Project Overview

Birch Technical Services delivered its section of a 15km fibre backhaul network
serving approximately 9,000 premises, forming part of a wider utilities
infrastructure programme.

A backhaul network is the part of a fibre build most people never think about.
It is not the connection into a home or business, it is the high-capacity route
carrying aggregated traffic from local distribution points back to the core
network. Everything downstream depends on it, which means the tolerance for
getting it wrong is low.

Scope of Works

•  Route survey across the full 15km corridor, identifying existing
  infrastructure, obstructions and constraints
•  Network design including duct routing, cabinet positions and splice
  planning
• Duct installation with civils avoidance where existing infrastructure allowed
• Blown fibre installation throughout the route
• Fusion splicing at joint positions and cabinet terminations
• Testing and certification across all installed fibre
• Street cabinet installation and commissioning

Challenges

Traffic management and restricted working hours
Much of the route ran through a live highway. Strict traffic management
requirements meant significant sections could only be worked during off-peak
windows, compressing the available working time and putting a premium on
getting each shift right the first time.

Blocked and silted infrastructure
Existing duct along parts of the route was blocked or heavily silted. Every
affected section had to be proved, cleared and re-proved before any fibre
could be blown, work that does not appear in a programme until you find it.

Seawater exposure
Sections of existing infrastructure had been exposed to seawater, with the
corrosion and contamination that brings. These required assessment and
remediation before they could carry new fibre with any confidence of a
working life.

Civils avoidance
Where existing duct could be reused it was, which reduces cost, programme
and disruption, but it also means working with infrastructure you did not
install and cannot assume anything about. Survey work carries the weight
here.

Why blown fibre for a route like this?

Blown fibre suited this project for the same reasons it suits most long
infrastructure routes. It removed the tension limit that would otherwise have
forced additional joint positions, it allowed duct and fibre to be installed as
separate operations around traffic management windows, and it left a route
that can be upgraded in future without reopening the highway.

On a 15km corridor through a live road network, never having to dig it again
has a value that is easy to calculate.

Results

A completed backhaul section carrying aggregated traffic for approximately
9,000 premises, tested and certified end to end, delivered within traffic
management constraints and with spare duct capacity in place for future
expansion.

Technologies Used

● Blown fibre installation
● Duct survey, proving and clearance
● Fusion splicing and termination
● OTDR testing and certification
● Street cabinet installation and commissioning
● NRSWA-accredited civils and reinstatement

Planning a backhaul or FTTP build? Get in touch today.