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Writer's pictureAntonia Z

Monoammonium phosphate - how does it work as a fire extinguisher?

Ammonium hydrogen phosphate (12-61-0) is the ammonium salt of phosphoric acid. The common names are monoammonium phosphate or MAP.


Industrial monoammonium phosphate (MAP) is a good flame retardant, fire extinguishing agent, widely used in wood, paper, fabric flame retardant, fiber processing and dye industry dispersant, glazing agent for enamel, fireproof paint matching agent, dry powder fire extinguishing agent.


Ammonium phosphate powder extinguishing agent (ABC dry powder)


Ammonium phosphate powder fire extinguishing agent (ABC dry powder) is a new type of dry powder fire extinguisher. Ammonium dihydrogen phosphate (NH4H2PO4) plays a key role in extinguishing the fire, and the rest of the auxiliary materials to prevent caking, additives and other functions. Ammonium phosphate dry powder extinguishing agent is more widely used than BC class dry powder extinguishing agent, in addition to the BC extinguishing agent extinguishing function, but also can extinguish A class solid fire; not only can extinguish plane fire, but also can extinguish three-dimensional space fire.


Ammonium phosphate dry powder extinguishing agent is mainly divided into three categories:


1) Ammonium phosphate or ammonium pyrophosphate as the base material of dry powder.


2) Ammonium phosphate or ammonium sulfate as the base material of the mixed dry powder.


3) Dry powder with ammonium polyphosphate salt as the base material.


How does monoammonium phosphate fire extinguisher work?


Ammonium phosphate is the centerpiece of ammonium phosphate dry powder extinguishing agent, ammonium phosphate physical and chemical properties of ammonium phosphate dry powder extinguishing agent performance have an important impact.


Asphyxiation, cooling, radiation, and chemical inhibition of flaming combustion is the concentration of ammonium phosphate dry powder fire extinguishing efficiency. Among them, chemical inhibition is the basic principle of fire extinguishing, play a key role in fire extinguishing. Ammonium dihydrogen phosphate in the combustion flame heat absorption decomposition of ammonia and phosphoric acid, followed by the generation of P2O5. Each step of the reaction is a heat-absorbing reaction, so there is a good cooling effect.


The free ammonia from decomposition can react with the OH radicals generated in the flame combustion reaction, reducing and terminating the free radicals generated by the combustion reaction and decreasing the rate of combustion reaction. When the concentration of free ammonia in the flame is high enough and the contact area with the flame is large enough, the rate of free radical abort is greater than the rate of combustion reaction generation, and the chain combustion reaction is terminated, resulting in flame extinction.


In addition, the decomposition of ammonium dihydrogen phosphate at high temperatures, in the solid material surface to generate a glassy film residual covering over the surface of the burning material, after cooling to form a brittle covering so that the burning surface and air isolation, when the covering reaches a certain thickness can prevent re-ignition.


Ammonium phosphate fire extinguisher features:


1. Wide applicability, it can put out A, B.C and electrical equipment fires. Such as warehouse fires have A class (B class) and electrical equipment fires, the choice of ammonium phosphate fire extinguishers, can meet the requirements.

2. Low toxicity. Its toxicity is second only to water fire extinguishers and foam fire extinguishers.


3. Small corrosive, its corrosive second only to gas fire extinguishers.


4. Good fire extinguishing performance, easy to operate.


5. Moderate price. Ammonium phosphate fire extinguishers in the warehouse application has a wide range of prospects for development.


In addition, Ammonium phosphate dry powder fire extinguishing agent because of high efficiency, speed, raw materials from a wide range of sources, non-toxic to the environment, humans, and animals, does not require special power and use a wide range of temperatures and other characteristics, has been very widely used.


Because of the multifunctional use of ammonium phosphate extinguishing agent, for the use of a single extinguishing agent to replace a variety of highly specialized extinguishing agent to provide greater convenience.




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