Fire extinguisher

I've just pulled this fire extinguisher out of the engine compartment of a second-hand boat:

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also flipped for ease of reading:
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)

I know nothing about the care and feeding of fire extinguishers.

Presumably this is out of date; does that matter? (there are no regulatory requirements here AFAIK). The pressure is still just about in the green, so is it worth putting back as better than nothing? I probably wouldn't buy a new one; the engine fire protection on most boats consists simply of a small hole to poke the cabin extinguisher nozzle through.

Is it likely to go pop on its own? Should I be handling it carefully? Presumably the red capsule in the frame is designed to melt in a fire; is it otherwise delicate and likely to redecorate my living room if someone knocks it over on the table it's sitting on?

If I decided to get it serviced, how much is that likely to be and where does one go? Can I service it myself?

If I decide to get rid of it, how? I assume just chucking it in the wheelie bin is frowned upon.

Cheers,

Pete

Reply to
Pete Verdon
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not in the least

good to go then

no

its pressurised, treat it like any other high pressure container

there's really no point if its still pressurised.

I dont know what the aqueous foam composition is. If it were just water then its easy enough.

give it away

NT

Reply to
NT

Given the date on it I'd be inclined to do anything except nothing...

.Yellow Pages for your locality will have loads of places listed who could advise you what the best course of action would be and dispose of it if that is what is required . .

I'm confused by what you ask about the "red capsule in the frame melting in a fire )...Can't see it but can't see what good that would do as the foam would probably go everywhere but where it was most useful. Modern extinguishers appear to be made with the usual squeezable handles .This looks more like the old type you turned upside down and hit the button on a surface like the floor to operate it .

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the only ones you can refill yourself are the water ones with the replaceable gas canister inside .

I'd suggest you get a modern one suitable for use on a boat .

Reply to
Usenet Nutter

Think "self contained automatic sprinkler system" and you'll have a better idea.

Reply to
Graham.

an old one then

NT

Reply to
NT

That's an AFFF with a revolving head, temperature activated. Basically above a certain temperature the foam comes out and is sprayed around the compartment. Sort of like a fire activated sprinkler head (which whirls round in the jet of water creating a spray).

I suspect the modern version is a pressurised tube type (Firetrace and others), the tube melts at the locality of the fire and distributes "whatever" all over it until exhausted. They are very expensive, about =A3120-180 as I recall. Beware using powder on metals like aluminium, they will put the fire out - but at the expense of that item usually :-)

AFFF foam do not "go off" in the way that powder do - which settle and go rigid inside thus are important to service often.

Reply to
js.b1

Why? It is a low pressure extinguisher with a benign and stable extinguishing agent.

If you want to dispose of it simply set it off, neither propellant (probably compressed air) nor extinguishing agent are harmful.

That's the idea, AFFF is very effective.

but where it was most

Nothing like.

Its about as good as you can get for the role, far better than dry powder.

Reply to
Peter Parry

Rather a nice Aqueous Film Forming Foam extinguisher which would originally have been quite expensive.

Not really.

Absolutely, it is a great deal better than nothing. You can usually re pressurise them using a compressed air line and the filling port on the control head (You can just see it in the side away from the monitor in your pictures).

No, it uses air at moderate pressure as the propellant.

Well you shouldn't drop it on the control head or you may get wet.

Yes. The water then gets spread by the sprinkler head design. AFFF is very safe and effective.

Depends how far it falls and what on to!

No servicing is really required other than making sure it is all clean,- pressure you can do it yourself but you might need to find someone with some odd bits of pneumatics to find something to fit the filler port. IF you do service it the AFFF is a liquid you can decant (Water with AFFF concentrate added) and needs no particular handling precautions, check the inside of the cylinder for corrosion, there shouldn't be any, clean up valves, replace extinguishing agent, re pressurise.

Set it off on the lawn. AFFF is quite benign.

Reply to
Peter Parry

Sorry, yes, I kind of had a choice of capturing the gauge or the capsule but not both. I assumed that someone knowledgeable in extinguishers would know what I was talking about.

What I didn't make clear was that this is an automatic extinguisher, mounted in the engine bay to go off if a fire occurs. So no handles, and yes the foam will go everywhere - that's the point. It's a very small space and mostly full of engine; a litre's worth of foam would give a pretty thorough covering I'd have thought.

There are two other manual fire extinguishers on this 24 foot boat. These I'll treat as "primary" devices and make sure they're up to scratch; the auto foam one was a kind of bonus. I'm not sure if the previous owner even knew it existed; it was pretty hidden away out of sight, and I only found it because I was disconnecting the engine before removing it for overhaul. The date on it is prior to his ownership of the boat.

Pete

Reply to
Pete Verdon

Thanks - sounds like you know what you're talking about :-)

I was actually talking specifically about the red capsule. It makes me slightly nervous just wedged in there between the vent and the frame; I'm worried about it either coming out or breaking (or me popping it out while playing with it, to be honest!)

There's a bit of corrosion on the valve. I'm nervous of doing anything to it in case I set it off :-) At least until I know how robustly the capsule is seated, which I can't really find out without dislodging it.

I have a mate with an air compressor. He probably doesn't have a wide range of odd fittings though. I suppose in extremis I could always go and visit my grandad and reactivate the lathe in his shed[1].

I think in practice I'll just put it back where it came from. The only problem I could forsee is internal corrosion causing the bottle to let go one day; you suggest that's unlikely and certainly it looks in good nick externally. Presumably in the event that that did happen (or it went off for some other reason) the AFFF isn't going to damage anything and could just be cleaned up?

Finally, what about mounting angle? Presumably it's meant to be mounted upside down, hence the label and the head that will spray outwards in all directions. On the boat, it's mounted horizontally on the deckhead (ceiling, for the landlubbers :-) ). Would this mean that only half of the foam would come out, or is there likely to be some kind of dip tube inside? I could try to mount it vertically, but that would probably put the head lower than what it was supposed to protect, and an engine in the way.

Cheers,

Pete

[1] He's offered it to me a couple of times, and while I'd love to play with it I don't actually have a need, and I certainly don't have the space. I'll make sure it's hung onto when he passes on though.
Reply to
Pete Verdon

These capsules are normally glass and contain a liquid (can't remember the make-up now) think it's just dyed water. As the temperature in the compartment is raised, the liquid in the capsule expands until it reaches the critical temperature, when it shatters, thus releasing the valve. The foam then spurts out and redecorates your living room. So don't keep it in a hot room.

If it is out of date and it's going to be re-used, take it to a proper servicing agent, fire is not something to mess about with and just hope it will be OK, especially in a boat. What price death? We used a lot of these in the RN and were all trained in fire fighting but wanted the kit to be top line.

This type is preferably fitted upside down but will work just as well horizontally. The pressure in the beast will eject all of the foam. When the foam is exuded it will spread itself out across the compartment, smothering everything. The pressure and design of the nozzle will spray most of it across the compartment but also, when the foam lands, it will continue to spread itself out and smother the fire. Not sure what the foaming agent is now but at one time it was Ox Blood.

Reply to
Old Git

Ox blood derived foam was the evil smelling yellow Protein Foam. Aqueous Film Forming Foam is quite different. It doesn't come out as a thick foam but more like water with a bit of washing up liquid added. It works by forming a film across the fuel surface so isn't that good on machinery fires (too many bits sticking out) but really good on pooled fuel. In an engine room its main use in a fixed extinguisher is to cover fuel on the floor with extinguishing agent so spilled fuel does not ignite.

It has the secondary advantage that it is non-corrosive and very simple to clean off (just rinse with fresh water) so you don't get any damage from the extinguisher (unlike Protein Foam which started to rot after a few days and in the bilges would render a vessel uninhabitable in a week in a warm climate!).

Reply to
Peter Parry

In article , Peter Parry writes

Any comments on the likely success of operation when not inverted? Having seen the way these heads work in sprinkler systems I'd be surprised if a satisfactory result came from horizontal mounting. Would it deploy fully on its side?

Reply to
fred

I've just found another use for ox blood ;-) the other was: During the construction of the Pontcysyllte Aqueduct the mortar used comprised of lime, water and ox blood.

Strange the things you can learn on UKDIY.

Stephen.

Reply to
stephen.hull

It would be less effective on its side. The AFFF would still prevent fire developing in fuel pools where it had coverage but if the engine room floor has strakes then some area may not be covered allowing fire to develop.

Reply to
Peter Parry

I still think it would only half deploy if used on its side (pressure lost without expelling liquid once fluid dropped below the outlet).

Reply to
fred

Point taken, but bear in mind that 90% of small pleasure craft have no automatic engine compartment extinguisher at all. I've sailed on many yachts (everything from Army sail training to Caribbean charter) and never knowingly on one with an engine extinguisher.

Standard equipment is a 1" teak ring with plastic bung fitted under the companionway steps. In the event of fire, one is supposed to take a cabin extinguisher and shove the nozzle through the ring, pushing out the bung, and then let it off. This is acceptable to insurance companies, the RNLI, the MCA, "coding" requirements for commercial charter, etc etc etc. If my engineroom stowaway fails to do its thing, I am no worse off than the thousands of people with the standard system. There are two sizeable extinguishers (in date) within arm's reach of the engine hatch, and since I'm working on the woodwork near the hatch I plan to install the normal hole and bung irrespective of any automatic system I may or may not have.

I only originally decided to post here to ask how to throw it away. The question broadened as I wrote it, and then Peter convinced me that the bottle is more use in the engine bay than my wheelie bin.

Pete

Reply to
Pete Verdon

It may not empty fully but it would certainly empty more than half as the turbulence caused by the sudden pressure drop would cause more than half the contents to be expelled when horizontal especially in a fairly narrow container.

Reply to
Peter Parry

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