Dry Powder extinguishers are DANGEROUS on yachts.

[oldharry]

Just come back from the annual mandatory Fire Training lecture the government insists we do.

I was astonished to hear the instructor say that Dry Powder exinguishers should NEVER be used in enclosed spaces. I asked if that included use below decks in a yacht: Yes they are now regarded as 'extremely dangerous' and totally unsuitable for that application, without a suitable filtration mask.

The reason? The operator needs to get fairly close to the fire for the extinguisher to be effective, and will be inside the cabin. There is a high risk of inhalation of the powder resulting in what he called 'porridge lung' - an extremely unpleasant and dangerous condition resulting from breathing in any quantity of airborne powder. Not just extinguishant, but any form of powder such as flour can do this apparently.

Now I find that very worrying, because as far as I can see nearly every extinguisher sold for use in boats is Dry Powder apart from specialist engine room auto extinguisher systems.

They would nowdays recommend CO2 - you can fill the cabin with it from outside and effectively stifle the fire. In a confined engine space it could be very effective, for example, and not risk damaging the engine if it is still running.

He also strongly recommended a new chemical extinguisher particularly for liquid fires - fuel or oil particularly, which is very effective and whose extinguisher feeds through a lance, which means the operator can be further away from the source of the fire.

I am no expert, but I pass this on for what it is worth, as I beleive most of us rely on Dry Powder extinguishers.

 

[Billjratt]

I would imagine CO2 would not leave the mess that powder does, so there's another plus.
Shame halon was outlawed...

 

[PilotWolf]

Have you any idea how large a CO2 extinguisher would need to be to fill a cabin? Not allowing for the fact that you would struggle to stop the gas leaking out everywhere too.

W.

 

[William_H]

CO2

Co2 does have a lot of cooling power as the gas moves from perhaps 150 bar to 1 bar.
However on the question of how much CO2 is in an extinguisher. My guess is to compare it to a SCUBA tank. typical smallish tank is called 100cuft. The scuba tank is usually at a higher pressure than CO2 extinguisher so a fairly big extinguisher might have 25 cuft of CO2.

If you had a fire in an engine compartment (sealed) that might have a volume of 4ft long 2ft high 3ft wide. or 24 cuft. So you put 25cuft of CO2 into 24cuft of space. Presumably you would dilute the oxygen by 50% assuming an even mix. This would certainly slow a fire down. But I imagine you would also be relying on the cooling power and perhaps localised concentration of CO2 at the fire. CO 2 being produced by the fire of course increasing concentration.

It means that a fire in the galley might need a lot more CO2 or a lot of luck in getting the CO2 right to the fire.

Are my assumptions any where near the mark. Does anyone know any more about it. Obviously CO2 works outdoors ie a burning racing car so what is going on? olewill

 

[DogWatch]

powder resulting in what he called 'porridge lung' - an extremely unpleasant and dangerous condition resulting from breathing in any quantity of airborne powder.

CO2 has a similar but often more lethal condition known as 'blue lung', fire has unfortunate side effects too.

I think we all have to work with a difficult environment and make the best compromise. For me that is lightweight powder extinguishers.

 

[nathanlee]

Am I just being simple here?

What about holding your breath? Gasp, extinguish, retreat to the cockpit, breath. Simple. Well, maybe not for you people with silly sized boats

Go back in after a few minutes and clean up, and oh how dry powder needs some cleaning.

 

[Csail]

Am I just being simple here?

What about holding your breath? Gasp, extinguish, retreat to the cockpit, breath. Simple. Well, maybe not for you people with silly sized boats

Go back in after a few minutes and clean up, and oh how dry powder needs some cleaning.

In the panic of your yacht on fire i doubt you could hold your breath, i guess a respirator next to the extinguisher may be better.

 

[oldsaltoz]

http://www.quick-fire.com/products-01.asp

 

[sailorman]

I would imagine CO2 would not leave the mess that powder does, so there's another plus.
Shame halon was outlawed...

some still have halon i think

 

[raggy]

Hmmm

You would have to carry a massive CO2 to fill the cabin with it????
I think i would rather risk breathing in a little powder than burning to death.
If you are worried you could simply buy some maskes place them in sandwich bags and tape them to your powder ones.

 

[maxi77]

http://www.quick-fire.com/products-01.asp

An interesting product, shame there doesn't seem to be any way of buying it.

 

[Ubergeekian]

Co2 does have a lot of cooling power as the gas moves from perhaps 150 bar to 1 bar.
However on the question of how much CO2 is in an extinguisher. My guess is to compare it to a SCUBA tank. typical smallish tank is called 100cuft. The scuba tank is usually at a higher pressure than CO2 extinguisher so a fairly big extinguisher might have 25 cuft of CO2.

B-i-i-i-i-i-g difference. Scuba tanks have gas in them, CO2 fire extinguishers have liquid. The standard handheld CO2 extinguisher is a 5kg one, which contains enough for 2 1/2 cubic metres of gas - that's 88 cubic feet.

 

[Kelpie]

B-i-i-i-i-i-g difference. Scuba tanks have gas in them, CO2 fire extinguishers have liquid. The standard handheld CO2 extinguisher is a 5kg one, which contains enough for 2 1/2 cubic metres of gas - that's 88 cubic feet.

OK that is confusing. I distincly remember my chemistry teacher telling me that CO2 was one of the few substances that does not really have a 'liquid' phase- it just sublimes form solid to gaseous. Hence you never find yourself slipping in a puddle of dry ice.

 

[savageseadog]

OK that is confusing. I distincly remember my chemistry teacher telling me that CO2 was one of the few substances that does not really have a 'liquid' phase- it just sublimes form solid to gaseous. Hence you never find yourself slipping in a puddle of dry ice.

There is a liquid phase at very high pressures. The CO2 in presurised bottles must be in solid form though.

 

[Salty John]

Don't go throwing away your dry powder extinguishers on the basis of this thread!
Actually the body has very effective systems for dealing with inhaled dust. I've never heard of porridge lung, despite a career in the design of grain processing facilities, but I do know that inhilation of flour dust is considered a very low health risk. If the chemical in a dry powder extinguisher is considered as hazardous as flour there is little to worry about.

There is a lot of scientific research on the effects of the inhilation of different sizes, shapes and composition of powder if you look for it - flour, talc and so on are considered very low risk as opposed to asbestos, for instance, which is considered very high risk.

Don't let the thought of the danger of inhaling the powder from an extinguisher influence your decision to use your extinguisher should circumstances demand it.


All in my opinion, of course, and in the interests of a balanced debate.

 

[Alfie168]

OK that is confusing. I distincly remember my chemistry teacher telling me that CO2 was one of the few substances that does not really have a 'liquid' phase- it just sublimes form solid to gaseous. Hence you never find yourself slipping in a puddle of dry ice.

Under pressure it is a liquid I am given to understand.

Tim

 

[RAI]

CO2 goes liquid under pressure and is liquid inside the fire extinguisher.

I am changing over to CO2 extinguishers as they are clean and don't carry a date stamp, - just weigh them to check their content. The mess that powder extinguishers make is very difficult to clean up. Each time one of my powder ones reaches its expiry/refurbish date, I buy a CO2 replacement.

 

[Gordonmc]

I have the usual mini dry power extinguishers stationed at the galley along with a fire blanket, but keep an industrial 5kg CO2 extinguisher in an open locker at the companionway. The theory goes that for a galley fire I would use the blanket and dry powder. If that doesn't do the job I would fill the cabin with CO2 from the cockpit. Similalrly if the fire was in the engine bay I would empty the CO2 into it.
That would have the advantage of stopping the engine without goosing it with dry powder 'cos if a fire did take hold the engine would be likely to race as it burned smoke adding to the woes.

 

[Ricd]

Of course we need to remember that CO2 is heavier than air and is very toxic at high concentrations - it kills instantly. Not sure i want the down below volume full of CO2 with no easy ventilation !

 

[lw395]

I've only once seen a CO2 extinguisher used on a fire, it spread the burning liquid and plastic over a wide area!
Any decent size fire will trash the boat with smoke residue anyway, the issue is to have enough effective extinguishers to hit it quickly. Powder ones are cheap, so you can reasonably have more of them, so respond quicker.
Do not forget the fire blanket it is more use in the most likely situation of a cooker fire.
Also being able to isolate volts, gas and fuel easily helps!
If you can remove the supply of electricity and fuel, a bucket of sea will deal with residual heat and smouldering.....