What condition does NOT contribute to dust becoming explosive?

Excess humidity is the condition that does not contribute to dust becoming explosive. In dust explosion scenarios, the physical properties and environmental conditions play significant roles.

When humidity is high, it can lead to the agglomeration of dust particles, causing them to clump together rather than remain dispersed. For a dust explosion to occur, a fine suspension of dust in the air is necessary, as this enables the particles to interact with oxygen and reach the required ignition point. Therefore, excessive moisture acts to reduce the likelihood of dust becoming airborne and can inhibit the conditions necessary for an explosion.

In contrast, particle size, ignition energy, and dispersal are essential factors in the explosiveness of dust. Smaller particles tend to have a larger surface area relative to their volume, making them more reactive. Ignition energy refers to the amount of energy required to ignite a dust particle cloud; lower ignition energy makes a dust mixture more susceptible to explosions. Dispersal is critical for forming a combustible dust cloud; without proper dispersal, dust may not form an ignitable atmosphere.