Futureproofing for FTTx: How to address the growing challenges of congested conduit

Segmented conduit can help operators to execute the "dig once" philosophy.

By Dale Willis, Milliken Infrastructure Solutions LLC

Earlier this year, Verizon surprised many by announcing its plans to extend its fiber network into Boston, a move that caught many off guard. On the surface, the move seems to contradict the communications company’s recent strategy to limit the expansion of its FiOS fiber-to-the-x (FTTx) services. But by upgrading existing copper networks to fiber, the company is actively working to create a single fiber-optic network that will support both wireless and wireline technologies.

In making its announcement, Verizon also suggested that it is in discussions with other cities about similar projects. Some would speculate that most of those cities would be in the northeastern U.S., where Verizon has a significantly larger footprint. However, it is worth noting that last year Verizon deployed fiber throughout San Francisco in preparation for the Super Bowl, so its plans for FTTx could extend elsewhere.

What made the San Francisco deployment possible was Verizon’s ability to utilize available space in the utility company’s conduit-a luxury that might not be available as the company tries to upgrade lines in the likes of Boston. Boston might be the birthplace of Benjamin Franklin, one of America’s great visionaries, but when it comes to infrastructure, it’s like many other larger metros wrought with issues that could have been addressed with long-term cable management planning.

Boston is a historic city with nearly 700,000 residents, so any project that requires dealing with the metro’s infrastructure will face a number of challenges. In addition to dealing with restrictions dictated by historical regulations, existing above-ground utility lines and a range of mixed-use buildings, one of the biggest obstacles any operator would face would be how to deal with areas where there is simply no more room to add new conduit.

In many cases, especially in large, developed metros, companies don’t have the benefit of utilizing existing conduit for new fiber runs similar to those Verizon handled in San Francisco. This may not be a possibility in places like Boston because existing conduits are already incredibly crowded, packed full of various cables from a range of different vendors, some of which aren’t even in operation any longer. In New York, for example, existing conduits are so congested that telecom companies are forced to route new runs via much longer-and much more expensive and time-consuming-detours.

While deploying FTTx within large, older cities has a myriad of challenges, some of that potential headache could be avoided by those cities looking to “futureproof” against similar problems. By avoiding the trap of trying to cut corners now to save time, FTTx owners and operators can look at emerging practices and deployment methods to ensure they’re set up for success-operationally and financially-in the long run.

There are several examples of public-private partnerships that help to address and possibly eliminate these issues. In some scenarios, a public entity (e.g. the state, county or city) takes ownership of the network infrastructure, working to deploy materials that can be easily upgraded as technologies change. The public organization then contracts out various vendors to operate the network systems and/or provide network maintenance as needed. This model ensures that the network is deployed in a way that enables local leaders to better plan for and finance FTTx, limiting the challenges of having multiple vendors fighting over the same infrastructure real estate. At the same time, telecom and other utility providers have assurance that they’ll have an available, organized infrastructure in place to meet their evolving needs.

In an ideal scenario, these deployments would focus on a “dig-once” mentality, installing minimal conduit, perhaps just one, limiting the amount of space needed. With the availability of segmented conduit, once a conduit is in place, multiple fiber cables could be run within a single conduit at the same location, thus increasing the limits of conduit capacity.

It’s worth noting that it is desirable from both a cost and time standpoint to make use of the dead space within an existing conduit, rather than laying a new length of conduit. However, it is difficult to insert fiber into a conduit that already contains cables or other wiring, which would be the case in most cities looking to deploy FTTx. When a new cable is blown or rodded into a conduit with an incumbent cable, the first cable often impedes placement. The rope can become tangled with, or twisted around, the first cable, causing damage to the cables’ protective outer sheaths. Industry standards dictate that only one fiber or cable run should be placed within a dedicated pathway. However, the size of fiber only occupies a very small percentage of the available space within the conduit, warranting the readdress of the use of existing conduit space.

With segmented conduit, a single conduit with multiple cells, network owners have spare pathways available to add capacity or bandwidth without requiring new construction-hence “digging once.” Additional bandwidth can be added without expensive and time-consuming engineering or permitting, avoiding the traffic disruption that occurs during construction activity.

The benefit of segmented conduit is perhaps greatest in applications in which the cost of conduit deployment is highest, which is often these areas where there is limited or no space in existing infrastructure. Its cost of the deployment is dependent on the size of the bore required, plus the location and terrain of the job-which if in a city like Boston, would make it even more difficult. The size of the bore is dependent on the number of conduits to be placed so if operators can limit the number of conduits, they obviously can reduce the size of the bore needed for the install.

Additionally, in major cities like Boston there are a multitude of existing utilities to avoid during the boring process. A smaller bore reduces the chance of hitting these existing utilities, such as water mains, natural gas distribution networks or telecom networks. Smaller bores equate to greater overall efficiency and cost savings. In addition, fewer conduits mean lower labor cost associated with handling, storage and installation.

If operators and owners want to get serious about FTTx, they have to take into consideration how future technologies could impact existing infrastructure. And a great way to plan against that is to ensure that the products being deployed now allow for future growth and expansion.

Dale Willis, a 20-year industry veteran, is vice president for Milliken Infrastructure Solutions LLC (infrastructure.milliken.com).

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