This International Standard specifies a System of porosity
grading, classifying and designating laboratory sintered (fritted)
filters by the determination of pore size index.
lt is applicable to laboratory filters made of glass, vitreous silica,
ceramics, metals and plastic materials.
Test methods are included in annexes B and C for the determination
of air permeability and uniformity of pore size, but
these characteristics do not form part of the requirements of
this International Standard.