IEC/TR 62048:2011(E) gives formulae to estimate the reliability of a fibre under a constant service stress. It is based on a power law for crack growth which is derived empirically. Reliability is expressed as an expected lifetime or as an expected failure rate. The main changes with respect to the previous edition are:
- correction to the FIT equation in addition to all call-outs and derivations;
- insertion of a new section explaining how to numerically calculate bends and tension;
- editorial corrections of inconsistencies.