Microtrenching vs Traditional Civils: How Product Selection Affects Reinstatement and Lifecycle Cost

Microtrenching and traditional civils are two different approaches to fibre installation. Learn which method suits your project and which ducts and cables keep networks reliable, durable and adaptable.

When fibre networks are deployed, it's essential to consider the method of installation used in order to meet installation project timelines and project costs, while avoiding prolonged or unnecessary disruption to communities. Within this, appropriate and capable equipment should be selected to ensure long term reliability and continued high-speed network delivery.

Microtrenching and traditional civils are two different approaches to fibre installation. In microtrenching, a narrow trench is created and filled with special grout material that provides stability. Best used for rapid deployment, microtrenching is often carried out in urban areas to avoid existing utilities. Alternatively, traditional civil trenching methods use heavy machinery to dig up larger sections of ground to lay conduits, refilling the entire area and resurfacing it. This is best used when installing heavy infrastructure or power cables that require heavy protection and deep burial.

This blog will help you to know which method works best for your project and what materials you should employ to keep network connectivity reliable, durable and adaptable for future development.

Microtrenching: The Pros and Cons

Microtrenching allows for fibre to be installed quickly, meaning that network connectivity can be provided in a timely manner with communities gaining access quickly. As a result of the quick installation process, microtrenching causes minimal disruption to surfaces, with shallow, narrow cuts being made to install cables, instead of entire sections of ground being dug up, avoiding disturbances caused by road closures and noise pollution. With this reduced need for excavation and surface repair, microtrenching becomes a cost effective option for cable installation. In the long term, microtrenched fibre can be more easily maintained, as it is more readily accessible from being shallowly buried, making upgrades simpler, faster, and overall cheaper.

Although on a smaller scale, microtrenching will still bring a level of disruption to communities with roadblocks and noise. It's also not suitable for all types of ground, designed primarily for hard stable surfaces like concrete, and while its shallow burial offers some benefit, when roads are eventually repaved, it's likely that the entire system would need to be dug up, due to being built closer to the surface.

Traditional Civils: The Pros and Cons

Traditional civil deployment allows for installation of large, heavy duty ducts that house multiple fibre optic cables, making it easier to pull more fibre through if there is an increased need for expansion due to demand. Cables are deeply buried underground, beneath concrete or plastic ducting, ensuring assets are protected from risk during works where they may be accidentally struck if they were buried any shallower. The heavy machinery used to install fibre networks through traditional civils is able to break through tougher, uneven surfaces that microtrenching blades may fail to.

The Impact of Product Selection: Microtrenching

Since microtrenching creates slots typically 0.5 to 1.5 inches wide, standard heavy-duty cables will not fit inside of trenches. HDPE (High-Density Polyethylene) microducts are flat and thin enough to fit into trenches with a small width, without the need to dig larger trenches to accommodate round ducts. Lightweight microcable can then be easily pulled or blown through these narrow ducts, minimising the need for underground jointing or civil engineering, greatly reducing project timescales due to quick installation times. By installing additional, empty microduct pathways, teams can prepare themselves for quick installation when there's a greater demand for connectivity, by being able to simply pull or blow cable through ducts without needing to re-cut the street, which will require more time, labour and money.

Because infrastructure sits close to the surface in microtrenching, likely on busy streets with high traffic levels and heavy earth loads, it is essential for chosen products to provide appropriate levels of protection against accidental damages to minimise disruption and potential loss of signal. Due to their density, flexibility and strength, HDPE microducts protect against crush damage, keeping fibre safely enclosed inside, resulting in consistent, reliable connectivity.

The Impact of Product Selection: Traditional Civils

The deep excavation and burial of infrastructure in traditional trenching requires products that are able to withstand high levels of soil pressure and external crushing forces. To avoid damages and disruption, HDPE ducts should be placed for their structural strength and ability to maintain their strength under heavy burial loads. Though PVC ducts offer similar properties, HDPE ducts are more flexible and can bend without breaking under challenging terrains, where traditional civils trenching often takes place.

Direct burial armored cables are another suitable alternative, designed to be laid at the bottom of a trench without needing a protective conduit. The cable adds a metal protective layer underneath the outer jacket with steel tape armouring, providing resistance against crushing and protection from works damage and other impacts.

Selecting the Right Products Ensures Longevity and Reliability

Choosing ducts and cables that can withstand the environments required for trenching will mean less need for repairs which can be time consuming, disruptive and costly, allowing networks to run smoothly and without interruption.

Both microtrenching and civil installation methods utilise similar products, with HDPE ducts having higher upfront costs than alternative PVC ducts. However, in the long term, these investments into better quality products will be worthwhile to ensure less money is spent overall on digging up ground and the infrastructure laid to replace cheaper, less effective equipment. Instead of project cost being impacted by products chosen at the build stage, operators need to consider the total cost of ownership across a project lifespan of their chosen method of deployment. Since microtrenching installs fibre quicker than traditional civil trenching, it drastically cuts costs needed to cover labour and major road reconstruction repairs, also meaning shorter road closures and reduced traffic management costs.

We advise customers how to select products that protect fibre infrastructure in all build environments, while ensuring it maintains its quality and connectivity. Contact a member of the team today to access the best solutions for your next installation.