MAN MADE VITREOUS FIBRES
LABORATORY
The classification of man-made vitreous fibers (MMVF) is carried out in accordance with the guidelines of the Italian Ministry of Health by measuring the length-weighted geometric mean diameter of the fibers minus two standard errors (DLG–2ES) and the percentage of alkali and alkaline earth oxides (Regulation CE No. 761/2009, European ECB Method), using Scanning Electron Microscopy and chemical microanalysis (SEM-EDS).
Man-made vitreous fibers (MMVF) constitute a group of inorganic fibers used as insulation materials in various industrial products (furnaces, piping, foundry molds, insulating panels, roofing...). The MMVF group includes the following types of fibers, differentiated on the basis of chemical composition and intended use: insulation wool, glass wool, special-purpose fibers, rock wool, slag wool, refractory ceramic fibers, alkaline earth silicate wool, and HT wool.
For regulatory classification, SEM analysis is required to measure the length-weighted geometric mean diameter minus two standard errors (DLG–2ES) and the percentage of alkali and alkaline earth oxides (Na2O, K2O, CaO, MgO, BaO), assigning MMVFs to three possible categories:
Non-hazardous fibers exempt from classification (DLG–2ES > 6 µm)
Category 2: fibers suspected of causing cancer (DLG–2ES < 6 µm, alkali and alkaline earth oxides > 18%)
Category 1B: hazardous fibers (DLG–2ES < 6 µm, alkali and alkaline earth oxides < 18%)
Measurement using the SEM-EDS technique of the length-weighted mean geometric diameter minus two standard errors (DLG-2ES) of man-made vitreous fibers (MMVF) and the percentage of alkali and alkaline-earth oxides.
Collection of airborne man-made vitreous fibers from emissions and workplace environments using high- and low-flow samplers, monitoring of workstations and personnel to assess occupational fiber exposure.
Analysis using phase contrast optical microscopy (PCOM) for the determination of total airborne fibers according to the guidelines reported in italian DM 6.9.94, Annex 2A.