What is the difference between OFNR and LSZH?
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. 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.
LSZH stands for Low Smoke Zero Halogen and describes a cable jacket material that is non-halogenated and flame retardant. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat, e.g. flame. Low smoke zero halogen cable reduces the amount of toxic and corrosive gas emitted during combustion. This type of material is typically used in poorly ventilated areas such as aircraft or rail cars. Low smoke zero halogen is becoming very popular and, in some cases, a requirement where the protection of people and equipment from toxic and corrosive gas is critical.