Smoke Alarms : Are Home Units Suitable on Boats?

[mickt243]

Originally Posted by Cadence

CO2 does the same thing by displacing oxygen. I haven't the slightest as to what dry chemicals do? They won't make dry ice for chilling beer.

depending on the age, manufacture and rating, "Dry Chemical Powder" can mean many things....

eons ago, it was bicarb soda (usualy rated "AB") - when sprayed into a fire it did 2 things, #1 it put a non combustible layer of powder between the fuel and oxygen #2 when bicarbis heated it releases CO2, so it also displaced some oxygen. big drawback is it often forms a solid block in the bottom of the extinguisher and wont come out when triggered.
Bicarb Soda is best used on small fat fires, like a frypan full of chips, or a backyard bbq (I keep a box on hand in the kitchen for this very use.)
if used on burning magnesium (or similar alkaline metals) these WILL NOT WORK (the CO2 produced is actually an oxidiser for burning metals)

more modern DCP extinguishers (rated AB(E) or better) use proprietary mixtures of compounds, more often than not wont clump in the bottom (but give em a jolly good shake every few months just to be sure), and these work in 2 ways - #1 they form a non flamable layer between the fuel and the oxygen, and #2 they attack the fire at the chemical level (fire is a self sustaining chemical reaction, the DCP mixture can directly influence this reaction) these extinguishers can be used (with varying degree of success) on any class of fire - including burning alkaline metals.

there is another grade of DCP made speciffically for burning metal fires - it is made of lithium compounds that on contact with the fire fuse together to form a hard crust seperating the fuel from the oxygen, they ONLY work on metal fires, you wont often see them except in specific occupational areas (like where I worked for a while, an aviation battery facility, where we worked on large lithium batteries. - yes, its a little ironic that we could put out burning lithium by pouring lithium compounds on it...)

[mickt243]

Originally Posted by Bill Seal

When dry chemical extinguishing agent (sodium bicarbonate, baking soda) hits a hot surface it decomposes, releasing CO2. I believe Halon did more than just displace oxygen, (and offend the greenies), but the information is kind of scarce.

the main difference was for fires in electronic stuff.... some electronics contain flamable metal (magnesium, lithium etc) - CO2 will not extinguish this, it actually becomes an oxidising agent for the metal, leaving lots of carbon dust which will happily combust when all the CO2 is used up and oxygen returns..., whereas halons will have a decent effect on burning metals if the space is sealed and they dont blow away....

there are dangers of both when dealing with burning metals though - #1 as both types come out the nozzle, they are a cryogenic liquid - if this touches the burning metal, it can cause a mechanical explosion - perhaps spreading the fire. #2 burning metals are such a reductive influence on their surrounding environment, and put out such a large amount of heat, if you use halon on them you run a very high risk of creating large amounts of phosgene gas which may well kill people at a later time when you ventilate the compartment. and #3 - as I mentioned above CO2 is an oxidising agent for metal fires.

CO2 is also disliked as an extinguishing agent around electronics, as it can create large amounts of static electricity when being blown through piping and nozzles. (but hey, the fire will kill the electronics too...)

[buzzstar]

The questions are great, as as most of the responses although based on option and personal experience. I would love some empirical data if any exists. Perhaps inquiries to the manufacturers of home products, the ABYC, and even Practical Sailor might be worthwhile. In the meantime, my conclusion is something is better than nothing, and you will want to test frequently, not just once per year or so when you happen to think about the batteries. For those with hearing losses, such as myself, tests under noisy conditions (engine running at anchor and while moving, wind, rain, storm, music, at the helm while sailing, maybe while hove to, and so on) all seem advisable to the extent feasible. I do not usually wear my hearing aids while sailing or powering, but....

[K_V_B]

Originally Posted by zeehag

ohmygods how did those sailors ever manage without all this crap.

Actually, they didn't.

Sailing was actually a very dangerous business before a lot of modern technology came along...



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[rwidman]

I have a combination CO/Smoke detector in my sleeping area. It's just a normal residential detector with a permanent ten year battery. It's been fine and it has a silence button for when it alarms due to cooking smoke.

I've never considered putting one in the engine compartment and if you read the installation instructions, you will probably find a warning against installing it near heating appliances, furnaces and such.

If in doubt, a call or email to the company would be best.

You probably won't hear an alarming smoke detector if it's mounted in an engine compartment but many smoke detectors are designed to be interconnected so all you need to do is buy two and install one where it can be heard, then connect them together.

[Cadence]

Originally Posted by rwidman

I have a combination CO/Smoke detector in my sleeping area. It's just a normal residential detector with a permanent ten year battery. It's been fine and it has a silence button for when it alarms due to cooking smoke.

I've never considered putting one in the engine compartment and if you read the installation instructions, you will probably find a warning against installing it near heating appliances, furnaces and such.

If in doubt, a call or email to the company would be best.

You probably won't hear an alarming smoke detector if it's mounted in an engine compartment but many smoke detectors are designed to be interconnected so all you need to do is buy two and install one where it can be heard, then connect them together.

They can also be air draft sensitive although I'd rather have one of those annoying things sound as a false alarm than not sound at all.

[dannc]

Originally Posted by George DuBose

Well...reading the fine print in the info sheet of a CO detector that I bought in a German home improvement center, it is telling me that this CO detector is specifically NOT for MARINE use.

Doesn't say "why".

Does anyone know "why"?

Just a guess, but I wonder if the detector will go off if there is too much humidity. Some home alarms WILL trigger if the humidity is too high. Reading the box and/or instructions state this can happen.

Later,
Dan

[rwidman]

Many years ago, part of my job was servicing fire alarm systems in school buildings. Smoke detectors were relatively new and unreliable. Many of the systems had heat detectors connected to them. One type was a "rate of rise" heat detector that didn't measure heat as such but how quickly the temperature rose. This contained an air chamber with a calibrated vent. If the temperature rose too fast for the air to escape, the pressure pushed out a plug which operated a set of contacts. The other had solder that held a small switch open. When the solder melted, it fell out and the contacts closed.

One of these connected to a power source and an alarm would work. You have to find the normal (non fire conditions) of the engine compartment and get one that's rated for a higher temperature. You could install multiple heat detectors in parallel.

[liveaboard60]

Originally Posted by zeehag

smoke alarms?? my ericson had one. it told me when it died by shrieking in my still sleeping after 34 days working gonna killitedead ears.. so i proceeded to remove it and never look back. this boat has no smoke alarm..
ohmygods how did those sailors ever manage without all this crap.
damn'
[snipage]

<LOL> I can tell you what we did before we had all of those new fangled contraptions.. We stood 4 hour fire watches.. You would walk into all of the compartments of the boat every 10 to 15 minutes or so, and make sure no fires were burning.. Sure glad I never ran into a fire when standing one of those watches.. Did loose a lot of sleep though.. flk k

[GordMay]

Originally Posted by rwidman

Many years ago, part of my job was servicing fire alarm systems in school buildings. Smoke detectors were relatively new and unreliable. Many of the systems had heat detectors connected to them. One type was a "rate of rise" heat detector that didn't measure heat as such but how quickly the temperature rose. This contained an air chamber with a calibrated vent. If the temperature rose too fast for the air to escape, the pressure pushed out a plug which operated a set of contacts. The other had solder that held a small switch open. When the solder melted, it fell out and the contacts closed.

One of these connected to a power source and an alarm would work. You have to find the normal (non fire conditions) of the engine compartment and get one that's rated for a higher temperature. You could install multiple heat detectors in parallel.

➥ Fire Detector Cct - Cruisers & Sailing Photo Gallery

[SailingFan]

Originally Posted by mickt243

CO2 extinguishes fire by displacing oxygen, that is its only mode of action. if you ventilate the compartment too soon you risk reignition.

Human beings require a much higher concentration of oxygen than a fire does.... if you are sleeping in a poorly ventilated below deck compartment when an automated CO2 system does its thing, you wont wake up.

IMNSHO, any automated fire supression system should also sound an unmuteable alarm, loud enough to wake the dead.



for my engine room - its approaching time to replace the old halon system, I'm starting to like the idea of a few "elide fire ball"s. (Welcome to Fire Extinguishing Ball)

Now this looks like a cool solution! I like it!! Wonder how much it costs...??

The concentration issue of CO2 is precisely what I am concerned about. It is also the main reason I have not attempted to rig the aforementioned auto extinguishing method, but the ball you linked looks to be a far better option. I don't know what other damage the chemical would do (is it corrosive at a later date, for instance, or can it cause some form of damage to fiberglass or wood?) if used, but it looks like it may be a good way to make an effort, especially if it is a flammable liquid being converted to toxic fumes and gasses (incorrectly aka "burning").

I wonder what the US Coast Guard thinks of this tool?

[Cadence]

Originally Posted by SailingFan

Now this looks like a cool solution! I like it!! Wonder how much it costs...??

The concentration issue of CO2 is precisely what I am concerned about. It is also the main reason I have not attempted to rig the aforementioned auto extinguishing method, but the ball you linked looks to be a far better option. I don't know what other damage the chemical would do (is it corrosive at a later date, for instance, or can it cause some form of damage to fiberglass or wood?) if used, but it looks like it may be a good way to make an effort, especially if it is a flammable liquid being converted to toxic fumes and gasses (incorrectly aka "burning").

I wonder what the US Coast Guard thinks of this tool?

Cool solution. Maybe I read it wrong but coming into contact with the fire did not light my fire. pun intended. By that time it may be to late? Just asking and giving readers a thought.

[SailingFan]

Originally Posted by Cadence

Cool solution. Maybe I read it wrong but coming into contact with the fire did not light my fire. pun intended. By that time it may be to late? Just asking and giving readers a thought.

Cadence, what I thought was excellent was the concept of placing it directly over the potential fire source, or very close to it, so that should an event occur, the ball would "release" its cargo. This means that nobody even need be on board for this to work should a fire break out. It also means that one can keep them strategically located about the vessel, and it can be close at hand anyplace below decks should you be, say, sleeping or cooking and have a fire event.

I don't know what it would do to your electronics or finishes, hull material, fabrics, etc., as stated, but the sheer easiness of mounting and placement in many locations to include the engine compartment makes this a very attractive option, especially since it is then almost an automatic system.

The fact that it can be tossed into the flames makes it even better, as I was trained that if the fire is taller than you are, you cannot expect to effectively fight it with an extinguisher (at least on land, where you have the option to run, at sea you have to do whatever is necessary to save crew, self, and ship, of course). I can throw this thing farther than the length of my tiny 27 footer, so it would work for me if the price is affordable for it!

[mickt243]

Generally speaking, Dry chemical powders tend to be very bad for most electronics, they tend to be micro-fine particles that get into pretty much everything and often corrosive... Weather it be from a hand held extinguisher, or one of the automatic balls I linked, if it's discharged in your engine room, be prepared to replace the starter and the alternator and and all of the wiring....

I have used several fire extinguishers in anger.... one was in an accomodation building bedroom, although insurance paid for all the electronics to be professionally cleaned, over the coming months, all failed - all having rapidly corroding circuits and wires.

It will get through an engines air filter - especially if running...


It makes a helluva mess that is a pain to cleanup.


But if the option is watching my boat burn, I vote for the powdery mess

[SailingFan]

Originally Posted by mickt243

Generally speaking, Dry chemical powders tend to be very bad for most electronics, they tend to be micro-fine particles that get into pretty much everything and often corrosive... Weather it be from a hand held extinguisher, or one of the automatic balls I linked, if it's discharged in your engine room, be prepared to replace the starter and the alternator and and all of the wiring....

I have used several fire extinguishers in anger.... one was in an accomodation building bedroom, although insurance paid for all the electronics to be professionally cleaned, over the coming months, all failed - all having rapidly corroding circuits and wires.

It will get through an engines air filter - especially if running...


It makes a helluva mess that is a pain to cleanup.


But if the option is watching my boat burn, I vote for the powdery mess

I may have missed something, but I thought this ball was not a powder, but a foaming agent. Still, I am concerned about the same things you are, and likewise would rather chuck a radio than lose the boat.