fire extinguishers in motorsport

[NEILPRICE]

hi,
I am trying to find information on afff extinguishers used in motorsport, reasons why they are used and technical information about them.

thanks

[AnthonyB]

Are you referring to plumbed in systems fitted to vehicles or the portables used trackside?

A summary of the different requirements for different MSA & FIA motor events is on this manufacturers site: http://www.lifeline-fire.co.uk/extinguisher/regulations.htm

For many years halon was the main installed extinguishing agent in motorsport as it was very effective in small quantities (thus saving on weight and space), penetrated and flooded  the engine compartments easily, had a quick knockdown, and was non damaging. However halon was found to have an extremely high ozone depleting potential & thus became subject to various legislation around the world. Voluntary phasing out started in the 90's, however motorsport held onto it's use for quite a while due to the trouble of finding a suitable replacement. It is now illegal in the UK (with some very few exceptions)

AFFF & more recently "clean agent" has become the replacement agent. Powder is normally prohibited for in car use. As to why AFFF, ask the MSA. But AFFF cools the fire well, will not cause vision problems, allows partial extinction as oppose to "all or nothing" and in fine spray/mist is reasonably quick on shallow fires.

Trackside in the UK a dual agent approach is used. Dry Powder (ideally Monnex or at least Purple K, but generally due to cost normal ABC Powder is often used) extinguishers are used for initial attack to ensure rapid knockdown to prevent spread and protect the driver. This is followed up by AFFF which will cool hot metal and seal any spilt fuel to prevent re-ignition. Most of the rest of the world just uses powder. A high standard of training is required as poor use of extinguishers trackside has had horrendous rsults over the years and I have several clips in my library illustrating the fact

[fireftrm]

AFFF is used in vehicles instead of Dry Powder due to the severe loss of visibility that the operation of DP causes. The adoption of AFFF as the most suitable (in the abscence of the beloved Halon) is logical. The MOT requirementrs for all buses (Class V I think) requires a water based extinguisher with a rating of 8A or 21B, the relevant water extinguisher is 6 or 9L being 13A (I am not aware of an 8A extinguisher itself). A 1L AFFF gives 5A 21B so is acceptable in fire rating, however BSEN3 does not recognise this size, a 2L AFFF gives 8A 55B so is more than adequate. Most of the sensible taxi licencing authorities have adopted the same requirements and I have no doubt that any motor sport body would be unlikely to stray either.

[AnthonyB]

Motor sport is far more strict in sizes than the PSV or Minibus Regs, an goes by capacity rather than rating. Also plumbed in systems are common and equipment generally must be FIA homologated. The design of the extinguishers usually differs too

The PCV & Minibus regs were written in the early 80's and BS5423 & the multitude of predecesors (BS1382, 138, 3709, etc) were still in force. In those days a 6 litre water (or even a 4.5litre/1 gallon) could only achieve 13A.

it's quite possible (& I've seen it) for a bus to have a 6 or 9 litre water or foam branchpipe extinguisher and be legit.
1 litre foams are still widely made and used as they meet the PCV regs (EN3 not mandatory for this use) and they take up the same space as the 1.5 kg halons previously used thus being handy for existing vehicles with limited size extinguisher compartments.

Motorsport and road vehicles requirements canbe very different and you are advised to check with the MSa and your local circuit/club (certain competitions exceed MSA/FIA  minimums in their requirements).
AFFF in motorsport is facing a strengthing challenge from new gaseous clean agents.

[fireftrm]

PCV regs state manufactured to BS EN3 or BS5423, not seen either ona 1L AFFF manufactured since 1998. EN3 approval is not mandatory but the marking that it was manufactured to the standard is............. it never could be as EN3 does not recognise 1L AFFF, a failing that should be addressed, now where are the manufacturers (standard writers) on this?

6 and 9L water or foam would be legit, they are both well above the requirement so no reason why they would not be, however obvioulsy a very inventive extinguisher salesperson ensured the sale, no doubt using the 8A, water based requirement as the rule. So many salespersons must have tried to demonstrate the reason for their product based on the 8A AND 21B, not 8A OR 21B!