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Physical & Chemical properties

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The test substances FMMVF fibres are inorganic (of mineral origin) solid fibres with ca. 99.9% purity, they are odorless and their color varies between white to grey-green. This assessment was made based on the data received from the manufacturer's own data including MSDS.

Company data, a guideline test and a comparable to guideline study suggest that the melting point of FMMVF fibres varies within the range of ca. 680 °C to 1220 °C depending on the fibre type.

Company data and a peer-reviewed publication show that the density of FMVF fibres varies between ca. 2.4 to 2.9 g/cm³ depending on the fibre type.

Similarly the geometry of FMMVF fibres varies depending on the fibre type. In addition, it also depends whether the fibres are prepared for commercial use or for the experimental studies (e.g. rat respirable). For some 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.

It is evaluated that FMMVF fibres are highly insoluble in water. An ECHA publication entitled "Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance" also states that a fibre is a water insoluble particle with an aspect ratio (length/diameter>3) and diameter <100µm.

The end-point studies on boiling point, vapour pressure, and auto flammability of FMMVF fibres are waived based on an adaptation according to column 2 of Annex VII, as FMMVF fibres are inorganic solids with melting points above 680 °C. Similarly, the end-point studies on partition coefficient, flash point and stability in organic solvents and identity of relevant degradation products are also waived based on an adaptation according to column 2 of Annex VII, as FMMVF fibres are inorganic. On the other hand, for the end-point study on surface tension, the waiving is done based on an adaptation according to column 2 of Annex VII. Because surface activity is not expected or predicted based on the structure and surface activity is not a desired property of the material.

For the end-point study on flammability the justification for the waiving is that FMMVF fibres are of inorganic origin and manufactured at temperatures of approx. 1500°C (molten glass). The ignition at room temperature with a flame as required by EU test method A10 - Flammability (solids) - is therefore not possible, and thus the study is evaluated to be technically not feasible.

The end-point study on explosiveness is waived, as the study scientifically unjustified. The justification is that FMMVF fibres are of inorganic origin and manufactured at temperatures of approx. 1500°C (molten glass). Absence of certain reactive groups in the structural formula establishes beyond reasonable doubt that the substance is incapable of rapid decomposition with evolution of gases or release of heat (EU test method A14 - Explosive properties). Furthermore a bibliographic source entitled Bretherick's Handbook of Reactive Chemical Hazards (7th edition), Vol 1&2, Elsevier, 2007, is also consulted. In accordance with this authoritative handbook and the other information, it is evaluated that FMMVF fibres do not hold explosive potential.

The end-point study on oxidising properties is also waived as the study scientifically unjustified. FMMVF fibres are of inorganic origin and manufactured at temperatures of approx. 1500 °C (molten glass). The examination of the structural formula establishes beyond reasonable doubt that the substance is incapable of reacting exothermically with a combustible material. EU test method A17 - Oxidising properties (solids) is therefore not applicable. Furthermore, a bibliographic source entitled Bretherick's Handbook of Reactive Chemical Hazards (7th edition), Vol 1&2, Elsevier, 2007, is also consulted. In accordance with this authoritative handbook and the other information it is evaluated that FMMVF fibres do not hold an oxidative potential.

The end-point study on dissociation constant is waived, as the study scientifically unjustified. Dissociation is defined as being the reversible splitting into two or more chemical species which may be ionic (OECD guideline 112). FMMVF fibres are inorganic mineral fibers and highly insoluble in water. They will not dissociate in water, since the splitting of FMMVF in the different species is not reversible.

The end-point study on viscosity is waived as the study technically not feasible. The justification for the waiving is that FMMVF are inorganic solids and the relevant test methods are not applicable to the test substance.