ISO 14644-1:2015 4.4: State the full designation: class, occupancy state and considered sizes, with a size ratio of at least 1,5

What does 4.4 require?

The full designation for a room or zone brings together the ISO Class number written as ISO Class N, the occupancy state the classification applies to, and the particle size or sizes considered. When more than one size is measured, each larger diameter must be at least one and a half times the next smaller one.