Fiber Optic Cable

Why We Choose Tight-Buffered Cable Over Loose-Tube Cable for Indoor/Outdoor Applications?

With local area network (LAN) reaching out further into the campus environment, often linking multiple buildings within short spans, the cable market is seeing an increased demand for a fiber optic cable suitable for both indoor and outdoor applications. In the past years, a number of manufacturers have introduced indoor/outdoor cable to answer the market’s call. Indoor/outdoor fiber optic cable that is capable of surviving the outdoor environment and meets the flammability requirements for use inside buildings offers many advantages to the end-user, as well as the installer and distributor. The use of this type of cable between and within buildings can save many labor hours and reduce material costs by eliminating the need to splice outdoor cables to flame-retardant indoor cables. Generally, indoor/outdoor cable is available in two designs: loose-tube and tight-buffered. But why we are more prone to tight-buffered cable instead of loose-tube cable? Read the following text, and you will get the detailed answer.

Advantages of Tight-Buffered Cable Over Loose-Tube Cable

Both tight-buffered and loose-tube cable have been available on the market for many years. However, loose-tube cable has its roots in outside-plant applications, while tight-buffered cable is typically used for applications. And most manufacturers of indoor/outdoor cable is to refine the design of loose-tube cable to make it suitable for interior use. But there are some unique advantages taken by tight-buffered cable instead of loose-tube cable.

Lower Termination and Splicing Cost

Termination and splicing cost of fiber optic cable can be one of the largest line items in an installation budget. A large number of products and alternative approaches make it possible to devise system layouts with considerable variations in installed costs. Historically, loose-tube gel-filled cable has been used for outdoor long-haul routes. Due to the fragile bare fibers and gel filling, which must be cleaned prior to termination, loose-tube gel-filled cable is the most difficult to splice and terminate and also has the highest termination material costs. Besides, this cable type must normally be terminated or spliced close to the cable entryway of a building to switch to indoor-style cable, as it is generally incompatible with indoor fire codes. Since fibers within the loose-tube gel-filled cable typically have a 250um coating, care must be taken to avoid damaging the fibers when removing the outer cable jacket and buffered tubes, as well as when the fiber is being cleaned or spliced. This time consuming and labor intensive process adds hidden costs to the installation of loose-tube gel-filled cable for indoor/outdoor use, and it creates another future failure point.

On the contrary, for tight-buffered cable, each fiber inside it is protected with its own 900um diameter buffer structure, which is nearly four times the diameter and six times thickness of 250un coating. This construction feature contributes to the excellent moisture and temperature performance of the tight-buffered indoor-outdoor cables and also permits their direct termination with connectors. The following image shows the different inner structure of tight-buffered and loose-tube cable.

inner fiber structure differences between loose-tube and tight-buffered cable


Reliability is another factor that we choose tight-buffered cable. Splicing is the weakest link in a fiber optic cable installation. During the splice operation, the fiber is stripped of all its cable, coating, and buffering protection, leaving the bare fiber open to dust, dirt, water vapor, and handling, which could reduce fiber strength and increase brittleness. Besides, the splices inside buildings may be held in a cabinet that is open to the air and may be located in a basement near a building entrance or in an electrical closet, both of which are uncontrolled environments, which leads to the splices being the item with the greatest failure rate in the cable system. However, as we have mentioned above, with tight-buffered cable, the splicing is eliminated and the installation reliability is greatly improved.


With tight-buffered indoor/outdoor cable, it can greatly simplifies maintenance and reduces restoration time. For routine terminations often require in moves, additions, and changes, only the skills and tooling for installing optical connectors are needed. However, loose-tube cable requires splicing with all the associated tooling and skills. Tight-buffered cable allows some portion of the fibers to be left dark for future termination with whatever type of connectors may be required. The installation of connectors terminated with the ends of optical fiber if the minimum skill required of the organization responsible for maintenance of a fiber optic cable plant.


Indoor/out door tight buffered cabling is gaining popularity in the campus deployment, since it can save time and labor by bringing one cable from an outside plant setting into a building without having to perform a transition splice. FS.COM provides a wide range of indoor/outdoor tight-buffered cables for your reference, like breakout fiber optic cable and fiber distribution cables.

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