# sieves

Sieves are a very ancient tool, at least as old as the open weave baskets used to separate grain from refuse. A later more sophisticated sieve was the medieval miller's bolting cloth. Even more precise sieves began to be made during the Industrial Revolution. In 1800, for example, to extend the supply of grain during an agricultural crisis the king of England forbade the baking of bread with flour that would pass through a sieve with 13 wires on each side of a square inch. (41 George III c 16, 1800)

Many occupations are concerned with the size of large numbers of small objects, such as grain, seeds or soil particles. If a graded series of sieves is available, a batch can be shaken through a stack of sieves with increasingly smaller holes. Weighing the amount left behind in each sieve gives a series of masses which is a size distribution for the particles in the batch. In such situations it is more accurate to describe the sizes of the particles in sieve numbers, rather than as particle diameters. For an example of how sieve numbers are used to grade a commercial product, see abrasives.

The sieves used in industry and the laboratory are precision products. The smaller the particle that is not to pass through the sieve, the finer the wires of the sieve–but despite that, the smaller the proportion of the sieve's area which is hole.

Test sieve
apertures
ISO
(See note 1.)
U.S. Alternate sieve designations,
a survival of an older system.
Mesh sizes are roughly
the number of openings per inch.
Tyler Screen Scale
Equivalent
Designation
125 mm 5 inches
106 mm (4.24 inches)
100 mm 4 inches
90 mm 3½ inches
75 mm 3 inches
63 mm 2½ inches
53 mm 2.12 inches
50 mm 2 inches
45 mm 1¾ inches
37.5 mm 1½ inches
31.5 mm 1¼ inches
26.5 mm 1.06 inches
25.00 mm 1 inch
19.00 mm 3/4 inch 0.742″
16.00 mm 5/8 inch 0.624″
14.00 mm (0.53 inch)
13.20 mm
12.50 mm ½ inch
11.20 mm (7/16 inch)
10.00 mm
9.50 mm 3/8 inch 0.371"
9.00 mm
8.00 mm 5/16 inch 2½ mesh
7.10 mm
6.70 mm (0.265)
6.30 mm ¼ inch
Fine Sieves
5.6 mm #3½ mesh 3½ mesh
5.00 mm
4.75 mm #4 4
4.50 mm
4.00 mm #5 5
3.55 mm
3.35 mm #6 6
3.15 mm
2.80 mm #7 7
2.50 mm
2.36 mm #8 8
2.24 mm
2.00 mm #10 9
1.80 mm
1.70 mm #12 10
1.60 mm
1.40 mm #14 12
1.25 mm
1.18 mm #16 14
1.12 mm
1.00 mm #18 16
900 µm
850 �m #20 20
800 �m
710 �m #25 24
630 �m
600 �m #30 28
560 �m
500 �m #35 32
450 �m
425 �m #40 35
400 �m
355 �m #45 42
315 �m
300 �m #50 48
280 �m
250 �m #60 60
224 �m
212 �m #70 65
200 �m
180 �m #80 80
160 �m
150 �m #100 100
140 �m
125 �m #120 115
112 �m
106 �m #140 150
100 �m
90 �m #170 170
80 �m
75 �m #200 200
71 �m
63 �m #230 250
56 �m
53 �m #270 270
50 �m
45 �m #325 325
40 �m
38 �m #400 400
36 �m
32 �m #450
28 �m
25 �m #500 500
22 �m
20 �m #635 625
15 �m   800
10 �m   1250
5 �m   2500

Notes:

(1) The ratio between adjacent sizes is the fourth root of 2, so the aperture size doubles every 5th size. Red lettering identifies sizes in common use in the United States that are ASTM supplementary values.

## Standards

ASTM E-11.

ANSI Z23.1.

AASHO M92.

Federal Spec. RR-S-366b.

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