Loose Tube Cables In Outdoor Applications

Fiber optic cables are constructed in two ways: Loose Tube and tight buffered. Loose tube optical cable designs are optimized for outside plant applications and have demonstrated over 20 years of proven field performance.


Loose tube cables are designed for harsh environmental conditions in the outdoors. They protect the Fiber core, cladding, and Coating by enclosing everything within fairly rigid protective sleeves or tubes. Many loose-tube cables contain a water-resistant Gel surrounding the fibers. The gel helps protect the fibers from moisture, making the cables ideal for high humidity environments, where water or condensation may otherwise be problematic. The gel-filled tubes can expand or contract with temperature changes, as well. Despite the benefits, gel-filled loose tube cables are not the right choice if the Cable needs to be submerged in water, or routed around multiple bends. Excess Strain may cause the fibers to emerge from the gel.

Tight-buffered cables are optimal for indoor applications. Being more robust than loose-tube cables, they are best suited for moderate length LAN or WAN connections, long indoor runs, direct burial, and for underwater use. Rather than using the gel Layer loose tube has, tight buffered cables have a two-layer coating. The first is plastic, and the other, waterproof acrylate. The Acrylate keeps moisture away from the cable. The Core is never exposed when bending or compressed underwater. Tight-buffered cables may be easier to install because there is no gel to clean up and it does not require a fan-out kit for Splicing or termination.


. Usable for ducts, direct burial, aerial installation
. Long distance communication system
. Subscriber network system
. A local area network system

Waterblocking requirement

loose tube fiber optic cable is designed to provide maximum protection against water penetration and water migration by utilizing intrusion preventative measures in both the cable core and the buffer tubes. Water-blocking protection of the cable core is accomplished by surrounding it with a dry water-swellable tape and yarns, or with a gel, to stop the entry and migration of water should the cable’s outer jacket be breached. This protective measure is included primarily to maintain the mechanical integrity of the cable itself (e.g. prevent ice crush from within the cable, fungus growth, or corrosion of metallic cable members when present). The water-blocking protection, water-swellable yarn or gel, is placed in the buffer tubes with the optical fiber during manufacture of the cable.


The predominant users of outside plant cable continue to specify loose tube cables in outdoor environments. Loose tube cables must pass rigorous mechanical, environmental and optical tests in accordance with accepted Electronic Industries Association/Telecommunications Industry Association (EIA/TIA) fiber optic test procedures (FOTPs). Loose tube cables are specifically designed to perform in harsh outdoor environments with minimal performance degradation. a new standard, ICEA S-104-696, “Standard for Indoor – Outdoor Optical Fiber Cables” has been developed which addresses the need for an inter-building and intrabuilding cable.

These cables can be a loose tube or tight buffered for the ease of termination such as premises cable but must offer the tensile strength, water blocking protection, and UV protection of an outside plant cable. These inter-/intrabuilding cables are typically used for short runs to connect to another building(s) and some limited premises applications.


Optical cables are designed to protect the optical fibers from damage due to the rigors of installation and from the demands of the surrounding environment. Fiber-Mart provides a wide range of quality optical fiber cables with detailed specifications displayed for your convenient selecting. Per foot price of each fiber cable is flexible depending on the quantities of your order, making your cost of large order unexpected lower. Customers can also have the flexibility to custom the cable plant to best fit their needs. Only fiber cable that meets or exceeds industry standards is used to ensure quality products with best-in-class performance.

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1 thought on “Loose Tube Cables In Outdoor Applications

  1. Good article. You forgot to mention about Ribbon cables. There are basically 3 types of protection methods such as 1. Loose tube, 2. Tight buffering and 3. Ribbonization.

    Ribbon cables are popular in Japan. Ribbons can be put into slots and aslo inside the loose tubes. Furukawa and Sumitomo had introduced rollable type Ribbons

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