Optical fiber, nonconductive, riser (OFNR) is a type of optical fiber cable. As designated by the National Fire Protection Association (NFPA), this name is used for interior fiber-optic cables which contain no electrically conductive components, and which are certified for use in riser applications; they are engineered to prevent the spread of fire from floor to floor in a building. Typically they are tested for compliance with ANSI/UL 1666-1997, Standard Test for Flame Propagation Height of Electrical and Optical-Fiber Cable Installed Vertically in Shafts. NFPA NEC 2005 Art 770.51(B) FPN.
They are distinct from optical fiber, nonconductive, plenum cable (OFNP), and general-purpose optical cable.
"OFNR cables can not be installed in plenum areas since they do not have the required fire and smoking rating as Plenum rated cables. OFNP plenum cables can be used as substitutes for OFNR cables."[1]
Underwriters Laboratories defines the following related abbreviations [1]: