Just like copper cables, NEC (National Electrical Code) requires that indoor fiber optic cables be marked with their fire and smoking ratings. NEC requires all indoor fiber cables to be properly marked and properly installed for their intended use.
According to NEC, the interior area of a building is divided into three types of sections: plenums, risers and areas of general use.
:: What is a Plenum Zone?
A Plenum zone is a building space used for an air circulation system or air distribution system. In most buildings, the area above a suspended ceiling or under a raised floor serves as a return air (air source) for air conditioning. These suspended ceilings and raised floors are also places where fiber cables are often installed. If these cables burn, they would release toxic fumes and vapors would be fed into the rest of the building by the air conditioner. As a result, people could be injured even though they are away from the fire.
:: What is a Riser Zone?
A Riser Zone is a ground, duct or conduit opening that vertically traverses one or more floors
:: What is the general area?
Any other area that is neither plenary nor riser and located on the same floor is a general purpose area.
:: Fiber Optic Cable Fire and Smoking Classification Marks
OFNP stands for Plenum Non-Conductive Fiber Optic. OFNP cables have fire resistance and low smoke production characteristics. They can be installed in ducts, plenums and other spaces used for the circulation of air. It is the most fire-resistant fiber optic cable and no other type of cable can be used as a substitute.
OFCP stands for Fiber Optic Fiber Plenum. OFCP cables have the same fire and smoking characteristics as OFNP cables, but they have a conductive armor or a central resistance element that is usually made of steel. OFCP cables must be properly grounded at both ends. Therefore, OFCP cables can not be installed in the same cable tray or conduit as the power cables.
OFNR stands for Riser Non-Conductive Fiber Optic. OFNR cables are used in assembly areas that are building vertical shafts or extending from one floor to the other. OFNR cables can not be installed in plenums, as they do not have the required fire and smoke characteristics as Plenum grade cables. OFNP plenum cables can be used as substitutes for OFNR cables.
OFCR is the acronym for Riser Conductive Fiber Optical. OFCR cables have the same fire resistance characteristics as OFNR cables, but they have a conductive armor or a central resistance element that is usually made of steel. OFCR cables must also be properly grounded at both ends. OFCP cables can be used instead of OFCR cables. OFCR cables can not be installed in the same cable trays or ducts as the power cables.
OFNG stands for non-conducting optical fiber for general use. They are typically used in horizontal wiring, single-stage applications. OFNG cables can not be used in plenums or risers. OFNP and OFNR cables can both be used as substitutes for OFNG cables.
OFCG is the abbreviation for General-Purpose Conductive Fiber. They have the same fire characteristics as OFNG cables but they have conductive armor or central resistance elements that are typically made of steel. OFCG cables must be properly grounded at both ends. They should not be installed in the same cable tray or conduit as the power cables.