Dry powder fire extinguisher fire extinguishing principle

Dry powder fire extinguishing agent is a dry and easy-flowing fine powder used for fire extinguishing. It is composed of inorganic salts with fire extinguishing effects and a small amount of additives that are dried, crushed, and mixed to form a fine solid powder. It is a fire extinguishing agent widely used in firefighting and is mainly used in fire extinguishers.
In addition to special dry powder chemical fire extinguishing agents for extinguishing metal fires, dry powder fire extinguishing agents are generally divided into two categories: BC dry powder fire extinguishing agents and ABC dry powder. Such as sodium bicarbonate dry powder, modified sodium salt dry powder, potassium salt dry powder, ammonium dihydrogen phosphate dry powder, diammonium hydrogen phosphate dry powder, phosphoric acid dry powder and amino dry powder fire extinguishing agent.
Dry powder fire extinguishing agents mainly extinguish fires through the physical and chemical effects that occur when the powder mist sprayed under the action of pressurized gas contacts and mixes with the flame:
First, the volatile decomposition products of the inorganic salts in the dry powder react chemically with the free radicals or active groups generated by the fuel during the combustion process and have side-catalytic effects, interrupting the combustion chain reaction and extinguishing the fire;
Second, the dry powder powder falls outside the surface of the combustible material, undergoes a chemical reaction, and forms a glass-like covering layer under the action of high temperature, thereby isolating oxygen and suffocating the fire. In addition, there is partial dilution of oxygen and cooling effects.