Hello,

Portable Fire Extinguishers are governed by NFPA 10. Types of fires are classified by what is mainly burning such as "A" ordinary combustibles, "B" Flammable Liquids, "C" Electrical, "D" Combustible metals, and "K" Kitchen (cooking grease/oil)based fires. Each has their own type of extinguishing agents. Extinguisher classifications and ratings are based upon how much fire (in a laboratory setting) the amount of agent in the dispensing container will extinguish before empty. Simply a 2A rated extinguisher will extinguish 2X the fire as a 1A. An "ABC" rated extinguisher has an agent that will work on ABC class fires or sometimes called multi-purpose extinguisher. A multi-class agent extinguisher will carry a rating for each class of fire it is capable of extinguishing such as a "1A, 2BC". "Class C Electrical" fires mean a fire involving energized electrical equipment and we know this usually also involve Class A and B items burning also.

AFFF was explained by Dana and is normally rated an AB class extinguisher.

Advantages and differences would be based upon the intended use. NFPA 10 addresses this.

The "older" 2.5 gallon pressurized water (or hand pump) Class A extinguishers fell out of favor mainly due to their weight (water and container) as some of the general population could not lift them off wall brackets.

Old copper and brass (sometimes riveted seam construction) tank pressurized water extinguishers that used a sodium bicarbonate in water solution along with a small acid vial inside, which needed to be inverted to mix the two solutions that reacted and caused pressure to dispense the mix out a hose, were banned about 25 years ago (by the standard) as they had a propensity to explode from a too violent reaction of the mix along with corroded tanks, plugged fittings, etc.

Just some basics to share..................

Ted J. Pagels
FIREPROSe, LLC