Abstract
IEC 60794-1-111: 2023 defines the test procedure to determine the ability of an optical fibre cable to withstand bending around a test mandrel. The primary purpose of this procedure is to measure the change in attenuation when the cable is bent around a test mandrel. A secondary purpose is to assess whether the cable has been physically damaged by bending. NOTE 1 This test can be utilized at any specified temperature, including the low or high temperature limits for the cable. NOTE 2 The bend test procedure for cable elements is specified in IEC 60794-1-301, method G1. This document partially cancels and replaces IEC 60794-1-21:2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 60794‑1‑21:2015:
a) the nominal sample length was newly specified as 10 m between the cable element fixing points at both ends, unless otherwise specified;
b) the number of turns on the mandrel in Figure 1 for the single-helix configuration were corrected to match the number of turns shown in the figure for the two-helix configuration;
c) requirements on the turnaround loop were added for method E11A, two-helix configuration;
d) the turnaround loop with the same diameter as the mandrel was taken into account for calculation of the number of turns of each helix for method E11A, two-helix configuration;
e) added a formula for calculation of the number of revolutions in each helix for method E11A, two-helix configuration;
f) added a description for the procedure when the turnaround loop diameter is larger than the mandrel diameter for method E11A, two-helix configuration;
g) all the figures were updated and the different components labelled;
h) added the attenuation monitoring equipment in 4.2 for the apparatus and the description to measure the change in attenuation in the test methods E11A and E11B;
i) added Clause 9 for details to be reported;
j) added Annex A showing an example of a special mandrel to perform the bend test according to method E11A, two-helix configuration;
k) added Annex B providing the rationale for the options of method E11A, two-helix configuration.
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