ISO 5079:2020

This document specifies the method and conditions of test for the determination of the breaking force and elongation at break of individual fibres in the conditioned or wet state.
The determination of these fibre properties, when carried out on different kinds of testing equipment, will not generally give identical results. To avoid such differences, this document is restricted to the use of constant-rate-of-extension testing machine.
It is applicable to all fibres, including crimped fibres, provided that the length of fibre available enables the gauge length specified in this document.
NOTE    For natural fibres (especially wool and cotton), the breaking test most commonly performed is that of bundles of fibres (see ISO 3060 and IWTO 32-82).