IEC 60794-1-219:2021 applies to optical fibre cables for use with telecommunication equipment and devices employing similar techniques, as well as hybrid telecommunication cables having a combination of both optical fibres and electrical conductors. The object of this document is to define test procedures to be used in establishing uniform requirements for the material compatibility performance of cables, cable components, and cable subassemblies. Compatibility of materials within a cable has the potential to involve a range of material pairs. However, experience has shown that the most pertinent evaluations are of the cable filling and flooding materials' interactions with other materials in the cable. NOTE Throughout the document the wording "optical cable" can also include optical fibre units, microduct fibre units, etc. See IEC 60794-1-2 for general requirements and definitions, as well as for a reference guide to test methods of all types.