Issue link: https://www.e-digitaleditions.com/i/1192126
January/February/March 2020 I 41 Though somewhat oversimpli- fied, Figure 7 can be a useful over- view in describing a blown fiber system and its major components. OUTSIDE PLANT FIBER APPLICATIONS With any optical fiber installa tion, the most time-consuming part is laying the fiber pathway. In an OSP burial application, there is usually trenching for the conduit that must be done prior to the fiber installation. Depending on the length of the con- duit, handholes or pull points must be established. Prior to installing this pathway, considerations have to be made for the amount of the fiber to be installed along with room for expansion should it be needed in the future. If multiple fibers are to be installed, it is critical to size the con- duits correctly. Once the conduit pathway is installed, either the conventional cabling or blown fiber method can be used. In many instances, a blown fiber system can often eliminate the need or reduce the amount of conduit required, along with not having to subdivide conduits with any type of innerduct which is commonly done when installing fiber conventionally. Whether using conventional cabling or blown fiber, it shall meet NEC and National Fire Protection Associ- ation (NFPA) codes for cabling rating when entering a building, and if the outside plant fiber installed does not, then a transition would be required. When an outdoor rated fiber cable enters a building, it should be termi- nated/spliced, either through a wall or flooring, to an indoor-type fiber Steel Manufacturing Plant Site Case Study: Blown Fiber System — OSP and Inside Building Example Within the industrial market, the amount of equipment and production machinery that continues to move to "smart intelligence" / "smart man- ufacturing" and becoming part of the internet of things (IoT) is growing every day. This requires advanced networks and sensors to communicate with each other and automate. Most manufacturing plants are 24 / 7 operations and have little to no time for lengthy shutdowns. A blown fiber infrastructure allows the installation of new and/or additional fiber (once the initial backbone of tube cables are installed) with little to no disruption or need for shutdowns. This steel manufacturing facility in Michigan needed to create two fiber optic paths to a brand-new building. Each path required 24 strands of fiber. The two redundant fiber pathways were approximately 4,800 feet long. The plant requested comparative costs for installing 24 strands of fiber. The fiber would be installed using a combination of cable trays and J-hooks running through production areas inside and outside of the buildings. A conventional 24 strand armored fiber optic cable would have been installed directly in the cable tray or J-hooks. Comparatively, for the blown fiber solution, tube cable with spare tubes would be installed in the same cable tray or J-hooks, as well as creating a pathway for future add-ons. The blown fiber pathway would utilize a 19-tube cable with TDUs installed along the pathway at strategic locations that act as "on & off ramps" for future needs. The blown fiber solution was approximately 30% more expensive for the initial installation. However, after requiring just two additional runs of fiber optic cable that utilized existing spare tubes within the tube cable vs. pulling additional conventional fiber optic cable, the plant saw an overall cost savings using blown fiber. The install- ing contractor quoted out each additional fiber cable installation using a conventional fiber cable vs. blown fiber. Here is an example of the cost-comparison for adding one new fiber cable within the same pathway. 2,200 feet of conventional fiber would be pulled through existing cable tray and/or J-hooks requiring a mini- mum of four installers. Total conventional fiber installation would take approximately three weeks with an approximate cost of $27,000. Vs. Blown fiber solution. The contractor would simply add a new 24-strand fiber bundle utilizing one of the spare 17 tubes available. Using the blowing equipment, the fiber bundle would be installed end-to-end in less than 20 minutes requiring just two installers. Total installation time was less than two days at an approximate cost of $6,700. Finally, after just the second need to add fiber, the blown fiber solu- tion proved to be overall less expensive than a conventional fiber installa- tion and still provided 15 additional pathways for future expansion. Over the next 3 years, the plant required over a dozen additional fiber cable runs, all with similar savings.