Halon discharge question...

[BarryD]

1st of my novice questions:

I've had the survey done now (results in the post, and he wouldn't tell) - however the surveyor did say that one of the engine bay halon fire extinguishers had gone off, probably from the engine hatch being dropped. My assumption is that the engine was not running so I doubt it ingested any - have I just got an afternoons cleaning with some gunk or the like to carry out? Or is it more serious?

Thanks in advance.

Barry D.

 

[peterg]

The Halon shouldn't have done any damage - it's only the dry powder ones that really b*gger engines up! Get the Gunk and Fairy Liquid out and send the small one into those hard to reach places!

 

[PaulJ]

Halon is a colourless gass and from what you say I get the impression it probably went off some time ago so I doubt if you will find any evidence of it in the engine bay though I think it is heavier than air so it could still be in the bilges. It has a very distinctive (and nasty) smell so you will soon know! Halon is a fantastic extinguishant - I was given a chance to try it and it extinguished a blazing tub of oil instantly from about ten feet away, though of course it doesn't remove any heat from whatever it is that's alight so in a real situation you may need so follow it up with water or powder to prevent re-ignition. I understand that Halon is being phased out because of the damage it can do to the ozone layer but I think that if my boat was on fire in the middle of the ocean, the hole in the ozone layer would be one of my lower priorities. IMHO the tiny amount of damage that a few fire extinguishers can do is a small price to pay for such a fantastic life saver.

 

[peterg]

Halon will be illegal soon...

see the article in this month's MBM - you can use existing installations for now but future equipment cannot use Halon and alternatives are invariably more expensive (FM200 etc.) - better check the insurance is up-to-date!

 

[BarryD]

Re: Halon will be illegal soon...

I've got a spare FM200 system but it's sized for a 12M by 6M computer room, we replaced it with Argonite so I've got two filing cabinet sized tank things plus all the switch gear. It might just be a bit heavy though for a 28'

I think one of the dry powder ones went off as well as the surveyor said it was a bit messy.

Barry D.

 

[aztec]

when halons come into contact with hot surfaces or flames they decompose. this decomposition gives off a gas that is toxic by inhalation. so you may save your boat but but receive lung damage in the process.

change to co2 as fixed fire protection, and back that up with powder and/or AFFF foam.

You will not be able to replace halon as it is not supplied anymore. if youuse gas on your boat Dry powder is the only means to extinguish gas fires so it pays to identify the risks and cover them with the best media available.. regards, steve

 

[peterg]

buyer?....

have a word with MattS as I'm sure they wouldn't be too big for his 23m Leopard!

 

[vyv_cox]

In my past role as a company fire warden, plus my interest in extinguishers for boating use, I looked at most of these issues. The gas emitted by Halon plus fire is unpleasant but not highly toxic. Certainly less terminal than being burnt.

CO2 fixed fire protection is very heavy and close to useless in anything but a closed room. A 35 ft boat would need a pressurised container close to the size of a 5-gallon drum to be certain to extinguish an internal fire. This would not be effective outside on deck. I would certainly not advocate use on a boat.

Foam is excellent for oil fires, as it contains chemicals that inhibit re-ignition. It is also quite effective for paint and polyester resin. Powder does not inhibit re-ignition and in my view is the next-to-least useful type for boating use

None of these is anywhere near as effective as Halon. Check Halon extinguishers by weighing, if they have not lost weight they are still OK. Unfortunately it will be illegal even to own a Halon extinguisher by the end of next year, so I shall have to hide mine on board and leave my foam ones visible.

Incidentally, "Which extinguisher do you use to put out gas fires" is a trick question beloved by firemen everywhere. The answer is, "none, either leave it burning or turn off the tap". If the gas bottle is alight no extinguisher on earth will put it out. If the flame is impinging on boat surfaces and lighting them, the best method is almost certainly water.

Fire blankets should not be overlooked but it takes skill to use one without being burnt. Wrap the hands inside it before trying to lay one over the fire. The old advice of a damp cloth for chip pan fires means what it says - damp. A couple of drops of water will cause the pan to effervesce violently and an egg-cup full is like a bomb going off.

 

[Bergman]

Re: Good Advice

Thanks Vyv that is really good information.

I think fire is one of the most neglected risks on a boat. I once worked with someone who had had a narrow escape in a hotel fire and he was most eloquent on the subject of fire precautions. It must be even more terrifying on a boat.

I have dry powder extinguishers on board, based one my experience of using one when I managed to start a petrol fire on a motor bike engine. The powder had it out in 2 or 3 seconds, I was really impressed. The mess was small inconvenience compared to the possible alternative.

If there are better types for a boat what should I replace them with? I have a halon in the engine box which is staying there for as long as it remains within its weight spec.

Cheers

 

[Guest]

Re: Good Advice

It sounds as if Vyv was on the same fire fighting course as I attended!
The fire-fighting instructors gave the same excellent advice. They strongly favoured the use of foam for fighting any petroleum product fire. Especially note the importance of being able to turn off the gas. The fire is then more manageable. The only solution if your gas bottle is actually alight is to don life jacket and take to the raft quickly.
The instructors stressed again and again the importance of smoke/gas detectors. Their least favourite job is pulling out corpses. The usual cause of death being smoke inhalation not burning. Applies at home too - fit the detectors.

 

[Guest]

We had our annual fire extinguisher check in my office back in early spring as part of our H&S responsibilities. The chap that did the check collected all of our Halon extinguishers and said that they had to be replaced by law with CO2. He would remove them from our premises but we would have to pay him £50 each for "safe environmental disposal". We did indeed buy the CO2 ones, but he was most upset when I insisted he leave the Halon ones, since they are our property etc. So now all our staff have them for their homes and I've got 5, 2.5Kg Halon extinguishers.

Interestingly, when I later anonymously 'phoned his company to see if I could purchase any of these "no longer valid" extinguishers, I was told that strictly speaking it was illegal for them to sell them but they would be prepared to sell me a 2.5Kg one for £150, cash only.

So, any of you working in an environment where they have the Halon extinguishers, find out when the next check is due and offer to take them off the company's hands.

BTW we also had a a fire awareness course run by our local fire brigade and they were very unhappy that Halon has to go. They say there's nothing to touch it.