Screen British Standard sieves

Screen sizes are defined in two ways by a mesh size number for small sizes and by the actual size of opening in the screen for the larger sizes. There are several different standards in use for mesh size, and it is important to quote the particular standard used when specifying particle size ranges by mesh size. In the UK the appropriate British Standards should be used BS 410 and BS 1796. A comparison of the various international standard sieve mesh sizes is given in Volume 2, Chapter 1. 

Consulting the British Standards Screen Scale in Appendix 5, the nominal aperture sizes in micrometers are tabulated versus the weight retained. Then, the fractions retained on each of the sieves used in the test can be listed as percentage of the original test sample weight, and finally as the oversize cumulative percentages (i.e., running totals). The results of these calculations can be tabulated on a second table (Table 2.8). 

Lawn. Term used in the British pottery industry for a fine-mesh screen or sieve. In the past, makers of these lawns gave them somewhat arbitrary numbers they are now largely replaced by meshes conforming to British Standards. 

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