This International Standard specifies a method for the determination of the tensile breaking force and elongation at break of glass yarns taken from packages.

The method is applicable to various types of glass yarn (single, folded, cabled, strands, structures without twist, rovings, etc.). It is basically intended for single, folded and cabled glass yarns having a diameter of less than 2 mm, or a linear density lower than 2 000 tex, taken from packages. Heavier yarns may be also tested providing the test conditions are acceptable to all interested parties.

The method is not applicable to glass yarns which, in equilibrium with the standard atmosphere and under a pre-tension of 5 mN/tex, are elongated by more than 0,5 %. Such yarns can be tested using a lower pre-tension (for example 2,5 mN/tex or 1 mN/tex), acceptable to all interested parties. This would occur mainly when dealing with staple-fibre yarns.