Which standard sieve number indicates materials that are considered combustible dust?

The standard sieve number that indicates materials considered as combustible dust is related to the particle size that can pose an explosion hazard when dispersed in air. In this context, a sieve number of 35 is recognized because it represents particles that are generally smaller than 500 micrometers but larger than 400 micrometers.

Particles within this size range have a higher tendency to remain airborne and can readily ignite if there are potential sources of ignition in their environment. These particles can accumulate and form dust layers, which when disturbed, can lead to an explosive atmosphere. Therefore, acknowledging this specific sieve number helps in identifying and managing materials that may lead to combustible dust incidents, emphasizing the importance of effective dust control measures in hazardous locations.

Sieve numbers like 20, 30, and 40 are linked to different particle sizes, some of which may not fall into the combustible dust category as clearly as the number 35 does, thus highlighting the unique considerations necessary for recognizing and mitigating fire and explosion risks associated with combustible dust.