Engine fire extinquisher system and fuses

[ArtJ]

I was wondering if any of you guys have experience with selecting and
installing a automatic fire extinquisher system for the engine compartment.
In the case of my Tartan 34c, the engine, batteries, regulators,battery
fuse and fuel tank are located in near proximity.

What type of automatic safety equipment is available?

Also with regard to Main battery fuse, are there intrinsically safe breakers
available?

Best Regards

Art

[Mo]

Art,
If everything is in a confined space it's relatively easy. For example, a 10lb dry chemical could be mounted in a lazarette and its nozzel through a bulkhead and into the engine compartment. Pull the pin and it would knock down any fire in that space.

The problem occurs when the space is large or there are no bulkheads actually enclosing the space. The dry chemical then may be dispersed too much to be effective. This is the situation on my boat. I have a 10 lb'er on one side of the lazarette and the nozzel pointed toward the engine...pull pin and squeeze. The whole area is not sealed off so it may or may not put a fire down first shot.

Proper safety regarding fuel issues should prevent "explosive" incidents. In the case of explosion these are, violent and immediate. You could not activate the device. The best you can do is PREVENT or put out a fire after... if you are able.

Most fires on boats are not explosive. However, they must be extinguished. The main problem is not having enough "umph" in the fire extinguisher. I'll phrase it like this...it's like going up against a machine gun with a .38 revolver. If the extinguisher is too small the chances of it working out for you are limited from the start.

Odyssey's fire extinguishers....(4) 10lb dry chemical and (2) 5 lbs dry chemical..the only reason there are 5 lb extinguishers on the boat is because she came with them. One 10 lb'er can knock down a decent fire....the other are just in case.

[ArtJ]

Thanks for the input Maurice

You are right, fuel related explosions are immediate and probably a
automatic fire extinqusher system would not be fast enough to prevent
a fire or explosion. Besides that, they are subject to possible accidental
activation and could create havoc with components.
I was hoping that some sort of foam bath for the engine could prevent
this issue. Maybe it could prevent a explosion when a fire occurred prior
to the explosion.
I have previously installed a fume detector alarm, possibly
that combined with a installed extinquisher as you suggestwould give time to
spray the compartment and prevent explosion.

The other method, as you mention, is to carefully monitor wiring,
fuses.

A few years back, I installed a 100A? fuse in the primary ckt of the
battery. The fear I have is that this fuse could catch fire and
not blow clean. There must be breakers or fuses that could
prevent this.

Regards

Arr

[msauntry]

An excellent thread to open up! My thoughts turn to the Fireboy automatic units. I was looking them up and they have models to cover various cubic footage. They have diesel and gasoline specific models and the agent is not supposed to harm or contaminate the boat after discharge. I know the dry chemical ones can damage and corrode any electronics. They trigger at a certain temperature and/or manually.

I do not know of any systems that will prevent a fire, only react to one already in progress. This is where the fume sniffers would come in handy. Anybody got specs on a fume sniffer that is comercially available? I know some of you have Pearsons that came with them installed but that part manufacturer is no longer running.

[67c&ccorv]

My 67 C&C Corvette had an automatic Halon fire extinguisher system mounted in the engine compartment but I removed it as it had long ago passed it's final inspection date.

[sastanley]

Micah, I think Neil has a sniffer in his boat. That might be for the CNG/propane system though..I cannot recall at this time.

[edwardc]

Originally Posted by ArtJ

A few years back, I installed a 100A? fuse in the primary ckt of the
battery. The fear I have is that this fuse could catch fire and
not blow clean. There must be breakers or fuses that could
prevent this.

Regards

Arr

The ANL fuses, sold by Defender and others, are ignition protected and rated for gasoline boats:

http://www.defender.com/product.jsp?...931&id=1334628

[ArtJ]

Originally Posted by edwardc

The ANL fuses, sold by Defender and others, are ignition protected and rated for gasoline boats:

http://www.defender.com/product.jsp?...931&id=1334628

I (mistakenly?) in the past took ignition protected to mean it somehow
protected engine ignition electrical parts, should I have read this
as FUSE IS FLAME IGNiTION PROOF as in flamming of the fuse and surrounding fumes?

Regards

Art

[Dockside Charlie]

Ignition protected is intended to mean the electrical componant,bat-chgr,pump,alt,dist,str,blwr,fuse,etc.in it's normal function,could possibly create a fuel source to ignite/combust(hydrg-gas from batteries,gasoline fumes,diesel or lube oil leaks on heated surfaces creating flammable vapors,propane)less likely but not garrenteed to ignite unintentionaly or expectedly.These units are resistant to,not infallible and do not relate to points and plugs firing the engines running.Safety is the focus.

[edwardc]

Originally Posted by ArtJ

I (mistakenly?) in the past took ignition protected to mean it somehow
protected engine ignition electrical parts, should I have read this
as FUSE IS FLAME IGNiTION PROOF as in flamming of the fuse and surrounding fumes?

Regards

Art

Ignition protected means it will not ignite a flamable vapor mixture.


Funny story: Years ago, when I worked for the Navy dept, we had these big, heavy black plastic flashlights that were ignition protected, but back then, they were labled as "Explosion Proof". One of my co-workers noticed that for the first time and said "Really? That's cool!", and proceeded to test it by smashing the flashlight on the edge of the workbench!

The look on his face was priceless when the flashlight head shattered into a dozen pieces!

[ArtJ]

HI guys

Would really appreciate input on the Fireboy extinquisher so I can
decide whether or not it can be safely installed.

Thanks very very much

Art

[ndutton]

I searched online and found the installation instructions. Essentially this is the same as the old Halon systems with a different smothering gas and as I understand it, there are four things to consider:

1. As you said, you have to find a place to mount it. I believe it should sense and smother the compartment where a fire is most likely to start, not where it may migrate to. To me this means high in the engine compartment. That is where the fuel is launched out of a closed system (carb) and where the likely ignition source exists. I'm not saying there aren't other places where fumes could collect and ignite but you have to go with the law of averages. You can't count on the system to extinguish a fire in an adjoining compartment. Some smothering agent may find its way there but probably not enough to be effective.
2. The reason they advise against athwartships horizontal mounting is on one tack the dispersing head will be below the tank and they caution strongly to mount it with the head higher than the tank. I expect the smothering agent is a liquid inside the tank that vaporizes on pressure drop (activation) and they want to be sure you're dispensing vapor rather than liquid in the compartment. Since you say there is no space inside the engine compartment, could it be mounted outside the compartment with only the sensor and dispersing head inside? Maybe camouflage it with a cover of some sort?
3. For a proper system you must wire the blower through the pressure switch on the unit. They use the switch for the indicator light but have instructions on how to wire the blower through it. Once the agent is dispensed you don't want the blower removing it and ventilating the space with fresh oxygen carrying air.
4. You might want to take some compartment temperature measurements underway to see what the ambient temperature actually is. The gauge and compartment temps should be very different. Of course, avoid mounting the unit in the vicinity of or above the exhaust hot section. Heat rises.

[ArtJ]

Originally Posted by ndutton

I searched online and found the installation instructions. Essentially this is the same as the old Halon systems with a different smothering gas and as I understand it, there are four things to consider:

1. As you said, you have to find a place to mount it. I believe it should sense and smother the compartment where a fire is most likely to start, not where it may migrate to. To me this means high in the engine compartment. That is where the fuel is launched out of a closed system (carb) and where the likely ignition source exists. I'm not saying there aren't other places where fumes could collect and ignite but you have to go with the law of averages. You can't count on the system to extinguish a fire in an adjoining compartment. Some smothering agent may find its way there but probably not enough to be effective.
2. The reason they advise against athwartships horizontal mounting is on one tack the dispersing head will be below the tank and they caution strongly to mount it with the head higher than the tank. I expect the smothering agent is a liquid inside the tank that vaporizes on pressure drop (activation) and they want to be sure you're dispensing vapor rather than liquid in the compartment. Since you say there is no space inside the engine compartment, could it be mounted outside the compartment with only the sensor and dispersing head inside? Maybe camouflage it with a cover of some sort?
3. For a proper system you must wire the blower through the pressure switch on the unit. They use the switch for the indicator light but have instructions on how to wire the blower through it. Once the agent is dispensed you don't want the blower removing it and ventilating the space with fresh oxygen carrying air.
4. You might want to take some compartment temperature measurements underway to see what the ambient temperature actually is. The gauge and compartment temps should be very different. Of course, avoid mounting the unit in the vicinity of or above the exhaust hot section. Heat rises.

Thank you for the information Neil
Unfortunately, I do not have room in the tiny Tartan34C engine box
for the extinquisher. Additionally, I am concerned about the ambient
temperature inside this tiny box reaching over 175 degrees easily in
normal operation. Bottom line: It's a nice unit if you can safely install
it which I cannot. The hazard outweighs it's value, so I am going to
return it.

Thanks again and best Regards

Art

[sastanley]

Art, My buddy's fancy Beneslow 343 has a simple plastic one-way hole cut into the stairs for jamming an extinguisher into the engine box. Anyway to remotely mount the system and plumb it into the engine box that way?

Art, on second thought, I googled "fire extinguisher port", and found this good Boat US article which says blindly spraying into an engine box is useless, unless it is a gaseous type that removes the oxygen.

http://www.boatus.com/seaworthy/swybf.asp

[ArtJ]

Originally Posted by sastanley

Art, My buddy's fancy Beneslow 343 has a simple plastic one-way hole cut into the stairs for jamming an extinguisher into the engine box. Anyway to remotely mount the system and plumb it into the engine box that way?

Art, on second thought, I googled "fire extinguisher port", and found this good Boat US article which says blindly spraying into an engine box is useless, unless it is a gaseous type that removes the oxygen.

http://www.boatus.com/seaworthy/swybf.asp

Thanks for the reply and suggestion Shawn. The Tartan 34 C
has the engine sitting in the middle of the main salon under a small
settee and half buried in the bilge. There is no adjacent bulkhead other
than the battery box which is jammed full. I have returned the
Extinquisher to Hamilton Marine for credit.

Best Regards and Thanks

Art