What is a dust explosion?

A dust explosion refers to an event that occurs when fine particles of combustible dust suspended in the air ignite, resulting in a rapid expansion of gas and heat. The correct choice identifies this series of combustible dust explosions that can occur under specific conditions. These conditions typically include a confined space, an adequate concentration of dust in the air, and a source of ignition.

In practice, once the dust particles are dispersed in the air, they can ignite when exposed to a spark, flame, or other ignition sources. This initial ignition can lead to a secondary explosion if the initial explosion sends more dust into the air, creating a chain reaction of further explosions. The phenomenon is particularly hazardous in industrial settings where various types of dust, such as flour, sugar, coal, or metal dust, can accumulate.

Understanding this process is critical in industrial safety to mitigate risks and implement control measures to prevent such explosive incidents. The other options describe related but distinct concepts, emphasizing that a dust explosion is specifically tied to the dynamics of combustible dust in a flammable environment.