Are foam extinguishers best for most places?

[Manu_2000]

Why powder extinguishers are still sold? If AFFF is best... 

They told me that for general multirisk protection of shops offices or hotels powder is not recommended. 

What about for a home? 

Is it OK to install 2 x 6 litres AFFF and 1xCo2?can I have a 2kg powder in my car? Can I use foam spray on live electrical equipment up to 1000v at at least 1m?

Is AFFF toxic or carcinogenic? 

Is true that ABC powder does not extinguish well class A fires? Are water based models better at this? 

Thanks

[AnthonyB]

Powder still has it's place, some examples:

- Spill & running fuel fires, where foam can struggle

- Large fires requiring rapid knockdown

- Low temperature areas

- Class C fires where there are specialist staff to safely extinguish the flame and manage the resulting explosion risk

- Multi risk areas where the secondary damage & personnel risks have been assessed as tolerable.

Due to low cost it's still the most common multipurpose extinguisher for the home, although ABF Foam & Water Mist would also suit.

Quantities of foam & CO2 extinguishers are based on risk, fire rating & travel distances - in some cases you might have a fire point of 2 x foam and 1 x CO2

Extinguishers that have passed the 35kV test are suitable for direct use on electrical fires up to 1000V - it's a peculiarly British thing that they avoid pointing this out and prefer to sell a CO2 as well.

AFFF is an Irritant in concentrate (certain special blends are corrosive), but not a toxin or carcongenic. It's harmful to the aquatic environment and older blends were worse for the environment generally.

Water (or water and wetting agent) is the best Class A medium as it cools and soaks, however powder can be effective if the right type:

- BC Powder, usually an alkaline bicarbonate based medium is very limited on Class A as there is no cooling or smothering effect, just chemical inhibition, making it ineffective on anything but the smallest surface fire

- ABC Powder, usually an acidic ammonium based medium has a greater effectiveness on Class A fires as it fluxes when heated and sticks to burning embers having a smothering effect as well as inhibition. There is still a risk of re-ignition in deep seated fires