The way to bio-soluble mineral wool: Regulatory aspects
Over the last 20 years, many new types of mineral wool have been developed by the mineral fibre industry in the European Union. During this period, the authorities' assessment of mineral wool has also changed. Below is a brief overview of the state of play.
What does the "carcinogenicity index" KI mean?
The KI was introduced in Germany in 1994 as an aid to differentiate fibre dusts from mineral wool for an occupational health assessment. This value should give an indication of the solubility of glassy silicate fibres in lung tissue. The AI is calculated from the difference between the sum of the mass contents (in %) of the oxides of sodium, potassium, boron, calcium, magnesium, barium and twice the mass content (in %) of aluminium oxide.
KI = Σ Na, K, B, Ca, Mg, Ba oxides - 2 x Al oxide
What has changed since 1994?
In 1997 the EU Directive 97/69 EC on the classification of artificial mineral fibres including mineral wool was adopted. It lays down binding criteria for the classification or non-classification of man-made mineral fibres as carcinogenic throughout Europe (legal classification). One of the four criteria refers to bio-solubility (Appendix 1 lists the criteria).
The KI is not a criterion under EU law.
Parallel to and in addition to the legal classification, three equal criteria have been defined in Germany which evaluate fibre dusts with regard to a carcinogenic effect for the interests of occupational health and safety. Accordingly, mineral wool (during production, processing and placing on the market) must fulfil one of the following three criteria. They are laid down in the Ordinance on Hazardous Substances and the Ordinance on the Prohibition of Chemicals:
1. a suitable intraperitoneal test has not shown any signs of excessive carcinogenicity,
2.the half-life after intratracheal instillation of 2 mg of a fibre suspension for fibres with a length greater than 5 micrometres, a diameter smaller than 3 micrometres and a length to diameter ratio greater than 3 to 1 (WHO fibres) is not more than 40 days,
3.the carcinogenicity index KI, which results from the difference between the sum of the mass contents (in %) of the oxides of sodium, potassium, boron, calcium, magnesium, barium and twice the mass content (in %) of aluminium oxide, is at least 40 for artificial mineral fibres.
Appendix 2 quotes the full text of Annex II No. 5 of the Hazardous Substances Ordinance.
Conclusions for the classification and evaluation of vitreous silicate fibres, in particular mineral wool
The Kanzerogenitätsindex KI is not a criterion for an exemption regarding the carcinogenicity of mineral wool according to EU law (legal classification).
Only in Germany is it one of three equally valid possible criteria for exemptions from the prohibitions under the Hazardous Substances Ordinance or the Chemicals Prohibition Ordinance.
The most important criterion under both EU law and German law is based on the biosolubility or biopersistence of the fibres.
According to the documents of the Gütegemeinschaft Mineralwolle, all mineral wool used in Germany for heat or sound insulation has been tested on the basis of a biopersistence test.
From this it can be seen that although the AI exists as a criterion for an approved fibre, this criterion has not prevailed with regard to the practical suitability of mineral wool. This also means that the assessment of a currently used fibre on the basis of the KI value does not correspond to the current state of knowledge.
Appendix
EU criteria, Note Q:
Classification as a carcinogen is not mandatory if it can be demonstrated that the substance meets one of the following conditions:
A short-term inhalation biopersistence test has shown that the weighted half-life of fibres longer than 20 µm is less than 10 days.
A short-term intratracheal biopersistence test has shown that the weighted half-life of fibres longer than 20 µm is less than 40 days.
In a suitable long-term inhalation test, no relevant pathogenicity or neoplastic changes were observed.
Appendix 2
(1) The following hazardous substances containing mineral fibres shall not be manufactured or used for thermal and acoustic insulation in building construction, including technical insulation, nor for ventilation systems:
1. artificial mineral fibres (artificially produced non-directional glassy (silicate) fibres with a total mass content of more than 18 % of the oxides of sodium, potassium, calcium, magnesium and barium),
2. preparations and products containing artificial mineral fibres with a total mass content of more than 0,1 %.
2. Paragraph 1 shall not apply if the artificial mineral fibres contain any of the following
Der KI wurde in Deutschland 1994 als Hilfsmittel eingeführt, um Faserstäube aus Mineralwollen für eine arbeitsmedizinische Bewertung differenzieren zu können. Dieser Wert sollte einen Anhalt für die Löslichkeit von glasigen, silicatischen Fasern im Lungengewebe geben. Rechnerisch wird der KI aus der Differenz zwischen der Summe der Massengehalte (in %) der Oxide von Natrium, Kalium, Bor, Calcium, Magnesium, Barium und dem doppelten Massengehalt (in %) von Aluminiumoxid bestimmt.
KI = Σ Na, K, B, Ca, Mg, Ba-Oxide - 2 x Al-Oxid