Do You Have Any Idea of Water-Resistant Fiber Optic Cable?

There is no doubt that fiber optic cables play an integral role in telecommunication industry. Applications like data centers, local area networks, telecommunication networks, industrial Ethernet, and wireless network are all needing fiber optics to ensure smooth connectivity. Each application requires a specific cable design based on performance requirements, environmental conditions, and installation type. The common fiber optic cables like LC to LC patch cord cannot adapt to the harsh environment (e.g. moisture environment or underground deployment), thus water-resistant fiber optic cables are highly demanded on the market due to their water proof nature. Here is what you should know about the water-resistant fiber optic cable.

Overview of Water-resistant Fiber Optic Cables

Water-resistant fiber optic cable refers to the special type of fiber optic cable that are designed and specified for installations where the cable will come in contact with water or moisture, such as aerial, direct buried, or in conduit. The cables in these applications are exposed to or can be temporarily submerged in water, so they contain either a water-resistant gel-filled or gel-free (dry gel) polymer.

Generally, fiber optic cables can be divided into three types—outside plant cable (OSP), indoor/outdoor, and indoor, which are specified based on the environment and location where they are installed. With the exception of indoor cables, all cables contain water-resistant gel-filled or gel-free material to protect them from water and moisture. Before the use of gel-filled and gel-free materials, flooded core was another water-blocking method that is rarely used today (it has been replaced with gel-filled). The following image shows the gel-filled cables.

The gel is a gooey substance that must be removed when accessing and installing the cable. Gel-free cables, which are now more widely used, contain a super-absorbent polymer powder that is activated when it comes in contact with water or moisture. This blocks the water from penetrating the cable and allows for some expansion and contraction with temperature changes. Indoor cables do not contain water-resistant material since they are not typically exposed to water. Indoor (and indoor/outdoor) cables must meet additional flammability requirements dictated by local codes, such as the National Electrical Code.

Tight-Buffered & Loose Tube Cable Construction Provides Excellent Moisture Resistance

Water-resistant materials and cables are included in many industry specifications and standards. Generally, there are two basic water-resistant cable designs: Tight-buffer cables (primarily used inside buildings), Loose tube cables (used for OSP and indoor/outdoor).

It is known to all that most tight-buffered cable designs (seen in image below) are specified for indoor use, but some of them are designed with water-resistant powder and yarn, making them suitable for some indoor/outdoor applications. This tight-buffered cable utilizes an different design approach to deal with the moisture issue. Buffer materials are low-porosity plastics with excellent moisture resistance. This construction very effectively minimises the water molecule and OH-ion concentration level at the glass surface and virtually eliminates the stress corrosion phenomenon.

In loose tube cables (seen in image below), in order to prevent the water from reaching the 250μm coated fibers, the tubes surrounding the fibers must be filled with water-absorbent powder or gel that withstands high-moisture conditions, making them excellent for outside plant applications. This approach is especially made to waterproof the cable by filling the empty spaces in the cable with gel. The gel-filled tubes can also expand and contract with temperature changes, which makes loose-tube cable great for harsh, high-humidity environments where water or condensation can be a problem. However, gels can move, flow, and settle, leaves an uncertainty of the filled level of any particular point of a loose-tube gel-filled cable. Because loose-tube cable is typically 250 microns, you'll need a fan-out kit to build up the individual fiber strands to 900 microns when making the transition at the entrance point from outdoor loose-tube to indoor to tight-buffered cable.

The same level of protection remains in place all along the fiber, regardless of installation conditions, environment, or time. The balance of the tight-buffered, tight bound cable designs is such that it minimizes the open spaces available in the cable structure in which water can reside. Even if an outer cable jacket is cut, or water otherwise enters the cable structure, only a very small percentage of the cross-sectional area is open to water.

Conclusion

When selecting the suitable fiber optic cables, one must consider the application, the installation location, and the appropriate cable design and type according to specifications and standards. The water-resistant optic cable is specially made for moisture environment to insure the smooth connectivity. However, whether to have the loose tube fiber optic cable or tight buffered cable, it depends on the installation location. FS.COM offers a full range of fiber optic cables at very economical rates. These cables are widely used and are highly demanded on the market due to their water proof nature. In addition to this, we offer these cables in various fiber optic cable specifications, such as duplex/simplex fiber cable, single-mode/multimode fiber optic cable, LC/FC/SC/ST fiber optic cable and so on. LC to FC patch cord is absolutely high quality and low price, just as the other fiber optic cables. If you want to know more about our products, please contact us directly.

Whether to Go for Aerial or Underground Deployment

In the fiber optic network, a carefully constructed network requires calculated planning and a high level of installation. It is not as easy a cavemen can do it, as many factors should be taken into account when installing a fiber optic network, such as construction costs, time constraints, existing infrastructure, and so on. There are two main types of land based network fiber optic installation—aerial and underground. This article will talk about these two cable installations in detail.

Aerial Fiber Construction

The fiber optic installation that occurs when fiber jumper is installed along a line of utility poles, is known as aerial fiber construction. When installing a placing aerial cable, besides the cables, a support strand is needed as well. A support strands can be deployed along the route first, with fiber pulled and lashed to the support strand later. Or the aerial fibers can be pre-lashed, making the installation less complex. Lashing refers to the process of securing the fiber cable to the support strand via lashing wire. When placing cable on a pole, the required spacing distance varies depending on the type of cable or equipment. These requirements are often set by local, state and national standards.

Underground Fiber Construction

Underground fiber construction refers to the fiber installation that occurs when fiber optic cable is installed under the ground in pipes, or conduits. The depth of the underground cables varies by many factors; however, it is typically between 12-36 inches below surface level. In underground fiber construction, the fiber optic cables are buried in a trench, but In colder areas, fiber cables are buried below the frost line to protect the cables from being damaged.

There are three main subcategories of underground fiber installation including direct buried, air-blown or micro trenching. In a direct buried cable construction, the fiber optic cable is installed directly into the ground rather than in protective conduits. When fiber optic cable is installed through a conduit via air, the process is known as air-blown or cable-jetting construction. And in air-blown installation, a device injects a high volume of air into the duct at high pressures to blow the cable through. Micro trenching construction occurs when the fiber optic cable is installed underground by way of a small groove, instead of a larger trench. Each of the above underground installations have a variety of benefits and are used in varying, and case specific scenarios.

Pros and Cons of Aerial and Underground Deployment

Aerial cables are one of the most preferred and cost-effective solutions for the end user, because installers can reuse existing pole infrastructure without digging up another roads to bury cables or ducts, what’s more, aerial cable construction is easily modified to add additional capacity.

However, aerial deployment is more susceptible to damage. The falling tree branches, high winds or ice storms, vehicle accidents, animals that chew on the fiber all can make the aerial cable strain or break. Therefore, calculations on the strength of both the cable and poles need to be taken into account when determining span lengths.

But it will typically takes some time and money to make ready requirements if poles and cable need to be made stronger. It is a good solution to the areas with existing pole networks or rural environments without urban restrictions.

While many customers do prefer their services, including fiber cables, to be installed underground. Unlike the aerial deployment, buried fiber deployments are less susceptible to wind and ice damage as they are buried below the layer, which makes it often at least ten times more reliable than aerial routes, especially where poor weather is common.

However this might be a costly solution because the cable needs to be buried deep in the ground to protect it from accidental damage. The deeper an operator has to dig, the more costly it is. Never to mention that if a buried direct cable is broken, it is expensive to repair. These buried direct cables cannot be removed and replaced because it tends to be firmly anchored into the ground.

Conclusion

As this blog shows, choose which method to install a fiber optic network will depend on a variety of factors including the landscape, cost of the labor and equipment, and so on. Both of the two deployment methods presents advantages and disadvantages that must be carefully evaluated by case basis. FS.COM offers a variety of fiber optic cables that can be used in different applications. The optical cables terminated with optical connectors like LC to FC patch cord have been widely utilized in fiber optic network. For more on the fiber optics provided by FS.COM, please contact us directly.