pHI size class | Size class diameters (mm) | Modelled riska | Risk range | |||||
---|---|---|---|---|---|---|---|---|
Minimum | Mid-range | Maximum | Minimum | Mid-range | Maximum | Within classification | Mid-range to mid-range | |
Smaller than thumb | 5b | 12.5 | 20 | 0.002 | 0.044 | 0.141 | 70.5× | NA |
Thumb-fist | 20 | 60 | 100 | 0.141 | 2.074 | 6.711 | 47.6× | 47.1× |
Fist-head | 100 | 175 | 250 | 6.711 | 20.286 | 41.180 | 6.1× | 9.8× |
Larger than head | 250 | 300c | NA | 41.180 | 59.177 | NA | ≫1.4× | 2.9× |