Test Sieve Sizes Conversion Between ASTM Standard and ISO/BS Standard
ASTM: American Society for Testing and Materials Standard
ISO/BS: International Organisation for Standardisation/British Standards
ASTM E11 and ISO 3310/BS 410 are the two most commonly applied standards that specify the technical requirements and corresponding test methods for test sieves. The technical requirements in the standards include sieve cloth used in the test sieves, the construction of test sieves, standard and non-standard test sieve frame sizes, and test procedures used to inspect sieve cloth and test sieves.
In ISO/BS standard, woven wire test sieves are designated by the nominal size of the apertures of the metal wire cloth. The aperture sizes are measured by the wire spacing. Nominal sizes of 1 mm and above are expressed in millimetres (mm); nominal aperture sizes below 1 mm are expressed in micrometres (μm).
In ASTM standard, the nominal sizes can be expressed in inches or in mesh numbers. Nominal aperture sizes above 1/4 inch (6.3 mm) are expressed in inches; nominal aperture sizes below 1/4 inch are expressed in numbers. The confusion for the end users normally comes from the mesh number expression. The mesh number stands for the number of wires or openings per linear inch (25.4 mm) counted from the centre of any wire to a point exactly in 1 inch (25.4 mm) distance.
For example, the NO.4 test sieves in ASTM standard is equivalent to 4.75mm test sieve in ISO/BS standard. The measuring method is shown in figure 1
End users can simply check the table below to convert mesh number into wire spacing (in mm or μm ). Download full standard size table for test sieve in PDF
1.BS410-1:2000 ISO 3310-1 International Standard Test sieves-Technical requirements and testing- Part1: test seives of metal wire cloth. (2000). Fourth edition 2000-07-15.
2.ASTM Standard E11-09 Specification for Woven Wire Test Sieve Clothes and Test Sieves. (2009).