Object
The purpose of this test is to determine the ability of an optical fiber cable or cable element to withstand bending when wrapped and unwrapped around a test mandrel.
Note: This test may be performed at any specified temperature, including the low or high temperature limits defined for the cable.

Apparatus
A single mandrel apparatus shall allow the cable sample to be wrapped tangentially in a close helix around the test mandrel under controlled tension.

Procedure 1 – Test Method E11A (Standard Test Procedure)
The sample shall be wrapped in a close helix around the mandrel at a uniform rate, applying sufficient tension to ensure that it conforms closely to the mandrel surface. The sample shall then be unwrapped.

Test Method E11A specifies the use of the apparatus shown in Figure 14a1, where the total number of coils in the helix is defined. Alternatively, the apparatus shown in Figure 14a2 may be used, which applies two helices (twice the number of coils). When using the Figure 14a2 setup, the number of mandrel turns shall be half of those specified to maintain the correct total number of coils.

When using the Figure 14a1 apparatus, the cable shall be applied without twists in the helix.
One test cycle consists of one wrapping and one unwrapping operation.

The mandrel diameter, number of turns per helix, and number of cycles shall be specified in the detail specification. The test shall be conducted at the specified temperature.

Requirements
Acceptance criteria shall be in accordance with the detail specification. Typical failure modes include:

• Loss of optical continuity
• Degradation of optical transmittance
• Physical damage to the cable structure