Fire Extinguishers / Types applications

[Joe CD MS 300]

As the smoke/fire thread below morphed into a related topic about the appropriate type and use of fire extinguishers I thought we might as well start a separate thread.

As with most issues it seems there is no perfect solution. Dean mentioned below that the use of an automatic Halotron system requires a auto shut off for diesel engines. The systems alone are pretty expensive. The auto shut off could add another $500 to the cost.

Aqueous (am i spelling that right) foam on the surface seems like a good solution. It works on a variety of fires and is not corrosive or damaging like some of the other dry chemical extinguishers. The big problem (at least as it seems to me) is the flair up issue when you open an engine compartment. I haven't read anything on it but I'm thinking that the foam would need to be directed at the base of any flames so it may not work with a fire port.

Very preliminarily it seems that the use of a fire port with a manual halotron extinguisher may be the best option (also considering cost) other than a full blown auto system with an engine shut off.

[Dean Abramson]

Very preliminarily it seems that the use of a fire port with a manual halotron extinguisher may be the best option (also considering cost) other than a full blown auto system with an engine shut off.

That's the tentative conclusion I have come too at this point also, for the engine.

I have two non-rechargeable ABC dry chem units. As long as they show proper pressure, do I consider them good to go? They are three years old now. Am I supposed to shake these now and then?

Dean

[Paul D.]

I don't know the best system but I am a fan of simplicity so I have two B-I's on Femme, one in the galley by the engine and one in the VBerth. Whenever I have people on a passage I show them where they are and do a complete explanation. Having been through the beginning of a fire once in workshop (with lots of nice flammables right nearby!) and having put it out with an extinguisher I know they work and work really well - if maintained properly which is cheap insurance.

One piece of info I got from our fire extinguisher guy (the type of guy you want checking all your fire extinguishers, you know, focused, knows all, tells only some, has the little dog that follows him around everywhere) was that for boats you want to store your fire extinguishers sideways and shake them up vigorously about twice a year to keep the powder uncaked. I am talking our regular B-I or B-II Dry Chemical types here. Sorry, cannot comment on systems and automation but I do have an aversion to automation and the complacence it can create.

Here in Minnesota, there is a new house code that REQUIRES sprinkler systems in new builds, which I think is a terrible idea for several reasons, even though it may sound logical.

All the best,
Paul

[j2sailor]

Hi Joe,
You can use a CO2 extinguisher, which will do well on all classes of fire without the mess of dry chemical or foam. Because it displaces oxygen, you don't want to be inside an enclosed space when using CO2. There are a couple of ways around this:

1. Fire short bursts of C02 into the intake vents. Take care to use one second bursts. The bottle only lasts about 30 seconds on a straight stream.

2. Make a small access port in the engine-room hatch cover just large enough to insert the extinguisher horn. Then spray the agent inside. You don't want to open the hatch unless absolutely necessary. Not only does this expose your crew, but the oxygen will feed the fire, making it harder to extinguish quickly.

As an alternate, take advantage of the expansion qualities of a single drop of water. At advanced marine firefighting school they show how steam smothers large fires. A fire is started in a small metal shed. When it's completely engulfed, the door is closed tight.

A small two inch access hole is drilled into the door and a charged garden hose nozzle (not fire hose) is inserted into the hole. The nozzle is opened on the mist setting for one second. Each drop of water coming out of the nozzle expanded 1600X and smothered the fire within seconds.

This presents a good backup to other types of extinguishing systems. Make a small hole in the engine access hatch and cover it with an access cover plate. Have a garden pump spray bottle nearby. Use the spray (not straight stream) setting. In the event of a fire, remove the hatch cover plate, insert your spray nozzle, and fire short bursts inside.

Best - Cap'n J.
www.skippertips.com

[Oswego John]

I go along with Cap'n J.

We used variable nozzles that could be adjusted from straight stream to what we called "fog". It was aerated water, finer than a spray. Very effective.

O J