Tight Buffer Versus Loose Buffer Cable Plants

Tight buffer or tight tube cable designs are typically used for ISP applications. Each fiber is coated with a buffer coating, usually with an outside diameter of 900 m. Tight buffer cables have the following cable ratings:

OFNR—Optical fiber, nonconductive riser rated

OFNP—Optical fiber, nonconductive plenum rated

LSZH—Low smoke, zero halogen rated

The type of ISP tight buffer cable selected usually depends on the application, environment, and building code. Loose-buffer or loose-tube cables mean that the fibers are placed loosely within a larger plastic tube. Usually 6 to 12 fibers are placed within a single tube. These tubes are filled with a gel compound that protects the fibers from moisture and physical stresses that may be experienced by the overall cable. Loose buffer designs are used for OSP applications such as underground installations, lashed or self-supporting aerial installations, and other OSP applications. These cables require additional cleaning, including the removal of the protective compounds when the fibers are to be terminated. Loose-tube cable designs include multifiber armored and non-armored cable systems.

August 29, 2011

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