(DCP) Dry Chemical Powder - Fire Extinguisher
A dry chemical extinguishing agent used on Class A, Class B and Class C fires are known as Monoammonium-phosphate, ABE powder, ABC Dry Chemical, Tri-class or Multi - purpose Dry Chemicals.
It uses a special liquid and silicone monoammonium phosphate powder. The ABC dry chemical is usually a mixture of monoammonium phosphate and ammonium sulfate, which is previously activated. The mixture between the two agents is 40-60%, 60-40%, or 90-10%, depending on local worldwide standards. The USGS uses a similar blend, called FOS Check G75F.
How does a Dry Chemical Powder fire Extinguisher work
General Uses - Dry chemical powder used on all classes of fire. Prevents chain reaction by smuggling. The pressure is generated by the gas cartridge stored inside the cylinder. Its force will remain for 2 minutes and can reach 10 - 15 feet.
Common combustible solids
It melts Class A fire at around 350 - 400 degrees F. Class A fires are caused by the burning of common combustible materials, such as wood, paper, or most plastics.Burning liquids and gases
The powder breaks the chain reaction of liquid and gas fire by coating the surface to which it is applied.These Class B in the American system; Classes B and C in European and Australian systems) include the burning of gasoline, oil, propane, and natural gas.
Electric fire
It is safe and effective for electric fire because it is a non-conductor of electricity. Wires connected to live electrical equipment (Class C in American systems; Class E in the Australian system) need to be outfitted with devices that will not return their energy to the user in case of water. Electricity can also cause other classes of fire.Chimney bomb
Chimney bombs are zip-lock bags or other small bags filled with ABC dry chemical powder.Chimney bombs are used by fire personnel to help extinguish chimney fires. Creosote, which is a by-product of incomplete burning of wood (usually due to chronic combustion-air insufficiency), is extinguished by the chain reaction caused by chimney bombs. The chimney bomb is first dropped directly down the chimney, where they explode when exposed to fire sediment and heat, releasing the powder.
Then, the draft of the natural chimney will transport the dried chemical powder to the shaft of the chimney, thus coating the creosote and eventually neutralizing the fire. Depending on how severe the fire is, the use of multiple chimney bombs may be necessary.
Chimney bombs can also be effective if they are opened and then the chimney is lowered. To make chimney bombs effective, it may be necessary to first open the chimney.
Improper Uses of Dry Chemical Powder
ABC dry chemical is improper for chlorine or oxidizer fires. The resulting chemical reaction can cause the explosion or breakdown of chemicals releasing toxic gases. On that time of case, water should be used.ABC Dry Chemical is unsuitable for certain metal fires (Class D) and does not have saponification characteristics and therefore should not be used on class fires.
ABC dry chemical has been found to be effective initially to prevent the combustion of oils or fats, although reuse of excess dry chemical may be necessary due to the possibility of re-flashing of oils or fats near or at their flash point.
The extinguisher of the A class is more effective in controlling fires that primarily involve vegetable oils because it causes chemical changes of oils or fats making re-flash less likely. When a class extinguisher is not available, the ABC Dry Chemical Extinguisher can be used carefully to control cooking oil or fat if the operator has the potential need to reapply more of the oil or fat regime. Be aware of (Class K).
Due to the corrosive properties of ABC dry chemistry, it is not recommended to be used around aircraft or sensitive equipment.
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