Gel Buffer Tubes vs. Dry Buffer Tubes | Product Knockout


“Our Product Knock-out series is a match-up between two similar products. In boxing terms, think same weight class, same caliber, and same level of experience and amount of exposure. The purpose of these posts are for you to see a side-by-side view of two similar products, and to be able to understand which one will be crowned champ for your specific purposes. Take your seats and prepare for battle, because the gloves are coming out.”

It is important to define and discuss what buffer tubes are in relation to fiber optic cable before comparing and contrasting gel and dry. Buffer tubes are used in fiber optic cable to block water from getting inside the tubes and disrupting the fiber. The prevention of water is especially important in environments where the freezing of water can occur and expand, which will break the optical fiber.

What are Gel Filled Buffer Tubes?

Gel in a fiber optic cable serves as blockage of water to the cable itself. The gel fills the entire part of the tube that is not occupied by the fiber itself. In addition to blocking water from getting to the fiber optic cable, the gel also provides an additional protective layer for the fiber. It also creates cohesion between the fiber and the tube. Now, let’s talk about dry buffer tubes.

What are Dry Buffer Tubes?

Dry buffer tubes are also used to block water from reaching the core of a fiber optic cable. This is done by using materials such as strings, tapes, and foams. These materials are often treated with some kind of super absorbent polymer (SAP) within the tube. The material and SAP absorbs any water that enters the tube and blocks the tube from further water infiltration. In most conditions the SAP will dry and reactivate, which will provide long term protection to the fiber optic cable.

Gel vs. Dry Buffer Tubes

Dry and gel buffer tubes have some similarities but are mostly defined by their differences. Both types of buffer tubes are used to block water from reaching the fiber in the cable. They also both act as a filler within the tube between the outer part of the cable and the core.

The differences of the two types of buffer tubes stand out more than the similarities. To start, one is gel insulation and one is dry. The gel fills the entire tube to block water. The dry fills part of the tube and then expands to absorb the water that gets inside the cable. A slight disadvantage to dry buffer tubes is that the SAP (super absorbent polymer) may not perform the same every time water infiltrates the tube. A disadvantage of the gel is that it is messy when a cable is spliced and requires cleaning. The dry buffers require no cleanup, which makes for easier cutting and splicing. However, when it comes to the gel, it stands up better to things such as salt water, where the dry will break down over time if repeatedly exposed to salt water.

buffer-tube-types, gel buffer tubes, dry buffer tubes, gel, dry

Gel vs. Dry

Winner by unanimous vote? Instead, it seems as if the match has ended in a technical decision.
In this case it looks like our crowned champ depends on your specific application use.

If you’re unsure about what cable or what kind of buffer tube you’ll need in order to meet the needs of your application, consult with one of Allied’s knowledgeable sales reps by submitting an RFQ. Visit our website to learn more about fiber optic cable and all of our Prysmian/Draka Group products.

About awcwire
Allied Wire & Cable is a value-added manufacturer and distributor of electrical wire and cable, tubing, and more. We are a family owned and operated company, serving a wide range of industries, including the military, automotive, aerospace, and telecommunications markets. Allied is headquartered in Collegeville, PA. Additional locations can be found across the US, in Merrimack, NH, Tampa, FL, Pewaukee, WI, and Las Vegas, NV. For more information on Allied, visit our main website at

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