the engine room and a sensor in the electrical space.

Kevin

Yes, I am a fire protection engineer. I have designed and specified fire protection for everything from nuclear power plants to offshore platforms.

The xintrex system looks like the one I would install on my boat. Smoke detectors in sleeping areas and electrical areas. Heat detectors in machinery areas. Almost any switching device or a device with a switch can be added to the detection circuit. Say a flame detector or a gas detector with ancillary contacts.

Good Luck, if you have anymore questions just ask.

O.B

obthomas said:

Kevin

Yes, I am a fire protection engineer. I have designed and specified fire protection for everything from nuclear power plants to offshore platforms.

The xintrex system looks like the one I would install on my boat. Smoke detectors in sleeping areas and electrical areas. Heat detectors in machinery areas. Almost any switching device or a device with a switch can be added to the detection circuit. Say a flame detector or a gas detector with ancillary contacts.

Good Luck, if you have anymore questions just ask.

O.B

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Thanks!

I did notice the circuit looks like how we pull fire panel alarms into our SCADA system, being a two resistor setup providing three states: alarm, normal supervisory. This must be a fire and gas standard. (I work the SCADA and Telecom side of the house).

If I wanted to get snazzy I could install a fire eye.

I am, wondering what the reason for the smoke alarm trouble in the engine spaces? Do the units fault out with a trouble, or false positive? What is the general failure mode?

Thanks!!

Kevin

When the initiating circuit is shorted you get alarm. This is often considered the failure mode. When the circuit is opened and the control can no longer see the EOL (end of line) device you get a fault alarm. In a fault you can still get a fire alarm if the detecting device is on the control side of the fault. So you see the circuit is being monitored all the time and which way it failes becomes sort of mute. You will get some sort of notification of failure no matter how the system fails.

obthomas said:

Kevin

When the initiating circuit is shorted you get alarm. This is often considered the failure mode. When the circuit is opened and the control can no longer see the EOL (end of line) device you get a fault alarm. In a fault you can still get a fire alarm if the detecting device is on the control side of the fault. So you see the circuit is being monitored all the time and which way it failes becomes sort of mute. You will get some sort of notification of failure no matter how the system fails.

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OK, now I understand.

Thanks!

Kevin

A fire eye (flame detector) in the engine room would be cool. Monitor the power eye power with a relay that opens the detection circuit and gives a fault if power is lost.

O.B.