EN 3745-412:2022

EN 3745-412:2022 Overview

EN 3745-412:2022 is a European standard established by CEN that specifies test methods to evaluate the humidity resistance of optical fibres and cables designed for aerospace and aircraft applications. This standard is part of the Aerospace series focused on fibres and cables for aircraft use, ensuring optical components maintain performance under varying humidity and temperature conditions representative of in-service aerospace environments.

The standard supersedes the previous version EN 3745-412:2006 and aligns with other aerospace fibre optic standards for electrical and optical connection testing, attenuation, and visual examination. It was approved in May 2022 and mandates harmonized test procedures to ensure reliability and durability of optical cables exposed to humid conditions in aviation.

Key Topics in EN 3745-412:2022

• Purpose: Assess resistance to humidity-induced degradation for aerospace optical fibres and cables under controlled cycling of temperature and humidity.
• Specimen Preparation: Requires standardized specimen length (10 ± 1 m), coil radius, and stabilization at standard test conditions before testing.
• Test Apparatus:
  • Controlled temperature and humidity test chamber.
  • Light Launch System (LLS) and Light Detector System (LDS) for continuous attenuation monitoring.
• Test Method:
  • Multi-phase humidity cycling involving:
    • Rapid temperature increase to 65 ± 3°C with 95% relative humidity,
    • Holding phase maintaining these conditions for 6 hours,
    • Gradual temperature decrease to 38 ± 4°C while humidity stays above 85%.
  • Cycles repeated (default 56 cycles if unspecified).
• Evaluation Criteria:
  • Continuous attenuation measurement during test.
  • Post-test recovery and final attenuation measurement per EN 3745-301.
  • Visual inspection for physical damage per EN 3745-201.
  • Attenuation variation must not exceed limits specified in product standards.

Applications of EN 3745-412:2022

This standard is critical for manufacturers and quality control specialists involved with:

• Aerospace Optical Cable Manufacturing: Ensuring fibre optic cables used in aircraft remain reliable and functional in humid and varying temperature environments.
• Aircraft Systems Maintenance: Verifying the ongoing performance and durability of optical networking and communication cables exposed to cabin and environmental humidity fluctuations.
• Aerospace Component Qualification: Supporting certification processes for aircraft subsystems incorporating optical fibres meeting rigorous environmental resistance standards.
• Design Verification: Enabling designers to select and validate moisture-resistant optical fibres to improve longevity and system integrity.
• Environmental Testing Laboratories: Providing a repeatable, industry-recognized method for humidity resistance testing aligned with aerospace industry requirements.

Related Standards

EN 3745-412:2022 is part of a comprehensive series of aerospace optical fibre and cable standards, which include:

• EN 3745-100: General test methods for aerospace fibres and cables.
• EN 3745-201: Visual examination methods for optical fibres and cables.
• EN 3745-301: Attenuation measurement and monitoring test methods.
• EN 2591-100: Test methods for elements of electrical and optical connections in aerospace applications.
• EN 4533: Aerospace Fibre Optic Systems Handbook, providing additional guidance and best practices.

These interconnected standards provide a full framework for the assessment, qualification, and continued reliability of fibre optic systems used in aviation and space applications.

Keywords: EN 3745-412:2022, aerospace optical fibres, humidity resistance testing, optical cable humidity test, fibre optic aircraft cables, aerospace cable standards, optical cable attenuation, temperature humidity cycling, aerospace fibre optic test methods, CEN aerospace standards.