Fiber optic cables are the best choice for long-distance telecommunications and high-speed data connections. As the world continues to undergo a digital transformation, the need for high-speed is greater than ever.
Data hungry services, such as on-demand video, social media live streaming, and online gaming have grown exponentially in the past decade.
As such, data providers are under constant pressure to meet growing consumer demand while installing fiber optic cables in the most economical way possible.
The Challenges With Using Conventional Installation Methods
To understand what makes trenchless technology perfect for fiber optic cable installations, we first need to examine the issues with current installation methods.
As with any construction work, the installation of fiber optic cables is not without risks. One of the most hazardous elements of installing underground cables is the presence of existing underground utilities.
While some utility companies willingly mark the location of their subterranean lines, the location of some existing lines may be harder to identify. (Read also: Effectively Using Utility Detecting Devices.)
Open cut methods, which typically involve using heavy machinery (such as a backhoe or excavator), do not have the precision to install fiber optic cables in areas with complex utility layouts. This increases their chances of striking existing underground infrastructure, which can often have disastrous consequences.
Open cut methods are also highly destructive. When installing fiber optic cables in developed areas, open-cut methods can be highly unfavorable. The act of digging trenches at the surface can have several undesirable consequences, such as traffic disruptions, damage to hardscapes and underground infrastructure, and overall inconvenience to the general public.
Also, depending on the existing soil conditions, the walls of some open cut trenches may need to be stabilized with earth retaining structures.
Figure 1: Open cut (excavated) cable installation (source)
Why Use Trenchless Technology for Fiber Optic Installation
Cost
As mentioned before, traditional open-cut methods for laying fiber optic lines require the digging of a trench to place the wires. While this is still a popular choice for many municipalities, it may not be the most cost-effective option. The destructive nature of trenching means that all areas disrupted by trenching must be reinstated to their original condition, making open-cut methods potentially time-consuming and costly. (Read also: Studies Claim the Trenchless Construction Cost Comparison is Massive.)
Safety
Trenches are inherently dangerous. They must be shored, barricaded, and have adequate access and exit points for workers in the event of wall collapse. Furthermore, for trenches of a specific depth, workers may also be required to wear fall protection systems in accordance with OSHA guidelines.
Trenchless installations, as their name implies, allow fiber optic cables to be installed without the need for extensive excavations. This reduces the overall safety risks to construction personnel as well as the general public.
Time
Conventional open-cut fiber installations involve numerous processes, including clearing, excavating, waste disposal, and backfilling, to name a few. All of these processes can be time-consuming, increasing the overall time for completing the installation. Trenchless installations, on the other hand, can be done with just a fraction of the preparation needed for excavating.
For example, an experienced horizontal directional drilling (HDD) team can install up to 600 ft of fiber optic cable in a day. By comparison, open cut excavation installations may require several days to install just 100 ft of cable.
Environment
The trenchless installation of fiber optic lines also minimizes the impact on the surrounding environment. Less earth is disturbed, meaning wildlife habitats and other protected areas are not destroyed. In addition, trenchless fiber optic installations produce less dust than their open cut counterparts, resulting in an overall reduction in air pollution. (Read also: Trenchless and the Environment: How No-Dig Construction Saves Ecosystems.)
Trenchless Methods of Fiber Optic Installation
Different trenchless methods are available for the installation of fiber optic lines. Below, we will outline some of the most common trenchless installation methods.
Fiber in sewer
The simplest and least intrusive way to install fiber optic cables is to run them in existing underground infrastructure. When using this method, workers only need to dig small access points to pull the wire in place.
Impact Moling
Impact moling involves using a tool to create a relatively small bore through which the fiber optic cable can be run. A torpedo-shaped piston with a cylindrical body is driven through the soil via the percussive action of a piston. The piston delivers blows to the boring tool, causing it to advance through the soil, like a hammer hitting a nail.
Once the borehole is complete, the fiber optic cable is pulled through it from the exit pit. Some boring tools may also have pulling adaptors to install the cable while the tool is being driven through the soil.
Figure 2: 3D illustration of the impact moling process (source)
Horizontal Directional Drilling
A final trenchless method for installing fiber optic cable is horizontal directional drilling. This trenchless technology is so named because of its ability to be steered during drilling. An operator from a remote location uses a control panel combined with locating techniques to guide the cutting head along an intended path. (Read also: A Quick Guide to Underground HDD Steering and Tools.)
With the HDD method, the drill first creates a pilot hole. After the pilot hole is completed, the borehole is widened using a reamer, and the new cable is installed by pulling it from the exit pit.
HDD is optimal for medium to long installations in challenging areas. This attribute makes HDD the ideal choice for fiber optic cable installations across terrain unsuitable for other trenchless methods, such as river crossing and other protected areas.
Figure 3: Illustration of the HDD installation process
Final Thoughts
While traditional trenching techniques may be necessary for some projects, upgrading and installing new fiber optic cable requires more advanced technology. Trenchless methods are safer, have less adverse impact on the surrounding environment, and allow for faster installations. All of these benefits ultimately equate to lower installation costs and overall higher profit margins.