IEC 60793-2-40-2021 OPTICAL FIBRES – Part 2-40: Product specifications – Sectional specification for category A4 multimode fibres. Test apparatus
The length of the sample between two clamping devices shall be between 1 00 mm and 200 mm.
The tensile strength measuring apparatus shall be a device, for example a vertical tensile tester, which provides relative motion to the test fibre. The apparatus shall be capable of imparting constant motion without jerking the fibre under test. The apparatus shall have the ability to simultaneously measure and record the resulting tensile force or load. To prevent fibre breakage, the means used to secure the fibre ends at the clamping points shall not stress the fibre excessively. Procedure
The tensile speed shall be 1 00 mm/min ± 1 0 %. Yield strength and yield elongation are obtained from the load-elongation curve described in Unless otherwise specified, tensile load at the yield peak and tensile load to induce 4 % elongation shall be recorded.
NOTE Elongation to breaking point is not applicable to category A4 fibres. Requirements
The requirements are stated in the family specifications found in Annex A to Annex J. If the fibre sample breaks at a clamping point, the test shall be regarded as invalid and another test shall be carried out. The number of samples tested shall be sufficient to allow for a statistical analysis.
4.3 Transmission requirements
Relevant transmission attributes and measurement methods are given in Table 8.
Additional attributes required in the family specifications are indicated in Table 9.
4.4 Environmental requirements
4.4.1 General
Environmental exposure tests and measurement methods are documented in two forms:
• relevant environmental attributes, test methods and test conditions given in Table 1 0;
• measurements of a particular mechanical and transmission attribute that may change during exposure to the environmental test listed in Table 1 1 .
These tests are normally conducted periodically as type-tests for a fibre design. Unless otherwise specified:
• the specimen shall be pre-conditioned by keeping it at standard atmospheric conditions for at least 24 h, and
• the recovery period allowed between the completion of the environmental exposure and measuring the attributes shall be as stated in the particular environmental test method.
Environmental exposure testing of subcategory A4a to A4e fibres are usually performed after the fibres are buffered (refer to IEC 60794-2-41 for environmental requirements on buffered fibres). Environmental exposure testing of unbuffered fibre is only required when the fibres are sold in unbuffered form.
4.4.2 Mechanical environmental requirements
Tensile strength shall be verified according to Table 1 2 following removal of the fibre from the environment but only after cooling down the specimen at standard atmospheric conditions.IEC 60793-2-40 pdf download.