Development and testing of a fire-resistant optical cable

A new type of fire-resistant optical cable has been developed. It is based on the loose tube concept employing special mica and glass tape wrappings together with a new type of buffer jacket material to provide the desired properties. With this design, ordinary acrylate-coated fibers are used. The cable has the unique property that during fire it converts from a cable, which mostly consists of organic materials, to a ceramic loose-tube structure that gives the fiber sufficient protection to prevent damage during fire. The cable has been tested according to IEC 331 which specifies a 750°C flame exposure for 3 h, and passed that test with negligible loss increase even at temperatures up to 900°C.