This part of IEC 60793 provides a practical method for evaluating fibre performance in a defined environment.

The purpose of this standard is to define a test that determines the suitability of sub-category A1a to A1d multimode fibres and class B and C single-mode fibres to withstand the environmental condition of immersion in distilled or demineralized water which may occur in actual use, storage and/or transport. The test is primarily intended to permit the observation of effects of immersion in water over a given period. This procedure is conducted in accordance with IEC 60068‑2‑18, Test R.