This document specifies the determination of the size-weighted fine fraction (SWFF) and the size-weighted fine fraction of crystalline silica (SWFFCS) in bulk materials by calculation. The document also specifies the assumptions and preconditions to be fulfilled for this method to be valid.
The purpose of this document is to allow users to evaluate bulk materials regarding their size-weighted fine fraction and crystalline silica content.
NOTE For preparation of the sample and determination of crystalline silica by X-ray Powder Diffractometry (XRD) or Fourier Transform Infrared Spectroscopy (FT-IR), see EN 17289-1.
The calculation method is applicable only after experiments have shown that the results are accurate and consistently equal or higher than the results from sedimentation, as specified in EN 17289 3, for that particular bulk material.
A specific method for the evaluation of the SWFF for diatomaceous earth bulk materials is given in Annex A. Due to the internal porosity of diatomaceous earth, the general instructions given in this document are adapted in order to take into account the material’s effective density.
This document is applicable for crystalline silica containing bulk materials which have been fully investigated and validated for the evaluation of the size-weighted fine fraction and crystalline silica.