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Dry Powder Fire Extinguishers
Dry Powder Fire Extinguishers are extremely versatile, as they can
be used on Class A, B and C fires and electrical fires. As well
as being suitable for use with flammable liquids, they can also
be used on flammable gases, and the non-conductivity of the dry
powder makes them safe on electrical fires too.This versatility
and their effectiveness in extinguishing fires make them one of
the most popular fire extinguishers in the home, as well as the
workplace. Dry powder fire extinguishers are best all around choice
for common fire situations. They have an advantage over CO2 and
"clean agent" extinguishers in that they leave a blanket
of non-flammable material on the extinguished material which reduces
the likelihood of reignition. Although they also make a terrible
mess - but if the choice is a fire or a mess, take the mess!
 
Dry Powder Fire Extinguishers - How They Work
Dry powder fire extinguishers are filled with an inert solid (chemical
powder) and pressurised with a gas, usually nitrogen. Several different
powders can be used, most typically sodium bicarbonate, potassium
bicarbonate and monoammonium phosphate. Sodium bicarbonate is a
suitable powder because it decomposes at 158 degrees Fahrenheit
(70 Celsius) and releases carbon dioxide gas as it decomposes. The
carbon dioxide helps to block out the oxygen supply to the fire
and the powder forms a coat over the burning fuel, again sealing
it off from the oxygen supply. This interrupts the combustion cycle,
puts the fire out and prevents it from re-igniting. Monoammonium
phosphate is probably the most widespread powder used for workplace
dry powder fire extinguishers. As the powder decomposes it produces
'free radicals', (unpaired electrons) which interrupt the process
of combustion, together with the insulating skin that the powder
forms
Using fire extinguishers
1. The fire is small, contained and not spreading beyond its starting
point.
2. The exit is clear, there is no imminent peril and you can fight
the fire with your back to the exit.
3. You can stay low and avoid smoke.
4. The proper extinguisher is immediately at hand.
5. You have read the instructions and know how to use the extinguisher.
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DET-FIRE
ENGINEERING PTE LTD