Annex to sections 4.1.2 and 4.3.3 of the Quality and Testing Regulations

The permitted tolerance range of the chemical composition of a fibre in the case of verification is defined according to the intraperitoneal test or the intratracheal test as follows:

19 % ≤ X permitted tolerance ± 2 %

2% ≤ X < 19 % permitted tolerance ± 1.5%

X < 2 % permitted tolerance ± 1 %


1. X is the content by weight (%w/w) of the relevant oxide of the glass composition.

The oxides of the relevant elements shall be stated as follows: SiO2, B2O3, Na2O, K2O, MgO, CaO, Al2O3, Fe2O3, TiO2, SO3, BaO, SrO, P2O5, Cr2O3, MnO, PbO, ZnO, ZrO2. 

2. In the chemical analysis, the standard deviation shall be stated for each oxide.

3. When checking the tolerance range, the oxides of calcium and magnesium and of sodium and potassium are treated as sum Σ, Σ (CaO + MgO) or Σ (Na2O + K2O); the other oxides are checked individually.

4. Sum Σ of the oxides determined individually by analysis must be 100%; 98% ≤ Σ ≤ 101% is permitted as the tolerance range.

5. The loss on ignition (at 550° C for 30 minutes) shall be determined.