Specification of Plenum Grade PVC for Outer Sheath of Indoor Cable

PVC (Poly Vinyl Chloride) is generally used in copper wire telephone cables. However, some of the optical fiber cable designs demand use of PVC. PVC contains Chlorine and hence it is a material that contains halogen. PVC itself is a good fire inhibitor. Since PVC contains halogen group element Chlorine, it gives out poisonous gas while burning.

PVC is mainly used as sheathing material in Indoor fiber optic cables. Flame retardant grades PVCs are available in the market. Here we focus on a typical specification of Polyvinyl Chloride (PVC) that can be used as outer sheath material in Indoor Optical Fiber Cables.

PVC is processed using the extrusion process.  Extrusion process shall not affect the properties of PVC. Process parameters shall be carefully set to achieve desired sheath properties. Hence, as a cable manufacturer, we need to clearly write to the material supplier that we are going to use this PVC in our extrusion process and the process shall not affect any of its properties.

Underwriters Laboratory specifies criteria for Indoor cables. When extruded the material shall meet the Plenum grade requirement of UL 910 specification.

Table of Properties for Plenum Grade PVC
S # Attribute Value
1 Specific gravity 1.5 – 1.65 g/cc
2 Tensile strength ≥15 MPa
3 Elongation ≥ 175 %
4 Shore D hardness ≥ 80
5 Oxygen Index ≥ 27

Test Certificate: Each incoming delivery/ batch shall be accompanied by a test certificate .

Packing: Material shall be supplied either in 25 kg bags. Bags shall be adequately packed to protect against moisture during transportation.

Author: Fiber

Chief Editor of Fiber Optic Mania Magazine

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