Tackling Tough Terrain

Taking Fiber Optic Cable Blowing to Extremes on the Digital 395 Project

Aug 15th, 2013
Condux 1

Taking Fiber Optic Cable Blowing to Extremes on the Digital 395 Project

The middle mile build out continues throughout portions of the United States. Several large-scale middle mile projects have occurred because of funding made available through the National Recovery Act. One project, the Digital 395 project, is putting contractors and equipment to the test along US Highway 395 in Nevada and California.

The project is being coordinated by a newly formed group of entities established as the California Broadband Cooperative Inc. (CBC). The CBC is a not-for-profit telecommunication cooperative corporation that will own and operate the Digital 395 network, providing high‐speed broadband services to members on a wholesale, open-access basis. As a cooperative, the organization will be under the direction of a board of directors representing key institutions and constituents in the Eastern Sierra region of California and Nevada.

To install the fiber optic cable needed to create the more than 580-mile-long network, the CBC has contracted Praxis Associates Inc., along with its sister company, Praxis Optical Networks Inc. to develop, engineer and construct the project. According to Praxis Construction Manager Bob Whitcomb, much of the project uses the latest in fiber optic cable blowing equipment.

"We typically utilize fiber optic cable blowing as much as we can because of the efficiency of the method. However, we do use fiber optic pulling equipment as well. That's a really nice tool to have. Sometimes, because of terrain or job site layout, etc., we can't use the blowers, so to have fiber optic cable pullers at our disposal is a big help," Whitcomb said.

For the massive middle mile project, Praxis is using fiber optic cable blowers from cable installation tools and equipment manufacturer Condux International of Mankato, Minn.

Condux International's Vice President of Global Sales Tom Ortolano said, "It's exciting and rewarding when contractors on the forefront of these major projects continue to choose Condux fiber blowing equipment as part of their installation solution. It lends itself well to the intense focus we put into customer experience and the innovation to develop the best products on the market."

Praxis crews are handling almost every facet of the project-from installing the conduit to installing the fiber and tying in the last mile anchor hookups along the way.

Project Overview

Much of the region along the corridor suffers from insufficient broadband capabilities. The existing telecommunications system is made up of aging telephone infrastructure, with wide sections of the Eastern Sierra region of California and Nevada underserved. The Digital 395 middle mile project is planning to provide a new network, 583 miles long, along the US Highway 395 corridor between Southern and Northern California and a portion of Nevada.

The project's service area is impressive, including 36 communities, six Native American reservations, two military bases, more than 26,000 households and 2,500 businesses. In addition, 35 public safety entities, 47 K-12 schools, 13 libraries, two community colleges, two universities, 15 healthcare facilities and 104 government offices will experience the benefits of the fiber optic network.

According to the project's Web site, unused, high-capacity fiber will be available to the region's last mile providers to expand or enhance service to households and businesses, as well as to government agencies or carriers seeking local or long haul transport.

Covering more than 580 miles along the Eastern Sierra Mountain range, the project's route travels through a diverse and extreme range of environments. Cable installation contractor Praxis is using fiber optic cable blowers from cable installation tools and equipment manufacturer Condux International.

Project Benefits

The project means big benefits for the areas' community antenna television (CATV) providers, as well as wireless providers. For the CATV industry, the last mile networks can support as much as 50 mbps, and, with Digital 395, providers will affordably be able to provide that level of service.

Wireless service providers will benefit from more tower space that will be made available, allowing new providers to enter the market and helping create a level playing field. The network will also provide backhaul support to providers and support the growth of 3G and 4G wireless data for smartphones and wireless devices.

Praxis and Fiber Optic Cable Blowing

The Praxis Companies are major California fiber optic contractors who have designed and constructed private and public networks to some 33,785 homes in more than 350 projects during the past several years. Praxis also has experience developing fiber networks on Native American reservations. The core Praxis project team has more than 120 years of telecommunications experience, with a wide range of markets, technologies and clients. The company is highly skilled in fiber optic cable blowing installations.

According to Clay Harris, fiber optic cable installation equipment specialist with Condux International, the typical cable blowing process consists of several steps.

"For your middle mile fiber optic cable, you're typically installing into long-run duct work, so you need to determine duct integrity first. This is done by pressurizing the duct and monitoring air loss. In addition to being air tight, the duct must be free of obstructions. Adding a small amount of lubricant and blowing through a foam carrier will ensure the duct is free of obstructions," Harris said.

"Next, the cable is prepared for installation. A properly sized cable carrier or parachute is attached to the end of the fiber. The cable is then fed through the cable blower and into the duct. Before inserting the carrier into the duct, a silicone-based, cable blowing lubricant is added. Additional lubricant is then applied behind the carrier."

Harris continued to explain that once the cable blower is connected to the system, compressed air is injected into the duct behind the cable carrier. As the pressure works to equalize, it seeks the path of least resistance, creating a pushing force on the cable carrier and causing forward motion. The moving cable carrier then exerts a pulling force on the cable and it begins to move through the duct.

An additional pushing force is applied to the cable by a hydraulic powered tractor drive on the cable blower. Use of a hydraulic tractor drive reduces the air compressor's air consumption requirements. In addition, the push force from the tractor drive provides cable slack, reduces back tension, and keeps the cable loose and flexible. Friction and resistance are then reduced, and the cable can freely travel through the ductwork.

Praxis crews are using smaller blower/pushers for the last mile sections. These units allow users to drive the system with a cordless, corded or pneumatic drill, and a small compressor.

On the Job

Praxis crews are handling almost every facet of the project-from installing the conduit to installing the fiber and tying in the last mile anchor hookups along the way. To safely and efficiently install the fiber optic cable, Praxis is using the newest in fiber optic blowing equipment for middle and last mile installations, as well as more traditional fiber optic pulling equipment.

The I-395 corridor stretches from Barstow, Calif. in the south to Carson City, Nev. in the north. Covering more than 580 miles along the Eastern Sierra mountain range, the project's route travels through a diverse and extreme range of environments. From Mount Whitney, the highest point in the contiguous US at an elevation of 14,505 feet, to the high desert region of Nevada, temperatures reach extremes in cold and heat.

"Equipment performance in the extreme conditions along the route is key to success," Whitcomb said. "One of the other challenges we face is extreme temperature. Last year, my crews placed fiber and conduit in temperatures ranging from -14 degrees to 114 degrees in temperature. That's one of the nice things about working with Condux and the fact they're out of Minnesota-they face extreme cold in the winter and heat in summer. If you look at the different places along the Eastern Sierras, you can go from 10 feet of snow to the desert floor where it's 115 degrees.

"The equipment has to be able to stand up to extremes, and keeping everything running smoothly is a big part of the job. The blowers did great in the extreme temperatures. We made a small adjustment in the viscosity of the hydraulic fluid for the power packs when operating in the cold."

In certain terrains, Praxis crews also use traditional fiber optic pulling equipment-in addition to fiber optic cable blowers.

In addition to using the larger blowers for the middle installations, Praxis crews are using smaller blower/pushers for the last mile sections. Those units allow users to drive the system with a cordless, corded or pneumatic drill, and a small compressor. A universal stem provides for right side and left side connections for forward drive and reverse drive. The units work on the same principle as the larger blower units but are able to work with much smaller fiber and shorter installations. The blowing technique can also be applied to micro fiber and micro duct with specially designed, recently introduced micro fiber blowers.

"For our last mile and anchor hookups, we're using the blower/pusher. The anchor hookups are basically the connections to schools, police stations, fire stations, county buildings, libraries, etc. For these final runs, the blower/pusher is a great option for those installations," Whitcomb said.

"The equipment that Praxis has chosen for the various stages of the project are really helping with efficiency," Harris said. "Plus, their crews are top-notch for sure-very skilled and accomplished. They're doing a great job on this project in some very challenging conditions."

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