Dual-layer fire retardant structure with air gap

摘要

The present invention provides a fiber optic cable having improved fire and smoke retardation characteristics. The cable according the present invention has at least two layers of thermally conductive tape wrapped around a center cable core, where a layer of flame-retardant yarn is placed between the layers of tape such that air gaps are created. Further, in the present invention, a powder having a low thermal conductivity is placed in the air gaps to further retard flame penetration and smoke generation. The thermally conductive tape of the present invention can be made from either Mica tape, or metallic foil and is wound helically along the length of the cable.