Man-made vitreous (silicate) fibres with random orientation with alkaline and alkali earth oxides (Na2O+K2O+CaO+ MgO+BaO) content greater than 18% by weight and fulfilling one of the CLP Regulation Annex VI Note Q conditions

Particle size distribution (Granulometry)

Description of key information

It is shown that the geometry of MMVF note Q fibres varies depending on the fibre type. Fibre length and fibre thickness are the most important parameters related to the fibre granulometry. For commercial fibres the average fibre length (mm) range is 1.05 -1.52; max fibre length (mm) is 6.9 -17.2 and the fibre thickness varies within the range of 0.7 - 20.5 µm.

Length weighted arithmetic thickness: Average (D): 4.39 µm, 4.27 µm, 3.86 µm

Length weighted geometric thickness: Average (Dg): 3.86 µm, 3.78 µm, 3.48 µm

Additional information

Information received from the data owner companies is presented along with a comparable to guideline study on the particle size distribution of MMVF note Q fibres. Particle size distrubition of both commercial fibres and particle size of the fibres specifically prepared for a carcinogenicity study is presented.

Length weighted arithmetic thickness:

Average (D): 4.39 µm, 4.27 µm, 3.86 µm

Standard deviation: 2.28 µm, 2.37 µm, 1.83 µm

95% confidence interval: 4.17-4.61 µm , 4.03-4.50 µm, 3.71-4.07 µm

Specific area: 7181 cm²/cm³, 7167 cm²/cm³, 8420 cm²/cm³

Length weighted geometric thickness of the three fibre types:

Average (Dg): 3.86 µm, 3.78 µm, 3.48 µm

Average -2*stdev (calculated 2.5%-limit): 1.14 µm, 1.16 µm, 1.07 µm

Alternatively, particle size of the fibres specifically prepared for a carcinogenicity study is presented below. It is noted that the data presented below is not representative of the commercial material, while the above data is.

Geometry of MMVF note Q fibres

Parameter	Unit	Approximate range
L<5 μm	%	18-27
5<L<15 μm	%	43-52
15<L<30 μm	%	17-19
30<L<50 μm	%	6-9
L>50 μm	%	2-9