Foam fire extinguishers?

[DHutch]

Somthing ive wondered for a while, why do boats always have drypower extinguishers?

- Ive had a skim though the bss read book, and cant find anything that states they must be of this type, and as far as i can see an equivalently rated foam extinguisher would be just as allowable?

 

Have i missed somthing?

- I mean, you cant have CO2 becuase of the confined space issue but foam would seam a good bet to me at times, or even water just for solid fuel fires?

 

 

Daniel

[ChrisPy]

Dan, I asked the same question in a thread about a year ago and the answer seemed to be inconclusive. There must be a good reason why dry powder has become the accepted standard, but I'm b*ggered if I know why.

[Tony Brooks]

Dan, I asked the same question in a thread about a year ago and the answer seemed to be inconclusive. There must be a good reason why dry powder has become the accepted standard, but I'm b*ggered if I know why.

 

 

This is not a known fact, but the first BSS looked very like the Thames Launch Bylaws which go long way back into the last century and they mentioned the weight of powder extinguishers.

 

I have no idea how modern foam is produced, but I suspect it is with a water content, so with the prevalence of inverters on board today I am not sure I would be wanting to be squirting a jet containing water at a fire if I was not extremely sure no mains 240V was anywhere near.

 

Tony Brooks

[1066]

Somthing ive wondered for a while, why do boats always have drypower extinguishers?

- Ive had a skim though the bss read book, and cant find anything that states they must be of this type, and as far as i can see an equivalently rated foam extinguisher would be just as allowable?

 

Have i missed somthing?

- I mean, you cant have CO2 becuase of the confined space issue but foam would seam a good bet to me at times, or even water just for solid fuel fires?

Daniel

 

I think it is mainly to do with the fact that dry powder can deal with most types of fire.

 

Foam, because of its liquid content, is not suitable for electrical fires, and ditto for water.

 

CO2 is not suitable in confined spaces, as you have mentioned.

 

In an emergency situation, it would be dangerous trying to decide which extinguisher to use if a choice was available,

so dry powder is the best all-round product to use.

[ChrisPy]

strange anomaly is that although foam extinguishers cannot be used on electrical fires, apparently they conform to BSS requirements.

no doubt Rob@BSS will clarify if their inspectors will accept them.

[DHutch]

I think it is mainly to do with the fact that dry powder can deal with most types of fire....

...In an emergency situation, it would be dangerous trying to decide which extinguisher to use if a choice was available,

so dry powder is the best all-round product to use.

I guess theres truth in that.

- I was just thinking, in terms of solidfuel/liquid fires (which a lot will be) foam is pritty good, and doesnt setle out like powder.

- Also, like ours, man boats have very little or no mains electical presents, making wet products again quite usable.

 

But yeah, is rob about?

 

 

Daniel

[Geoff]

According to an ex Fire Officer, doing a recent work related fire course I was on, the AFFF (foam extinguishers) were (are ?) safe to use on electrical fires due to the way they atomise the water jet. The problem is with the residue afterwards which obviously becomes a liquid and would conduct electricity

 

Geoff

[DHutch]

Yeah, i have seen some foam extinguishers that state they are ok and often wondered how that worked.

- But yeah, i would just serously thinking that a foam/water extinguisher would be a usfull addition to dry poweredin the event of a fire on emilyanne, an if it was allowed.

 

I know people with CO2 units have to hide them for the BSS man. And was wondering if, should i get a foam/water unit i would have to do the sam. :S

 

 

Daniel

[pagan witch]

I spoke to a fireman at an event recently and had a similar discussion. He couldn't think why we shouldn't use foam - after all the fire brigade usually shoot water at everything domestic and there's just about always electricity in a house.

 

Yes - it does conduct but typically it is OK at up to 1,000 V - well below our normal range of stuff even with an inverter - and we all have an isolation switch so could kill all power anyway.

 

As for CO2 yes - it is an asphixiant (bet I've spelt that wrong) but in a narrowboat we always have the situation where if there were a fire we would have an open exit on one side of us and the fire on the other so there should be enough air flow to sustain us and a hasty exit route available.

 

He also said that he'd have to be REALLY desperate to use a powder extinguisher anywhere. He set one of in a building some time ago and within 1/2 hour the powder had permated the entire building and the were still hoovering it up 3 weeks later.

 

All that said I guess it is safe on anything (although not always the most effective) and in a panic situatio with untrained people using them you need that flexibility.

 

As far as I am aware there isn't anything that says we can't have a CO2 extinguisher - would be very handy for killing engine fires where we could squirt it through the air intake.

[1066]

This link gives a fairly good account of the types of extinguishers commonly available, and their recommended uses.

 

http://www.firesafe.org.uk/html/fsequip/exting1.htm

[Rob@BSSOffice]

Yeah, i have seen some foam extinguishers that state they are ok and often wondered how that worked.

- But yeah, i would just serously thinking that a foam/water extinguisher would be a usfull addition to dry poweredin the event of a fire on emilyanne, an if it was allowed.

 

I know people with CO2 units have to hide them for the BSS man. And was wondering if, should i get a foam/water unit i would have to do the sam. :S

Daniel

 

No, don't hide them, just ensure there are enough A and B types for the size of the boat (and in good condition). Please be careful if you ever use CO2 in the cabin as it kills the fire by replacing the oxygen. The website 1066 points to also explains this.

Regards

Rob

[ChrisPy]

No, don't hide them, just ensure there are enough A and B types for the size of the boat (and in good condition). Please be careful if you ever use CO2 in the cabin as it kills the fire by replacing the oxygen. The website 1066 points to also explains this.

Regards

Rob

the other point was whether the inspector will count foam extinguishers towards the A & B total.

[Rob@BSSOffice]

the other point was whether the inspector will count foam extinguishers towards the A & B total.

 

If they are at least 5A and 34B rated, have the attestation mark and are in compliant condition, yes indeed.

 

Regards

Rob

[DHutch]

Right, so we can use foam extinguishers inplace and as well as the drypower powder types.

- They count towards the total A & B ratings just the same, and as long as there indate/serviced/certified/etc there good to go?

 

And water? But not CO2, and if we do use it, we need to be carefull, for obvous reasons.

 

Sorry to be all questions, but im just trying to clear this up and get it straight in my own mind. Thankyou for the answers so far.

 

 

 

Daniel

[Boaty Jo]

Just a supplementary from another part of the site that 1066 suggested. May clarify things a bit.

 

Classes of fire

Combustible and flammable fuels involved in fires have been broken down into five categories:

 

Class A fires - are fires involving organic solids like paper, wood, Esc

Class B fires - are fires involving flammable Liquids.

Class C fires - are fires involving flammable Gasses

Class D fires - are fires involving Metals .

Class F fires - are fires involving Cooking oils.

 

Jo

[AllanW]

I think it is mainly to do with the fact that dry powder can deal with most types of fire.

 

That's probably right - plus I *think* iirc that the dry powder extinguisher has a longer shelf life

 

Allan

[ChrisPy]

I *think* iirc that the dry powder extinguisher has a longer shelf life

as long as you shake 'em up occasionally

[Alastair]

No, don't hide them, just ensure there are enough A and B types for the size of the boat (and in good condition). Please be careful if you ever use CO2 in the cabin as it kills the fire by replacing the oxygen. The website 1066 points to also explains this.

Regards

Rob

Has anyone tried setting off a dry powder extinquisher inside a narrowboat, and breathing?

 

Rob, I believe that water extinguishers are ok under BSS rules, so the water content of foam is immaterial.

[bottle]

Each portable fire extinguisher must have an individual fire rating of

5A/34B or greater.

 

The BSS does not state, that I can find, the type of extinguisher that should be available, it only states the rating as above.

 

So it could be filled with blanmange as long as it is certified to the correct rating with the correct markings etc.

[BEngo]

Has anyone tried setting off a dry powder extinquisher inside a narrowboat, and breathing?

 

Rob, I believe that water extinguishers are ok under BSS rules, so the water content of foam is immaterial.

 

I am not absolutely certain none exist, but I have never seen a "B" rated water extinguisher as water is generally the last thing you want on a flammable liquid fire. If you don't believe me ask your local fire prevention man to show you the chip-pan video.

 

In general terms Dry-Powder extinguishers are very good at knocking down a fire, but they don't much disrupt the fire triangle (heat, fuel and air). There is then a tendency for the fire to come back. Powder extinguishers are pretty versatile, low maintenance , fairly small in size for their capabilities and knock-down is fine because it gives you time to escape. Whether you can still breathe will depend on how well you apply the powder and what the propellant is.

 

Foam fire extinguishers are more effective at putting fires out, because they deny the fire air and then the water in the foam cools things down. They are good on solids and liquids and can work on gases if the foam is able to exclude the air from the gas Another advantage is that the foam will flow so they can sometimes be effective if applied remotely as to a bilge fire. They are larger, need to be applied properly to a liquid fire and require more maintenance because the foaming agent is often corrosive and the foam is based on water.

 

Water extinguishers are good on solid fires, generally lethal on liquids, useless on gas and OK on Low Voltage electrical fires (In a demo I have used a salt-water extinguisher on a live 440 volt electrical box. The safety trip went out at about 3 feet.) As with foam they effectively disrupt the fire triangle by cooling things down.

 

Best of all were Halon, which disrupted the chemistry of the burning process and worked on almost everything provided the gas was contained with the fire. They are banned now because of the Ozone layer damage from Halons.

 

The BSS, and its predecessors, drove the initial installation of fire extinguishers in a lot of boats on BW water. At the time, powder extinguishers were readily available, small and easy to understand so they they became the item of choice. Since then better (AFFF) foam has become available and some foam extinguishers are rated for A and B fires so can comply with the BSS as Rob has said.

 

What you really need depends on your fire risks. I have a mixture, including CO2 for the electrical space and engine 'ole, because I know that CO2 is best for electrical fires and would support a foam extinguisher in dealing with a fire beneath the engine, which is a somewhat oily and incontinent beast. Dry powder and foam are in the living spaces because they will sort out the fires that might happen there. If all else fails there is usually some water outside.

 

All fires make a filthy mess, regardless of why or how they are put out. Prevention is a much better opttion. When was the last time you really looked at what might catch fire in your boat and what you could do to stop it?

 

Regards

 

BEngs

[BlueStringPudding]

So it could be filled with blanmange as long as it is certified to the correct rating with the correct markings etc.

 

Where can I get one of those? Does it come in strawberry flavour?

[bristol & argo]

Somthing ive wondered for a while, why do boats always have drypower extinguishers?

- Ive had a skim though the bss read book, and cant find anything that states they must be of this type, and as far as i can see an equivalently rated foam extinguisher would be just as allowable?

 

Have i missed somthing?

- I mean, you cant have CO2 becuase of the confined space issue but foam would seam a good bet to me at times, or even water just for solid fuel fires?

Daniel

 

We've allways had a Big CO2 as an extra (as it came with the boat)

We only have two dry powder, one in the boatmans cabin due to the size, one in the engine room since it will stick to any diesel fire.

The cabin has two 9l AFFF extinguishers. Theres no way i will have Dry Powder in the cabin as if you have to use it, and it doesn't work, you might not find your way out through the cloud!!!

 

If you look on the Underground in London you don't find any Dry Powder for that reason.

 

Simon

[Alastair]

BEngo, you seem to know what you are talking about!

 

I have a mixture - dry powder, water and CO2 (in the engine room).

 

BTW, how did you come by your boat name? Most people in the uk have never heard of Jarrah.