Soil Particle Size Scales for Soil Classification Purposes
An important factor in soil classification presented in the upcoming pages is the soil particle size (grain size). Two scales are used for classification purposes of soil grain size: the US Sieve Series and the Tyler Equivalent. The table below presents the most common sieve mesh opening sizes for these two scales is presented in the table below.
Table:
The most common mesh opening sizes used for particle size classification purposes in the US [AZO Materials]
|
US Sieve Size
|
Tyler Equivalent
|
Mesh Opening
|
|
|
mm
|
in.
|
||
|
-
|
2 1/2 Mesh
|
8.00
|
0.312
|
|
-
|
3 Mesh
|
6.73
|
0.265
|
|
No. 3 1/2
|
3 1/2 Mesh
|
5.66
|
0.233
|
|
No. 4
|
4 Mesh
|
4.76
|
0.187
|
|
No. 5
|
5 Mesh
|
4.00
|
0.157
|
|
No. 6
|
6 Mesh
|
3.36
|
0.132
|
|
No. 7
|
7 Mesh
|
2.83
|
0.111
|
|
No. 8
|
8 Mesh
|
2.38
|
0.0937
|
|
No. 10
|
9 Mesh
|
2.00
|
0.0787
|
|
No. 12
|
10 Mesh
|
1.68
|
0.0661
|
|
No. 14
|
12 Mesh
|
1.41
|
0.0555
|
|
No. 16
|
14 Mesh
|
1.19
|
0.0469
|
|
No. 18
|
16 Mesh
|
1.00
|
0.0394
|
|
No. 20
|
20 Mesh
|
0.841
|
0.0331
|
|
No. 25
|
24 Mesh
|
0.707
|
0.0278
|
|
No. 30
|
28 Mesh
|
0.595
|
0.0234
|
|
No. 35
|
32 Mesh
|
0.500
|
0.0197
|
|
No. 40
|
35 Mesh
|
0.420
|
0.0165
|
|
No. 45
|
42 Mesh
|
0.354
|
0.0137
|
|
No. 50
|
48 Mesh
|
0.297
|
0.0117
|
|
No. 60
|
60 Mesh
|
0.250
|
0.0098
|
|
No. 70
|
65 Mesh
|
0.210
|
0.0083
|
|
No. 80
|
80 Mesh
|
0.177
|
0.0070
|
|
No. 100
|
100 Mesh
|
0.149
|
0.0059
|
|
No. 120
|
115 Mesh
|
0.125
|
0.0049
|
|
No. 140
|
150 Mesh
|
0.105
|
0.0041
|
|
No. 170
|
170 Mesh
|
0.088
|
0.0035
|
|
No. 200
|
200 Mesh
|
0.074
|
0.0029
|
|
No. 230
|
250 Mesh
|
0.063
|
0.0025
|
|
No. 270
|
270 Mesh
|
0.053
|
0.0021
|
|
No. 325
|
325 Mesh
|
0.044
|
0.0017
|
|
No. 400
|
400 Mesh
|
0.037
|
0.0015
|
