Wire & Cable Section of the SPI

Fluoropolymer Use in Wire and Cable Products

Fluoropolymers refer to a family of plastic materials that contain a large amount of fluorine in their make up. Fluorine, being the most electronegative element, forms a very strong bond with carbon atoms in the polymer. This gives a plastic that is extremely inert, and having a variety of other useful characteristics. The best known use of fluoropolymers is coatings on non-stick cookware. The combination of surface properties and thermal stability lead to the extraordinary performance that people have come to recognize as the best in everyday cooking.

Other properties exhibited by fluoropolymers are resistance to burning, very low smoke generation when exposed to flames (which leads to low corrosivity under fire conditions), excellent electrical properties, high mechanical properties, and ease of fabrication. It is the combination of these characteristics that make fluoropolymers uniquely suited for wire and cable insulation for plenum data cables. Fluoropolymers are used as insulators over conventional copper conductors which transmit data by electrical impulse, as well as fiber optic cables which transmit data using light waves. The wide range of properties exhibited by fluoropolymers make them suitable for both technologies, even though the requirements for each are very different. The term "plenum" refers to open spaces in commercial buildings, typically over suspended ceilings or beneath raised floors. Plenum spaces are usually part of a building’s air handling system, and connect many parts of the building and can be a route of fire propagation and smoke distribution throughout the structure during a fire if not properly designed and constructed. Because plenum spaces are typically hidden with either ceiling or floor tiles, the location of fires within them can be difficult to detect. For these reasons any materials used in plenum spaces are required to meet strict flammability and smoke generation requirements. In the USA, for wire and cables, these requirements are mandated by the National Electrical Code as defined in standards developed by the National Fire Protection Association.

Although plenum spaces are governed by strict flammability and smoke generation requirements, they offer an excellent location for installation of data communications cabling. Plenum spaces are easily accessible, making them convenient when installing and rerouting data cables for a variety of office needs (local area networks, printing, voice transmission, etc.). To meet the flame and smoke requirements of the plenum environment, historically plenum cables were installed within steel or aluminum conduit. This practice improves the fire characteristics by protecting the cable. However, the molten and gaseous products of polymer decomposition could still ignite if they leaked from the conduit at connections. Also, once the cable is installed within conduit, it is very difficult to re-route.

The limited flexibility of conduit and cable combinations makes the use of fixed conduit highly impractical in today’s information age. According to recent statistics, local area networks are typically reconfigured every three years. So, although fluoropolymers can be more expensive than commodity plastics, the total installed cost for plenum cabling is actually lower for fluoropolymer-insulated cables than for cables insulated with conventional polymers that must be installed within conduit.

The introduction of plenum cable insulated with fluoropolymers has led to the ideal solution. Fluoropolymers meet the standards developed by the National Fire Protection Association for plenum cables without the need for metal conduit. So, safe plenums can be designed, yet flexibility maintained for future office redesign or expansion. And, due to the excellent electrical properties, fluoropolymer insulated cables are staying ahead of system transmission speed requirements. Cables with communication speeds of over 600 MHz have been commercially produced. Additionally, although not required by every building code, fluoropolymers have very high temperature ratings, typically greater than 250 degrees Fahrenheit, allowing for long service life under a wide-range of conditions.

This web page is sponsored by the Wire & Cable Subcommittee of the Fluoropolymers Business Unit of the Society of the Plastics Industry. The following fluoropolymer producers are the members of the Wire and Cable Subcommittee:

Arkema

Ausimont USA, Inc.

DuPont

Dyneon

Fluortek Compounding

The charter for the Wire & Cable Subcommittee is to facilitate the growth of fluoropolymers in the wire and cable industry by supplying information regarding the performance advantages of fluoropolymer materials.