U.S. Standard Specifications

Newark Wire Cloth manufactures testing sieves in both the U.S. Standard ASTM E-II specification and the Market Grade series.

Testing Sieves conforming to the ASTM E-II. specification combine the former 'coarse' and 'fine' series into one comprehensive listing.

This specification stipulates that sieves having aperture openings one millimeter and larger be identified by the opening sit expressed in millimeters, and sieves having an aperture smaller than one millimeter be identified by the opening size expressed in microns.

This series was derived from the "Fourth Root of Two" mathematical calculation, as explained below:

The National Bureau of Standards developed-  the sieve numbering system for U. S. Standard Testing Sieves based on the "fourth root of two" ratio. Sieve openings are exact geometric series in the ratio "Fourth Root of Two". All Newark Standard Testing Sieves comply with this accepted "fourth root of two" ratio, which is equal to 1.189.

Sieve No. 18, which is the "base", has an opening of 0.0394 inches. Multiplying 0.0394 inches by 1.189 gives us 0.0469 inches, and that is the opening for the next sieve in the series, No. 16. Next, 0.0469 x 1.189 = 0.0555 inches, which is the opening for the next sieve, No. 14. This brings us to the reason why the ratio "Fourth Root of Two" , has been adopted. Squaring these openings gives the area of each opening -- and you will find that the area of No. 14 is fwice that of No. 18.

Sieve construction conforms to the latest revision of ASTM E-II. This revision takes advantage of the latest weaving technology. It extends the U.S. Standard series from its previous limit o a U.S. standard #400 (38 microns) through #635 (20 microns). Today's stringent controls placed on the woven wire cloth ensure greater sieving accuracy whether your using stainless steel or brass.

U.S Standard Series Testing Sieves

Sieve Designation Nominal
Sieve
Opening,
in.		 Permissible Variation
of Average
Opening from the
Standard Sieve
Designation		 Maximum
Opening
Size for Not
More than
5 percent of
Openings		 Maximum
Individual
Opening
 Nominal
Wire
Diameter
mm
Standard Alternative
125 mm 5 in. 5 +3.7 mm 130.0 mm 130.9 mm 8.0
106 mm 4.24 in. 4.24 +3.2 mm 110.2 mm 111.1 mm 6.40
*100 mm *4 in. 4 +3.0 mm 104.0 mm 104.8 mm 6.30
90 mm 3 1/2 in. 3.5 +2.7 mm 93.6 mm 94.4 mm 6.08
75 mm 3 in. 3 +2.2 mm 78.1 mm 78.7 mm 5.80
63 mm 2 1/2 in. 2.5 +1.9 mm 65.6 mm 66.2 mm 5.50
53 mm 2.12 in. 2.12 +1.6 mm 55.2 mm 55.7 mm 5.15
*50 mm *2 in. 2 +1.5 mm 52.1 mm 52.6 mm 5.05
45 mm 1 3/4 in. 1.75 +1.4 mm 46.9 mm 47.4 mm 4.85
37.5 mm 1 1/2 in. 1.5 +l.l mm 39.1 mm 39.5 mm 4.59
31.5 mm 1 1/4 in. 1.25 +1.0 mm 32.9 mm 33.2 mm 4.23
26.5 mm 1.06 in. 1.06 +0.8 mm 27.7 mm 28.0 mm 3.90
*25.0 mm *1 in. 1 +0.8 mm 26.1 mm 26.4 mm 3.80
22.4 mm **7/8 in. 0.875 +0.7 mm 23.4 mm 23.7 mm 3.50
19.0 mm 3/4 in. 0.75 +0.6 mm 19.9 mm 20.1 mm 3.30
16.0 mm 5/8 in. 0.625 +0.5 mm 16.7 mm 17.0 mm 3.00
13.2 mm 0.530 in. 0.53 +0.41 mm 13.83 mm 14.05 mm 2.75
*12.5 mm *1/2 in. 0.5 +0.39 mm 13. 10 mm 13.31 mm 2.67
11.2 mm **7/16 in. 0.438 +0.35 mm 11.75· mm 11.94 mm 2.45
9.5 mm 3/8 in. 0.375 +0.30 mm 9.97 mm 10.16 mm 2.27
8.0 mm 5/16 in. 0.312 +0.25 mm 8.41 mm 8.58 mm 2.07
6.7 mm 0.265 in. 0.265 +0.21 mm 7.05 mm 7.20 mm 1.87
*6.3 mm *1/4 in. 0.25 +0.20 mm 6.64 mm 6.78 mm 1.82
5.6 mm **No. 3 1/2 0.223 +0.18 mm 5.90 mm 6.04 mm 1.68
4.75 mm No. 4 0.187 +0.15 mm 5.02mm 5.14 1.54
4.00 mm **No. 5 0.157 +0.13 mm 4.23 mm 4.35 1.37
3.35 mm No.60 0.132 +0.11 mm 3.55 mm 3.66 mm 1.23
2.80 mm No. 70 0.111 +0.095 mm 2.975 mm 3.070 mm 1.10
2.36 mm No. 80 0.0937 +0.080 mm 2.515 mm 2.600 mm 1.00
2.00 mm **No. 10 0.0787 +0.070 mm 2.135 mm 2.215 mm 0.900
1.70 mm No. 12 0.0661 +0.60 mm 1.82 mm 1.89 0.81
1.40 mm **No. 14 0.0555 +0.50 mm 1.505 mm 1.565mm 0.725
1.18 mm No. 16 0.0469 +0.045 mm 1.27 mm 1.330mm 0.650
1.00 mm **No. 18 0.0394 +0.040 mm 1.080 mm 1.135 mm 0.580
850 µm No. 20 0.0331 +35 mm 925  µm 970  µm 0.510
710 µm **No. 25 0.0278 +30 mm 775  µm 815   µm 0.450
600 µm No. 30 0.0234 +25 mm 660  µm 695   µm 0.390
500 µm **No. 35 0.0197 +20 mm 550  µm 585   µm 0.340
425 µm No. 40 0.0165 +19 mm 471  µm 502   µm 0.290
355 µm **No. 45 0.0139 +16 mm 396  µm 425   µm 0.247
300 µm No. 50 0.0117 +14 mm 337  µm 363   µm 0.215
250 µm **No. 60 0.0098 +12 mm 283  µm 306   µm 0.180
212 µm No. 70 0.0083 +10 mm 242  µm 263   µm 0.152
180 µm **No. 80 0.007 +9 mm 207  µm 227   µm 0.131
150 µm No. 100 0.0059 +8 mm 174  µm 192   µm 0.110
125 µm **No. 120 0.0049 +7 mm 147 µm 163   µm 0.091
106 µm No. 140 0.0041 +6 mm 126  µm 141  µm 0.076
90 µm **No. 170 0.0035 +5 mm 108  µm 122   µm 0.064
75 µm No. 200 0.0029 +5 mm 91  µm 103   µm 0.053
63 µm **No. 230 0.0025 +4 mm 77  µm 89   µm 0.044
53 µm No. 270 0.0021 +4 mm 66  µm 76   µm 0.037
45 µm **No. 325 0.0017 +3 mm 57  µm 66   µm 0.03
38 µm No. 400 0.0015 +3 mm 48 µm 57   µm 0.025
32 µm No. 450 0.00126 +3 mm 42  µm 50  µm 0.028
25 µm No. 500 0.00098 +2 mm 34  µm 41 µm  0.025
20 µm No. 635 0.00079 +2 mm 29  µm 35  µm 0.020
Specific nominal wire diameters have been specified to produce a progressive relationship between seive openings and wire diameters throughout the entire series. * Standard designations correspondence to the values for test seive apertures recommended by the ISO and should be used when reporting seive tests outside the U.S. ** These seives are not in the standard series, but have been included because they are in common usage.