Posted By Peter Younger
As part of a review of my fire safety management, myself and a work colleague attended a refresher course on fire safety management run by a well renowned national provider. During the days training, the course instructor ( an ex brigade fire safety officer) stated that AFFF where a far more efficient extinguisher for electrical fires, and where tested and safe on voltages up to 35000 volts. This immediately drew my interest, as I could then use the same kind of extinguishers right across the business, without the confusion of what puts out what! Having then run it past the fire safety officer at my local station, he stated he preferred the use of CO2 on electrical fires, but confessed that he was not sure. Opinions and suggestions, would be much appreciated

Posted By David Bruce
I may be wrong but I thought there was a possiblity that the foam could conduct electricity and therefore cause electric shock. Additionally, in the event of small electrical fire, would C02 not cause signficant less damage to the building finishes and surrounding equipment than foam?

Posted By Peter Younger
To continue with the debate. My course instructor stated that it was the suppliers of extinguishers that stick by the rule that CO2 is only suitable for electrical fires, thereby selling more extinguishers. Foam is apparently non conducting

Posted By WTaylor
AFFF is essentially water with an additive. I agree that it's foreseeable that the water will pool on the floor and possibly conduct the electricity to the user. It may be a good idea to check with your extinguisher manufacturer and get the technical data on the conductivity!

Also, you should consider the difficulty you may have when using a foam extinguisher on electrical applicances. If the fire is contained inside of a closed unit or box, it helps if the extinguishing agent actually penetrates the casing to the fire inside. A CO2 would be far more effective as it can be fired through gaps in the casing or through ventilation panels.

And let's not forget that the first thing you should do with an electrical fire is turn off the electricity. That will stop the fire 9 times out of 10 (as long as you catch it early enough). A CO2 extinguisher may put it out temporarily, but if you leave the power on the fire will just start again!

Kind regards,

Will

Posted By Rob Hughes
I have heard that you could use a foam extinguisher on an electrical fire and the reason in some cases it has passed the test is due to the electricity not passing up the stream coming from the extinguisher to the user as the foam is aspirated via the nozel. However, as mentioned in previous posts this does not stop it pooling on the floor and potentially reaching the user.
Also I think you could be on sticky ground if the extinguisher was clear on what it can be used for and specifically if electrical fires are not covered.
The extinguishers in place must relate to the potential fire risks and remember that it is now a specific legal requirement to undertake training on fire.

Posted By shaun mckeever
I cannot believe we are having this debate!

Some foam extinguishgers, specifically spray foam extinguishers, are safe if accidentally discharged onto electrical fires up to 35kV.

If you know what you are doing, you can even use water for tackling electrical fires. Firefighters are trained at the fire service college in using water to extinguish electrical fires, but only in specific circumstances and only if correctly applied as a spray.

I would not recommend the use of water based extinguishers as the norm for tackling electrical fires particularly where the user is unlikely to be trained to the same standard as professional firefighters.

Use dry powder or CO2 but not water or foam.

Posted By Robert K Lewis
You will find that foam is more effective in the open air than powder or CO2 for electrical fires but as Ashley states the problem is the secondary materials involved thus CO2 and powder abilities to extinguish are stretched to the limit. Electricity without combustible materials will not provide a stable fire - only an electrical discharge. Neither CO2 nor powder have significant cooling effect - they merely reduces the O2 level at the fire point and thus rely on confinement to be fully effective.

In general terms AFFF, please distinguish this from chemical foam as they are not the same thing, has many advantages - They are 1/3rd smaller for the same fire rating and thus easier to manage weight wise. They will also not conduct electrical power through the spray. As an all round extinguisher they are thus much to be preferred and are much better than water alone. This does not mean CO2 is defunct - if you have electrical equipment that catches fire and the air movement is low then they have a role to play. My choice always rests on these two with occasional placement of Powder in open situations external to the building.

Bob

Posted By Richie Wilson
If only B.C.F. wre still about CO2 is one of the most overated media ever. Check your foams carefully as there are several to choose from ie, FFFP, AFFP, AFFF Protien and alchohol based foams and generaly there is no mention of the foam type used in the extinguishers.

Posted By Andrew Joule Land

I thought that the term "electrical Fire" had been defunct for years. There are fires that involve electrical energy source. and if this is the case as far as is practicable this energy source should have been removed by a safety device e.g. fuse RCD Etc.
If it is thought that through neglect or and unsafe act that has taken place to defeat safety devices ISOLATE EQUIPMENT FROM ALL ENERGY SOURCES BEFORE YOU TACKLE A FIRE -
Then at no risk to yourself attack the fire IF YOU HAVE BEEN TRAINED TO DO SO if not raise the alarm by the company recognised method evacuate to a designated safe place making sure you shut doors etc behind you to limit the spread of fire the leave it to the professionals.

The use of inert gas drenching is preferred by engineers to enable salvage of equipment. Dry powder is great for knocking FIRE out but used internally you have the problem of dust Clouding.
CO2 knocks out flame but is not to good at cooling down the fire source so there is a risk of re ignition.
There are the other risks with CO2
The Person who attacks the fire may try and open cabinet or other covers to enable them to reach the fire source - backflash - injuries thus making the situation worse becase now you have a casualty.
DONT BECOME PART OF THE PROBLEM
Attachments can be procured for extinguishers and electrical energy sourced equipment so that you can inject the inert gas into cabinets etc. without having to open them up. but again this would be operated by specially trained staff.

There are to many dead and maimed heroes already.

I don't consider the advice given by the fire trainer very good for average staff who would normally only be expected to deal with minor fires - I think he fell into the trap of many instructors from a "profession" in the assumption that their students are already "semi professional"

as always - Personal View.

Posted By Ken Taylor
As far as portable extinguishers go, CO2 gets into the electrical works and puts the fire out rather well. OK, so there is the issue with very confined spaces where O2 is displaced - but the fire is also depleting the O2 at a pace in addition to producing toxic combustion products. I'd like to be very sure of complete electrical isolation before applying water from a portable!