Optical cables in ducts must be installed or dismantled following strict mechanical, environmental, and procedural standards to prevent damage and ensure long-term performance.

Pre-Installation Planning

Before laying or dismantling optical cables, a thorough route survey is essential. This includes identifying drum placement, splice locations, potential obstacles, and required machinery or tools. All work must comply with local regulations and obtain necessary authorizations. Cable drums should be inspected for physical damage, and fibers tested for continuity and attenuation before installation to ensure quality control .

Installation Methods

Two primary methods are used for duct installation:

• Pulling Method: The cable is mechanically pulled through the duct. Maximum pulling tension must not exceed the cable's rated tensile load, typically specified in the cable datasheet. For example, stranded loose tube and ribbon cables often have a maximum pulling tension of 600 lbF (2,700 N), .
• Blowing Method: High-speed airflow propels microcables through microducts, reducing mechanical stress and eliminating the need for a pulling rope . Both methods require careful attention to minimum bend radius, avoiding twisting, pinching, or crushing, as these can increase attenuation or permanently damage fibers .

Mechanical and Environmental Considerations

• Bend Radius: During installation, the minimum bend radius is typically 15 times the cable diameter; after installation, it may be reduced to 10 times the diameter .
• Tensile Load: Never exceed the rated pulling tension. Cable sections exposed to maximum tension may remain under stress permanently .
• Handling: Use figure-eight coiling for unreeled cable to prevent kinking. Avoid continuous coiling for lengths over 30 m .
• Protection: Barricades or traffic control should be used when cables are unreeled on surfaces to prevent damage .

Supervision and Quality Control

All tasks should be supervised by trained personnel responsible for work control and adherence to specifications. Cable handling must maintain the cable in its original format (drum, box, or coil) to prevent pre-installation damage. Post-installation inspection ensures proper performance and compliance with optical and mechanical standards .

Compliance with Standards

Installations should follow ITU-T L.100 and IEC 60794-3-11 standards, which define cable characteristics, test methods, and performance criteria for duct applications. These standards cover mechanical strength, environmental resistance, and optical performance, including electrical continuity for metallic elements if present .

Safety and Environmental Measures

• Implement a security plan and signaling systems depending on surroundings.
• Take environmental precautions to minimize impact during installation or dismantling.
• Ensure all personnel are trained in safe handling and emergency procedures . By adhering to these requirements, optical fiber cables can be installed or dismantled in ducts safely, efficiently, and without compromising long-term performance.