BS/EN 3745-404-2019 pdf download.Aerospace series – Fibres and cables, optical, aircraft use – Test methods
Part 404: Thermal shock.
This BS/EN 3745-404 specifies a method to determine the effects of thermal shock on an optical fibre or cable. 2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 2591-100, Aerospace series — Elements of electrical and optical connection — Test methods — Part 100: General
EN 3745-100, Aerospace series — Fibres and cables, optical, aircraft use — Test methods — Part 100: General
EN 3745-20 1, Aerospace series — Fibres and cables, optical, aircraft use — Test methods — Part 201: Visual examination
EN 3745-30 1,Aerospace series — Fibres and cables, optical, aircraft use — Test methods — Part 301: Attenuation
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
4 Preparation of specimens
4.1 If not at standard test conditions, the specimens shall be subjected to standard test conditions and stabilised at these conditions for 24 h as defined in EN 3745-100.
4.2 The following details shall be specified if not already included in the product standard:
• the number of specimens;
• the number of temperature cycles, if not four cycles;
• maximum permissible variation in attenuation;
• the upper and lower temperatures at which test is carried out;
• relative humidity during the test;
• diameter of the coil.
5 Apparatus
The test requires a suitable oven, a cold chamber capable of temperature control 0±2 °C, a Light Launch System (LLS) and Light Detector System (LDS) as defined in EN 2591-100. A device to control the relative humidity during the test may also be required.
6 Method
6.1 General
The specimen shall be coiled at all times and shall be arranged to be easily moved between the two temperature chambers. Once the sample is prepared, the attenuation reference measurement shall be taken in accordance with EN 3745-301 Method C.
The specimen shall then be subjected to the required higher temperature for a period of 30 mm. The specimen shall be removed from the oven and, within 2 mm, placed in the cold chamber at lower temperature for 30 mm. After the final chamber, bring the specimen back to the standard test conditions.
The duration shall be suflicient to allow the specimen to reach standard conditions.
6.2 Method A (discrete)
This method is used by default.
Attenuation shall be measured immediately after the cycle defined Clause 5, test in accordance with EN 3745-301, Method C.
The cycle shalt be carried out four times or the number of times specified in the product standard, on the same sample.
6.3 Method B (continuous)
This method is used if required by the product standard.
Attenuation shall be measured continuously from the beginning of the cycle to the end at a rate of
1 measure per 30 s as a maximum in accordance with EN 3745-301, Method C.
The cycle shall be carried out four times or the number of times specified in the product standard, on the
same sample.
6.4 Final measurements and requirements
The following shalt be carried out after the test:
• EN 3745-20 1: Visual examination;
• Method A:
• EN 3745-301: Attenuation, Method C, maximum change in attenuation shall be within that specified.
• Method B:
• EN 3745-30 1: Attenuation, Method C, maximum change in attenuation shall be within that specified during the cycles.BS/EN 3745-404-2019 pdf download.